v0.14.0

- Added ErrQueueNotFound and ErrQueueNotEmpty type to indicate the kind
  of an error returned from the method.

.travis.yml

@@ -5,9 +5,9 @@ git:
 go: [1.13.x, 1.14.x, 1.15.x]
 script:
   - go test -race -v -coverprofile=coverage.txt -covermode=atomic ./...
-  - go test -run=XXX -bench=. -loglevel=debug ./...
+  - go test -run=^$ -bench=. -loglevel=debug ./...
 services:
   - redis-server
 after_success:
-  - bash ./.travis/benchcmp.sh
+  - travis_wait 60 bash ./.travis/benchstat.sh
   - bash <(curl -s https://codecov.io/bash)

.travis/benchstat.sh

@@ -2,17 +2,19 @@ if [ "${TRAVIS_PULL_REQUEST_BRANCH:-$TRAVIS_BRANCH}" != "master" ]; then
     REMOTE_URL="$(git config --get remote.origin.url)";
     cd ${TRAVIS_BUILD_DIR}/.. && \
     git clone ${REMOTE_URL} "${TRAVIS_REPO_SLUG}-bench" && \
+    # turn the detached message off
+    git config --global advice.detachedHead false && \
     cd "${TRAVIS_REPO_SLUG}-bench" && \
 
     # Benchmark master
     git checkout master && \
-    go test -run=XXX -bench=. ./... > master.txt && \
+    go test -run=^$ -bench=. -count=5 -timeout=60m -benchmem ./... > master.txt && \
 
     # Benchmark feature branch
     git checkout ${TRAVIS_COMMIT} && \
-    go test -run=XXX -bench=. ./... > feature.txt && \
+    go test -run=^$ -bench=. -count=5 -timeout=60m -benchmem ./... > feature.txt && \
 
     # compare two benchmarks
-    go get -u golang.org/x/tools/cmd/benchcmp && \
-    benchcmp master.txt feature.txt;
+    go get -u golang.org/x/perf/cmd/benchstat && \
+    benchstat master.txt feature.txt;
 fi

CHANGELOG.md

@@ -7,14 +7,60 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.14.0] - 2021-01-14
+
+**IMPORTATNT**: Please run `asynq migrate` command to migrate from the previous versions.
+
+### Changed
+
+- Renamed `DeadTask` to `ArchivedTask`.
+- Renamed the operation `Kill` to `Archive` in `Inpsector`.
+- Print stack trace when Handler panics.
+- Include a file name and a line number in the error message when recovering from a panic.
+
+### Added
+
+- `DefaultRetryDelayFunc` is now a public API, which can be used in the custom `RetryDelayFunc`.
+- `SkipRetry` error is added to be used as a return value from `Handler`.
+- `Servers` method is added to `Inspector`
+- `CancelActiveTask` method is added to `Inspector`.
+- `ListSchedulerEnqueueEvents` method is added to `Inspector`.
+- `SchedulerEntries` method is added to `Inspector`.
+- `DeleteQueue` method is added to `Inspector`.
+
+## [0.13.1] - 2020-11-22
+
+### Fixed
+
+- Fixed processor to wait for specified time duration before forcefully shutdown workers.
+
+## [0.13.0] - 2020-10-13
+
+### Added
+
+- `Scheduler` type is added to enable periodic tasks. See the godoc for its APIs and [wiki](https://github.com/hibiken/asynq/wiki/Periodic-Tasks) for the getting-started guide.
+
+### Changed
+
+- interface `Option` has changed. See the godoc for the new interface.
+  This change would have no impact as long as you are using exported functions (e.g. `MaxRetry`, `Queue`, etc)
+  to create `Option`s.
+
+### Added
+
+- `Payload.String() string` method is added
+- `Payload.MarshalJSON() ([]byte, error)` method is added
+
 ## [0.12.0] - 2020-09-12
 
-**IMPORTANT**: If you are upgrading from a previous version, please install the latest version of the CLI `go get -u github.com/hibiken/asynq/tools/asynq` and run `asynq migrate` command. No process should be writing to Redis while you run the migration command. 
+**IMPORTANT**: If you are upgrading from a previous version, please install the latest version of the CLI `go get -u github.com/hibiken/asynq/tools/asynq` and run `asynq migrate` command. No process should be writing to Redis while you run the migration command.
 
 ## The semantics of queue have changed
-Previously, we called tasks that are ready to be processed *"Enqueued tasks"*, and other tasks that are scheduled to be processed in the future *"Scheduled tasks"*, etc.
-We changed the semantics of *"Enqueue"* slightly; All tasks that client pushes to Redis are *Enqueued* to a queue. Within a queue, tasks will transition from one state to another. 
+
+Previously, we called tasks that are ready to be processed _"Enqueued tasks"_, and other tasks that are scheduled to be processed in the future _"Scheduled tasks"_, etc.
+We changed the semantics of _"Enqueue"_ slightly; All tasks that client pushes to Redis are _Enqueued_ to a queue. Within a queue, tasks will transition from one state to another.
 Possible task states are:
+
 - `Pending`: task is ready to be processed (previously called "Enqueued")
 - `Active`: tasks is currently being processed (previously called "InProgress")
 - `Scheduled`: task is scheduled to be processed in the future
@@ -26,23 +72,28 @@ Possible task states are:
 ---
 
 ### Changed
+
 #### `Client`
+
 Use `ProcessIn` or `ProcessAt` option to schedule a task instead of `EnqueueIn` or `EnqueueAt`.
 
 | Previously                  | v0.12.0                                    |
-|-----------------------------|--------------------------------------------|
-| `client.EnqueueAt(t, task)` | `client.Enqueue(task, asynq.ProcessAt(t))` |  
-| `client.EnqueueIn(d, task)` | `client.Enqueue(task, asynq.ProcessIn(d))` |  
+| --------------------------- | ------------------------------------------ |
+| `client.EnqueueAt(t, task)` | `client.Enqueue(task, asynq.ProcessAt(t))` |
+| `client.EnqueueIn(d, task)` | `client.Enqueue(task, asynq.ProcessIn(d))` |
 
 #### `Inspector`
+
 All Inspector methods are scoped to a queue, and the methods take `qname (string)` as the first argument.  
 `EnqueuedTask` is renamed to `PendingTask` and its corresponding methods.  
 `InProgressTask` is renamed to `ActiveTask` and its corresponding methods.  
 Command "Enqueue" is replaced by the verb "Run" (e.g. `EnqueueAllScheduledTasks` --> `RunAllScheduledTasks`)
 
 #### `CLI`
+
 CLI commands are restructured to use subcommands. Commands are organized into a few management commands:
 To view details on any command, use `asynq help <command> <subcommand>`.
+
 - `asynq stats`
 - `asynq queue [ls inspect history rm pause unpause]`
 - `asynq task [ls cancel delete kill run delete-all kill-all run-all]`
@@ -51,19 +102,23 @@ To view details on any command, use `asynq help <command> <subcommand>`.
 ### Added
 
 #### `RedisConnOpt`
+
 - `RedisClusterClientOpt` is added to connect to Redis Cluster.
 - `Username` field is added to all `RedisConnOpt` types in order to authenticate connection when Redis ACLs are used.
 
 #### `Client`
+
 - `ProcessIn(d time.Duration) Option` and `ProcessAt(t time.Time) Option` are added to replace `EnqueueIn` and `EnqueueAt` functionality.
 
 #### `Inspector`
+
 - `Queues() ([]string, error)` method is added to get all queue names.
 - `ClusterKeySlot(qname string) (int64, error)` method is added to get queue's hash slot in Redis cluster.
-- `ClusterNodes(qname string) ([]ClusterNode, error)` method is added to get a list of Redis cluster nodes for the given queue. 
+- `ClusterNodes(qname string) ([]ClusterNode, error)` method is added to get a list of Redis cluster nodes for the given queue.
 - `Close() error` method is added to close connection with redis.
 
-### `Handler` 
+### `Handler`
+
 - `GetQueueName(ctx context.Context) (string, bool)` helper is added to extract queue name from a context.
 
 ## [0.11.0] - 2020-07-28
@@ -80,7 +135,7 @@ To view details on any command, use `asynq help <command> <subcommand>`.
 
 - All tasks now requires timeout or deadline. By default, timeout is set to 30 mins.
 - Tasks that exceed its deadline are automatically retried.
-- Encoding schema for task message has changed. Please install the latest CLI and run `migrate` command if 
+- Encoding schema for task message has changed. Please install the latest CLI and run `migrate` command if
   you have tasks enqueued with the previous version of asynq.
 - API of `(*Client).Enqueue`, `(*Client).EnqueueIn`, and `(*Client).EnqueueAt` has changed to return a `*Result`.
 - API of `ErrorHandler` has changed. It now takes context as the first argument and removed `retried`, `maxRetry` from the argument list.
@@ -98,7 +153,6 @@ To view details on any command, use `asynq help <command> <subcommand>`.
 
 - Fixes the JSON number overflow issue (https://github.com/hibiken/asynq/issues/166).
 
-
 ## [0.9.2] - 2020-06-08
 
 ### Added

README.md

@@ -1,11 +1,10 @@
 # Asynq
 
 [![Build Status](https://travis-ci.com/hibiken/asynq.svg?token=paqzfpSkF4p23s5Ux39b&branch=master)](https://travis-ci.com/hibiken/asynq)
-[![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://opensource.org/licenses/MIT)
-[![Go Report Card](https://goreportcard.com/badge/github.com/hibiken/asynq)](https://goreportcard.com/report/github.com/hibiken/asynq)
 [![GoDoc](https://godoc.org/github.com/hibiken/asynq?status.svg)](https://godoc.org/github.com/hibiken/asynq)
+[![Go Report Card](https://goreportcard.com/badge/github.com/hibiken/asynq)](https://goreportcard.com/report/github.com/hibiken/asynq)
+[![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://opensource.org/licenses/MIT)
 [![Gitter chat](https://badges.gitter.im/go-asynq/gitter.svg)](https://gitter.im/go-asynq/community)
-[![codecov](https://codecov.io/gh/hibiken/asynq/branch/master/graph/badge.svg)](https://codecov.io/gh/hibiken/asynq)
 
 ## Overview
 
@@ -42,6 +41,7 @@ A system can consist of multiple worker servers and brokers, giving way to high
 - Allow [timeout and deadline per task](https://github.com/hibiken/asynq/wiki/Task-Timeout-and-Cancelation)
 - [Flexible handler interface with support for middlewares](https://github.com/hibiken/asynq/wiki/Handler-Deep-Dive)
 - [Ability to pause queue](/tools/asynq/README.md#pause) to stop processing tasks from the queue
+- [Periodic Tasks](https://github.com/hibiken/asynq/wiki/Periodic-Tasks)
 - [Support Redis Cluster](https://github.com/hibiken/asynq/wiki/Redis-Cluster) for automatic sharding and high availability
 - [Support Redis Sentinels](https://github.com/hibiken/asynq/wiki/Automatic-Failover) for high availability
 - [CLI](#command-line-tool) to inspect and remote-control queues and tasks
@@ -109,7 +109,7 @@ func HandleEmailDeliveryTask(ctx context.Context, t *asynq.Task) error {
 }
 
 // ImageProcessor implements asynq.Handler interface.
-type ImageProcesser struct {
+type ImageProcessor struct {
     // ... fields for struct
 }
 
@@ -134,6 +134,8 @@ In your application code, import the above package and use [`Client`](https://pk
 package main
 
 import (
+    "fmt"
+    "log"
     "time"
 
     "github.com/hibiken/asynq"
@@ -178,7 +180,7 @@ func main() {
     //            Options include MaxRetry, Queue, Timeout, Deadline, Unique etc.
     // ----------------------------------------------------------------------------
 
-    c.SetDefaultOptions(tasks.ImageProcessing, asynq.MaxRetry(10), asynq.Timeout(3*time.Minute))
+    c.SetDefaultOptions(tasks.TypeImageResize, asynq.MaxRetry(10), asynq.Timeout(3*time.Minute))
 
     t = tasks.NewImageResizeTask("some/blobstore/path")
     res, err = c.Enqueue(t)

client.go

@@ -7,6 +7,7 @@ package asynq
 import (
 	"errors"
 	"fmt"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -28,7 +29,7 @@ type Client struct {
 	rdb  *rdb.RDB
 }
 
-// NewClient and returns a new Client given a redis connection option.
+// NewClient returns a new Client instance given a redis connection option.
 func NewClient(r RedisConnOpt) *Client {
 	rdb := rdb.NewRDB(createRedisClient(r))
 	return &Client{
@@ -37,8 +38,29 @@ func NewClient(r RedisConnOpt) *Client {
 	}
 }
 
+type OptionType int
+
+const (
+	MaxRetryOpt OptionType = iota
+	QueueOpt
+	TimeoutOpt
+	DeadlineOpt
+	UniqueOpt
+	ProcessAtOpt
+	ProcessInOpt
+)
+
 // Option specifies the task processing behavior.
-type Option interface{}
+type Option interface {
+	// String returns a string representation of the option.
+	String() string
+
+	// Type describes the type of the option.
+	Type() OptionType
+
+	// Value returns a value used to create this option.
+	Value() interface{}
+}
 
 // Internal option representations.
 type (
@@ -62,13 +84,21 @@ func MaxRetry(n int) Option {
 	return retryOption(n)
 }
 
+func (n retryOption) String() string     { return fmt.Sprintf("MaxRetry(%d)", int(n)) }
+func (n retryOption) Type() OptionType   { return MaxRetryOpt }
+func (n retryOption) Value() interface{} { return int(n) }
+
 // Queue returns an option to specify the queue to enqueue the task into.
 //
 // Queue name is case-insensitive and the lowercased version is used.
-func Queue(name string) Option {
-	return queueOption(strings.ToLower(name))
+func Queue(qname string) Option {
+	return queueOption(strings.ToLower(qname))
 }
 
+func (qname queueOption) String() string     { return fmt.Sprintf("Queue(%q)", string(qname)) }
+func (qname queueOption) Type() OptionType   { return QueueOpt }
+func (qname queueOption) Value() interface{} { return string(qname) }
+
 // Timeout returns an option to specify how long a task may run.
 // If the timeout elapses before the Handler returns, then the task
 // will be retried.
@@ -81,6 +111,10 @@ func Timeout(d time.Duration) Option {
 	return timeoutOption(d)
 }
 
+func (d timeoutOption) String() string     { return fmt.Sprintf("Timeout(%v)", time.Duration(d)) }
+func (d timeoutOption) Type() OptionType   { return TimeoutOpt }
+func (d timeoutOption) Value() interface{} { return time.Duration(d) }
+
 // Deadline returns an option to specify the deadline for the given task.
 // If it reaches the deadline before the Handler returns, then the task
 // will be retried.
@@ -91,6 +125,12 @@ func Deadline(t time.Time) Option {
 	return deadlineOption(t)
 }
 
+func (t deadlineOption) String() string {
+	return fmt.Sprintf("Deadline(%v)", time.Time(t).Format(time.UnixDate))
+}
+func (t deadlineOption) Type() OptionType   { return DeadlineOpt }
+func (t deadlineOption) Value() interface{} { return time.Time(t) }
+
 // Unique returns an option to enqueue a task only if the given task is unique.
 // Task enqueued with this option is guaranteed to be unique within the given ttl.
 // Once the task gets processed successfully or once the TTL has expired, another task with the same uniqueness may be enqueued.
@@ -104,6 +144,10 @@ func Unique(ttl time.Duration) Option {
 	return uniqueOption(ttl)
 }
 
+func (ttl uniqueOption) String() string     { return fmt.Sprintf("Unique(%v)", time.Duration(ttl)) }
+func (ttl uniqueOption) Type() OptionType   { return UniqueOpt }
+func (ttl uniqueOption) Value() interface{} { return time.Duration(ttl) }
+
 // ProcessAt returns an option to specify when to process the given task.
 //
 // If there's a conflicting ProcessIn option, the last option passed to Enqueue overrides the others.
@@ -111,6 +155,12 @@ func ProcessAt(t time.Time) Option {
 	return processAtOption(t)
 }
 
+func (t processAtOption) String() string {
+	return fmt.Sprintf("ProcessAt(%v)", time.Time(t).Format(time.UnixDate))
+}
+func (t processAtOption) Type() OptionType   { return ProcessAtOpt }
+func (t processAtOption) Value() interface{} { return time.Time(t) }
+
 // ProcessIn returns an option to specify when to process the given task relative to the current time.
 //
 // If there's a conflicting ProcessAt option, the last option passed to Enqueue overrides the others.
@@ -118,6 +168,78 @@ func ProcessIn(d time.Duration) Option {
 	return processInOption(d)
 }
 
+func (d processInOption) String() string     { return fmt.Sprintf("ProcessIn(%v)", time.Duration(d)) }
+func (d processInOption) Type() OptionType   { return ProcessInOpt }
+func (d processInOption) Value() interface{} { return time.Duration(d) }
+
+// parseOption interprets a string s as an Option and returns the Option if parsing is successful,
+// otherwise returns non-nil error.
+func parseOption(s string) (Option, error) {
+	fn, arg := parseOptionFunc(s), parseOptionArg(s)
+	switch fn {
+	case "Queue":
+		qname, err := strconv.Unquote(arg)
+		if err != nil {
+			return nil, err
+		}
+		return Queue(qname), nil
+	case "MaxRetry":
+		n, err := strconv.Atoi(arg)
+		if err != nil {
+			return nil, err
+		}
+		return MaxRetry(n), nil
+	case "Timeout":
+		d, err := time.ParseDuration(arg)
+		if err != nil {
+			return nil, err
+		}
+		return Timeout(d), nil
+	case "Deadline":
+		t, err := time.Parse(time.UnixDate, arg)
+		if err != nil {
+			return nil, err
+		}
+		return Deadline(t), nil
+	case "Unique":
+		d, err := time.ParseDuration(arg)
+		if err != nil {
+			return nil, err
+		}
+		return Unique(d), nil
+	case "ProcessAt":
+		t, err := time.Parse(time.UnixDate, arg)
+		if err != nil {
+			return nil, err
+		}
+		return ProcessAt(t), nil
+	case "ProcessIn":
+		d, err := time.ParseDuration(arg)
+		if err != nil {
+			return nil, err
+		}
+		return ProcessIn(d), nil
+	default:
+		return nil, fmt.Errorf("cannot not parse option string %q", s)
+	}
+}
+
+func parseOptionFunc(s string) string {
+	i := strings.Index(s, "(")
+	return s[:i]
+}
+
+func parseOptionArg(s string) string {
+	i := strings.Index(s, "(")
+	if i >= 0 {
+		j := strings.Index(s, ")")
+		if j > i {
+			return s[i+1 : j]
+		}
+	}
+	return ""
+}
+
 // ErrDuplicateTask indicates that the given task could not be enqueued since it's a duplicate of another task.
 //
 // ErrDuplicateTask error only applies to tasks enqueued with a Unique option.
@@ -208,6 +330,9 @@ type Result struct {
 	// ID is a unique identifier for the task.
 	ID string
 
+	// EnqueuedAt is the time the task was enqueued in UTC.
+	EnqueuedAt time.Time
+
 	// ProcessAt indicates when the task should be processed.
 	ProcessAt time.Time
 
@@ -298,12 +423,13 @@ func (c *Client) Enqueue(task *Task, opts ...Option) (*Result, error) {
 		return nil, err
 	}
 	return &Result{
-		ID:        msg.ID.String(),
-		ProcessAt: opt.processAt,
-		Queue:     msg.Queue,
-		Retry:     msg.Retry,
-		Timeout:   timeout,
-		Deadline:  deadline,
+		ID:         msg.ID.String(),
+		EnqueuedAt: time.Now().UTC(),
+		ProcessAt:  opt.processAt,
+		Queue:      msg.Queue,
+		Retry:      msg.Retry,
+		Timeout:    timeout,
+		Deadline:   deadline,
 	}, nil
 }
 

client_test.go

@@ -42,11 +42,12 @@ func TestClientEnqueueWithProcessAtOption(t *testing.T) {
 			processAt: now,
 			opts:      []Option{},
 			wantRes: &Result{
-				ProcessAt: now,
-				Queue:     "default",
-				Retry:     defaultMaxRetry,
-				Timeout:   defaultTimeout,
-				Deadline:  noDeadline,
+				EnqueuedAt: now.UTC(),
+				ProcessAt:  now,
+				Queue:      "default",
+				Retry:      defaultMaxRetry,
+				Timeout:    defaultTimeout,
+				Deadline:   noDeadline,
 			},
 			wantPending: map[string][]*base.TaskMessage{
 				"default": {
@@ -70,11 +71,12 @@ func TestClientEnqueueWithProcessAtOption(t *testing.T) {
 			processAt: oneHourLater,
 			opts:      []Option{},
 			wantRes: &Result{
-				ProcessAt: oneHourLater,
-				Queue:     "default",
-				Retry:     defaultMaxRetry,
-				Timeout:   defaultTimeout,
-				Deadline:  noDeadline,
+				EnqueuedAt: now.UTC(),
+				ProcessAt:  oneHourLater,
+				Queue:      "default",
+				Retry:      defaultMaxRetry,
+				Timeout:    defaultTimeout,
+				Deadline:   noDeadline,
 			},
 			wantPending: map[string][]*base.TaskMessage{
 				"default": {},
@@ -111,8 +113,8 @@ func TestClientEnqueueWithProcessAtOption(t *testing.T) {
 			cmpopts.EquateApproxTime(500 * time.Millisecond),
 		}
 		if diff := cmp.Diff(tc.wantRes, gotRes, cmpOptions...); diff != "" {
-			t.Errorf("%s;\nEnqueueAt(processAt, task) returned %v, want %v; (-want,+got)\n%s",
-				tc.desc, gotRes, tc.wantRes, diff)
+			t.Errorf("%s;\nEnqueue(task, ProcessAt(%v)) returned %v, want %v; (-want,+got)\n%s",
+				tc.desc, tc.processAt, gotRes, tc.wantRes, diff)
 		}
 
 		for qname, want := range tc.wantPending {
@@ -366,7 +368,7 @@ func TestClientEnqueue(t *testing.T) {
 			continue
 		}
 		cmpOptions := []cmp.Option{
-			cmpopts.IgnoreFields(Result{}, "ID"),
+			cmpopts.IgnoreFields(Result{}, "ID", "EnqueuedAt"),
 			cmpopts.EquateApproxTime(500 * time.Millisecond),
 		}
 		if diff := cmp.Diff(tc.wantRes, gotRes, cmpOptions...); diff != "" {
@@ -471,12 +473,12 @@ func TestClientEnqueueWithProcessInOption(t *testing.T) {
 			continue
 		}
 		cmpOptions := []cmp.Option{
-			cmpopts.IgnoreFields(Result{}, "ID"),
+			cmpopts.IgnoreFields(Result{}, "ID", "EnqueuedAt"),
 			cmpopts.EquateApproxTime(500 * time.Millisecond),
 		}
 		if diff := cmp.Diff(tc.wantRes, gotRes, cmpOptions...); diff != "" {
-			t.Errorf("%s;\nEnqueueIn(delay, task) returned %v, want %v; (-want,+got)\n%s",
-				tc.desc, gotRes, tc.wantRes, diff)
+			t.Errorf("%s;\nEnqueue(task, ProcessIn(%v)) returned %v, want %v; (-want,+got)\n%s",
+				tc.desc, tc.delay, gotRes, tc.wantRes, diff)
 		}
 
 		for qname, want := range tc.wantPending {
@@ -617,7 +619,7 @@ func TestClientDefaultOptions(t *testing.T) {
 			t.Fatal(err)
 		}
 		cmpOptions := []cmp.Option{
-			cmpopts.IgnoreFields(Result{}, "ID"),
+			cmpopts.IgnoreFields(Result{}, "ID", "EnqueuedAt"),
 			cmpopts.EquateApproxTime(500 * time.Millisecond),
 		}
 		if diff := cmp.Diff(tc.wantRes, gotRes, cmpOptions...); diff != "" {
@@ -772,3 +774,71 @@ func TestClientEnqueueUniqueWithProcessAtOption(t *testing.T) {
 		}
 	}
 }
+
+func TestParseOption(t *testing.T) {
+	oneHourFromNow := time.Now().Add(1 * time.Hour)
+	tests := []struct {
+		s        string
+		wantType OptionType
+		wantVal  interface{}
+	}{
+		{`MaxRetry(10)`, MaxRetryOpt, 10},
+		{`Queue("email")`, QueueOpt, "email"},
+		{`Timeout(3m)`, TimeoutOpt, 3 * time.Minute},
+		{Deadline(oneHourFromNow).String(), DeadlineOpt, oneHourFromNow},
+		{`Unique(1h)`, UniqueOpt, 1 * time.Hour},
+		{ProcessAt(oneHourFromNow).String(), ProcessAtOpt, oneHourFromNow},
+		{`ProcessIn(10m)`, ProcessInOpt, 10 * time.Minute},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.s, func(t *testing.T) {
+			got, err := parseOption(tc.s)
+			if err != nil {
+				t.Fatalf("returned error: %v", err)
+			}
+			if got == nil {
+				t.Fatal("returned nil")
+			}
+			if got.Type() != tc.wantType {
+				t.Fatalf("got type %v, want type %v ", got.Type(), tc.wantType)
+			}
+			switch tc.wantType {
+			case QueueOpt:
+				gotVal, ok := got.Value().(string)
+				if !ok {
+					t.Fatal("returned Option with non-string value")
+				}
+				if gotVal != tc.wantVal.(string) {
+					t.Fatalf("got value %v, want %v", gotVal, tc.wantVal)
+				}
+			case MaxRetryOpt:
+				gotVal, ok := got.Value().(int)
+				if !ok {
+					t.Fatal("returned Option with non-int value")
+				}
+				if gotVal != tc.wantVal.(int) {
+					t.Fatalf("got value %v, want %v", gotVal, tc.wantVal)
+				}
+			case TimeoutOpt, UniqueOpt, ProcessInOpt:
+				gotVal, ok := got.Value().(time.Duration)
+				if !ok {
+					t.Fatal("returned Option with non duration value")
+				}
+				if gotVal != tc.wantVal.(time.Duration) {
+					t.Fatalf("got value %v, want %v", gotVal, tc.wantVal)
+				}
+			case DeadlineOpt, ProcessAtOpt:
+				gotVal, ok := got.Value().(time.Time)
+				if !ok {
+					t.Fatal("returned Option with non time value")
+				}
+				if cmp.Equal(gotVal, tc.wantVal.(time.Time)) {
+					t.Fatalf("got value %v, want %v", gotVal, tc.wantVal)
+				}
+			default:
+				t.Fatalf("returned Option with unexpected type: %v", got.Type())
+			}
+		})
+	}
+}

example_test.go

@@ -9,6 +9,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"time"
 
 	"github.com/hibiken/asynq"
 	"golang.org/x/sys/unix"
@@ -78,6 +79,25 @@ func ExampleServer_Quiet() {
 	srv.Stop()
 }
 
+func ExampleScheduler() {
+	scheduler := asynq.NewScheduler(
+		asynq.RedisClientOpt{Addr: ":6379"},
+		&asynq.SchedulerOpts{Location: time.Local},
+	)
+
+	if _, err := scheduler.Register("* * * * *", asynq.NewTask("task1", nil)); err != nil {
+		log.Fatal(err)
+	}
+	if _, err := scheduler.Register("@every 30s", asynq.NewTask("task2", nil)); err != nil {
+		log.Fatal(err)
+	}
+
+	// Run blocks and waits for os signal to terminate the program.
+	if err := scheduler.Run(); err != nil {
+		log.Fatal(err)
+	}
+}
+
 func ExampleParseRedisURI() {
 	rconn, err := asynq.ParseRedisURI("redis://localhost:6379/10")
 	if err != nil {

forwarder.go

@@ -0,0 +1,75 @@
+// Copyright 2020 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+package asynq
+
+import (
+	"sync"
+	"time"
+
+	"github.com/hibiken/asynq/internal/base"
+	"github.com/hibiken/asynq/internal/log"
+)
+
+// A forwarder is responsible for moving scheduled and retry tasks to pending state
+// so that the tasks get processed by the workers.
+type forwarder struct {
+	logger *log.Logger
+	broker base.Broker
+
+	// channel to communicate back to the long running "forwarder" goroutine.
+	done chan struct{}
+
+	// list of queue names to check and enqueue.
+	queues []string
+
+	// poll interval on average
+	avgInterval time.Duration
+}
+
+type forwarderParams struct {
+	logger   *log.Logger
+	broker   base.Broker
+	queues   []string
+	interval time.Duration
+}
+
+func newForwarder(params forwarderParams) *forwarder {
+	return &forwarder{
+		logger:      params.logger,
+		broker:      params.broker,
+		done:        make(chan struct{}),
+		queues:      params.queues,
+		avgInterval: params.interval,
+	}
+}
+
+func (f *forwarder) terminate() {
+	f.logger.Debug("Forwarder shutting down...")
+	// Signal the forwarder goroutine to stop polling.
+	f.done <- struct{}{}
+}
+
+// start starts the "forwarder" goroutine.
+func (f *forwarder) start(wg *sync.WaitGroup) {
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for {
+			select {
+			case <-f.done:
+				f.logger.Debug("Forwarder done")
+				return
+			case <-time.After(f.avgInterval):
+				f.exec()
+			}
+		}
+	}()
+}
+
+func (f *forwarder) exec() {
+	if err := f.broker.CheckAndEnqueue(f.queues...); err != nil {
+		f.logger.Errorf("Could not enqueue scheduled tasks: %v", err)
+	}
+}

forwarder_test.go

@@ -0,0 +1,137 @@
+// Copyright 2020 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+package asynq
+
+import (
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/google/go-cmp/cmp"
+	h "github.com/hibiken/asynq/internal/asynqtest"
+	"github.com/hibiken/asynq/internal/base"
+	"github.com/hibiken/asynq/internal/rdb"
+)
+
+func TestForwarder(t *testing.T) {
+	r := setup(t)
+	defer r.Close()
+	rdbClient := rdb.NewRDB(r)
+	const pollInterval = time.Second
+	s := newForwarder(forwarderParams{
+		logger:   testLogger,
+		broker:   rdbClient,
+		queues:   []string{"default", "critical"},
+		interval: pollInterval,
+	})
+	t1 := h.NewTaskMessageWithQueue("gen_thumbnail", nil, "default")
+	t2 := h.NewTaskMessageWithQueue("send_email", nil, "critical")
+	t3 := h.NewTaskMessageWithQueue("reindex", nil, "default")
+	t4 := h.NewTaskMessageWithQueue("sync", nil, "critical")
+	now := time.Now()
+
+	tests := []struct {
+		initScheduled map[string][]base.Z            // scheduled queue initial state
+		initRetry     map[string][]base.Z            // retry queue initial state
+		initPending   map[string][]*base.TaskMessage // default queue initial state
+		wait          time.Duration                  // wait duration before checking for final state
+		wantScheduled map[string][]*base.TaskMessage // schedule queue final state
+		wantRetry     map[string][]*base.TaskMessage // retry queue final state
+		wantPending   map[string][]*base.TaskMessage // default queue final state
+	}{
+		{
+			initScheduled: map[string][]base.Z{
+				"default":  {{Message: t1, Score: now.Add(time.Hour).Unix()}},
+				"critical": {{Message: t2, Score: now.Add(-2 * time.Second).Unix()}},
+			},
+			initRetry: map[string][]base.Z{
+				"default":  {{Message: t3, Score: time.Now().Add(-500 * time.Millisecond).Unix()}},
+				"critical": {},
+			},
+			initPending: map[string][]*base.TaskMessage{
+				"default":  {},
+				"critical": {t4},
+			},
+			wait: pollInterval * 2,
+			wantScheduled: map[string][]*base.TaskMessage{
+				"default":  {t1},
+				"critical": {},
+			},
+			wantRetry: map[string][]*base.TaskMessage{
+				"default":  {},
+				"critical": {},
+			},
+			wantPending: map[string][]*base.TaskMessage{
+				"default":  {t3},
+				"critical": {t2, t4},
+			},
+		},
+		{
+			initScheduled: map[string][]base.Z{
+				"default": {
+					{Message: t1, Score: now.Unix()},
+					{Message: t3, Score: now.Add(-500 * time.Millisecond).Unix()},
+				},
+				"critical": {
+					{Message: t2, Score: now.Add(-2 * time.Second).Unix()},
+				},
+			},
+			initRetry: map[string][]base.Z{
+				"default":  {},
+				"critical": {},
+			},
+			initPending: map[string][]*base.TaskMessage{
+				"default":  {},
+				"critical": {t4},
+			},
+			wait: pollInterval * 2,
+			wantScheduled: map[string][]*base.TaskMessage{
+				"default":  {},
+				"critical": {},
+			},
+			wantRetry: map[string][]*base.TaskMessage{
+				"default":  {},
+				"critical": {},
+			},
+			wantPending: map[string][]*base.TaskMessage{
+				"default":  {t1, t3},
+				"critical": {t2, t4},
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		h.FlushDB(t, r)                                  // clean up db before each test case.
+		h.SeedAllScheduledQueues(t, r, tc.initScheduled) // initialize scheduled queue
+		h.SeedAllRetryQueues(t, r, tc.initRetry)         // initialize retry queue
+		h.SeedAllPendingQueues(t, r, tc.initPending)     // initialize default queue
+
+		var wg sync.WaitGroup
+		s.start(&wg)
+		time.Sleep(tc.wait)
+		s.terminate()
+
+		for qname, want := range tc.wantScheduled {
+			gotScheduled := h.GetScheduledMessages(t, r, qname)
+			if diff := cmp.Diff(want, gotScheduled, h.SortMsgOpt); diff != "" {
+				t.Errorf("mismatch found in %q after running forwarder: (-want, +got)\n%s", base.ScheduledKey(qname), diff)
+			}
+		}
+
+		for qname, want := range tc.wantRetry {
+			gotRetry := h.GetRetryMessages(t, r, qname)
+			if diff := cmp.Diff(want, gotRetry, h.SortMsgOpt); diff != "" {
+				t.Errorf("mismatch found in %q after running forwarder: (-want, +got)\n%s", base.RetryKey(qname), diff)
+			}
+		}
+
+		for qname, want := range tc.wantPending {
+			gotPending := h.GetPendingMessages(t, r, qname)
+			if diff := cmp.Diff(want, gotPending, h.SortMsgOpt); diff != "" {
+				t.Errorf("mismatch found in %q after running forwarder: (-want, +got)\n%s", base.QueueKey(qname), diff)
+			}
+		}
+	}
+}

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/go-redis/redis/v7 v7.4.0
 	github.com/google/go-cmp v0.4.0
 	github.com/google/uuid v1.1.1
+	github.com/robfig/cron/v3 v3.0.1
 	github.com/spf13/cast v1.3.1
 	go.uber.org/goleak v0.10.0
 	golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e

go.sum

@@ -27,6 +27,8 @@ github.com/onsi/gomega v1.7.0 h1:XPnZz8VVBHjVsy1vzJmRwIcSwiUO+JFfrv/xGiigmME=
 github.com/onsi/gomega v1.7.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
+github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
 github.com/spf13/cast v1.3.1 h1:nFm6S0SMdyzrzcmThSipiEubIDy8WEXKNZ0UOgiRpng=
 github.com/spf13/cast v1.3.1/go.mod h1:Qx5cxh0v+4UWYiBimWS+eyWzqEqokIECu5etghLkUJE=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=

heartbeat.go

@@ -147,13 +147,14 @@ func (h *heartbeater) beat() {
 	var ws []*base.WorkerInfo
 	for id, stat := range h.workers {
 		ws = append(ws, &base.WorkerInfo{
-			Host:    h.host,
-			PID:     h.pid,
-			ID:      id,
-			Type:    stat.msg.Type,
-			Queue:   stat.msg.Queue,
-			Payload: stat.msg.Payload,
-			Started: stat.started,
+			Host:     h.host,
+			PID:      h.pid,
+			ServerID: h.serverID,
+			ID:       id,
+			Type:     stat.msg.Type,
+			Queue:    stat.msg.Queue,
+			Payload:  stat.msg.Payload,
+			Started:  stat.started,
 		})
 	}
 

inspector.go

@@ -20,7 +20,7 @@ type Inspector struct {
 	rdb *rdb.RDB
 }
 
-// New returns a new instance of Inspector.
+// NewInspector returns a new instance of Inspector.
 func NewInspector(r RedisConnOpt) *Inspector {
 	return &Inspector{
 		rdb: rdb.NewRDB(createRedisClient(r)),
@@ -42,7 +42,7 @@ type QueueStats struct {
 	// Name of the queue.
 	Queue string
 	// Size is the total number of tasks in the queue.
-	// The value is the sum of Pending, Active, Scheduled, Retry, and Dead.
+	// The value is the sum of Pending, Active, Scheduled, Retry, and Archived.
 	Size int
 	// Number of pending tasks.
 	Pending int
@@ -52,8 +52,8 @@ type QueueStats struct {
 	Scheduled int
 	// Number of retry tasks.
 	Retry int
-	// Number of dead tasks.
-	Dead int
+	// Number of archived tasks.
+	Archived int
 	// Total number of tasks being processed during the given date.
 	// The number includes both succeeded and failed tasks.
 	Processed int
@@ -82,7 +82,7 @@ func (i *Inspector) CurrentStats(qname string) (*QueueStats, error) {
 		Active:    stats.Active,
 		Scheduled: stats.Scheduled,
 		Retry:     stats.Retry,
-		Dead:      stats.Dead,
+		Archived:  stats.Archived,
 		Processed: stats.Processed,
 		Failed:    stats.Failed,
 		Paused:    stats.Paused,
@@ -124,6 +124,45 @@ func (i *Inspector) History(qname string, n int) ([]*DailyStats, error) {
 	return res, nil
 }
 
+// ErrQueueNotFound indicates that the specified queue does not exist.
+type ErrQueueNotFound struct {
+	qname string
+}
+
+func (e *ErrQueueNotFound) Error() string {
+	return fmt.Sprintf("queue %q does not exist", e.qname)
+}
+
+// ErrQueueNotEmpty indicates that the specified queue is not empty.
+type ErrQueueNotEmpty struct {
+	qname string
+}
+
+func (e *ErrQueueNotEmpty) Error() string {
+	return fmt.Sprintf("queue %q is not empty", e.qname)
+}
+
+// DeleteQueue removes the specified queue.
+//
+// If force is set to true, DeleteQueue will remove the queue regardless of
+// the queue size as long as no tasks are active in the queue.
+// If force is set to false, DeleteQueue will remove the queue only if
+// the queue is empty.
+//
+// If the specified queue does not exist, DeleteQueue returns ErrQueueNotFound.
+// If force is set to false and the specified queue is not empty, DeleteQueue
+// returns ErrQueueNotEmpty.
+func (i *Inspector) DeleteQueue(qname string, force bool) error {
+	err := i.rdb.RemoveQueue(qname, force)
+	if _, ok := err.(*rdb.ErrQueueNotFound); ok {
+		return &ErrQueueNotFound{qname}
+	}
+	if _, ok := err.(*rdb.ErrQueueNotEmpty); ok {
+		return &ErrQueueNotEmpty{qname}
+	}
+	return err
+}
+
 // PendingTask is a task in a queue and is ready to be processed.
 type PendingTask struct {
 	*Task
@@ -162,9 +201,11 @@ type RetryTask struct {
 	score int64
 }
 
-// DeadTask is a task exhausted its retries.
-// DeadTask won't be retried automatically.
-type DeadTask struct {
+// ArchivedTask is a task archived for debugging and inspection purposes, and
+// it won't be retried automatically.
+// A task can be archived when the task exhausts its retry counts or manually
+// archived by a user via the CLI or Inspector.
+type ArchivedTask struct {
 	*Task
 	ID           string
 	Queue        string
@@ -176,19 +217,19 @@ type DeadTask struct {
 	score int64
 }
 
-// Key returns a key used to delete, run, and kill the task.
+// Key returns a key used to delete, run, and archive the task.
 func (t *ScheduledTask) Key() string {
 	return fmt.Sprintf("s:%v:%v", t.ID, t.score)
 }
 
-// Key returns a key used to delete, run, and kill the task.
+// Key returns a key used to delete, run, and archive the task.
 func (t *RetryTask) Key() string {
 	return fmt.Sprintf("r:%v:%v", t.ID, t.score)
 }
 
-// Key returns a key used to delete, run, and kill the task.
-func (t *DeadTask) Key() string {
-	return fmt.Sprintf("d:%v:%v", t.ID, t.score)
+// Key returns a key used to delete, run, and archive the task.
+func (t *ArchivedTask) Key() string {
+	return fmt.Sprintf("a:%v:%v", t.ID, t.score)
 }
 
 // parseTaskKey parses a key string and returns each part of key with proper
@@ -207,7 +248,7 @@ func parseTaskKey(key string) (id uuid.UUID, score int64, state string, err erro
 		return uuid.Nil, 0, "", fmt.Errorf("invalid id")
 	}
 	state = parts[0]
-	if len(state) != 1 || !strings.Contains("srd", state) {
+	if len(state) != 1 || !strings.Contains("sra", state) {
 		return uuid.Nil, 0, "", fmt.Errorf("invalid id")
 	}
 	return id, score, state, nil
@@ -384,25 +425,25 @@ func (i *Inspector) ListRetryTasks(qname string, opts ...ListOption) ([]*RetryTa
 	return tasks, nil
 }
 
-// ListDeadTasks retrieves dead tasks from the specified queue.
+// ListArchivedTasks retrieves archived tasks from the specified queue.
 // Tasks are sorted by LastFailedAt field in descending order.
 //
 // By default, it retrieves the first 30 tasks.
-func (i *Inspector) ListDeadTasks(qname string, opts ...ListOption) ([]*DeadTask, error) {
+func (i *Inspector) ListArchivedTasks(qname string, opts ...ListOption) ([]*ArchivedTask, error) {
 	if err := validateQueueName(qname); err != nil {
 		return nil, err
 	}
 	opt := composeListOptions(opts...)
 	pgn := rdb.Pagination{Size: opt.pageSize, Page: opt.pageNum - 1}
-	zs, err := i.rdb.ListDead(qname, pgn)
+	zs, err := i.rdb.ListArchived(qname, pgn)
 	if err != nil {
 		return nil, err
 	}
-	var tasks []*DeadTask
+	var tasks []*ArchivedTask
 	for _, z := range zs {
 		failedAt := time.Unix(z.Score, 0)
 		t := NewTask(z.Message.Type, z.Message.Payload)
-		tasks = append(tasks, &DeadTask{
+		tasks = append(tasks, &ArchivedTask{
 			Task:         t,
 			ID:           z.Message.ID.String(),
 			Queue:        z.Message.Queue,
@@ -414,7 +455,6 @@ func (i *Inspector) ListDeadTasks(qname string, opts ...ListOption) ([]*DeadTask
 		})
 	}
 	return tasks, nil
-	return nil, nil
 }
 
 // DeleteAllScheduledTasks deletes all scheduled tasks from the specified queue,
@@ -437,13 +477,13 @@ func (i *Inspector) DeleteAllRetryTasks(qname string) (int, error) {
 	return int(n), err
 }
 
-// DeleteAllDeadTasks deletes all dead tasks from the specified queue,
+// DeleteAllArchivedTasks deletes all archived tasks from the specified queue,
 // and reports the number tasks deleted.
-func (i *Inspector) DeleteAllDeadTasks(qname string) (int, error) {
+func (i *Inspector) DeleteAllArchivedTasks(qname string) (int, error) {
 	if err := validateQueueName(qname); err != nil {
 		return 0, err
 	}
-	n, err := i.rdb.DeleteAllDeadTasks(qname)
+	n, err := i.rdb.DeleteAllArchivedTasks(qname)
 	return int(n), err
 }
 
@@ -461,8 +501,8 @@ func (i *Inspector) DeleteTaskByKey(qname, key string) error {
 		return i.rdb.DeleteScheduledTask(qname, id, score)
 	case "r":
 		return i.rdb.DeleteRetryTask(qname, id, score)
-	case "d":
-		return i.rdb.DeleteDeadTask(qname, id, score)
+	case "a":
+		return i.rdb.DeleteArchivedTask(qname, id, score)
 	default:
 		return fmt.Errorf("invalid key")
 	}
@@ -488,13 +528,13 @@ func (i *Inspector) RunAllRetryTasks(qname string) (int, error) {
 	return int(n), err
 }
 
-// RunAllDeadTasks transition all dead tasks to pending state within the given queue,
+// RunAllArchivedTasks transition all archived tasks to pending state within the given queue,
 // and reports the number of tasks transitioned.
-func (i *Inspector) RunAllDeadTasks(qname string) (int, error) {
+func (i *Inspector) RunAllArchivedTasks(qname string) (int, error) {
 	if err := validateQueueName(qname); err != nil {
 		return 0, err
 	}
-	n, err := i.rdb.RunAllDeadTasks(qname)
+	n, err := i.rdb.RunAllArchivedTasks(qname)
 	return int(n), err
 }
 
@@ -512,35 +552,35 @@ func (i *Inspector) RunTaskByKey(qname, key string) error {
 		return i.rdb.RunScheduledTask(qname, id, score)
 	case "r":
 		return i.rdb.RunRetryTask(qname, id, score)
-	case "d":
-		return i.rdb.RunDeadTask(qname, id, score)
+	case "a":
+		return i.rdb.RunArchivedTask(qname, id, score)
 	default:
 		return fmt.Errorf("invalid key")
 	}
 }
 
-// KillAllScheduledTasks kills all scheduled tasks within the given queue,
-// and reports the number of tasks killed.
-func (i *Inspector) KillAllScheduledTasks(qname string) (int, error) {
+// ArchiveAllScheduledTasks archives all scheduled tasks within the given queue,
+// and reports the number of tasks archiveed.
+func (i *Inspector) ArchiveAllScheduledTasks(qname string) (int, error) {
 	if err := validateQueueName(qname); err != nil {
 		return 0, err
 	}
-	n, err := i.rdb.KillAllScheduledTasks(qname)
+	n, err := i.rdb.ArchiveAllScheduledTasks(qname)
 	return int(n), err
 }
 
-// KillAllRetryTasks kills all retry tasks within the given queue,
-// and reports the number of tasks killed.
-func (i *Inspector) KillAllRetryTasks(qname string) (int, error) {
+// ArchiveAllRetryTasks archives all retry tasks within the given queue,
+// and reports the number of tasks archiveed.
+func (i *Inspector) ArchiveAllRetryTasks(qname string) (int, error) {
 	if err := validateQueueName(qname); err != nil {
 		return 0, err
 	}
-	n, err := i.rdb.KillAllRetryTasks(qname)
+	n, err := i.rdb.ArchiveAllRetryTasks(qname)
 	return int(n), err
 }
 
-// KillTaskByKey kills a task with the given key in the given queue.
-func (i *Inspector) KillTaskByKey(qname, key string) error {
+// ArchiveTaskByKey archives a task with the given key in the given queue.
+func (i *Inspector) ArchiveTaskByKey(qname, key string) error {
 	if err := validateQueueName(qname); err != nil {
 		return err
 	}
@@ -550,16 +590,24 @@ func (i *Inspector) KillTaskByKey(qname, key string) error {
 	}
 	switch state {
 	case "s":
-		return i.rdb.KillScheduledTask(qname, id, score)
+		return i.rdb.ArchiveScheduledTask(qname, id, score)
 	case "r":
-		return i.rdb.KillRetryTask(qname, id, score)
-	case "d":
-		return fmt.Errorf("task already dead")
+		return i.rdb.ArchiveRetryTask(qname, id, score)
+	case "a":
+		return fmt.Errorf("task already archived")
 	default:
 		return fmt.Errorf("invalid key")
 	}
 }
 
+// CancelActiveTask sends a signal to cancel processing of the task with
+// the given id. CancelActiveTask is best-effort, which means that it does not
+// guarantee that the task with the given id will be canceled. The return
+// value only indicates whether the cancelation signal has been sent.
+func (i *Inspector) CancelActiveTask(id string) error {
+	return i.rdb.PublishCancelation(id)
+}
+
 // PauseQueue pauses task processing on the specified queue.
 // If the queue is already paused, it will return a non-nil error.
 func (i *Inspector) PauseQueue(qname string) error {
@@ -578,6 +626,84 @@ func (i *Inspector) UnpauseQueue(qname string) error {
 	return i.rdb.Unpause(qname)
 }
 
+// Servers return a list of running servers' information.
+func (i *Inspector) Servers() ([]*ServerInfo, error) {
+	servers, err := i.rdb.ListServers()
+	if err != nil {
+		return nil, err
+	}
+	workers, err := i.rdb.ListWorkers()
+	if err != nil {
+		return nil, err
+	}
+	m := make(map[string]*ServerInfo) // ServerInfo keyed by serverID
+	for _, s := range servers {
+		m[s.ServerID] = &ServerInfo{
+			ID:             s.ServerID,
+			Host:           s.Host,
+			PID:            s.PID,
+			Concurrency:    s.Concurrency,
+			Queues:         s.Queues,
+			StrictPriority: s.StrictPriority,
+			Started:        s.Started,
+			Status:         s.Status,
+			ActiveWorkers:  make([]*WorkerInfo, 0),
+		}
+	}
+	for _, w := range workers {
+		srvInfo, ok := m[w.ServerID]
+		if !ok {
+			continue
+		}
+		wrkInfo := &WorkerInfo{
+			Started: w.Started,
+			Task: &ActiveTask{
+				Task:  NewTask(w.Type, w.Payload),
+				ID:    w.ID,
+				Queue: w.Queue,
+			},
+		}
+		srvInfo.ActiveWorkers = append(srvInfo.ActiveWorkers, wrkInfo)
+	}
+	var out []*ServerInfo
+	for _, srvInfo := range m {
+		out = append(out, srvInfo)
+	}
+	return out, nil
+}
+
+// ServerInfo describes a running Server instance.
+type ServerInfo struct {
+	// Unique Identifier for the server.
+	ID string
+	// Host machine on which the server is running.
+	Host string
+	// PID of the process in which the server is running.
+	PID int
+
+	// Server configuration details.
+	// See Config doc for field descriptions.
+	Concurrency    int
+	Queues         map[string]int
+	StrictPriority bool
+
+	// Time the server started.
+	Started time.Time
+	// Status indicates the status of the server.
+	// TODO: Update comment with more details.
+	Status string
+	// A List of active workers currently processing tasks.
+	ActiveWorkers []*WorkerInfo
+}
+
+// WorkerInfo describes a running worker processing a task.
+type WorkerInfo struct {
+	// The task the worker is processing.
+	Task *ActiveTask
+	// Time the worker started processing the task.
+	Started time.Time
+}
+
 // ClusterKeySlot returns an integer identifying the hash slot the given queue hashes to.
 func (i *Inspector) ClusterKeySlot(qname string) (int64, error) {
 	return i.rdb.ClusterKeySlot(qname)
@@ -592,7 +718,7 @@ type ClusterNode struct {
 	Addr string
 }
 
-// ClusterNode returns a list of nodes the given queue belongs to.
+// ClusterNodes returns a list of nodes the given queue belongs to.
 func (i *Inspector) ClusterNodes(qname string) ([]ClusterNode, error) {
 	nodes, err := i.rdb.ClusterNodes(qname)
 	if err != nil {
@@ -604,3 +730,80 @@ func (i *Inspector) ClusterNodes(qname string) ([]ClusterNode, error) {
 	}
 	return res, nil
 }
+
+// SchedulerEntry holds information about a periodic task registered with a scheduler.
+type SchedulerEntry struct {
+	// Identifier of this entry.
+	ID string
+
+	// Spec describes the schedule of this entry.
+	Spec string
+
+	// Periodic Task registered for this entry.
+	Task *Task
+
+	// Opts is the options for the periodic task.
+	Opts []Option
+
+	// Next shows the next time the task will be enqueued.
+	Next time.Time
+
+	// Prev shows the last time the task was enqueued.
+	// Zero time if task was never enqueued.
+	Prev time.Time
+}
+
+// SchedulerEntries returns a list of all entries registered with
+// currently running schedulers.
+func (i *Inspector) SchedulerEntries() ([]*SchedulerEntry, error) {
+	var entries []*SchedulerEntry
+	res, err := i.rdb.ListSchedulerEntries()
+	if err != nil {
+		return nil, err
+	}
+	for _, e := range res {
+		task := NewTask(e.Type, e.Payload)
+		var opts []Option
+		for _, s := range e.Opts {
+			if o, err := parseOption(s); err == nil {
+				// ignore bad data
+				opts = append(opts, o)
+			}
+		}
+		entries = append(entries, &SchedulerEntry{
+			ID:   e.ID,
+			Spec: e.Spec,
+			Task: task,
+			Opts: opts,
+			Next: e.Next,
+			Prev: e.Prev,
+		})
+	}
+	return entries, nil
+}
+
+// SchedulerEnqueueEvent holds information about an enqueue event by a scheduler.
+type SchedulerEnqueueEvent struct {
+	// ID of the task that was enqueued.
+	TaskID string
+
+	// Time the task was enqueued.
+	EnqueuedAt time.Time
+}
+
+// ListSchedulerEnqueueEvents retrieves a list of enqueue events from the specified scheduler entry.
+//
+// By default, it retrieves the first 30 tasks.
+func (i *Inspector) ListSchedulerEnqueueEvents(entryID string, opts ...ListOption) ([]*SchedulerEnqueueEvent, error) {
+	opt := composeListOptions(opts...)
+	pgn := rdb.Pagination{Size: opt.pageSize, Page: opt.pageNum - 1}
+	data, err := i.rdb.ListSchedulerEnqueueEvents(entryID, pgn)
+	if err != nil {
+		return nil, err
+	}
+	var events []*SchedulerEnqueueEvent
+	for _, e := range data {
+		events = append(events, &SchedulerEnqueueEvent{TaskID: e.TaskID, EnqueuedAt: e.EnqueuedAt})
+	}
+	return events, nil
+}

internal/asynqtest/asynqtest.go

@@ -65,6 +65,24 @@ var SortWorkerInfoOpt = cmp.Transformer("SortWorkerInfo", func(in []*base.Worker
 	return out
 })
 
+// SortSchedulerEntryOpt is a cmp.Option to sort base.SchedulerEntry for comparing slice of entries.
+var SortSchedulerEntryOpt = cmp.Transformer("SortSchedulerEntry", func(in []*base.SchedulerEntry) []*base.SchedulerEntry {
+	out := append([]*base.SchedulerEntry(nil), in...) // Copy input to avoid mutating it
+	sort.Slice(out, func(i, j int) bool {
+		return out[i].Spec < out[j].Spec
+	})
+	return out
+})
+
+// SortSchedulerEnqueueEventOpt is a cmp.Option to sort base.SchedulerEnqueueEvent for comparing slice of events.
+var SortSchedulerEnqueueEventOpt = cmp.Transformer("SortSchedulerEnqueueEvent", func(in []*base.SchedulerEnqueueEvent) []*base.SchedulerEnqueueEvent {
+	out := append([]*base.SchedulerEnqueueEvent(nil), in...)
+	sort.Slice(out, func(i, j int) bool {
+		return out[i].EnqueuedAt.Unix() < out[j].EnqueuedAt.Unix()
+	})
+	return out
+})
+
 // SortStringSliceOpt is a cmp.Option to sort string slice.
 var SortStringSliceOpt = cmp.Transformer("SortStringSlice", func(in []string) []string {
 	out := append([]string(nil), in...)
@@ -202,11 +220,11 @@ func SeedRetryQueue(tb testing.TB, r redis.UniversalClient, entries []base.Z, qn
 	seedRedisZSet(tb, r, base.RetryKey(qname), entries)
 }
 
-// SeedDeadQueue initializes the dead queue with the given messages.
-func SeedDeadQueue(tb testing.TB, r redis.UniversalClient, entries []base.Z, qname string) {
+// SeedArchivedQueue initializes the archived queue with the given messages.
+func SeedArchivedQueue(tb testing.TB, r redis.UniversalClient, entries []base.Z, qname string) {
 	tb.Helper()
 	r.SAdd(base.AllQueues, qname)
-	seedRedisZSet(tb, r, base.DeadKey(qname), entries)
+	seedRedisZSet(tb, r, base.ArchivedKey(qname), entries)
 }
 
 // SeedDeadlines initializes the deadlines set with the given entries.
@@ -246,10 +264,10 @@ func SeedAllRetryQueues(tb testing.TB, r redis.UniversalClient, retry map[string
 	}
 }
 
-// SeedAllDeadQueues initializes all of the specified dead queues with the given entries.
-func SeedAllDeadQueues(tb testing.TB, r redis.UniversalClient, dead map[string][]base.Z) {
-	for q, entries := range dead {
-		SeedDeadQueue(tb, r, entries, q)
+// SeedAllArchivedQueues initializes all of the specified archived queues with the given entries.
+func SeedAllArchivedQueues(tb testing.TB, r redis.UniversalClient, archived map[string][]base.Z) {
+	for q, entries := range archived {
+		SeedArchivedQueue(tb, r, entries, q)
 	}
 }
 
@@ -302,10 +320,10 @@ func GetRetryMessages(tb testing.TB, r redis.UniversalClient, qname string) []*b
 	return getZSetMessages(tb, r, base.RetryKey(qname))
 }
 
-// GetDeadMessages returns all dead messages in the given queue.
-func GetDeadMessages(tb testing.TB, r redis.UniversalClient, qname string) []*base.TaskMessage {
+// GetArchivedMessages returns all archived messages in the given queue.
+func GetArchivedMessages(tb testing.TB, r redis.UniversalClient, qname string) []*base.TaskMessage {
 	tb.Helper()
-	return getZSetMessages(tb, r, base.DeadKey(qname))
+	return getZSetMessages(tb, r, base.ArchivedKey(qname))
 }
 
 // GetScheduledEntries returns all scheduled messages and its score in the given queue.
@@ -320,10 +338,10 @@ func GetRetryEntries(tb testing.TB, r redis.UniversalClient, qname string) []bas
 	return getZSetEntries(tb, r, base.RetryKey(qname))
 }
 
-// GetDeadEntries returns all dead messages and its score in the given queue.
-func GetDeadEntries(tb testing.TB, r redis.UniversalClient, qname string) []base.Z {
+// GetArchivedEntries returns all archived messages and its score in the given queue.
+func GetArchivedEntries(tb testing.TB, r redis.UniversalClient, qname string) []base.Z {
 	tb.Helper()
-	return getZSetEntries(tb, r, base.DeadKey(qname))
+	return getZSetEntries(tb, r, base.ArchivedKey(qname))
 }
 
 // GetDeadlinesEntries returns all task messages and its score in the deadlines set for the given queue.

internal/base/base.go

@@ -19,7 +19,7 @@ import (
 )
 
 // Version of asynq library and CLI.
-const Version = "0.12.0"
+const Version = "0.14.0"
 
 // DefaultQueueName is the queue name used if none are specified by user.
 const DefaultQueueName = "default"
@@ -29,10 +29,11 @@ var DefaultQueue = QueueKey(DefaultQueueName)
 
 // Global Redis keys.
 const (
-	AllServers    = "asynq:servers" // ZSET
-	AllWorkers    = "asynq:workers" // ZSET
-	AllQueues     = "asynq:queues"  // SET
-	CancelChannel = "asynq:cancel"  // PubSub channel
+	AllServers    = "asynq:servers"    // ZSET
+	AllWorkers    = "asynq:workers"    // ZSET
+	AllSchedulers = "asynq:schedulers" // ZSET
+	AllQueues     = "asynq:queues"     // SET
+	CancelChannel = "asynq:cancel"     // PubSub channel
 )
 
 // QueueKey returns a redis key for the given queue name.
@@ -55,9 +56,9 @@ func RetryKey(qname string) string {
 	return fmt.Sprintf("asynq:{%s}:retry", qname)
 }
 
-// DeadKey returns a redis key for the dead tasks.
-func DeadKey(qname string) string {
-	return fmt.Sprintf("asynq:{%s}:dead", qname)
+// ArchivedKey returns a redis key for the archived tasks.
+func ArchivedKey(qname string) string {
+	return fmt.Sprintf("asynq:{%s}:archived", qname)
 }
 
 // DeadlinesKey returns a redis key for the deadlines.
@@ -81,13 +82,23 @@ func FailedKey(qname string, t time.Time) string {
 }
 
 // ServerInfoKey returns a redis key for process info.
-func ServerInfoKey(hostname string, pid int, sid string) string {
-	return fmt.Sprintf("asynq:servers:{%s:%d:%s}", hostname, pid, sid)
+func ServerInfoKey(hostname string, pid int, serverID string) string {
+	return fmt.Sprintf("asynq:servers:{%s:%d:%s}", hostname, pid, serverID)
 }
 
 // WorkersKey returns a redis key for the workers given hostname, pid, and server ID.
-func WorkersKey(hostname string, pid int, sid string) string {
-	return fmt.Sprintf("asynq:workers:{%s:%d:%s}", hostname, pid, sid)
+func WorkersKey(hostname string, pid int, serverID string) string {
+	return fmt.Sprintf("asynq:workers:{%s:%d:%s}", hostname, pid, serverID)
+}
+
+// SchedulerEntriesKey returns a redis key for the scheduler entries given scheduler ID.
+func SchedulerEntriesKey(schedulerID string) string {
+	return fmt.Sprintf("asynq:schedulers:{%s}", schedulerID)
+}
+
+// SchedulerHistoryKey returns a redis key for the scheduler's history for the given entry.
+func SchedulerHistoryKey(entryID string) string {
+	return fmt.Sprintf("asynq:scheduler_history:%s", entryID)
 }
 
 // UniqueKey returns a redis key with the given type, payload, and queue name.
@@ -145,7 +156,7 @@ type TaskMessage struct {
 
 	// Timeout specifies timeout in seconds.
 	// If task processing doesn't complete within the timeout, the task will be retried
-	// if retry count is remaining. Otherwise it will be moved to the dead queue.
+	// if retry count is remaining. Otherwise it will be moved to the archive.
 	//
 	// Use zero to indicate no timeout.
 	Timeout int64
@@ -153,7 +164,7 @@ type TaskMessage struct {
 	// Deadline specifies the deadline for the task in Unix time,
 	// the number of seconds elapsed since January 1, 1970 UTC.
 	// If task processing doesn't complete before the deadline, the task will be retried
-	// if retry count is remaining. Otherwise it will be moved to the dead queue.
+	// if retry count is remaining. Otherwise it will be moved to the archive.
 	//
 	// Use zero to indicate no deadline.
 	Deadline int64
@@ -208,10 +219,10 @@ const (
 	// StatusIdle indicates the server is in idle state.
 	StatusIdle ServerStatusValue = iota
 
-	// StatusRunning indicates the servier is up and processing tasks.
+	// StatusRunning indicates the server is up and active.
 	StatusRunning
 
-	// StatusQuiet indicates the server is up but not processing new tasks.
+	// StatusQuiet indicates the server is up but not active.
 	StatusQuiet
 
 	// StatusStopped indicates the server server has been stopped.
@@ -264,13 +275,48 @@ type ServerInfo struct {
 
 // WorkerInfo holds information about a running worker.
 type WorkerInfo struct {
-	Host    string
-	PID     int
-	ID      string
-	Type    string
-	Queue   string
+	Host     string
+	PID      int
+	ServerID string
+	ID       string
+	Type     string
+	Queue    string
+	Payload  map[string]interface{}
+	Started  time.Time
+}
+
+// SchedulerEntry holds information about a periodic task registered with a scheduler.
+type SchedulerEntry struct {
+	// Identifier of this entry.
+	ID string
+
+	// Spec describes the schedule of this entry.
+	Spec string
+
+	// Type is the task type of the periodic task.
+	Type string
+
+	// Payload is the payload of the periodic task.
 	Payload map[string]interface{}
-	Started time.Time
+
+	// Opts is the options for the periodic task.
+	Opts []string
+
+	// Next shows the next time the task will be enqueued.
+	Next time.Time
+
+	// Prev shows the last time the task was enqueued.
+	// Zero time if task was never enqueued.
+	Prev time.Time
+}
+
+// SchedulerEnqueueEvent holds information about an enqueue event by a scheduler.
+type SchedulerEnqueueEvent struct {
+	// ID of the task that was enqueued.
+	TaskID string
+
+	// Time the task was enqueued.
+	EnqueuedAt time.Time
 }
 
 // Cancelations is a collection that holds cancel functions for all active tasks.
@@ -323,7 +369,7 @@ type Broker interface {
 	Schedule(msg *TaskMessage, processAt time.Time) error
 	ScheduleUnique(msg *TaskMessage, processAt time.Time, ttl time.Duration) error
 	Retry(msg *TaskMessage, processAt time.Time, errMsg string) error
-	Kill(msg *TaskMessage, errMsg string) error
+	Archive(msg *TaskMessage, errMsg string) error
 	CheckAndEnqueue(qnames ...string) error
 	ListDeadlineExceeded(deadline time.Time, qnames ...string) ([]*TaskMessage, error)
 	WriteServerState(info *ServerInfo, workers []*WorkerInfo, ttl time.Duration) error

internal/base/base_test.go

@@ -100,19 +100,19 @@ func TestRetryKey(t *testing.T) {
 	}
 }
 
-func TestDeadKey(t *testing.T) {
+func TestArchivedKey(t *testing.T) {
 	tests := []struct {
 		qname string
 		want  string
 	}{
-		{"default", "asynq:{default}:dead"},
-		{"custom", "asynq:{custom}:dead"},
+		{"default", "asynq:{default}:archived"},
+		{"custom", "asynq:{custom}:archived"},
 	}
 
 	for _, tc := range tests {
-		got := DeadKey(tc.qname)
+		got := ArchivedKey(tc.qname)
 		if got != tc.want {
-			t.Errorf("DeadKey(%q) = %q, want %q", tc.qname, got, tc.want)
+			t.Errorf("ArchivedKey(%q) = %q, want %q", tc.qname, got, tc.want)
 		}
 	}
 }
@@ -212,6 +212,41 @@ func TestWorkersKey(t *testing.T) {
 	}
 }
 
+func TestSchedulerEntriesKey(t *testing.T) {
+	tests := []struct {
+		schedulerID string
+		want        string
+	}{
+		{"localhost:9876:scheduler123", "asynq:schedulers:{localhost:9876:scheduler123}"},
+		{"127.0.0.1:1234:scheduler987", "asynq:schedulers:{127.0.0.1:1234:scheduler987}"},
+	}
+
+	for _, tc := range tests {
+		got := SchedulerEntriesKey(tc.schedulerID)
+		if got != tc.want {
+			t.Errorf("SchedulerEntriesKey(%q) = %q, want %q", tc.schedulerID, got, tc.want)
+		}
+	}
+}
+
+func TestSchedulerHistoryKey(t *testing.T) {
+	tests := []struct {
+		entryID string
+		want    string
+	}{
+		{"entry876", "asynq:scheduler_history:entry876"},
+		{"entry345", "asynq:scheduler_history:entry345"},
+	}
+
+	for _, tc := range tests {
+		got := SchedulerHistoryKey(tc.entryID)
+		if got != tc.want {
+			t.Errorf("SchedulerHistoryKey(%q) = %q, want %q",
+				tc.entryID, got, tc.want)
+		}
+	}
+}
+
 func TestUniqueKey(t *testing.T) {
 	tests := []struct {
 		desc     string
@@ -328,14 +363,14 @@ func TestStatusConcurrentAccess(t *testing.T) {
 	go func() {
 		defer wg.Done()
 		status.Get()
-		status.String()
+		_ = status.String()
 	}()
 
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
 		status.Set(StatusStopped)
-		status.String()
+		_ = status.String()
 	}()
 
 	wg.Wait()

internal/rdb/inspect.go

@@ -35,7 +35,7 @@ type Stats struct {
 	Active    int
 	Scheduled int
 	Retry     int
-	Dead      int
+	Archived  int
 	// Total number of tasks processed during the current date.
 	// The number includes both succeeded and failed tasks.
 	Processed int
@@ -62,7 +62,7 @@ type DailyStats struct {
 // KEYS[2] -> asynq:<qname>:active
 // KEYS[3] -> asynq:<qname>:scheduled
 // KEYS[4] -> asynq:<qname>:retry
-// KEYS[5] -> asynq:<qname>:dead
+// KEYS[5] -> asynq:<qname>:archived
 // KEYS[6] -> asynq:<qname>:processed:<yyyy-mm-dd>
 // KEYS[7] -> asynq:<qname>:failed:<yyyy-mm-dd>
 // KEYS[8] -> asynq:<qname>:paused
@@ -111,7 +111,7 @@ func (r *RDB) CurrentStats(qname string) (*Stats, error) {
 		base.ActiveKey(qname),
 		base.ScheduledKey(qname),
 		base.RetryKey(qname),
-		base.DeadKey(qname),
+		base.ArchivedKey(qname),
 		base.ProcessedKey(qname, now),
 		base.FailedKey(qname, now),
 		base.PausedKey(qname),
@@ -144,8 +144,8 @@ func (r *RDB) CurrentStats(qname string) (*Stats, error) {
 		case base.RetryKey(qname):
 			stats.Retry = val
 			size += val
-		case base.DeadKey(qname):
-			stats.Dead = val
+		case base.ArchivedKey(qname):
+			stats.Archived = val
 			size += val
 		case base.ProcessedKey(qname, now):
 			stats.Processed = val
@@ -328,12 +328,12 @@ func (r *RDB) ListRetry(qname string, pgn Pagination) ([]base.Z, error) {
 	return r.listZSetEntries(base.RetryKey(qname), pgn)
 }
 
-// ListDead returns all tasks from the given queue that have exhausted its retry limit.
-func (r *RDB) ListDead(qname string, pgn Pagination) ([]base.Z, error) {
+// ListArchived returns all tasks from the given queue that have exhausted its retry limit.
+func (r *RDB) ListArchived(qname string, pgn Pagination) ([]base.Z, error) {
 	if !r.client.SIsMember(base.AllQueues, qname).Val() {
 		return nil, fmt.Errorf("queue %q does not exist", qname)
 	}
-	return r.listZSetEntries(base.DeadKey(qname), pgn)
+	return r.listZSetEntries(base.ArchivedKey(qname), pgn)
 }
 
 // listZSetEntries returns a list of message and score pairs in Redis sorted-set
@@ -353,16 +353,16 @@ func (r *RDB) listZSetEntries(key string, pgn Pagination) ([]base.Z, error) {
 		if err != nil {
 			continue // bad data, ignore and continue
 		}
-		res = append(res, base.Z{msg, int64(z.Score)})
+		res = append(res, base.Z{Message: msg, Score: int64(z.Score)})
 	}
 	return res, nil
 }
 
-// RunDeadTask finds a dead task that matches the given id and score from
+// RunArchivedTask finds an archived task that matches the given id and score from
 // the given queue and enqueues it for processing.
-//If a task that matches the id and score does not exist, it returns ErrTaskNotFound.
-func (r *RDB) RunDeadTask(qname string, id uuid.UUID, score int64) error {
-	n, err := r.removeAndRun(base.DeadKey(qname), base.QueueKey(qname), id.String(), float64(score))
+// If a task that matches the id and score does not exist, it returns ErrTaskNotFound.
+func (r *RDB) RunArchivedTask(qname string, id uuid.UUID, score int64) error {
+	n, err := r.removeAndRun(base.ArchivedKey(qname), base.QueueKey(qname), id.String(), float64(score))
 	if err != nil {
 		return err
 	}
@@ -412,10 +412,10 @@ func (r *RDB) RunAllRetryTasks(qname string) (int64, error) {
 	return r.removeAndRunAll(base.RetryKey(qname), base.QueueKey(qname))
 }
 
-// RunAllDeadTasks enqueues all tasks from dead queue
+// RunAllArchivedTasks enqueues all archived tasks from the given queue
 // and returns the number of tasks enqueued.
-func (r *RDB) RunAllDeadTasks(qname string) (int64, error) {
-	return r.removeAndRunAll(base.DeadKey(qname), base.QueueKey(qname))
+func (r *RDB) RunAllArchivedTasks(qname string) (int64, error) {
+	return r.removeAndRunAll(base.ArchivedKey(qname), base.QueueKey(qname))
 }
 
 var removeAndRunCmd = redis.NewScript(`
@@ -462,10 +462,10 @@ func (r *RDB) removeAndRunAll(zset, qkey string) (int64, error) {
 	return n, nil
 }
 
-// KillRetryTask finds a retry task that matches the given id and score from the given queue
-// and kills it. If a task that maches the id and score does not exist, it returns ErrTaskNotFound.
-func (r *RDB) KillRetryTask(qname string, id uuid.UUID, score int64) error {
-	n, err := r.removeAndKill(base.RetryKey(qname), base.DeadKey(qname), id.String(), float64(score))
+// ArchiveRetryTask finds a retry task that matches the given id and score from the given queue
+// and archives it. If a task that maches the id and score does not exist, it returns ErrTaskNotFound.
+func (r *RDB) ArchiveRetryTask(qname string, id uuid.UUID, score int64) error {
+	n, err := r.removeAndArchive(base.RetryKey(qname), base.ArchivedKey(qname), id.String(), float64(score))
 	if err != nil {
 		return err
 	}
@@ -475,10 +475,10 @@ func (r *RDB) KillRetryTask(qname string, id uuid.UUID, score int64) error {
 	return nil
 }
 
-// KillScheduledTask finds a scheduled task that matches the given id and score from the given queue
-// and kills it. If a task that maches the id and score does not exist, it returns ErrTaskNotFound.
-func (r *RDB) KillScheduledTask(qname string, id uuid.UUID, score int64) error {
-	n, err := r.removeAndKill(base.ScheduledKey(qname), base.DeadKey(qname), id.String(), float64(score))
+// ArchiveScheduledTask finds a scheduled task that matches the given id and score from the given queue
+// and archives it. If a task that maches the id and score does not exist, it returns ErrTaskNotFound.
+func (r *RDB) ArchiveScheduledTask(qname string, id uuid.UUID, score int64) error {
+	n, err := r.removeAndArchive(base.ScheduledKey(qname), base.ArchivedKey(qname), id.String(), float64(score))
 	if err != nil {
 		return err
 	}
@@ -488,26 +488,26 @@ func (r *RDB) KillScheduledTask(qname string, id uuid.UUID, score int64) error {
 	return nil
 }
 
-// KillAllRetryTasks kills all retry tasks from the given queue and
+// ArchiveAllRetryTasks archives all retry tasks from the given queue and
 // returns the number of tasks that were moved.
-func (r *RDB) KillAllRetryTasks(qname string) (int64, error) {
-	return r.removeAndKillAll(base.RetryKey(qname), base.DeadKey(qname))
+func (r *RDB) ArchiveAllRetryTasks(qname string) (int64, error) {
+	return r.removeAndArchiveAll(base.RetryKey(qname), base.ArchivedKey(qname))
 }
 
-// KillAllScheduledTasks kills all scheduled tasks from the given queue and
+// ArchiveAllScheduledTasks archives all scheduled tasks from the given queue and
 // returns the number of tasks that were moved.
-func (r *RDB) KillAllScheduledTasks(qname string) (int64, error) {
-	return r.removeAndKillAll(base.ScheduledKey(qname), base.DeadKey(qname))
+func (r *RDB) ArchiveAllScheduledTasks(qname string) (int64, error) {
+	return r.removeAndArchiveAll(base.ScheduledKey(qname), base.ArchivedKey(qname))
 }
 
 // KEYS[1] -> ZSET to move task from (e.g., retry queue)
-// KEYS[2] -> asynq:{<qname>}:dead
-// ARGV[1] -> score of the task to kill
-// ARGV[2] -> id of the task to kill
+// KEYS[2] -> asynq:{<qname>}:archived
+// ARGV[1] -> score of the task to archive
+// ARGV[2] -> id of the task to archive
 // ARGV[3] -> current timestamp
 // ARGV[4] -> cutoff timestamp (e.g., 90 days ago)
-// ARGV[5] -> max number of tasks in dead queue (e.g., 100)
-var removeAndKillCmd = redis.NewScript(`
+// ARGV[5] -> max number of tasks in archived state (e.g., 100)
+var removeAndArchiveCmd = redis.NewScript(`
 local msgs = redis.call("ZRANGEBYSCORE", KEYS[1], ARGV[1], ARGV[1])
 for _, msg in ipairs(msgs) do
 	local decoded = cjson.decode(msg)
@@ -521,12 +521,12 @@ for _, msg in ipairs(msgs) do
 end
 return 0`)
 
-func (r *RDB) removeAndKill(src, dst, id string, score float64) (int64, error) {
+func (r *RDB) removeAndArchive(src, dst, id string, score float64) (int64, error) {
 	now := time.Now()
-	limit := now.AddDate(0, 0, -deadExpirationInDays).Unix() // 90 days ago
-	res, err := removeAndKillCmd.Run(r.client,
+	limit := now.AddDate(0, 0, -archivedExpirationInDays).Unix() // 90 days ago
+	res, err := removeAndArchiveCmd.Run(r.client,
 		[]string{src, dst},
-		score, id, now.Unix(), limit, maxDeadTasks).Result()
+		score, id, now.Unix(), limit, maxArchiveSize).Result()
 	if err != nil {
 		return 0, err
 	}
@@ -538,11 +538,11 @@ func (r *RDB) removeAndKill(src, dst, id string, score float64) (int64, error) {
 }
 
 // KEYS[1] -> ZSET to move task from (e.g., retry queue)
-// KEYS[2] -> asynq:{<qname>}:dead
+// KEYS[2] -> asynq:{<qname>}:archived
 // ARGV[1] -> current timestamp
 // ARGV[2] -> cutoff timestamp (e.g., 90 days ago)
-// ARGV[3] -> max number of tasks in dead queue (e.g., 100)
-var removeAndKillAllCmd = redis.NewScript(`
+// ARGV[3] -> max number of tasks in archive (e.g., 100)
+var removeAndArchiveAllCmd = redis.NewScript(`
 local msgs = redis.call("ZRANGE", KEYS[1], 0, -1)
 for _, msg in ipairs(msgs) do
 	redis.call("ZADD", KEYS[2], ARGV[1], msg)
@@ -552,11 +552,11 @@ for _, msg in ipairs(msgs) do
 end
 return table.getn(msgs)`)
 
-func (r *RDB) removeAndKillAll(src, dst string) (int64, error) {
+func (r *RDB) removeAndArchiveAll(src, dst string) (int64, error) {
 	now := time.Now()
-	limit := now.AddDate(0, 0, -deadExpirationInDays).Unix() // 90 days ago
-	res, err := removeAndKillAllCmd.Run(r.client, []string{src, dst},
-		now.Unix(), limit, maxDeadTasks).Result()
+	limit := now.AddDate(0, 0, -archivedExpirationInDays).Unix() // 90 days ago
+	res, err := removeAndArchiveAllCmd.Run(r.client, []string{src, dst},
+		now.Unix(), limit, maxArchiveSize).Result()
 	if err != nil {
 		return 0, err
 	}
@@ -567,10 +567,10 @@ func (r *RDB) removeAndKillAll(src, dst string) (int64, error) {
 	return n, nil
 }
 
-// DeleteDeadTask deletes a dead task that matches the given id and score from the given queue.
+// DeleteArchivedTask deletes an archived task that matches the given id and score from the given queue.
 // If a task that matches the id and score does not exist, it returns ErrTaskNotFound.
-func (r *RDB) DeleteDeadTask(qname string, id uuid.UUID, score int64) error {
-	return r.deleteTask(base.DeadKey(qname), id.String(), float64(score))
+func (r *RDB) DeleteArchivedTask(qname string, id uuid.UUID, score int64) error {
+	return r.deleteTask(base.ArchivedKey(qname), id.String(), float64(score))
 }
 
 // DeleteRetryTask deletes a retry task that matches the given id and score from the given queue.
@@ -617,10 +617,10 @@ local n = redis.call("ZCARD", KEYS[1])
 redis.call("DEL", KEYS[1])
 return n`)
 
-// DeleteAllDeadTasks deletes all dead tasks from the given queue
+// DeleteAllArchivedTasks deletes all archived tasks from the given queue
 // and returns the number of tasks deleted.
-func (r *RDB) DeleteAllDeadTasks(qname string) (int64, error) {
-	return r.deleteAll(base.DeadKey(qname))
+func (r *RDB) DeleteAllArchivedTasks(qname string) (int64, error) {
+	return r.deleteAll(base.ArchivedKey(qname))
 }
 
 // DeleteAllRetryTasks deletes all retry tasks from the given queue
@@ -670,7 +670,7 @@ func (e *ErrQueueNotEmpty) Error() string {
 // KEYS[2] -> asynq:{<qname>}:active
 // KEYS[3] -> asynq:{<qname>}:scheduled
 // KEYS[4] -> asynq:{<qname>}:retry
-// KEYS[5] -> asynq:{<qname>}:dead
+// KEYS[5] -> asynq:{<qname>}:archived
 // KEYS[6] -> asynq:{<qname>}:deadlines
 var removeQueueForceCmd = redis.NewScript(`
 local active = redis.call("LLEN", KEYS[2])
@@ -690,15 +690,15 @@ return redis.status_reply("OK")`)
 // KEYS[2] -> asynq:{<qname>}:active
 // KEYS[3] -> asynq:{<qname>}:scheduled
 // KEYS[4] -> asynq:{<qname>}:retry
-// KEYS[5] -> asynq:{<qname>}:dead
+// KEYS[5] -> asynq:{<qname>}:archived
 // KEYS[6] -> asynq:{<qname>}:deadlines
 var removeQueueCmd = redis.NewScript(`
 local pending = redis.call("LLEN", KEYS[1]) 
 local active = redis.call("LLEN", KEYS[2])
 local scheduled = redis.call("SCARD", KEYS[3])
 local retry = redis.call("SCARD", KEYS[4])
-local dead = redis.call("SCARD", KEYS[5])
-local total = pending + active + scheduled + retry + dead
+local archived = redis.call("SCARD", KEYS[5])
+local total = pending + active + scheduled + retry + archived
 if total > 0 then
 	return redis.error_reply("QUEUE NOT EMPTY")
 end
@@ -735,7 +735,7 @@ func (r *RDB) RemoveQueue(qname string, force bool) error {
 		base.ActiveKey(qname),
 		base.ScheduledKey(qname),
 		base.RetryKey(qname),
-		base.DeadKey(qname),
+		base.ArchivedKey(qname),
 		base.DeadlinesKey(qname),
 	}
 	if err := script.Run(r.client, keys).Err(); err != nil {
@@ -745,7 +745,6 @@ func (r *RDB) RemoveQueue(qname string, force bool) error {
 			return err
 		}
 	}
-
 	return r.client.SRem(base.AllQueues, qname).Err()
 }
 
@@ -758,7 +757,7 @@ return keys`)
 
 // ListServers returns the list of server info.
 func (r *RDB) ListServers() ([]*base.ServerInfo, error) {
-	now := time.Now().UTC()
+	now := time.Now()
 	res, err := listServerKeysCmd.Run(r.client, []string{base.AllServers}, now.Unix()).Result()
 	if err != nil {
 		return nil, err
@@ -791,7 +790,7 @@ return keys`)
 
 // ListWorkers returns the list of worker stats.
 func (r *RDB) ListWorkers() ([]*base.WorkerInfo, error) {
-	now := time.Now().UTC()
+	now := time.Now()
 	res, err := listWorkerKeysCmd.Run(r.client, []string{base.AllWorkers}, now.Unix()).Result()
 	if err != nil {
 		return nil, err
@@ -818,6 +817,63 @@ func (r *RDB) ListWorkers() ([]*base.WorkerInfo, error) {
 	return workers, nil
 }
 
+// Note: Script also removes stale keys.
+var listSchedulerKeysCmd = redis.NewScript(`
+local now = tonumber(ARGV[1])
+local keys = redis.call("ZRANGEBYSCORE", KEYS[1], now, "+inf")
+redis.call("ZREMRANGEBYSCORE", KEYS[1], "-inf", now-1)
+return keys`)
+
+// ListSchedulerEntries returns the list of scheduler entries.
+func (r *RDB) ListSchedulerEntries() ([]*base.SchedulerEntry, error) {
+	now := time.Now()
+	res, err := listSchedulerKeysCmd.Run(r.client, []string{base.AllSchedulers}, now.Unix()).Result()
+	if err != nil {
+		return nil, err
+	}
+	keys, err := cast.ToStringSliceE(res)
+	if err != nil {
+		return nil, err
+	}
+	var entries []*base.SchedulerEntry
+	for _, key := range keys {
+		data, err := r.client.LRange(key, 0, -1).Result()
+		if err != nil {
+			continue // skip bad data
+		}
+		for _, s := range data {
+			var e base.SchedulerEntry
+			if err := json.Unmarshal([]byte(s), &e); err != nil {
+				continue // skip bad data
+			}
+			entries = append(entries, &e)
+		}
+	}
+	return entries, nil
+}
+
+// ListSchedulerEnqueueEvents returns the list of scheduler enqueue events.
+func (r *RDB) ListSchedulerEnqueueEvents(entryID string, pgn Pagination) ([]*base.SchedulerEnqueueEvent, error) {
+	key := base.SchedulerHistoryKey(entryID)
+	zs, err := r.client.ZRevRangeWithScores(key, pgn.start(), pgn.stop()).Result()
+	if err != nil {
+		return nil, err
+	}
+	var events []*base.SchedulerEnqueueEvent
+	for _, z := range zs {
+		data, err := cast.ToStringE(z.Member)
+		if err != nil {
+			return nil, err
+		}
+		var e base.SchedulerEnqueueEvent
+		if err := json.Unmarshal([]byte(data), &e); err != nil {
+			return nil, err
+		}
+		events = append(events, &e)
+	}
+	return events, nil
+}
+
 // Pause pauses processing of tasks from the given queue.
 func (r *RDB) Pause(qname string) error {
 	key := base.PausedKey(qname)

internal/rdb/rdb.go

@@ -381,22 +381,22 @@ func (r *RDB) Retry(msg *base.TaskMessage, processAt time.Time, errMsg string) e
 }
 
 const (
-	maxDeadTasks         = 10000
-	deadExpirationInDays = 90
+	maxArchiveSize           = 10000 // maximum number of tasks in archive
+	archivedExpirationInDays = 90    // number of days before an archived task gets deleted permanently
 )
 
 // KEYS[1] -> asynq:{<qname>}:active
 // KEYS[2] -> asynq:{<qname>}:deadlines
-// KEYS[3] -> asynq:{<qname>}:dead
+// KEYS[3] -> asynq:{<qname>}:archived
 // KEYS[4] -> asynq:{<qname>}:processed:<yyyy-mm-dd>
 // KEYS[5] -> asynq:{<qname>}:failed:<yyyy-mm-dd>
-// ARGV[1] -> base.TaskMessage value to remove from base.ActiveQueue queue
-// ARGV[2] -> base.TaskMessage value to add to Dead queue
+// ARGV[1] -> base.TaskMessage value to remove
+// ARGV[2] -> base.TaskMessage value to add
 // ARGV[3] -> died_at UNIX timestamp
 // ARGV[4] -> cutoff timestamp (e.g., 90 days ago)
-// ARGV[5] -> max number of tasks in dead queue (e.g., 100)
+// ARGV[5] -> max number of tasks in archive (e.g., 100)
 // ARGV[6] -> stats expiration timestamp
-var killCmd = redis.NewScript(`
+var archiveCmd = redis.NewScript(`
 if redis.call("LREM", KEYS[1], 0, ARGV[1]) == 0 then
   return redis.error_reply("NOT FOUND")
 end
@@ -416,10 +416,9 @@ if tonumber(m) == 1 then
 end
 return redis.status_reply("OK")`)
 
-// Kill sends the task to "dead" queue from active queue, assigning
-// the error message to the task.
-// It also trims the set by timestamp and set size.
-func (r *RDB) Kill(msg *base.TaskMessage, errMsg string) error {
+// Archive sends the given task to archive, attaching the error message to the task.
+// It also trims the archive by timestamp and set size.
+func (r *RDB) Archive(msg *base.TaskMessage, errMsg string) error {
 	msgToRemove, err := base.EncodeMessage(msg)
 	if err != nil {
 		return err
@@ -431,13 +430,13 @@ func (r *RDB) Kill(msg *base.TaskMessage, errMsg string) error {
 		return err
 	}
 	now := time.Now()
-	limit := now.AddDate(0, 0, -deadExpirationInDays).Unix() // 90 days ago
+	limit := now.AddDate(0, 0, -archivedExpirationInDays).Unix() // 90 days ago
 	processedKey := base.ProcessedKey(msg.Queue, now)
 	failedKey := base.FailedKey(msg.Queue, now)
 	expireAt := now.Add(statsTTL)
-	return killCmd.Run(r.client,
-		[]string{base.ActiveKey(msg.Queue), base.DeadlinesKey(msg.Queue), base.DeadKey(msg.Queue), processedKey, failedKey},
-		msgToRemove, msgToAdd, now.Unix(), limit, maxDeadTasks, expireAt.Unix()).Err()
+	return archiveCmd.Run(r.client,
+		[]string{base.ActiveKey(msg.Queue), base.DeadlinesKey(msg.Queue), base.ArchivedKey(msg.Queue), processedKey, failedKey},
+		msgToRemove, msgToAdd, now.Unix(), limit, maxArchiveSize, expireAt.Unix()).Err()
 }
 
 // CheckAndEnqueue checks for scheduled/retry tasks for the given queues
@@ -575,6 +574,45 @@ func (r *RDB) ClearServerState(host string, pid int, serverID string) error {
 	return clearServerStateCmd.Run(r.client, []string{skey, wkey}).Err()
 }
 
+// KEYS[1]  -> asynq:schedulers:{<schedulerID>}
+// ARGV[1]  -> TTL in seconds
+// ARGV[2:] -> schedler entries
+var writeSchedulerEntriesCmd = redis.NewScript(`
+redis.call("DEL", KEYS[1])
+for i = 2, #ARGV do
+	redis.call("LPUSH", KEYS[1], ARGV[i])
+end
+redis.call("EXPIRE", KEYS[1], ARGV[1])
+return redis.status_reply("OK")`)
+
+// WriteSchedulerEntries writes scheduler entries data to redis with expiration set to the value ttl.
+func (r *RDB) WriteSchedulerEntries(schedulerID string, entries []*base.SchedulerEntry, ttl time.Duration) error {
+	args := []interface{}{ttl.Seconds()}
+	for _, e := range entries {
+		bytes, err := json.Marshal(e)
+		if err != nil {
+			continue // skip bad data
+		}
+		args = append(args, bytes)
+	}
+	exp := time.Now().Add(ttl).UTC()
+	key := base.SchedulerEntriesKey(schedulerID)
+	err := r.client.ZAdd(base.AllSchedulers, &redis.Z{Score: float64(exp.Unix()), Member: key}).Err()
+	if err != nil {
+		return err
+	}
+	return writeSchedulerEntriesCmd.Run(r.client, []string{key}, args...).Err()
+}
+
+// ClearSchedulerEntries deletes scheduler entries data from redis.
+func (r *RDB) ClearSchedulerEntries(scheduelrID string) error {
+	key := base.SchedulerEntriesKey(scheduelrID)
+	if err := r.client.ZRem(base.AllSchedulers, key).Err(); err != nil {
+		return err
+	}
+	return r.client.Del(key).Err()
+}
+
 // CancelationPubSub returns a pubsub for cancelation messages.
 func (r *RDB) CancelationPubSub() (*redis.PubSub, error) {
 	pubsub := r.client.Subscribe(base.CancelChannel)
@@ -590,3 +628,26 @@ func (r *RDB) CancelationPubSub() (*redis.PubSub, error) {
 func (r *RDB) PublishCancelation(id string) error {
 	return r.client.Publish(base.CancelChannel, id).Err()
 }
+
+// KEYS[1] -> asynq:scheduler_history:<entryID>
+// ARGV[1] -> enqueued_at timestamp
+// ARGV[2] -> serialized SchedulerEnqueueEvent data
+// ARGV[3] -> max number of events to be persisted
+var recordSchedulerEnqueueEventCmd = redis.NewScript(`
+redis.call("ZADD", KEYS[1], ARGV[1], ARGV[2])
+redis.call("ZREMRANGEBYSCORE", KEYS[1], "-inf", ARGV[3])
+return redis.status_reply("OK")`)
+
+// Maximum number of enqueue events to store per entry.
+const maxEvents = 10000
+
+// RecordSchedulerEnqueueEvent records the time when the given task was enqueued.
+func (r *RDB) RecordSchedulerEnqueueEvent(entryID string, event *base.SchedulerEnqueueEvent) error {
+	key := base.SchedulerHistoryKey(entryID)
+	data, err := json.Marshal(event)
+	if err != nil {
+		return err
+	}
+	return recordSchedulerEnqueueEventCmd.Run(
+		r.client, []string{key}, event.EnqueuedAt.Unix(), data, maxEvents).Err()
+}

internal/rdb/rdb_test.go

@@ -1008,7 +1008,7 @@ func TestRetry(t *testing.T) {
 	}
 }
 
-func TestKill(t *testing.T) {
+func TestArchive(t *testing.T) {
 	r := setup(t)
 	defer r.Close()
 	now := time.Now()
@@ -1058,11 +1058,11 @@ func TestKill(t *testing.T) {
 	tests := []struct {
 		inProgress    map[string][]*base.TaskMessage
 		deadlines     map[string][]base.Z
-		dead          map[string][]base.Z
-		target        *base.TaskMessage // task to kill
+		archived      map[string][]base.Z
+		target        *base.TaskMessage // task to archive
 		wantActive    map[string][]*base.TaskMessage
 		wantDeadlines map[string][]base.Z
-		wantDead      map[string][]base.Z
+		wantArchived  map[string][]base.Z
 	}{
 		{
 			inProgress: map[string][]*base.TaskMessage{
@@ -1074,7 +1074,7 @@ func TestKill(t *testing.T) {
 					{Message: t2, Score: t2Deadline},
 				},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default": {
 					{Message: t3, Score: now.Add(-time.Hour).Unix()},
 				},
@@ -1086,7 +1086,7 @@ func TestKill(t *testing.T) {
 			wantDeadlines: map[string][]base.Z{
 				"default": {{Message: t2, Score: t2Deadline}},
 			},
-			wantDead: map[string][]base.Z{
+			wantArchived: map[string][]base.Z{
 				"default": {
 					{Message: h.TaskMessageWithError(*t1, errMsg), Score: now.Unix()},
 					{Message: t3, Score: now.Add(-time.Hour).Unix()},
@@ -1104,7 +1104,7 @@ func TestKill(t *testing.T) {
 					{Message: t3, Score: t3Deadline},
 				},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default": {},
 			},
 			target: t1,
@@ -1117,7 +1117,7 @@ func TestKill(t *testing.T) {
 					{Message: t3, Score: t3Deadline},
 				},
 			},
-			wantDead: map[string][]base.Z{
+			wantArchived: map[string][]base.Z{
 				"default": {
 					{Message: h.TaskMessageWithError(*t1, errMsg), Score: now.Unix()},
 				},
@@ -1136,7 +1136,7 @@ func TestKill(t *testing.T) {
 					{Message: t4, Score: t4Deadline},
 				},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default": {},
 				"custom":  {},
 			},
@@ -1149,7 +1149,7 @@ func TestKill(t *testing.T) {
 				"default": {{Message: t1, Score: t1Deadline}},
 				"custom":  {},
 			},
-			wantDead: map[string][]base.Z{
+			wantArchived: map[string][]base.Z{
 				"default": {},
 				"custom": {
 					{Message: h.TaskMessageWithError(*t4, errMsg), Score: now.Unix()},
@@ -1162,11 +1162,11 @@ func TestKill(t *testing.T) {
 		h.FlushDB(t, r.client) // clean up db before each test case
 		h.SeedAllActiveQueues(t, r.client, tc.inProgress)
 		h.SeedAllDeadlines(t, r.client, tc.deadlines)
-		h.SeedAllDeadQueues(t, r.client, tc.dead)
+		h.SeedAllArchivedQueues(t, r.client, tc.archived)
 
-		err := r.Kill(tc.target, errMsg)
+		err := r.Archive(tc.target, errMsg)
 		if err != nil {
-			t.Errorf("(*RDB).Kill(%v, %v) = %v, want nil", tc.target, errMsg, err)
+			t.Errorf("(*RDB).Archive(%v, %v) = %v, want nil", tc.target, errMsg, err)
 			continue
 		}
 
@@ -1179,13 +1179,13 @@ func TestKill(t *testing.T) {
 		for queue, want := range tc.wantDeadlines {
 			gotDeadlines := h.GetDeadlinesEntries(t, r.client, queue)
 			if diff := cmp.Diff(want, gotDeadlines, h.SortZSetEntryOpt); diff != "" {
-				t.Errorf("mismatch found in %q after calling (*RDB).Kill: (-want, +got):\n%s", base.DeadlinesKey(queue), diff)
+				t.Errorf("mismatch found in %q after calling (*RDB).Archive: (-want, +got):\n%s", base.DeadlinesKey(queue), diff)
 			}
 		}
-		for queue, want := range tc.wantDead {
-			gotDead := h.GetDeadEntries(t, r.client, queue)
-			if diff := cmp.Diff(want, gotDead, h.SortZSetEntryOpt, zScoreCmpOpt); diff != "" {
-				t.Errorf("mismatch found in %q after calling (*RDB).Kill: (-want, +got):\n%s", base.DeadKey(queue), diff)
+		for queue, want := range tc.wantArchived {
+			gotArchived := h.GetArchivedEntries(t, r.client, queue)
+			if diff := cmp.Diff(want, gotArchived, h.SortZSetEntryOpt, zScoreCmpOpt); diff != "" {
+				t.Errorf("mismatch found in %q after calling (*RDB).Archive: (-want, +got):\n%s", base.ArchivedKey(queue), diff)
 			}
 		}
 

internal/testbroker/testbroker.go

@@ -117,13 +117,13 @@ func (tb *TestBroker) Retry(msg *base.TaskMessage, processAt time.Time, errMsg s
 	return tb.real.Retry(msg, processAt, errMsg)
 }
 
-func (tb *TestBroker) Kill(msg *base.TaskMessage, errMsg string) error {
+func (tb *TestBroker) Archive(msg *base.TaskMessage, errMsg string) error {
 	tb.mu.Lock()
 	defer tb.mu.Unlock()
 	if tb.sleeping {
 		return errRedisDown
 	}
-	return tb.real.Kill(msg, errMsg)
+	return tb.real.Archive(msg, errMsg)
 }
 
 func (tb *TestBroker) CheckAndEnqueue(qnames ...string) error {

payload.go

@@ -44,6 +44,16 @@ func toInt(v interface{}) (int, error) {
 	}
 }
 
+// String returns a string representation of payload data.
+func (p Payload) String() string {
+	return fmt.Sprint(p.data)
+}
+
+// MarshalJSON returns the JSON encoding of payload data.
+func (p Payload) MarshalJSON() ([]byte, error) {
+	return json.Marshal(p.data)
+}
+
 // GetString returns a string value if a string type is associated with
 // the key, otherwise reports an error.
 func (p Payload) GetString(key string) (string, error) {

payload_test.go

@@ -6,6 +6,7 @@ package asynq
 
 import (
 	"encoding/json"
+	"fmt"
 	"testing"
 	"time"
 
@@ -645,3 +646,30 @@ func TestPayloadHas(t *testing.T) {
 		t.Errorf("Payload.Has(%q) = true, want false", "name")
 	}
 }
+
+func TestPayloadDebuggingStrings(t *testing.T) {
+	data := map[string]interface{}{
+		"foo": 123,
+		"bar": "hello",
+		"baz": false,
+	}
+	payload := Payload{data: data}
+
+	if payload.String() != fmt.Sprint(data) {
+		t.Errorf("Payload.String() = %q, want %q",
+			payload.String(), fmt.Sprint(data))
+	}
+
+	got, err := payload.MarshalJSON()
+	if err != nil {
+		t.Fatal(err)
+	}
+	want, err := json.Marshal(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if diff := cmp.Diff(got, want); diff != "" {
+		t.Errorf("Payload.MarhsalJSON() = %s, want %s; (-want,+got)\n%s",
+			got, want, diff)
+	}
+}

processor.go

@@ -6,9 +6,13 @@ package asynq
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"math/rand"
+	"runtime"
+	"runtime/debug"
 	"sort"
+	"strings"
 	"sync"
 	"time"
 
@@ -29,7 +33,7 @@ type processor struct {
 	// orderedQueues is set only in strict-priority mode.
 	orderedQueues []string
 
-	retryDelayFunc retryDelayFunc
+	retryDelayFunc RetryDelayFunc
 
 	errHandler ErrorHandler
 
@@ -63,12 +67,10 @@ type processor struct {
 	finished chan<- *base.TaskMessage
 }
 
-type retryDelayFunc func(n int, err error, task *Task) time.Duration
-
 type processorParams struct {
 	logger          *log.Logger
 	broker          base.Broker
-	retryDelayFunc  retryDelayFunc
+	retryDelayFunc  RetryDelayFunc
 	syncCh          chan<- *syncRequest
 	cancelations    *base.Cancelations
 	concurrency     int
@@ -88,22 +90,23 @@ func newProcessor(params processorParams) *processor {
 		orderedQueues = sortByPriority(queues)
 	}
 	return &processor{
-		logger:         params.logger,
-		broker:         params.broker,
-		queueConfig:    queues,
-		orderedQueues:  orderedQueues,
-		retryDelayFunc: params.retryDelayFunc,
-		syncRequestCh:  params.syncCh,
-		cancelations:   params.cancelations,
-		errLogLimiter:  rate.NewLimiter(rate.Every(3*time.Second), 1),
-		sema:           make(chan struct{}, params.concurrency),
-		done:           make(chan struct{}),
-		quit:           make(chan struct{}),
-		abort:          make(chan struct{}),
-		errHandler:     params.errHandler,
-		handler:        HandlerFunc(func(ctx context.Context, t *Task) error { return fmt.Errorf("handler not set") }),
-		starting:       params.starting,
-		finished:       params.finished,
+		logger:          params.logger,
+		broker:          params.broker,
+		queueConfig:     queues,
+		orderedQueues:   orderedQueues,
+		retryDelayFunc:  params.retryDelayFunc,
+		syncRequestCh:   params.syncCh,
+		cancelations:    params.cancelations,
+		errLogLimiter:   rate.NewLimiter(rate.Every(3*time.Second), 1),
+		sema:            make(chan struct{}, params.concurrency),
+		done:            make(chan struct{}),
+		quit:            make(chan struct{}),
+		abort:           make(chan struct{}),
+		errHandler:      params.errHandler,
+		handler:         HandlerFunc(func(ctx context.Context, t *Task) error { return fmt.Errorf("handler not set") }),
+		shutdownTimeout: params.shutdownTimeout,
+		starting:        params.starting,
+		finished:        params.finished,
 	}
 }
 
@@ -202,7 +205,7 @@ func (p *processor) exec() {
 
 			resCh := make(chan error, 1)
 			go func() {
-				resCh <- perform(ctx, NewTask(msg.Type, msg.Payload), p.handler)
+				resCh <- p.perform(ctx, NewTask(msg.Type, msg.Payload))
 			}()
 
 			select {
@@ -216,9 +219,9 @@ func (p *processor) exec() {
 				return
 			case resErr := <-resCh:
 				// Note: One of three things should happen.
-				// 1) Done  -> Removes the message from Active
-				// 2) Retry -> Removes the message from Active & Adds the message to Retry
-				// 3) Kill  -> Removes the message from Active & Adds the message to Dead
+				// 1) Done     -> Removes the message from Active
+				// 2) Retry    -> Removes the message from Active & Adds the message to Retry
+				// 3) Archive  -> Removes the message from Active & Adds the message to archive
 				if resErr != nil {
 					p.retryOrKill(ctx, msg, resErr)
 					return
@@ -257,13 +260,17 @@ func (p *processor) markAsDone(ctx context.Context, msg *base.TaskMessage) {
 	}
 }
 
+// SkipRetry is used as a return value from Handler.ProcessTask to indicate that
+// the task should not be retried and should be archived instead.
+var SkipRetry = errors.New("skip retry for the task")
+
 func (p *processor) retryOrKill(ctx context.Context, msg *base.TaskMessage, err error) {
 	if p.errHandler != nil {
 		p.errHandler.HandleError(ctx, NewTask(msg.Type, msg.Payload), err)
 	}
-	if msg.Retried >= msg.Retry {
+	if msg.Retried >= msg.Retry || errors.Is(err, SkipRetry) {
 		p.logger.Warnf("Retry exhausted for task id=%s", msg.ID)
-		p.kill(ctx, msg, err)
+		p.archive(ctx, msg, err)
 	} else {
 		p.retry(ctx, msg, err)
 	}
@@ -290,10 +297,10 @@ func (p *processor) retry(ctx context.Context, msg *base.TaskMessage, e error) {
 	}
 }
 
-func (p *processor) kill(ctx context.Context, msg *base.TaskMessage, e error) {
-	err := p.broker.Kill(msg, e.Error())
+func (p *processor) archive(ctx context.Context, msg *base.TaskMessage, e error) {
+	err := p.broker.Archive(msg, e.Error())
 	if err != nil {
-		errMsg := fmt.Sprintf("Could not move task id=%s from %q to %q", msg.ID, base.ActiveKey(msg.Queue), base.DeadKey(msg.Queue))
+		errMsg := fmt.Sprintf("Could not move task id=%s from %q to %q", msg.ID, base.ActiveKey(msg.Queue), base.ArchivedKey(msg.Queue))
 		deadline, ok := ctx.Deadline()
 		if !ok {
 			panic("asynq: internal error: missing deadline in context")
@@ -301,7 +308,7 @@ func (p *processor) kill(ctx context.Context, msg *base.TaskMessage, e error) {
 		p.logger.Warnf("%s; Will retry syncing", errMsg)
 		p.syncRequestCh <- &syncRequest{
 			fn: func() error {
-				return p.broker.Kill(msg, e.Error())
+				return p.broker.Archive(msg, e.Error())
 			},
 			errMsg:   errMsg,
 			deadline: deadline,
@@ -339,13 +346,26 @@ func (p *processor) queues() []string {
 // perform calls the handler with the given task.
 // If the call returns without panic, it simply returns the value,
 // otherwise, it recovers from panic and returns an error.
-func perform(ctx context.Context, task *Task, h Handler) (err error) {
+func (p *processor) perform(ctx context.Context, task *Task) (err error) {
 	defer func() {
 		if x := recover(); x != nil {
-			err = fmt.Errorf("panic: %v", x)
+			p.logger.Errorf("recovering from panic. See the stack trace below for details:\n%s", string(debug.Stack()))
+			_, file, line, ok := runtime.Caller(1) // skip the first frame (panic itself)
+			if ok && strings.Contains(file, "runtime/") {
+				// The panic came from the runtime, most likely due to incorrect
+				// map/slice usage. The parent frame should have the real trigger.
+				_, file, line, ok = runtime.Caller(2)
+			}
+
+			// Include the file and line number info in the error, if runtime.Caller returned ok.
+			if ok {
+				err = fmt.Errorf("panic [%s:%d]: %v", file, line, x)
+			} else {
+				err = fmt.Errorf("panic: %v", x)
+			}
 		}
 	}()
-	return h.ProcessTask(ctx, task)
+	return p.handler.ProcessTask(ctx, task)
 }
 
 // uniq dedupes elements and returns a slice of unique names of length l.

processor_test.go

@@ -96,7 +96,7 @@ func TestProcessorSuccessWithSingleQueue(t *testing.T) {
 		p := newProcessor(processorParams{
 			logger:          testLogger,
 			broker:          rdbClient,
-			retryDelayFunc:  defaultDelayFunc,
+			retryDelayFunc:  DefaultRetryDelayFunc,
 			syncCh:          syncCh,
 			cancelations:    base.NewCancelations(),
 			concurrency:     10,
@@ -187,7 +187,7 @@ func TestProcessorSuccessWithMultipleQueues(t *testing.T) {
 		p := newProcessor(processorParams{
 			logger:         testLogger,
 			broker:         rdbClient,
-			retryDelayFunc: defaultDelayFunc,
+			retryDelayFunc: DefaultRetryDelayFunc,
 			syncCh:         syncCh,
 			cancelations:   base.NewCancelations(),
 			concurrency:    10,
@@ -268,7 +268,7 @@ func TestProcessTasksWithLargeNumberInPayload(t *testing.T) {
 		p := newProcessor(processorParams{
 			logger:          testLogger,
 			broker:          rdbClient,
-			retryDelayFunc:  defaultDelayFunc,
+			retryDelayFunc:  DefaultRetryDelayFunc,
 			syncCh:          syncCh,
 			cancelations:    base.NewCancelations(),
 			concurrency:     10,
@@ -307,19 +307,22 @@ func TestProcessorRetry(t *testing.T) {
 	m4 := h.NewTaskMessage("sync", nil)
 
 	errMsg := "something went wrong"
+	wrappedSkipRetry := fmt.Errorf("%s:%w", errMsg, SkipRetry)
 	now := time.Now()
 
 	tests := []struct {
+		desc         string              // test description
 		pending      []*base.TaskMessage // initial default queue state
 		incoming     []*base.TaskMessage // tasks to be enqueued during run
 		delay        time.Duration       // retry delay duration
 		handler      Handler             // task handler
 		wait         time.Duration       // wait duration between starting and stopping processor for this test case
 		wantRetry    []base.Z            // tasks in retry queue at the end
-		wantDead     []*base.TaskMessage // tasks in dead queue at the end
+		wantArchived []*base.TaskMessage // tasks in archived queue at the end
 		wantErrCount int                 // number of times error handler should be called
 	}{
 		{
+			desc:     "Should automatically retry errored tasks",
 			pending:  []*base.TaskMessage{m1, m2},
 			incoming: []*base.TaskMessage{m3, m4},
 			delay:    time.Minute,
@@ -332,9 +335,41 @@ func TestProcessorRetry(t *testing.T) {
 				{Message: h.TaskMessageAfterRetry(*m3, errMsg), Score: now.Add(time.Minute).Unix()},
 				{Message: h.TaskMessageAfterRetry(*m4, errMsg), Score: now.Add(time.Minute).Unix()},
 			},
-			wantDead:     []*base.TaskMessage{h.TaskMessageWithError(*m1, errMsg)},
+			wantArchived: []*base.TaskMessage{h.TaskMessageWithError(*m1, errMsg)},
 			wantErrCount: 4,
 		},
+		{
+			desc:     "Should skip retry errored tasks",
+			pending:  []*base.TaskMessage{m1, m2},
+			incoming: []*base.TaskMessage{},
+			delay:    time.Minute,
+			handler: HandlerFunc(func(ctx context.Context, task *Task) error {
+				return SkipRetry // return SkipRetry without wrapping
+			}),
+			wait:      2 * time.Second,
+			wantRetry: []base.Z{},
+			wantArchived: []*base.TaskMessage{
+				h.TaskMessageWithError(*m1, SkipRetry.Error()),
+				h.TaskMessageWithError(*m2, SkipRetry.Error()),
+			},
+			wantErrCount: 2, // ErrorHandler should still be called with SkipRetry error
+		},
+		{
+			desc:     "Should skip retry errored tasks (with error wrapping)",
+			pending:  []*base.TaskMessage{m1, m2},
+			incoming: []*base.TaskMessage{},
+			delay:    time.Minute,
+			handler: HandlerFunc(func(ctx context.Context, task *Task) error {
+				return wrappedSkipRetry
+			}),
+			wait:      2 * time.Second,
+			wantRetry: []base.Z{},
+			wantArchived: []*base.TaskMessage{
+				h.TaskMessageWithError(*m1, wrappedSkipRetry.Error()),
+				h.TaskMessageWithError(*m2, wrappedSkipRetry.Error()),
+			},
+			wantErrCount: 2, // ErrorHandler should still be called with SkipRetry error
+		},
 	}
 
 	for _, tc := range tests {
@@ -389,16 +424,16 @@ func TestProcessorRetry(t *testing.T) {
 		cmpOpt := h.EquateInt64Approx(1) // allow up to a second difference in zset score
 		gotRetry := h.GetRetryEntries(t, r, base.DefaultQueueName)
 		if diff := cmp.Diff(tc.wantRetry, gotRetry, h.SortZSetEntryOpt, cmpOpt); diff != "" {
-			t.Errorf("mismatch found in %q after running processor; (-want, +got)\n%s", base.RetryKey(base.DefaultQueueName), diff)
+			t.Errorf("%s: mismatch found in %q after running processor; (-want, +got)\n%s", tc.desc, base.RetryKey(base.DefaultQueueName), diff)
 		}
 
-		gotDead := h.GetDeadMessages(t, r, base.DefaultQueueName)
-		if diff := cmp.Diff(tc.wantDead, gotDead, h.SortMsgOpt); diff != "" {
-			t.Errorf("mismatch found in %q after running processor; (-want, +got)\n%s", base.DeadKey(base.DefaultQueueName), diff)
+		gotDead := h.GetArchivedMessages(t, r, base.DefaultQueueName)
+		if diff := cmp.Diff(tc.wantArchived, gotDead, h.SortMsgOpt); diff != "" {
+			t.Errorf("%s: mismatch found in %q after running processor; (-want, +got)\n%s", tc.desc, base.ArchivedKey(base.DefaultQueueName), diff)
 		}
 
 		if l := r.LLen(base.ActiveKey(base.DefaultQueueName)).Val(); l != 0 {
-			t.Errorf("%q has %d tasks, want 0", base.ActiveKey(base.DefaultQueueName), l)
+			t.Errorf("%s: %q has %d tasks, want 0", base.ActiveKey(base.DefaultQueueName), tc.desc, l)
 		}
 
 		if n != tc.wantErrCount {
@@ -443,7 +478,7 @@ func TestProcessorQueues(t *testing.T) {
 		p := newProcessor(processorParams{
 			logger:          testLogger,
 			broker:          nil,
-			retryDelayFunc:  defaultDelayFunc,
+			retryDelayFunc:  DefaultRetryDelayFunc,
 			syncCh:          nil,
 			cancelations:    base.NewCancelations(),
 			concurrency:     10,
@@ -534,7 +569,7 @@ func TestProcessorWithStrictPriority(t *testing.T) {
 		p := newProcessor(processorParams{
 			logger:          testLogger,
 			broker:          rdbClient,
-			retryDelayFunc:  defaultDelayFunc,
+			retryDelayFunc:  DefaultRetryDelayFunc,
 			syncCh:          syncCh,
 			cancelations:    base.NewCancelations(),
 			concurrency:     1, // Set concurrency to 1 to make sure tasks are processed one at a time.
@@ -564,7 +599,7 @@ func TestProcessorWithStrictPriority(t *testing.T) {
 	}
 }
 
-func TestPerform(t *testing.T) {
+func TestProcessorPerform(t *testing.T) {
 	tests := []struct {
 		desc    string
 		handler HandlerFunc
@@ -596,9 +631,16 @@ func TestPerform(t *testing.T) {
 			wantErr: true,
 		},
 	}
+	// Note: We don't need to fully initialize the processor since we are only testing
+	// perform method.
+	p := newProcessor(processorParams{
+		logger: testLogger,
+		queues: defaultQueueConfig,
+	})
 
 	for _, tc := range tests {
-		got := perform(context.Background(), tc.task, tc.handler)
+		p.handler = tc.handler
+		got := p.perform(context.Background(), tc.task)
 		if !tc.wantErr && got != nil {
 			t.Errorf("%s: perform() = %v, want nil", tc.desc, got)
 			continue

recoverer.go

@@ -16,7 +16,7 @@ import (
 type recoverer struct {
 	logger         *log.Logger
 	broker         base.Broker
-	retryDelayFunc retryDelayFunc
+	retryDelayFunc RetryDelayFunc
 
 	// channel to communicate back to the long running "recoverer" goroutine.
 	done chan struct{}
@@ -33,7 +33,7 @@ type recovererParams struct {
 	broker         base.Broker
 	queues         []string
 	interval       time.Duration
-	retryDelayFunc retryDelayFunc
+	retryDelayFunc RetryDelayFunc
 }
 
 func newRecoverer(params recovererParams) *recoverer {
@@ -75,7 +75,7 @@ func (r *recoverer) start(wg *sync.WaitGroup) {
 				const errMsg = "deadline exceeded" // TODO: better error message
 				for _, msg := range msgs {
 					if msg.Retried >= msg.Retry {
-						r.kill(msg, errMsg)
+						r.archive(msg, errMsg)
 					} else {
 						r.retry(msg, errMsg)
 					}
@@ -94,8 +94,8 @@ func (r *recoverer) retry(msg *base.TaskMessage, errMsg string) {
 	}
 }
 
-func (r *recoverer) kill(msg *base.TaskMessage, errMsg string) {
-	if err := r.broker.Kill(msg, errMsg); err != nil {
-		r.logger.Warnf("recoverer: could not move task to dead queue: %v", err)
+func (r *recoverer) archive(msg *base.TaskMessage, errMsg string) {
+	if err := r.broker.Archive(msg, errMsg); err != nil {
+		r.logger.Warnf("recoverer: could not move task to archive: %v", err)
 	}
 }

recoverer_test.go

@@ -37,11 +37,11 @@ func TestRecoverer(t *testing.T) {
 		inProgress    map[string][]*base.TaskMessage
 		deadlines     map[string][]base.Z
 		retry         map[string][]base.Z
-		dead          map[string][]base.Z
+		archived      map[string][]base.Z
 		wantActive    map[string][]*base.TaskMessage
 		wantDeadlines map[string][]base.Z
 		wantRetry     map[string][]*base.TaskMessage
-		wantDead      map[string][]*base.TaskMessage
+		wantArchived  map[string][]*base.TaskMessage
 	}{
 		{
 			desc: "with one active task",
@@ -54,7 +54,7 @@ func TestRecoverer(t *testing.T) {
 			retry: map[string][]base.Z{
 				"default": {},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default": {},
 			},
 			wantActive: map[string][]*base.TaskMessage{
@@ -66,7 +66,7 @@ func TestRecoverer(t *testing.T) {
 			wantRetry: map[string][]*base.TaskMessage{
 				"default": {h.TaskMessageAfterRetry(*t1, "deadline exceeded")},
 			},
-			wantDead: map[string][]*base.TaskMessage{
+			wantArchived: map[string][]*base.TaskMessage{
 				"default": {},
 			},
 		},
@@ -84,7 +84,7 @@ func TestRecoverer(t *testing.T) {
 				"default":  {},
 				"critical": {},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default":  {},
 				"critical": {},
 			},
@@ -100,7 +100,7 @@ func TestRecoverer(t *testing.T) {
 				"default":  {},
 				"critical": {},
 			},
-			wantDead: map[string][]*base.TaskMessage{
+			wantArchived: map[string][]*base.TaskMessage{
 				"default":  {h.TaskMessageWithError(*t4, "deadline exceeded")},
 				"critical": {},
 			},
@@ -124,7 +124,7 @@ func TestRecoverer(t *testing.T) {
 				"default":  {},
 				"critical": {},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default":  {},
 				"critical": {},
 			},
@@ -140,7 +140,7 @@ func TestRecoverer(t *testing.T) {
 				"default":  {h.TaskMessageAfterRetry(*t1, "deadline exceeded")},
 				"critical": {},
 			},
-			wantDead: map[string][]*base.TaskMessage{
+			wantArchived: map[string][]*base.TaskMessage{
 				"default":  {},
 				"critical": {},
 			},
@@ -164,7 +164,7 @@ func TestRecoverer(t *testing.T) {
 				"default": {},
 				"cricial": {},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default": {},
 				"cricial": {},
 			},
@@ -179,7 +179,7 @@ func TestRecoverer(t *testing.T) {
 				"default":  {h.TaskMessageAfterRetry(*t1, "deadline exceeded")},
 				"critical": {h.TaskMessageAfterRetry(*t3, "deadline exceeded")},
 			},
-			wantDead: map[string][]*base.TaskMessage{
+			wantArchived: map[string][]*base.TaskMessage{
 				"default":  {},
 				"critical": {},
 			},
@@ -198,7 +198,7 @@ func TestRecoverer(t *testing.T) {
 				"default":  {},
 				"critical": {},
 			},
-			dead: map[string][]base.Z{
+			archived: map[string][]base.Z{
 				"default":  {},
 				"critical": {},
 			},
@@ -214,7 +214,7 @@ func TestRecoverer(t *testing.T) {
 				"default":  {},
 				"critical": {},
 			},
-			wantDead: map[string][]*base.TaskMessage{
+			wantArchived: map[string][]*base.TaskMessage{
 				"default":  {},
 				"critical": {},
 			},
@@ -226,7 +226,7 @@ func TestRecoverer(t *testing.T) {
 		h.SeedAllActiveQueues(t, r, tc.inProgress)
 		h.SeedAllDeadlines(t, r, tc.deadlines)
 		h.SeedAllRetryQueues(t, r, tc.retry)
-		h.SeedAllDeadQueues(t, r, tc.dead)
+		h.SeedAllArchivedQueues(t, r, tc.archived)
 
 		recoverer := newRecoverer(recovererParams{
 			logger:         testLogger,
@@ -259,10 +259,10 @@ func TestRecoverer(t *testing.T) {
 				t.Errorf("%s; mismatch found in %q: (-want, +got)\n%s", tc.desc, base.RetryKey(qname), diff)
 			}
 		}
-		for qname, want := range tc.wantDead {
-			gotDead := h.GetDeadMessages(t, r, qname)
+		for qname, want := range tc.wantArchived {
+			gotDead := h.GetArchivedMessages(t, r, qname)
 			if diff := cmp.Diff(want, gotDead, h.SortMsgOpt); diff != "" {
-				t.Errorf("%s; mismatch found in %q: (-want, +got)\n%s", tc.desc, base.DeadKey(qname), diff)
+				t.Errorf("%s; mismatch found in %q: (-want, +got)\n%s", tc.desc, base.ArchivedKey(qname), diff)
 			}
 		}
 	}

scheduler.go

@@ -5,69 +5,235 @@
 package asynq
 
 import (
+	"fmt"
+	"os"
 	"sync"
 	"time"
 
+	"github.com/google/uuid"
 	"github.com/hibiken/asynq/internal/base"
 	"github.com/hibiken/asynq/internal/log"
+	"github.com/hibiken/asynq/internal/rdb"
+	"github.com/robfig/cron/v3"
 )
 
-type scheduler struct {
-	logger *log.Logger
-	broker base.Broker
-
-	// channel to communicate back to the long running "scheduler" goroutine.
-	done chan struct{}
-
-	// list of queue names to check and enqueue.
-	queues []string
-
-	// poll interval on average
-	avgInterval time.Duration
+// A Scheduler kicks off tasks at regular intervals based on the user defined schedule.
+type Scheduler struct {
+	id         string
+	status     *base.ServerStatus
+	logger     *log.Logger
+	client     *Client
+	rdb        *rdb.RDB
+	cron       *cron.Cron
+	location   *time.Location
+	done       chan struct{}
+	wg         sync.WaitGroup
+	errHandler func(task *Task, opts []Option, err error)
 }
 
-type schedulerParams struct {
-	logger   *log.Logger
-	broker   base.Broker
-	queues   []string
-	interval time.Duration
-}
+// NewScheduler returns a new Scheduler instance given the redis connection option.
+// The parameter opts is optional, defaults will be used if opts is set to nil
+func NewScheduler(r RedisConnOpt, opts *SchedulerOpts) *Scheduler {
+	if opts == nil {
+		opts = &SchedulerOpts{}
+	}
 
-func newScheduler(params schedulerParams) *scheduler {
-	return &scheduler{
-		logger:      params.logger,
-		broker:      params.broker,
-		done:        make(chan struct{}),
-		queues:      params.queues,
-		avgInterval: params.interval,
+	logger := log.NewLogger(opts.Logger)
+	loglevel := opts.LogLevel
+	if loglevel == level_unspecified {
+		loglevel = InfoLevel
+	}
+	logger.SetLevel(toInternalLogLevel(loglevel))
+
+	loc := opts.Location
+	if loc == nil {
+		loc = time.UTC
+	}
+
+	return &Scheduler{
+		id:         generateSchedulerID(),
+		status:     base.NewServerStatus(base.StatusIdle),
+		logger:     logger,
+		client:     NewClient(r),
+		rdb:        rdb.NewRDB(createRedisClient(r)),
+		cron:       cron.New(cron.WithLocation(loc)),
+		location:   loc,
+		done:       make(chan struct{}),
+		errHandler: opts.EnqueueErrorHandler,
 	}
 }
 
-func (s *scheduler) terminate() {
-	s.logger.Debug("Scheduler shutting down...")
-	// Signal the scheduler goroutine to stop polling.
-	s.done <- struct{}{}
+func generateSchedulerID() string {
+	host, err := os.Hostname()
+	if err != nil {
+		host = "unknown-host"
+	}
+	return fmt.Sprintf("%s:%d:%v", host, os.Getpid(), uuid.New())
 }
 
-// start starts the "scheduler" goroutine.
-func (s *scheduler) start(wg *sync.WaitGroup) {
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
-		for {
-			select {
-			case <-s.done:
-				s.logger.Debug("Scheduler done")
-				return
-			case <-time.After(s.avgInterval):
-				s.exec()
-			}
+// SchedulerOpts specifies scheduler options.
+type SchedulerOpts struct {
+	// Logger specifies the logger used by the scheduler instance.
+	//
+	// If unset, the default logger is used.
+	Logger Logger
+
+	// LogLevel specifies the minimum log level to enable.
+	//
+	// If unset, InfoLevel is used by default.
+	LogLevel LogLevel
+
+	// Location specifies the time zone location.
+	//
+	// If unset, the UTC time zone (time.UTC) is used.
+	Location *time.Location
+
+	// EnqueueErrorHandler gets called when scheduler cannot enqueue a registered task
+	// due to an error.
+	EnqueueErrorHandler func(task *Task, opts []Option, err error)
+}
+
+// enqueueJob encapsulates the job of enqueing a task and recording the event.
+type enqueueJob struct {
+	id         uuid.UUID
+	cronspec   string
+	task       *Task
+	opts       []Option
+	location   *time.Location
+	logger     *log.Logger
+	client     *Client
+	rdb        *rdb.RDB
+	errHandler func(task *Task, opts []Option, err error)
+}
+
+func (j *enqueueJob) Run() {
+	res, err := j.client.Enqueue(j.task, j.opts...)
+	if err != nil {
+		j.logger.Errorf("scheduler could not enqueue a task %+v: %v", j.task, err)
+		if j.errHandler != nil {
+			j.errHandler(j.task, j.opts, err)
 		}
-	}()
-}
-
-func (s *scheduler) exec() {
-	if err := s.broker.CheckAndEnqueue(s.queues...); err != nil {
-		s.logger.Errorf("Could not enqueue scheduled tasks: %v", err)
+		return
+	}
+	j.logger.Debugf("scheduler enqueued a task: %+v", res)
+	event := &base.SchedulerEnqueueEvent{
+		TaskID:     res.ID,
+		EnqueuedAt: res.EnqueuedAt.In(j.location),
+	}
+	err = j.rdb.RecordSchedulerEnqueueEvent(j.id.String(), event)
+	if err != nil {
+		j.logger.Errorf("scheduler could not record enqueue event of enqueued task %+v: %v", j.task, err)
 	}
 }
+
+// Register registers a task to be enqueued on the given schedule specified by the cronspec.
+// It returns an ID of the newly registered entry.
+func (s *Scheduler) Register(cronspec string, task *Task, opts ...Option) (entryID string, err error) {
+	job := &enqueueJob{
+		id:         uuid.New(),
+		cronspec:   cronspec,
+		task:       task,
+		opts:       opts,
+		location:   s.location,
+		client:     s.client,
+		rdb:        s.rdb,
+		logger:     s.logger,
+		errHandler: s.errHandler,
+	}
+	if _, err = s.cron.AddJob(cronspec, job); err != nil {
+		return "", err
+	}
+	return job.id.String(), nil
+}
+
+// Run starts the scheduler until an os signal to exit the program is received.
+// It returns an error if scheduler is already running or has been stopped.
+func (s *Scheduler) Run() error {
+	if err := s.Start(); err != nil {
+		return err
+	}
+	s.waitForSignals()
+	return s.Stop()
+}
+
+// Start starts the scheduler.
+// It returns an error if the scheduler is already running or has been stopped.
+func (s *Scheduler) Start() error {
+	switch s.status.Get() {
+	case base.StatusRunning:
+		return fmt.Errorf("asynq: the scheduler is already running")
+	case base.StatusStopped:
+		return fmt.Errorf("asynq: the scheduler has already been stopped")
+	}
+	s.logger.Info("Scheduler starting")
+	s.logger.Infof("Scheduler timezone is set to %v", s.location)
+	s.cron.Start()
+	s.wg.Add(1)
+	go s.runHeartbeater()
+	s.status.Set(base.StatusRunning)
+	return nil
+}
+
+// Stop stops the scheduler.
+// It returns an error if the scheduler is not currently running.
+func (s *Scheduler) Stop() error {
+	if s.status.Get() != base.StatusRunning {
+		return fmt.Errorf("asynq: the scheduler is not running")
+	}
+	s.logger.Info("Scheduler shutting down")
+	close(s.done) // signal heartbeater to stop
+	ctx := s.cron.Stop()
+	<-ctx.Done()
+	s.wg.Wait()
+
+	s.client.Close()
+	s.rdb.Close()
+	s.status.Set(base.StatusStopped)
+	s.logger.Info("Scheduler stopped")
+	return nil
+}
+
+func (s *Scheduler) runHeartbeater() {
+	defer s.wg.Done()
+	ticker := time.NewTicker(5 * time.Second)
+	for {
+		select {
+		case <-s.done:
+			s.logger.Debugf("Scheduler heatbeater shutting down")
+			s.rdb.ClearSchedulerEntries(s.id)
+			return
+		case <-ticker.C:
+			s.beat()
+		}
+	}
+}
+
+// beat writes a snapshot of entries to redis.
+func (s *Scheduler) beat() {
+	var entries []*base.SchedulerEntry
+	for _, entry := range s.cron.Entries() {
+		job := entry.Job.(*enqueueJob)
+		e := &base.SchedulerEntry{
+			ID:      job.id.String(),
+			Spec:    job.cronspec,
+			Type:    job.task.Type,
+			Payload: job.task.Payload.data,
+			Opts:    stringifyOptions(job.opts),
+			Next:    entry.Next,
+			Prev:    entry.Prev,
+		}
+		entries = append(entries, e)
+	}
+	s.logger.Debugf("Writing entries %v", entries)
+	if err := s.rdb.WriteSchedulerEntries(s.id, entries, 5*time.Second); err != nil {
+		s.logger.Warnf("Scheduler could not write heartbeat data: %v", err)
+	}
+}
+
+func stringifyOptions(opts []Option) []string {
+	var res []string
+	for _, opt := range opts {
+		res = append(res, opt.String())
+	}
+	return res
+}

scheduler_test.go

@@ -10,128 +10,109 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
-	h "github.com/hibiken/asynq/internal/asynqtest"
+	"github.com/hibiken/asynq/internal/asynqtest"
 	"github.com/hibiken/asynq/internal/base"
-	"github.com/hibiken/asynq/internal/rdb"
 )
 
 func TestScheduler(t *testing.T) {
-	r := setup(t)
-	defer r.Close()
-	rdbClient := rdb.NewRDB(r)
-	const pollInterval = time.Second
-	s := newScheduler(schedulerParams{
-		logger:   testLogger,
-		broker:   rdbClient,
-		queues:   []string{"default", "critical"},
-		interval: pollInterval,
-	})
-	t1 := h.NewTaskMessageWithQueue("gen_thumbnail", nil, "default")
-	t2 := h.NewTaskMessageWithQueue("send_email", nil, "critical")
-	t3 := h.NewTaskMessageWithQueue("reindex", nil, "default")
-	t4 := h.NewTaskMessageWithQueue("sync", nil, "critical")
-	now := time.Now()
-
 	tests := []struct {
-		initScheduled map[string][]base.Z            // scheduled queue initial state
-		initRetry     map[string][]base.Z            // retry queue initial state
-		initPending   map[string][]*base.TaskMessage // default queue initial state
-		wait          time.Duration                  // wait duration before checking for final state
-		wantScheduled map[string][]*base.TaskMessage // schedule queue final state
-		wantRetry     map[string][]*base.TaskMessage // retry queue final state
-		wantPending   map[string][]*base.TaskMessage // default queue final state
+		cronspec string
+		task     *Task
+		opts     []Option
+		wait     time.Duration
+		queue    string
+		want     []*base.TaskMessage
 	}{
 		{
-			initScheduled: map[string][]base.Z{
-				"default":  {{Message: t1, Score: now.Add(time.Hour).Unix()}},
-				"critical": {{Message: t2, Score: now.Add(-2 * time.Second).Unix()}},
-			},
-			initRetry: map[string][]base.Z{
-				"default":  {{Message: t3, Score: time.Now().Add(-500 * time.Millisecond).Unix()}},
-				"critical": {},
-			},
-			initPending: map[string][]*base.TaskMessage{
-				"default":  {},
-				"critical": {t4},
-			},
-			wait: pollInterval * 2,
-			wantScheduled: map[string][]*base.TaskMessage{
-				"default":  {t1},
-				"critical": {},
-			},
-			wantRetry: map[string][]*base.TaskMessage{
-				"default":  {},
-				"critical": {},
-			},
-			wantPending: map[string][]*base.TaskMessage{
-				"default":  {t3},
-				"critical": {t2, t4},
-			},
-		},
-		{
-			initScheduled: map[string][]base.Z{
-				"default": {
-					{Message: t1, Score: now.Unix()},
-					{Message: t3, Score: now.Add(-500 * time.Millisecond).Unix()},
+			cronspec: "@every 3s",
+			task:     NewTask("task1", nil),
+			opts:     []Option{MaxRetry(10)},
+			wait:     10 * time.Second,
+			queue:    "default",
+			want: []*base.TaskMessage{
+				{
+					Type:    "task1",
+					Payload: nil,
+					Retry:   10,
+					Timeout: int64(defaultTimeout.Seconds()),
+					Queue:   "default",
 				},
-				"critical": {
-					{Message: t2, Score: now.Add(-2 * time.Second).Unix()},
+				{
+					Type:    "task1",
+					Payload: nil,
+					Retry:   10,
+					Timeout: int64(defaultTimeout.Seconds()),
+					Queue:   "default",
+				},
+				{
+					Type:    "task1",
+					Payload: nil,
+					Retry:   10,
+					Timeout: int64(defaultTimeout.Seconds()),
+					Queue:   "default",
 				},
-			},
-			initRetry: map[string][]base.Z{
-				"default":  {},
-				"critical": {},
-			},
-			initPending: map[string][]*base.TaskMessage{
-				"default":  {},
-				"critical": {t4},
-			},
-			wait: pollInterval * 2,
-			wantScheduled: map[string][]*base.TaskMessage{
-				"default":  {},
-				"critical": {},
-			},
-			wantRetry: map[string][]*base.TaskMessage{
-				"default":  {},
-				"critical": {},
-			},
-			wantPending: map[string][]*base.TaskMessage{
-				"default":  {t1, t3},
-				"critical": {t2, t4},
 			},
 		},
 	}
 
+	r := setup(t)
+
 	for _, tc := range tests {
-		h.FlushDB(t, r)                                  // clean up db before each test case.
-		h.SeedAllScheduledQueues(t, r, tc.initScheduled) // initialize scheduled queue
-		h.SeedAllRetryQueues(t, r, tc.initRetry)         // initialize retry queue
-		h.SeedAllPendingQueues(t, r, tc.initPending)     // initialize default queue
+		scheduler := NewScheduler(getRedisConnOpt(t), nil)
+		if _, err := scheduler.Register(tc.cronspec, tc.task, tc.opts...); err != nil {
+			t.Fatal(err)
+		}
 
-		var wg sync.WaitGroup
-		s.start(&wg)
+		if err := scheduler.Start(); err != nil {
+			t.Fatal(err)
+		}
 		time.Sleep(tc.wait)
-		s.terminate()
-
-		for qname, want := range tc.wantScheduled {
-			gotScheduled := h.GetScheduledMessages(t, r, qname)
-			if diff := cmp.Diff(want, gotScheduled, h.SortMsgOpt); diff != "" {
-				t.Errorf("mismatch found in %q after running scheduler: (-want, +got)\n%s", base.ScheduledKey(qname), diff)
-			}
+		if err := scheduler.Stop(); err != nil {
+			t.Fatal(err)
 		}
 
-		for qname, want := range tc.wantRetry {
-			gotRetry := h.GetRetryMessages(t, r, qname)
-			if diff := cmp.Diff(want, gotRetry, h.SortMsgOpt); diff != "" {
-				t.Errorf("mismatch found in %q after running scheduler: (-want, +got)\n%s", base.RetryKey(qname), diff)
-			}
-		}
-
-		for qname, want := range tc.wantPending {
-			gotPending := h.GetPendingMessages(t, r, qname)
-			if diff := cmp.Diff(want, gotPending, h.SortMsgOpt); diff != "" {
-				t.Errorf("mismatch found in %q after running scheduler: (-want, +got)\n%s", base.QueueKey(qname), diff)
-			}
+		got := asynqtest.GetPendingMessages(t, r, tc.queue)
+		if diff := cmp.Diff(tc.want, got, asynqtest.IgnoreIDOpt); diff != "" {
+			t.Errorf("mismatch found in queue %q: (-want,+got)\n%s", tc.queue, diff)
 		}
 	}
 }
+
+func TestSchedulerWhenRedisDown(t *testing.T) {
+	var (
+		mu      sync.Mutex
+		counter int
+	)
+	errorHandler := func(task *Task, opts []Option, err error) {
+		mu.Lock()
+		counter++
+		mu.Unlock()
+	}
+
+	// Connect to non-existent redis instance to simulate a redis server being down.
+	scheduler := NewScheduler(
+		RedisClientOpt{Addr: ":9876"},
+		&SchedulerOpts{EnqueueErrorHandler: errorHandler},
+	)
+
+	task := NewTask("test", nil)
+
+	if _, err := scheduler.Register("@every 3s", task); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := scheduler.Start(); err != nil {
+		t.Fatal(err)
+	}
+	// Scheduler should attempt to enqueue the task three times (every 3s).
+	time.Sleep(10 * time.Second)
+	if err := scheduler.Stop(); err != nil {
+		t.Fatal(err)
+	}
+
+	mu.Lock()
+	if counter != 3 {
+		t.Errorf("EnqueueErrorHandler was called %d times, want 3", counter)
+	}
+	mu.Unlock()
+}

server.go

@@ -20,18 +20,17 @@ import (
 	"github.com/hibiken/asynq/internal/rdb"
 )
 
-// Server is responsible for managing the background-task processing.
+// Server is responsible for managing the task processing.
 //
 // Server pulls tasks off queues and processes them.
-// If the processing of a task is unsuccessful, server will
-// schedule it for a retry.
+// If the processing of a task is unsuccessful, server will schedule it for a retry.
 // A task will be retried until either the task gets processed successfully
 // or until it reaches its max retry count.
 //
-// If a task exhausts its retries, it will be moved to the "dead" queue and
-// will be kept in the queue for some time until a certain condition is met
-// (e.g., queue size reaches a certain limit, or the task has been in the
-// queue for a certain amount of time).
+// If a task exhausts its retries, it will be moved to the archive and
+// will be kept in the archive for some time until a certain condition is met
+// (e.g., archive size reaches a certain limit, or the task has been in the
+// archive for a certain amount of time).
 type Server struct {
 	logger *log.Logger
 
@@ -41,7 +40,7 @@ type Server struct {
 
 	// wait group to wait for all goroutines to finish.
 	wg            sync.WaitGroup
-	scheduler     *scheduler
+	forwarder     *forwarder
 	processor     *processor
 	syncer        *syncer
 	heartbeater   *heartbeater
@@ -61,11 +60,7 @@ type Config struct {
 	// Function to calculate retry delay for a failed task.
 	//
 	// By default, it uses exponential backoff algorithm to calculate the delay.
-	//
-	// n is the number of times the task has been retried.
-	// e is the error returned by the task handler.
-	// t is the task in question.
-	RetryDelayFunc func(n int, e error, t *Task) time.Duration
+	RetryDelayFunc RetryDelayFunc
 
 	// List of queues to process with given priority value. Keys are the names of the
 	// queues and values are associated priority value.
@@ -75,11 +70,13 @@ type Config struct {
 	// Priority is treated as follows to avoid starving low priority queues.
 	//
 	// Example:
-	// Queues: map[string]int{
-	//     "critical": 6,
-	//     "default":  3,
-	//     "low":      1,
-	// }
+	//
+	//     Queues: map[string]int{
+	//         "critical": 6,
+	//         "default":  3,
+	//         "low":      1,
+	//     }
+	//
 	// With the above config and given that all queues are not empty, the tasks
 	// in "critical", "default", "low" should be processed 60%, 30%, 10% of
 	// the time respectively.
@@ -99,14 +96,17 @@ type Config struct {
 	// HandleError is invoked only if the task handler returns a non-nil error.
 	//
 	// Example:
-	// func reportError(task *asynq.Task, err error, retried, maxRetry int) {
-	// 	   if retried >= maxRetry {
-	//         err = fmt.Errorf("retry exhausted for task %s: %w", task.Type, err)
-	// 	   }
-	//     errorReportingService.Notify(err)
-	// })
 	//
-	// ErrorHandler: asynq.ErrorHandlerFunc(reportError)
+	//     func reportError(ctx context, task *asynq.Task, err error) {
+	//         retried, _ := asynq.GetRetryCount(ctx)
+	//         maxRetry, _ := asynq.GetMaxRetry(ctx)
+	//     	   if retried >= maxRetry {
+	//             err = fmt.Errorf("retry exhausted for task %s: %w", task.Type, err)
+	//     	   }
+	//         errorReportingService.Notify(err)
+	//     })
+	//
+	//     ErrorHandler: asynq.ErrorHandlerFunc(reportError)
 	ErrorHandler ErrorHandler
 
 	// Logger specifies the logger used by the server instance.
@@ -149,6 +149,14 @@ func (fn ErrorHandlerFunc) HandleError(ctx context.Context, task *Task, err erro
 	fn(ctx, task, err)
 }
 
+// RetryDelayFunc calculates the retry delay duration for a failed task given
+// the retry count, error, and the task.
+//
+// n is the number of times the task has been retried.
+// e is the error returned by the task handler.
+// t is the task in question.
+type RetryDelayFunc func(n int, e error, t *Task) time.Duration
+
 // Logger supports logging at various log levels.
 type Logger interface {
 	// Debug logs a message at Debug level.
@@ -249,9 +257,11 @@ func toInternalLogLevel(l LogLevel) log.Level {
 	panic(fmt.Sprintf("asynq: unexpected log level: %v", l))
 }
 
-// Formula taken from https://github.com/mperham/sidekiq.
-func defaultDelayFunc(n int, e error, t *Task) time.Duration {
+// DefaultRetryDelayFunc is the default RetryDelayFunc used if one is not specified in Config.
+// It uses exponential back-off strategy to calculate the retry delay.
+func DefaultRetryDelayFunc(n int, e error, t *Task) time.Duration {
 	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	// Formula taken from https://github.com/mperham/sidekiq.
 	s := int(math.Pow(float64(n), 4)) + 15 + (r.Intn(30) * (n + 1))
 	return time.Duration(s) * time.Second
 }
@@ -275,7 +285,7 @@ func NewServer(r RedisConnOpt, cfg Config) *Server {
 	}
 	delayFunc := cfg.RetryDelayFunc
 	if delayFunc == nil {
-		delayFunc = defaultDelayFunc
+		delayFunc = DefaultRetryDelayFunc
 	}
 	queues := make(map[string]int)
 	for qname, p := range cfg.Queues {
@@ -287,7 +297,7 @@ func NewServer(r RedisConnOpt, cfg Config) *Server {
 		queues = defaultQueueConfig
 	}
 	var qnames []string
-	for q, _ := range queues {
+	for q := range queues {
 		qnames = append(qnames, q)
 	}
 	shutdownTimeout := cfg.ShutdownTimeout
@@ -328,7 +338,7 @@ func NewServer(r RedisConnOpt, cfg Config) *Server {
 		starting:       starting,
 		finished:       finished,
 	})
-	scheduler := newScheduler(schedulerParams{
+	forwarder := newForwarder(forwarderParams{
 		logger:   logger,
 		broker:   rdb,
 		queues:   qnames,
@@ -370,7 +380,7 @@ func NewServer(r RedisConnOpt, cfg Config) *Server {
 		logger:        logger,
 		broker:        rdb,
 		status:        status,
-		scheduler:     scheduler,
+		forwarder:     forwarder,
 		processor:     processor,
 		syncer:        syncer,
 		heartbeater:   heartbeater,
@@ -387,6 +397,9 @@ func NewServer(r RedisConnOpt, cfg Config) *Server {
 //
 // If ProcessTask return a non-nil error or panics, the task
 // will be retried after delay.
+// One exception to this rule is when ProcessTask returns SkipRetry error.
+// If the returned error is SkipRetry or the error wraps SkipRetry, retry is
+// skipped and task will be archived instead.
 type Handler interface {
 	ProcessTask(context.Context, *Task) error
 }
@@ -448,7 +461,7 @@ func (srv *Server) Start(handler Handler) error {
 	srv.subscriber.start(&srv.wg)
 	srv.syncer.start(&srv.wg)
 	srv.recoverer.start(&srv.wg)
-	srv.scheduler.start(&srv.wg)
+	srv.forwarder.start(&srv.wg)
 	srv.processor.start(&srv.wg)
 	return nil
 }
@@ -469,7 +482,7 @@ func (srv *Server) Stop() {
 	// Sender goroutines should be terminated before the receiver goroutines.
 	// processor -> syncer (via syncCh)
 	// processor -> heartbeater (via starting, finished channels)
-	srv.scheduler.terminate()
+	srv.forwarder.terminate()
 	srv.processor.terminate()
 	srv.recoverer.terminate()
 	srv.syncer.terminate()

server_test.go

@@ -127,7 +127,7 @@ func TestServerWithRedisDown(t *testing.T) {
 	testBroker := testbroker.NewTestBroker(r)
 	srv := NewServer(RedisClientOpt{Addr: ":6379"}, Config{LogLevel: testLogLevel})
 	srv.broker = testBroker
-	srv.scheduler.broker = testBroker
+	srv.forwarder.broker = testBroker
 	srv.heartbeater.broker = testBroker
 	srv.processor.broker = testBroker
 	srv.subscriber.broker = testBroker
@@ -160,7 +160,7 @@ func TestServerWithFlakyBroker(t *testing.T) {
 	redisConnOpt := getRedisConnOpt(t)
 	srv := NewServer(redisConnOpt, Config{LogLevel: testLogLevel})
 	srv.broker = testBroker
-	srv.scheduler.broker = testBroker
+	srv.forwarder.broker = testBroker
 	srv.heartbeater.broker = testBroker
 	srv.processor.broker = testBroker
 	srv.subscriber.broker = testBroker

signals_unix.go

@@ -28,3 +28,10 @@ func (srv *Server) waitForSignals() {
 		break
 	}
 }
+
+func (s *Scheduler) waitForSignals() {
+	s.logger.Info("Send signal TERM or INT to stop the scheduler")
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, unix.SIGTERM, unix.SIGINT)
+	<-sigs
+}

signals_windows.go

@@ -20,3 +20,10 @@ func (srv *Server) waitForSignals() {
 	signal.Notify(sigs, windows.SIGTERM, windows.SIGINT)
 	<-sigs
 }
+
+func (s *Scheduler) waitForSignals() {
+	s.logger.Info("Send signal TERM or INT to stop the scheduler")
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, windows.SIGTERM, windows.SIGINT)
+	<-sigs
+}

tools/asynq/README.md

@@ -24,7 +24,7 @@ To view details on any command, use `asynq help <command> <subcommand>`.
 
 - `asynq stats`
 - `asynq queue [ls inspect history rm pause unpause]`
-- `asynq task [ls cancel delete kill run delete-all kill-all run-all]`
+- `asynq task [ls cancel delete archive run delete-all archive-all run-all]`
 - `asynq server [ls]`
 
 ### Global flags

tools/asynq/cmd/cron.go

@@ -0,0 +1,129 @@
+// Copyright 2020 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+package cmd
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sort"
+	"time"
+
+	"github.com/hibiken/asynq"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(cronCmd)
+	cronCmd.AddCommand(cronListCmd)
+	cronCmd.AddCommand(cronHistoryCmd)
+	cronHistoryCmd.Flags().Int("page", 1, "page number")
+	cronHistoryCmd.Flags().Int("size", 30, "page size")
+}
+
+var cronCmd = &cobra.Command{
+	Use:   "cron",
+	Short: "Manage cron",
+}
+
+var cronListCmd = &cobra.Command{
+	Use:   "ls",
+	Short: "List cron entries",
+	Run:   cronList,
+}
+
+var cronHistoryCmd = &cobra.Command{
+	Use:   "history [ENTRY_ID...]",
+	Short: "Show history of each cron tasks",
+	Args:  cobra.MinimumNArgs(1),
+	Run:   cronHistory,
+}
+
+func cronList(cmd *cobra.Command, args []string) {
+	inspector := createInspector()
+
+	entries, err := inspector.SchedulerEntries()
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	if len(entries) == 0 {
+		fmt.Println("No scheduler entries")
+		return
+	}
+
+	// Sort entries by spec.
+	sort.Slice(entries, func(i, j int) bool {
+		x, y := entries[i], entries[j]
+		return x.Spec < y.Spec
+	})
+
+	cols := []string{"EntryID", "Spec", "Type", "Payload", "Options", "Next", "Prev"}
+	printRows := func(w io.Writer, tmpl string) {
+		for _, e := range entries {
+			fmt.Fprintf(w, tmpl, e.ID, e.Spec, e.Task.Type, e.Task.Payload, e.Opts,
+				nextEnqueue(e.Next), prevEnqueue(e.Prev))
+		}
+	}
+	printTable(cols, printRows)
+}
+
+// Returns a string describing when the next enqueue will happen.
+func nextEnqueue(nextEnqueueAt time.Time) string {
+	d := nextEnqueueAt.Sub(time.Now()).Round(time.Second)
+	if d < 0 {
+		return "Now"
+	}
+	return fmt.Sprintf("In %v", d)
+}
+
+// Returns a string describing when the previous enqueue was.
+func prevEnqueue(prevEnqueuedAt time.Time) string {
+	if prevEnqueuedAt.IsZero() {
+		return "N/A"
+	}
+	return fmt.Sprintf("%v ago", time.Since(prevEnqueuedAt).Round(time.Second))
+}
+
+func cronHistory(cmd *cobra.Command, args []string) {
+	pageNum, err := cmd.Flags().GetInt("page")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	pageSize, err := cmd.Flags().GetInt("size")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	inspector := createInspector()
+	for i, entryID := range args {
+		if i > 0 {
+			fmt.Printf("\n%s\n", separator)
+		}
+		fmt.Println()
+
+		fmt.Printf("Entry: %s\n\n", entryID)
+
+		events, err := inspector.ListSchedulerEnqueueEvents(
+			entryID, asynq.PageSize(pageSize), asynq.Page(pageNum))
+		if err != nil {
+			fmt.Printf("error: %v\n", err)
+			continue
+		}
+		if len(events) == 0 {
+			fmt.Printf("No scheduler enqueue events found for entry: %s\n", entryID)
+			continue
+		}
+
+		cols := []string{"TaskID", "EnqueuedAt"}
+		printRows := func(w io.Writer, tmpl string) {
+			for _, e := range events {
+				fmt.Fprintf(w, tmpl, e.TaskID, e.EnqueuedAt)
+			}
+		}
+		printTable(cols, printRows)
+	}
+}

tools/asynq/cmd/migrate.go

@@ -98,7 +98,9 @@ func migrate(cmd *cobra.Command, args []string) {
 		printError(err)
 		os.Exit(1)
 	}
-	if err := partitionZSetMembersByQueue(c, "asynq:dead", base.DeadKey); err != nil {
+	// Note: base.DeadKey function was renamed in v0.14. We define the legacy function here since we need it for this migration script.
+	deadKeyFunc := func(qname string) string { return fmt.Sprintf("asynq:{%s}:dead", qname) } 
+	if err := partitionZSetMembersByQueue(c, "asynq:dead", deadKeyFunc); err != nil {
 		printError(err)
 		os.Exit(1)
 	}
@@ -113,7 +115,7 @@ func migrate(cmd *cobra.Command, args []string) {
 
 	paused, err := c.SMembers("asynq:paused").Result()
 	if err != nil {
-		printError(fmt.Errorf("command SMEMBERS asynq:paused failed: ", err))
+		printError(fmt.Errorf("command SMEMBERS asynq:paused failed: %v", err))
 		os.Exit(1)
 	}
 	for _, qkey := range paused {
@@ -136,6 +138,27 @@ func migrate(cmd *cobra.Command, args []string) {
 		printError(err)
 		os.Exit(1)
 	}
+
+	/*** Migrate from 0.13 to 0.14 compatible ***/
+
+	// Move all dead tasks to archived ZSET.
+	for _, qname := range allQueues {
+		zs, err := c.ZRangeWithScores(deadKeyFunc(qname), 0, -1).Result()
+		if err != nil {
+			printError(err)
+			os.Exit(1)
+		}
+		for _, z := range zs {
+			if err := c.ZAdd(base.ArchivedKey(qname), &z).Err(); err != nil {
+				printError(err)
+				os.Exit(1)
+			}
+		}
+		if err := deleteKey(c, deadKeyFunc(qname)); err != nil {
+			printError(err)
+			os.Exit(1)
+		}
+	}
 }
 
 func backupKey(key string) string {

tools/asynq/cmd/queue.go

@@ -149,9 +149,9 @@ func printQueueStats(s *asynq.QueueStats) {
 	fmt.Printf("Paused: %t\n\n", s.Paused)
 	bold.Println("Task Count by State")
 	printTable(
-		[]string{"active", "pending", "scheduled", "retry", "dead"},
+		[]string{"active", "pending", "scheduled", "retry", "archived"},
 		func(w io.Writer, tmpl string) {
-			fmt.Fprintf(w, tmpl, s.Active, s.Pending, s.Scheduled, s.Retry, s.Dead)
+			fmt.Fprintf(w, tmpl, s.Active, s.Pending, s.Scheduled, s.Retry, s.Archived)
 		},
 	)
 	fmt.Println()

tools/asynq/cmd/root.go

@@ -5,6 +5,7 @@
 package cmd
 
 import (
+	"crypto/tls"
 	"fmt"
 	"io"
 	"os"
@@ -31,6 +32,7 @@ var (
 
 	useRedisCluster bool
 	clusterAddrs    string
+	tlsServerName   string
 )
 
 // rootCmd represents the base command when called without any subcommands
@@ -74,12 +76,15 @@ func init() {
 	rootCmd.PersistentFlags().StringVar(&clusterAddrs, "cluster_addrs",
 		"127.0.0.1:7000,127.0.0.1:7001,127.0.0.1:7002,127.0.0.1:7003,127.0.0.1:7004,127.0.0.1:7005",
 		"list of comma-separated redis server addresses")
+	rootCmd.PersistentFlags().StringVar(&tlsServerName, "tls_server",
+		"", "server name for TLS validation")
 	// Bind flags with config.
 	viper.BindPFlag("uri", rootCmd.PersistentFlags().Lookup("uri"))
 	viper.BindPFlag("db", rootCmd.PersistentFlags().Lookup("db"))
 	viper.BindPFlag("password", rootCmd.PersistentFlags().Lookup("password"))
 	viper.BindPFlag("cluster", rootCmd.PersistentFlags().Lookup("cluster"))
 	viper.BindPFlag("cluster_addrs", rootCmd.PersistentFlags().Lookup("cluster_addrs"))
+	viper.BindPFlag("tls_server", rootCmd.PersistentFlags().Lookup("tls_server"))
 }
 
 // initConfig reads in config file and ENV variables if set.
@@ -114,14 +119,16 @@ func createRDB() *rdb.RDB {
 	if useRedisCluster {
 		addrs := strings.Split(viper.GetString("cluster_addrs"), ",")
 		c = redis.NewClusterClient(&redis.ClusterOptions{
-			Addrs:    addrs,
-			Password: viper.GetString("password"),
+			Addrs:     addrs,
+			Password:  viper.GetString("password"),
+			TLSConfig: getTLSConfig(),
 		})
 	} else {
 		c = redis.NewClient(&redis.Options{
-			Addr:     viper.GetString("uri"),
-			DB:       viper.GetInt("db"),
-			Password: viper.GetString("password"),
+			Addr:      viper.GetString("uri"),
+			DB:        viper.GetInt("db"),
+			Password:  viper.GetString("password"),
+			TLSConfig: getTLSConfig(),
 		})
 	}
 	return rdb.NewRDB(c)
@@ -133,19 +140,29 @@ func createInspector() *asynq.Inspector {
 	if useRedisCluster {
 		addrs := strings.Split(viper.GetString("cluster_addrs"), ",")
 		connOpt = asynq.RedisClusterClientOpt{
-			Addrs:    addrs,
-			Password: viper.GetString("password"),
+			Addrs:     addrs,
+			Password:  viper.GetString("password"),
+			TLSConfig: getTLSConfig(),
 		}
 	} else {
 		connOpt = asynq.RedisClientOpt{
-			Addr:     viper.GetString("uri"),
-			DB:       viper.GetInt("db"),
-			Password: viper.GetString("password"),
+			Addr:      viper.GetString("uri"),
+			DB:        viper.GetInt("db"),
+			Password:  viper.GetString("password"),
+			TLSConfig: getTLSConfig(),
 		}
 	}
 	return asynq.NewInspector(connOpt)
 }
 
+func getTLSConfig() *tls.Config {
+	tlsServer := viper.GetString("tls_server")
+	if tlsServer == "" {
+		return nil
+	}
+	return &tls.Config{ServerName: tlsServer}
+}
+
 // printTable is a helper function to print data in table format.
 //
 // cols is a list of headers and printRow specifies how to print rows.

tools/asynq/cmd/stats.go

@@ -57,7 +57,7 @@ type AggregateStats struct {
 	Pending   int
 	Scheduled int
 	Retry     int
-	Dead      int
+	Archived  int
 	Processed int
 	Failed    int
 	Timestamp time.Time
@@ -84,7 +84,7 @@ func stats(cmd *cobra.Command, args []string) {
 		aggStats.Pending += s.Pending
 		aggStats.Scheduled += s.Scheduled
 		aggStats.Retry += s.Retry
-		aggStats.Dead += s.Dead
+		aggStats.Archived += s.Archived
 		aggStats.Processed += s.Processed
 		aggStats.Failed += s.Failed
 		aggStats.Timestamp = s.Timestamp
@@ -126,9 +126,9 @@ func stats(cmd *cobra.Command, args []string) {
 func printStatsByState(s *AggregateStats) {
 	format := strings.Repeat("%v\t", 5) + "\n"
 	tw := new(tabwriter.Writer).Init(os.Stdout, 0, 8, 2, ' ', 0)
-	fmt.Fprintf(tw, format, "active", "pending", "scheduled", "retry", "dead")
+	fmt.Fprintf(tw, format, "active", "pending", "scheduled", "retry", "archived")
 	fmt.Fprintf(tw, format, "----------", "--------", "---------", "-----", "----")
-	fmt.Fprintf(tw, format, s.Active, s.Pending, s.Scheduled, s.Retry, s.Dead)
+	fmt.Fprintf(tw, format, s.Active, s.Pending, s.Scheduled, s.Retry, s.Archived)
 	tw.Flush()
 }
 

tools/asynq/cmd/task.go

@@ -26,11 +26,11 @@ func init() {
 
 	taskCmd.AddCommand(taskCancelCmd)
 
-	taskCmd.AddCommand(taskKillCmd)
-	taskKillCmd.Flags().StringP("queue", "q", "", "queue to which the task belongs")
-	taskKillCmd.Flags().StringP("key", "k", "", "key of the task")
-	taskKillCmd.MarkFlagRequired("queue")
-	taskKillCmd.MarkFlagRequired("key")
+	taskCmd.AddCommand(taskArchiveCmd)
+	taskArchiveCmd.Flags().StringP("queue", "q", "", "queue to which the task belongs")
+	taskArchiveCmd.Flags().StringP("key", "k", "", "key of the task")
+	taskArchiveCmd.MarkFlagRequired("queue")
+	taskArchiveCmd.MarkFlagRequired("key")
 
 	taskCmd.AddCommand(taskDeleteCmd)
 	taskDeleteCmd.Flags().StringP("queue", "q", "", "queue to which the task belongs")
@@ -44,11 +44,11 @@ func init() {
 	taskRunCmd.MarkFlagRequired("queue")
 	taskRunCmd.MarkFlagRequired("key")
 
-	taskCmd.AddCommand(taskKillAllCmd)
-	taskKillAllCmd.Flags().StringP("queue", "q", "", "queue to which the tasks belong")
-	taskKillAllCmd.Flags().StringP("state", "s", "", "state of the tasks")
-	taskKillAllCmd.MarkFlagRequired("queue")
-	taskKillAllCmd.MarkFlagRequired("state")
+	taskCmd.AddCommand(taskArchiveAllCmd)
+	taskArchiveAllCmd.Flags().StringP("queue", "q", "", "queue to which the tasks belong")
+	taskArchiveAllCmd.Flags().StringP("state", "s", "", "state of the tasks")
+	taskArchiveAllCmd.MarkFlagRequired("queue")
+	taskArchiveAllCmd.MarkFlagRequired("state")
 
 	taskCmd.AddCommand(taskDeleteAllCmd)
 	taskDeleteAllCmd.Flags().StringP("queue", "q", "", "queue to which the tasks belong")
@@ -78,7 +78,7 @@ The value for the state flag should be one of:
 - pending
 - scheduled
 - retry
-- dead
+- archived
 
 List opeartion paginates the result set.
 By default, the command fetches the first 30 tasks.
@@ -100,9 +100,9 @@ var taskCancelCmd = &cobra.Command{
 	Run:   taskCancel,
 }
 
-var taskKillCmd = &cobra.Command{
-	Use:   "kill --queue=QUEUE --key=KEY",
-	Short: "Kill a task with the given key",
+var taskArchiveCmd = &cobra.Command{
+	Use:   "archive --queue=QUEUE --key=KEY",
+	Short: "Archive a task with the given key",
 	Args:  cobra.NoArgs,
 	Run:   taskKill,
 }
@@ -121,11 +121,11 @@ var taskRunCmd = &cobra.Command{
 	Run:   taskRun,
 }
 
-var taskKillAllCmd = &cobra.Command{
-	Use:   "kill-all --queue=QUEUE --state=STATE",
-	Short: "Kill all tasks in the given state",
+var taskArchiveAllCmd = &cobra.Command{
+	Use:   "archive-all --queue=QUEUE --state=STATE",
+	Short: "Archive all tasks in the given state",
 	Args:  cobra.NoArgs,
-	Run:   taskKillAll,
+	Run:   taskArchiveAll,
 }
 
 var taskDeleteAllCmd = &cobra.Command{
@@ -173,8 +173,8 @@ func taskList(cmd *cobra.Command, args []string) {
 		listScheduledTasks(qname, pageNum, pageSize)
 	case "retry":
 		listRetryTasks(qname, pageNum, pageSize)
-	case "dead":
-		listDeadTasks(qname, pageNum, pageSize)
+	case "archived":
+		listArchivedTasks(qname, pageNum, pageSize)
 	default:
 		fmt.Printf("error: state=%q is not supported\n", state)
 		os.Exit(1)
@@ -273,15 +273,15 @@ func listRetryTasks(qname string, pageNum, pageSize int) {
 	)
 }
 
-func listDeadTasks(qname string, pageNum, pageSize int) {
+func listArchivedTasks(qname string, pageNum, pageSize int) {
 	i := createInspector()
-	tasks, err := i.ListDeadTasks(qname, asynq.PageSize(pageSize), asynq.Page(pageNum))
+	tasks, err := i.ListArchivedTasks(qname, asynq.PageSize(pageSize), asynq.Page(pageNum))
 	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
 	if len(tasks) == 0 {
-		fmt.Printf("No dead tasks in %q queue\n", qname)
+		fmt.Printf("No archived tasks in %q queue\n", qname)
 		return
 	}
 	printTable(
@@ -318,12 +318,12 @@ func taskKill(cmd *cobra.Command, args []string) {
 	}
 
 	i := createInspector()
-	err = i.KillTaskByKey(qname, key)
+	err = i.ArchiveTaskByKey(qname, key)
 	if err != nil {
 		fmt.Printf("error: %v\n", err)
 		os.Exit(1)
 	}
-	fmt.Println("task transitioned to dead state")
+	fmt.Println("task transitioned to archived state")
 }
 
 func taskDelete(cmd *cobra.Command, args []string) {
@@ -368,7 +368,7 @@ func taskRun(cmd *cobra.Command, args []string) {
 	fmt.Println("task transitioned to pending state")
 }
 
-func taskKillAll(cmd *cobra.Command, args []string) {
+func taskArchiveAll(cmd *cobra.Command, args []string) {
 	qname, err := cmd.Flags().GetString("queue")
 	if err != nil {
 		fmt.Printf("error: %v\n", err)
@@ -384,9 +384,9 @@ func taskKillAll(cmd *cobra.Command, args []string) {
 	var n int
 	switch state {
 	case "scheduled":
-		n, err = i.KillAllScheduledTasks(qname)
+		n, err = i.ArchiveAllScheduledTasks(qname)
 	case "retry":
-		n, err = i.KillAllRetryTasks(qname)
+		n, err = i.ArchiveAllRetryTasks(qname)
 	default:
 		fmt.Printf("error: unsupported state %q\n", state)
 		os.Exit(1)
@@ -395,7 +395,7 @@ func taskKillAll(cmd *cobra.Command, args []string) {
 		fmt.Printf("error: %v\n", err)
 		os.Exit(1)
 	}
-	fmt.Printf("%d tasks transitioned to dead state\n", n)
+	fmt.Printf("%d tasks transitioned to archived state\n", n)
 }
 
 func taskDeleteAll(cmd *cobra.Command, args []string) {
@@ -417,8 +417,8 @@ func taskDeleteAll(cmd *cobra.Command, args []string) {
 		n, err = i.DeleteAllScheduledTasks(qname)
 	case "retry":
 		n, err = i.DeleteAllRetryTasks(qname)
-	case "dead":
-		n, err = i.DeleteAllDeadTasks(qname)
+	case "archived":
+		n, err = i.DeleteAllArchivedTasks(qname)
 	default:
 		fmt.Printf("error: unsupported state %q\n", state)
 		os.Exit(1)
@@ -449,8 +449,8 @@ func taskRunAll(cmd *cobra.Command, args []string) {
 		n, err = i.RunAllScheduledTasks(qname)
 	case "retry":
 		n, err = i.RunAllRetryTasks(qname)
-	case "dead":
-		n, err = i.RunAllDeadTasks(qname)
+	case "archived":
+		n, err = i.RunAllArchivedTasks(qname)
 	default:
 		fmt.Printf("error: unsupported state %q\n", state)
 		os.Exit(1)

tools/go.sum

@@ -108,6 +108,8 @@ github.com/prometheus/common v0.4.0/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y8
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/prometheus/procfs v0.0.0-20190507164030-5867b95ac084/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/tsdb v0.7.1/go.mod h1:qhTCs0VvXwvX/y3TZrWD7rabWM+ijKTux40TwIPHuXU=
+github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
+github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
 github.com/russross/blackfriday v1.5.2/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=