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asynq/internal/rdb/rdb.go
2020-02-13 06:23:51 -08:00

429 lines
13 KiB
Go

// 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 rdb encapsulates the interactions with redis.
package rdb
import (
"encoding/json"
"errors"
"fmt"
"time"
"github.com/go-redis/redis/v7"
"github.com/hibiken/asynq/internal/base"
"github.com/spf13/cast"
)
var (
// ErrNoProcessableTask indicates that there are no tasks ready to be processed.
ErrNoProcessableTask = errors.New("no tasks are ready for processing")
// ErrTaskNotFound indicates that a task that matches the given identifier was not found.
ErrTaskNotFound = errors.New("could not find a task")
)
const statsTTL = 90 * 24 * time.Hour // 90 days
// RDB is a client interface to query and mutate task queues.
type RDB struct {
client *redis.Client
}
// NewRDB returns a new instance of RDB.
func NewRDB(client *redis.Client) *RDB {
return &RDB{client}
}
// Close closes the connection with redis server.
func (r *RDB) Close() error {
return r.client.Close()
}
// KEYS[1] -> asynq:queues:<qname>
// KEYS[2] -> asynq:queues
// ARGV[1] -> task message data
var enqueueCmd = redis.NewScript(`
redis.call("LPUSH", KEYS[1], ARGV[1])
redis.call("SADD", KEYS[2], KEYS[1])
return 1`)
// Enqueue inserts the given task to the tail of the queue.
func (r *RDB) Enqueue(msg *base.TaskMessage) error {
bytes, err := json.Marshal(msg)
if err != nil {
return err
}
key := base.QueueKey(msg.Queue)
return enqueueCmd.Run(r.client, []string{key, base.AllQueues}, bytes).Err()
}
// Dequeue queries given queues in order and pops a task message if there is one and returns it.
// If all queues are empty, ErrNoProcessableTask error is returned.
func (r *RDB) Dequeue(qnames ...string) (*base.TaskMessage, error) {
var data string
var err error
if len(qnames) == 1 {
data, err = r.dequeueSingle(base.QueueKey(qnames[0]))
} else {
// TODO(hibiken): Take keys are argument and don't compute every time
var keys []string
for _, q := range qnames {
keys = append(keys, base.QueueKey(q))
}
data, err = r.dequeue(keys...)
}
if err == redis.Nil {
return nil, ErrNoProcessableTask
}
if err != nil {
return nil, err
}
var msg base.TaskMessage
err = json.Unmarshal([]byte(data), &msg)
if err != nil {
return nil, err
}
return &msg, nil
}
func (r *RDB) dequeueSingle(queue string) (data string, err error) {
// timeout needed to avoid blocking forever
return r.client.BRPopLPush(queue, base.InProgressQueue, time.Second).Result()
}
// KEYS[1] -> asynq:in_progress
// ARGV -> List of queues to query in order
var dequeueCmd = redis.NewScript(`
local res
for _, qkey in ipairs(ARGV) do
res = redis.call("RPOPLPUSH", qkey, KEYS[1])
if res then
return res
end
end
return res`)
func (r *RDB) dequeue(queues ...string) (data string, err error) {
var args []interface{}
for _, qkey := range queues {
args = append(args, qkey)
}
res, err := dequeueCmd.Run(r.client, []string{base.InProgressQueue}, args...).Result()
if err != nil {
return "", err
}
return cast.ToStringE(res)
}
// KEYS[1] -> asynq:in_progress
// KEYS[2] -> asynq:processed:<yyyy-mm-dd>
// ARGV[1] -> base.TaskMessage value
// ARGV[2] -> stats expiration timestamp
// Note: LREM count ZERO means "remove all elements equal to val"
var doneCmd = redis.NewScript(`
redis.call("LREM", KEYS[1], 0, ARGV[1])
local n = redis.call("INCR", KEYS[2])
if tonumber(n) == 1 then
redis.call("EXPIREAT", KEYS[2], ARGV[2])
end
return redis.status_reply("OK")
`)
// Done removes the task from in-progress queue to mark the task as done.
func (r *RDB) Done(msg *base.TaskMessage) error {
bytes, err := json.Marshal(msg)
if err != nil {
return err
}
now := time.Now()
processedKey := base.ProcessedKey(now)
expireAt := now.Add(statsTTL)
return doneCmd.Run(r.client,
[]string{base.InProgressQueue, processedKey},
bytes, expireAt.Unix()).Err()
}
// KEYS[1] -> asynq:in_progress
// KEYS[2] -> asynq:queues:<qname>
// ARGV[1] -> base.TaskMessage value
// Note: Use RPUSH to push to the head of the queue.
var requeueCmd = redis.NewScript(`
redis.call("LREM", KEYS[1], 0, ARGV[1])
redis.call("RPUSH", KEYS[2], ARGV[1])
return redis.status_reply("OK")`)
// Requeue moves the task from in-progress queue to the specified queue.
func (r *RDB) Requeue(msg *base.TaskMessage) error {
bytes, err := json.Marshal(msg)
if err != nil {
return err
}
return requeueCmd.Run(r.client,
[]string{base.InProgressQueue, base.QueueKey(msg.Queue)},
string(bytes)).Err()
}
// Schedule adds the task to the backlog queue to be processed in the future.
func (r *RDB) Schedule(msg *base.TaskMessage, processAt time.Time) error {
bytes, err := json.Marshal(msg)
if err != nil {
return err
}
score := float64(processAt.Unix())
return r.client.ZAdd(base.ScheduledQueue,
&redis.Z{Member: string(bytes), Score: score}).Err()
}
// KEYS[1] -> asynq:in_progress
// KEYS[2] -> asynq:retry
// KEYS[3] -> asynq:processed:<yyyy-mm-dd>
// KEYS[4] -> asynq:failure:<yyyy-mm-dd>
// ARGV[1] -> base.TaskMessage value to remove from base.InProgressQueue queue
// ARGV[2] -> base.TaskMessage value to add to Retry queue
// ARGV[3] -> retry_at UNIX timestamp
// ARGV[4] -> stats expiration timestamp
var retryCmd = redis.NewScript(`
redis.call("LREM", KEYS[1], 0, ARGV[1])
redis.call("ZADD", KEYS[2], ARGV[3], ARGV[2])
local n = redis.call("INCR", KEYS[3])
if tonumber(n) == 1 then
redis.call("EXPIREAT", KEYS[3], ARGV[4])
end
local m = redis.call("INCR", KEYS[4])
if tonumber(m) == 1 then
redis.call("EXPIREAT", KEYS[4], ARGV[4])
end
return redis.status_reply("OK")`)
// Retry moves the task from in-progress to retry queue, incrementing retry count
// and assigning error message to the task message.
func (r *RDB) Retry(msg *base.TaskMessage, processAt time.Time, errMsg string) error {
bytesToRemove, err := json.Marshal(msg)
if err != nil {
return err
}
modified := *msg
modified.Retried++
modified.ErrorMsg = errMsg
bytesToAdd, err := json.Marshal(&modified)
if err != nil {
return err
}
now := time.Now()
processedKey := base.ProcessedKey(now)
failureKey := base.FailureKey(now)
expireAt := now.Add(statsTTL)
return retryCmd.Run(r.client,
[]string{base.InProgressQueue, base.RetryQueue, processedKey, failureKey},
string(bytesToRemove), string(bytesToAdd), processAt.Unix(), expireAt.Unix()).Err()
}
const (
maxDeadTasks = 10000
deadExpirationInDays = 90
)
// KEYS[1] -> asynq:in_progress
// KEYS[2] -> asynq:dead
// KEYS[3] -> asynq:processed:<yyyy-mm-dd>
// KEYS[4] -> asynq.failure:<yyyy-mm-dd>
// ARGV[1] -> base.TaskMessage value to remove from base.InProgressQueue queue
// ARGV[2] -> base.TaskMessage value to add to Dead queue
// 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[6] -> stats expiration timestamp
var killCmd = redis.NewScript(`
redis.call("LREM", KEYS[1], 0, ARGV[1])
redis.call("ZADD", KEYS[2], ARGV[3], ARGV[2])
redis.call("ZREMRANGEBYSCORE", KEYS[2], "-inf", ARGV[4])
redis.call("ZREMRANGEBYRANK", KEYS[2], 0, -ARGV[5])
local n = redis.call("INCR", KEYS[3])
if tonumber(n) == 1 then
redis.call("EXPIREAT", KEYS[3], ARGV[6])
end
local m = redis.call("INCR", KEYS[4])
if tonumber(m) == 1 then
redis.call("EXPIREAT", KEYS[4], ARGV[6])
end
return redis.status_reply("OK")`)
// Kill sends the task to "dead" queue from in-progress 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 {
bytesToRemove, err := json.Marshal(msg)
if err != nil {
return err
}
modified := *msg
modified.ErrorMsg = errMsg
bytesToAdd, err := json.Marshal(&modified)
if err != nil {
return err
}
now := time.Now()
limit := now.AddDate(0, 0, -deadExpirationInDays).Unix() // 90 days ago
processedKey := base.ProcessedKey(now)
failureKey := base.FailureKey(now)
expireAt := now.Add(statsTTL)
return killCmd.Run(r.client,
[]string{base.InProgressQueue, base.DeadQueue, processedKey, failureKey},
string(bytesToRemove), string(bytesToAdd), now.Unix(), limit, maxDeadTasks, expireAt.Unix()).Err()
}
// KEYS[1] -> asynq:in_progress
// ARGV[1] -> queue prefix
var requeueAllCmd = redis.NewScript(`
local msgs = redis.call("LRANGE", KEYS[1], 0, -1)
for _, msg in ipairs(msgs) do
local decoded = cjson.decode(msg)
local qkey = ARGV[1] .. decoded["Queue"]
redis.call("RPUSH", qkey, msg)
redis.call("LREM", KEYS[1], 0, msg)
end
return table.getn(msgs)`)
// RequeueAll moves all tasks from in-progress list to the queue
// and reports the number of tasks restored.
func (r *RDB) RequeueAll() (int64, error) {
res, err := requeueAllCmd.Run(r.client, []string{base.InProgressQueue}, base.QueuePrefix).Result()
if err != nil {
return 0, err
}
n, ok := res.(int64)
if !ok {
return 0, fmt.Errorf("could not cast %v to int64", res)
}
return n, nil
}
// CheckAndEnqueue checks for all scheduled tasks and enqueues any tasks that
// have to be processed.
//
// qnames specifies to which queues to send tasks.
func (r *RDB) CheckAndEnqueue(qnames ...string) error {
delayed := []string{base.ScheduledQueue, base.RetryQueue}
for _, zset := range delayed {
var err error
if len(qnames) == 1 {
err = r.forwardSingle(zset, base.QueueKey(qnames[0]))
} else {
err = r.forward(zset)
}
if err != nil {
return err
}
}
return nil
}
// KEYS[1] -> source queue (e.g. scheduled or retry queue)
// ARGV[1] -> current unix time
// ARGV[2] -> queue prefix
var forwardCmd = redis.NewScript(`
local msgs = redis.call("ZRANGEBYSCORE", KEYS[1], "-inf", ARGV[1])
for _, msg in ipairs(msgs) do
local decoded = cjson.decode(msg)
local qkey = ARGV[2] .. decoded["Queue"]
redis.call("LPUSH", qkey, msg)
redis.call("ZREM", KEYS[1], msg)
end
return msgs`)
// forward moves all tasks with a score less than the current unix time
// from the src zset.
func (r *RDB) forward(src string) error {
now := float64(time.Now().Unix())
return forwardCmd.Run(r.client,
[]string{src}, now, base.QueuePrefix).Err()
}
// KEYS[1] -> source queue (e.g. scheduled or retry queue)
// KEYS[2] -> destination queue
var forwardSingleCmd = redis.NewScript(`
local msgs = redis.call("ZRANGEBYSCORE", KEYS[1], "-inf", ARGV[1])
for _, msg in ipairs(msgs) do
redis.call("LPUSH", KEYS[2], msg)
redis.call("ZREM", KEYS[1], msg)
end
return msgs`)
// forwardSingle moves all tasks with a score less than the current unix time
// from the src zset to dst list.
func (r *RDB) forwardSingle(src, dst string) error {
now := float64(time.Now().Unix())
return forwardSingleCmd.Run(r.client,
[]string{src, dst}, now).Err()
}
// KEYS[1] -> asynq:ps
// KEYS[2] -> asynq:ps:<host:pid>
// ARGV[1] -> expiration time
// ARGV[2] -> TTL in seconds
// ARGV[3] -> process info
var writeProcessInfoCmd = redis.NewScript(`
redis.call("ZADD", KEYS[1], ARGV[1], KEYS[2])
redis.call("SETEX", KEYS[2], ARGV[2], ARGV[3])
return redis.status_reply("OK")`)
// WriteProcessInfo writes process information to redis with expiration
// set to the value ttl.
func (r *RDB) WriteProcessInfo(ps *base.ProcessInfo, ttl time.Duration) error {
bytes, err := json.Marshal(ps)
if err != nil {
return err
}
// Note: Add key to ZSET with expiration time as score.
// ref: https://github.com/antirez/redis/issues/135#issuecomment-2361996
exp := time.Now().Add(ttl).UTC()
key := base.ProcessInfoKey(ps.Host, ps.PID)
return writeProcessInfoCmd.Run(r.client, []string{base.AllProcesses, key}, float64(exp.Unix()), ttl.Seconds(), string(bytes)).Err()
}
// ReadProcessInfo reads process information stored in redis.
func (r *RDB) ReadProcessInfo(host string, pid int) (*base.ProcessInfo, error) {
key := base.ProcessInfoKey(host, pid)
data, err := r.client.Get(key).Result()
if err != nil {
return nil, err
}
var pinfo base.ProcessInfo
err = json.Unmarshal([]byte(data), &pinfo)
if err != nil {
return nil, err
}
return &pinfo, nil
}
// KEYS[1] -> asynq:ps
// KEYS[2] -> asynq:ps:<host:pid>
var clearProcessInfoCmd = redis.NewScript(`
redis.call("ZREM", KEYS[1], KEYS[2])
redis.call("DEL", KEYS[2])
return redis.status_reply("OK")`)
// ClearProcessInfo deletes process information from redis.
func (r *RDB) ClearProcessInfo(ps *base.ProcessInfo) error {
key := base.ProcessInfoKey(ps.Host, ps.PID)
return clearProcessInfoCmd.Run(r.client, []string{base.AllProcesses, key}).Err()
}
// CancelationPubSub returns a pubsub for cancelation messages.
func (r *RDB) CancelationPubSub() (*redis.PubSub, error) {
pubsub := r.client.Subscribe(base.CancelChannel)
_, err := pubsub.Receive()
if err != nil {
return nil, err
}
return pubsub, nil
}
// PublishCancelation publish cancelation message to all subscribers.
// The message is the ID for the task to be canceled.
func (r *RDB) PublishCancelation(id string) error {
return r.client.Publish(base.CancelChannel, id).Err()
}