Add custom logger

background.go

@@ -6,7 +6,6 @@ package asynq
 
 import (
 	"fmt"
-	"log"
 	"math"
 	"math/rand"
 	"os"
@@ -150,9 +149,15 @@ func (fn HandlerFunc) ProcessTask(task *Task) error {
 // a signal, it gracefully shuts down all pending workers and other
 // goroutines to process the tasks.
 func (bg *Background) Run(handler Handler) {
+	logger.SetPrefix(fmt.Sprintf("asynq: pid=%d ", os.Getpid()))
+	logger.info("Starting processing")
+
 	bg.start(handler)
 	defer bg.stop()
 
+	logger.info("Send signal TSTP to stop processing new tasks")
+	logger.info("Send signal TERM or INT to terminate the process")
+
 	// Wait for a signal to terminate.
 	sigs := make(chan os.Signal, 1)
 	signal.Notify(sigs, syscall.SIGTERM, syscall.SIGINT, syscall.SIGTSTP)
@@ -165,7 +170,7 @@ func (bg *Background) Run(handler Handler) {
 		break
 	}
 	fmt.Println()
-	log.Println("[INFO] Starting graceful shutdown...")
+	logger.info("Starting graceful shutdown")
 }
 
 // starts the background-task processing.
@@ -201,6 +206,8 @@ func (bg *Background) stop() {
 	bg.rdb.Close()
 	bg.processor.handler = nil
 	bg.running = false
+
+	logger.info("Bye!")
 }
 
 // normalizeQueueCfg divides priority numbers by their

logger.go

@@ -0,0 +1,35 @@
+package asynq
+
+import (
+	"io"
+	"log"
+	"os"
+)
+
+// global logger used in asynq package.
+var logger = newLogger(os.Stderr)
+
+func newLogger(out io.Writer) *asynqLogger {
+	return &asynqLogger{
+		log.New(out, "", log.Ldate|log.Ltime|log.Lmicroseconds|log.LUTC),
+	}
+}
+
+type asynqLogger struct {
+	*log.Logger
+}
+
+func (l *asynqLogger) info(format string, args ...interface{}) {
+	format = "INFO: " + format
+	l.Printf(format, args...)
+}
+
+func (l *asynqLogger) warn(format string, args ...interface{}) {
+	format = "WARN: " + format
+	l.Printf(format, args...)
+}
+
+func (l *asynqLogger) error(format string, args ...interface{}) {
+	format = "ERROR: " + format
+	l.Printf(format, args...)
+}

logger_test.go

@@ -0,0 +1,117 @@
+package asynq
+
+import (
+	"bytes"
+	"fmt"
+	"regexp"
+	"testing"
+)
+
+// regexp for timestamps
+const (
+	rgxdate         = `[0-9][0-9][0-9][0-9]/[0-9][0-9]/[0-9][0-9]`
+	rgxtime         = `[0-9][0-9]:[0-9][0-9]:[0-9][0-9]`
+	rgxmicroseconds = `\.[0-9][0-9][0-9][0-9][0-9][0-9]`
+)
+
+type tester struct {
+	desc        string
+	message     string
+	wantPattern string // regexp that log output must match
+}
+
+func TestLoggerInfo(t *testing.T) {
+	tests := []tester{
+		{
+			desc:        "without trailing newline, logger adds newline",
+			message:     "hello, world!",
+			wantPattern: fmt.Sprintf("^%s %s%s INFO: hello, world!\n$", rgxdate, rgxtime, rgxmicroseconds),
+		},
+		{
+			desc:        "with trailing newline, logger preserves newline",
+			message:     "hello, world!\n",
+			wantPattern: fmt.Sprintf("^%s %s%s INFO: hello, world!\n$", rgxdate, rgxtime, rgxmicroseconds),
+		},
+	}
+
+	for _, tc := range tests {
+		var buf bytes.Buffer
+		logger := newLogger(&buf)
+
+		logger.info(tc.message)
+
+		got := buf.String()
+		matched, err := regexp.MatchString(tc.wantPattern, got)
+		if err != nil {
+			t.Fatal("pattern did not compile:", err)
+		}
+		if !matched {
+			t.Errorf("logger.info(%q) outputted %q, should match pattern %q",
+				tc.message, got, tc.wantPattern)
+		}
+	}
+}
+
+func TestLoggerWarn(t *testing.T) {
+	tests := []tester{
+		{
+			desc:        "without trailing newline, logger adds newline",
+			message:     "hello, world!",
+			wantPattern: fmt.Sprintf("^%s %s%s WARN: hello, world!\n$", rgxdate, rgxtime, rgxmicroseconds),
+		},
+		{
+			desc:        "with trailing newline, logger preserves newline",
+			message:     "hello, world!\n",
+			wantPattern: fmt.Sprintf("^%s %s%s WARN: hello, world!\n$", rgxdate, rgxtime, rgxmicroseconds),
+		},
+	}
+
+	for _, tc := range tests {
+		var buf bytes.Buffer
+		logger := newLogger(&buf)
+
+		logger.warn(tc.message)
+
+		got := buf.String()
+		matched, err := regexp.MatchString(tc.wantPattern, got)
+		if err != nil {
+			t.Fatal("pattern did not compile:", err)
+		}
+		if !matched {
+			t.Errorf("logger.info(%q) outputted %q, should match pattern %q",
+				tc.message, got, tc.wantPattern)
+		}
+	}
+}
+
+func TestLoggerError(t *testing.T) {
+	tests := []tester{
+		{
+			desc:        "without trailing newline, logger adds newline",
+			message:     "hello, world!",
+			wantPattern: fmt.Sprintf("^%s %s%s ERROR: hello, world!\n$", rgxdate, rgxtime, rgxmicroseconds),
+		},
+		{
+			desc:        "with trailing newline, logger preserves newline",
+			message:     "hello, world!\n",
+			wantPattern: fmt.Sprintf("^%s %s%s ERROR: hello, world!\n$", rgxdate, rgxtime, rgxmicroseconds),
+		},
+	}
+
+	for _, tc := range tests {
+		var buf bytes.Buffer
+		logger := newLogger(&buf)
+
+		logger.error(tc.message)
+
+		got := buf.String()
+		matched, err := regexp.MatchString(tc.wantPattern, got)
+		if err != nil {
+			t.Fatal("pattern did not compile:", err)
+		}
+		if !matched {
+			t.Errorf("logger.info(%q) outputted %q, should match pattern %q",
+				tc.message, got, tc.wantPattern)
+		}
+	}
+}

processor.go

@@ -6,7 +6,6 @@ package asynq
 
 import (
 	"fmt"
-	"log"
 	"math/rand"
 	"sort"
 	"sync"
@@ -79,7 +78,7 @@ func newProcessor(r *rdb.RDB, n int, qcfg map[string]uint, strict bool, fn retry
 // It's safe to call this method multiple times.
 func (p *processor) stop() {
 	p.once.Do(func() {
-		log.Println("[INFO] Processor shutting down...")
+		logger.info("Processor shutting down...")
 		// Unblock if processor is waiting for sema token.
 		close(p.abort)
 		// Signal the processor goroutine to stop processing tasks
@@ -95,12 +94,12 @@ func (p *processor) terminate() {
 	// IDEA: Allow user to customize this timeout value.
 	const timeout = 8 * time.Second
 	time.AfterFunc(timeout, func() { close(p.quit) })
-	log.Println("[INFO] Waiting for all workers to finish...")
+	logger.info("Waiting for all workers to finish...")
 	// block until all workers have released the token
 	for i := 0; i < cap(p.sema); i++ {
 		p.sema <- struct{}{}
 	}
-	log.Println("[INFO] All workers have finished.")
+	logger.info("All workers have finished")
 	p.restore() // move any unfinished tasks back to the queue.
 }
 
@@ -112,7 +111,7 @@ func (p *processor) start() {
 		for {
 			select {
 			case <-p.done:
-				log.Println("[INFO] Processor done.")
+				logger.info("Processor done")
 				return
 			default:
 				p.exec()
@@ -137,7 +136,7 @@ func (p *processor) exec() {
 		return
 	}
 	if err != nil {
-		log.Printf("[ERROR] unexpected error while pulling a task out of queue: %v\n", err)
+		logger.error("Dequeue error: %v", err)
 		return
 	}
 
@@ -159,7 +158,7 @@ func (p *processor) exec() {
 			select {
 			case <-p.quit:
 				// time is up, quit this worker goroutine.
-				log.Printf("[WARN] Terminating in-progress task %+v\n", msg)
+				logger.warn("Quitting worker to process task id=%s", msg.ID)
 				return
 			case resErr := <-resCh:
 				// Note: One of three things should happen.
@@ -185,25 +184,25 @@ func (p *processor) exec() {
 func (p *processor) restore() {
 	n, err := p.rdb.RestoreUnfinished()
 	if err != nil {
-		log.Printf("[ERROR] Could not restore unfinished tasks: %v\n", err)
+		logger.error("Could not restore unfinished tasks: %v", err)
 	}
 	if n > 0 {
-		log.Printf("[INFO] Restored %d unfinished tasks back to queue.\n", n)
+		logger.info("Restored %d unfinished tasks back to queue", n)
 	}
 }
 
 func (p *processor) requeue(msg *base.TaskMessage) {
 	err := p.rdb.Requeue(msg)
 	if err != nil {
-		log.Printf("[ERROR] Could not move task from InProgress back to queue: %v\n", err)
+		logger.error("Could not push task id=%s back to queue: %v", msg.ID, err)
 	}
 }
 
 func (p *processor) markAsDone(msg *base.TaskMessage) {
 	err := p.rdb.Done(msg)
 	if err != nil {
-		errMsg := fmt.Sprintf("could not remove task %+v from %q", msg, base.InProgressQueue)
+		errMsg := fmt.Sprintf("Could not remove task id=%s from %q", msg.ID, base.InProgressQueue)
-		log.Printf("[WARN] %s; will retry\n", errMsg)
+		logger.warn("%s; Will retry syncing", errMsg)
 		p.syncRequestCh <- &syncRequest{
 			fn: func() error {
 				return p.rdb.Done(msg)
@@ -218,8 +217,8 @@ func (p *processor) retry(msg *base.TaskMessage, e error) {
 	retryAt := time.Now().Add(d)
 	err := p.rdb.Retry(msg, retryAt, e.Error())
 	if err != nil {
-		errMsg := fmt.Sprintf("could not move task %+v from %q to %q", msg, base.InProgressQueue, base.RetryQueue)
+		errMsg := fmt.Sprintf("Could not move task id=%s from %q to %q", msg.ID, base.InProgressQueue, base.RetryQueue)
-		log.Printf("[WARN] %s; will retry\n", errMsg)
+		logger.warn("%s; Will retry syncing", errMsg)
 		p.syncRequestCh <- &syncRequest{
 			fn: func() error {
 				return p.rdb.Retry(msg, retryAt, e.Error())
@@ -230,11 +229,11 @@ func (p *processor) retry(msg *base.TaskMessage, e error) {
 }
 
 func (p *processor) kill(msg *base.TaskMessage, e error) {
-	log.Printf("[WARN] Retry exhausted for task(Type: %q, ID: %v)\n", msg.Type, msg.ID)
+	logger.warn("Retry exhausted for task id=%s", msg.ID)
 	err := p.rdb.Kill(msg, e.Error())
 	if err != nil {
-		errMsg := fmt.Sprintf("could not move task %+v from %q to %q", msg, base.InProgressQueue, base.DeadQueue)
+		errMsg := fmt.Sprintf("Could not move task id=%s from %q to %q", msg.ID, base.InProgressQueue, base.DeadQueue)
-		log.Printf("[WARN] %s; will retry\n", errMsg)
+		logger.warn("%s; Will retry syncing", errMsg)
 		p.syncRequestCh <- &syncRequest{
 			fn: func() error {
 				return p.rdb.Kill(msg, e.Error())

scheduler.go

@@ -5,7 +5,6 @@
 package asynq
 
 import (
-	"log"
 	"time"
 
 	"github.com/hibiken/asynq/internal/rdb"
@@ -38,7 +37,7 @@ func newScheduler(r *rdb.RDB, avgInterval time.Duration, qcfg map[string]uint) *
 }
 
 func (s *scheduler) terminate() {
-	log.Println("[INFO] Scheduler shutting down...")
+	logger.info("Scheduler shutting down...")
 	// Signal the scheduler goroutine to stop polling.
 	s.done <- struct{}{}
 }
@@ -49,7 +48,7 @@ func (s *scheduler) start() {
 		for {
 			select {
 			case <-s.done:
-				log.Println("[INFO] Scheduler done.")
+				logger.info("Scheduler done")
 				return
 			case <-time.After(s.avgInterval):
 				s.exec()
@@ -60,6 +59,6 @@ func (s *scheduler) start() {
 
 func (s *scheduler) exec() {
 	if err := s.rdb.CheckAndEnqueue(s.qnames...); err != nil {
-		log.Printf("[ERROR] could not forward scheduled tasks: %v\n", err)
+		logger.error("Could not enqueue scheduled tasks: %v", err)
 	}
 }

syncer.go

@@ -5,7 +5,6 @@
 package asynq
 
 import (
-	"log"
 	"time"
 )
 
@@ -35,7 +34,7 @@ func newSyncer(requestsCh <-chan *syncRequest, interval time.Duration) *syncer {
 }
 
 func (s *syncer) terminate() {
-	log.Println("[INFO] Syncer shutting down...")
+	logger.info("Syncer shutting down...")
 	// Signal the syncer goroutine to stop.
 	s.done <- struct{}{}
 }
@@ -49,10 +48,10 @@ func (s *syncer) start() {
 				// Try sync one last time before shutting down.
 				for _, req := range requests {
 					if err := req.fn(); err != nil {
-						log.Printf("[ERROR] %s\n", req.errMsg)
+						logger.error(req.errMsg)
 					}
 				}
-				log.Println("[INFO] Syncer done.")
+				logger.info("Syncer done")
 				return
 			case req := <-s.requestsCh:
 				requests = append(requests, req)