jitter: add NewTickerContext

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

util/jitter/ticker.go

@@ -1,6 +1,7 @@
-package jitter
+package jitter // import "go.unistack.org/micro/v3/util/jitter"
 
 import (
+	"context"
 	"time"
 
 	"go.unistack.org/micro/v3/util/rand"
@@ -10,13 +11,31 @@ import (
 // the min and max duration values (stored internally as int64 nanosecond
 // counts).
 type Ticker struct {
-	C    chan time.Time
+	ctx  context.Context
 	done chan chan struct{}
+	C    chan time.Time
 	min  int64
 	max  int64
+	exp  int64
+	exit bool
 	rng  rand.Rand
 }
 
+// NewTickerContext returns a pointer to an initialized instance of the Ticker.
+// It works like NewTicker except that it has ability to close via context.
+// Also it works fine with context.WithTimeout to handle max time to run ticker.
+func NewTickerContext(ctx context.Context, min, max time.Duration) *Ticker {
+	ticker := &Ticker{
+		C:    make(chan time.Time),
+		done: make(chan chan struct{}),
+		min:  min.Nanoseconds(),
+		max:  max.Nanoseconds(),
+		ctx:  ctx,
+	}
+	go ticker.run()
+	return ticker
+}
+
 // NewTicker returns a pointer to an initialized instance of the Ticker.
 // Min and max are durations of the shortest and longest allowed
 // ticks. Ticker will run in a goroutine until explicitly stopped.
@@ -26,6 +45,7 @@ func NewTicker(min, max time.Duration) *Ticker {
 		done: make(chan chan struct{}),
 		min:  min.Nanoseconds(),
 		max:  max.Nanoseconds(),
+		ctx:  context.Background(),
 	}
 	go ticker.run()
 	return ticker
@@ -33,9 +53,14 @@ func NewTicker(min, max time.Duration) *Ticker {
 
 // Stop terminates the ticker goroutine and closes the C channel.
 func (ticker *Ticker) Stop() {
+	if ticker.exit {
+		return
+	}
 	c := make(chan struct{})
 	ticker.done <- c
 	<-c
+	// close(ticker.C)
+	ticker.exit = true
 }
 
 func (ticker *Ticker) run() {
@@ -44,6 +69,8 @@ func (ticker *Ticker) run() {
 	for {
 		// either a stop signal or a timeout
 		select {
+		case <-ticker.ctx.Done():
+			t.Stop()
 		case c := <-ticker.done:
 			t.Stop()
 			close(c)