Add option to turn off automatically purge

Signed-off-by: zhenshan.cao <zhenshan.cao@zilliz.com>

ants_test.go

@@ -23,6 +23,7 @@
 package ants
 
 import (
+	"fmt"
 	"log"
 	"os"
 	"runtime"
@@ -563,6 +564,53 @@ func TestInfinitePool(t *testing.T) {
 	}
 }
 
+func TestWithDisablePurge(t *testing.T) {
+	numWorker := 2
+	p, _ := NewPool(numWorker, WithDisablePurge(true))
+	_ = p.Submit(func() {
+		fmt.Println("work1")
+		time.Sleep(time.Second)
+	})
+
+	_ = p.Submit(func() {
+		fmt.Println("work2")
+		time.Sleep(time.Second)
+	})
+
+	if n := p.Running(); n != 2 {
+		t.Errorf("expect 2 workers running, but got %d", n)
+	}
+
+	if n := p.Free(); n != 0 {
+		t.Errorf("expect zero of free workers, but got %d", n)
+	}
+
+	p.Tune(10)
+	if capacity := p.Cap(); capacity != 10 {
+		t.Fatalf("expect capacity: 10 but got %d", capacity)
+	}
+
+	_ = p.Submit(func() {
+		fmt.Println("work3")
+		time.Sleep(time.Second)
+	})
+
+	if n := p.Running(); n != 3 {
+		t.Errorf("expect 3 workers running, but got %d", n)
+	}
+
+	if n := p.Free(); n != 7 {
+		t.Errorf("expect 7 of free workers, but got %d", n)
+	}
+
+	p.Release()
+	p.Reboot()
+	if n := p.Running(); n != 3 {
+		t.Errorf("expect 3 workers running, but got %d", n)
+	}
+
+}
+
 func TestInfinitePoolWithFunc(t *testing.T) {
 	c := make(chan struct{})
 	p, _ := NewPoolWithFunc(-1, func(i interface{}) {

options.go

@@ -39,6 +39,10 @@ type Options struct {
 	// Logger is the customized logger for logging info, if it is not set,
 	// default standard logger from log package is used.
 	Logger Logger
+
+	// When DisablePurge is false, a separate goroutine is started and periodically purges expired workers.
+	// default is false.
+	DisablePurge bool
 }
 
 // WithOptions accepts the whole options config.
@@ -89,3 +93,10 @@ func WithLogger(logger Logger) Option {
 		opts.Logger = logger
 	}
 }
+
+// WithDisablePurge indicates whether we turn off automatically purge.
+func WithDisablePurge(disable bool) Option {
+	return func(opts *Options) {
+		opts.DisablePurge = disable
+	}
+}

pool.go

@@ -150,8 +150,9 @@ func NewPool(size int, options ...Option) (*Pool, error) {
 	// Start a goroutine to clean up expired workers periodically.
 	var ctx context.Context
 	ctx, p.stopHeartbeat = context.WithCancel(context.Background())
-	go p.purgePeriodically(ctx)
-
+	if !p.options.DisablePurge {
+		go p.purgePeriodically(ctx)
+	}
 	return p, nil
 }
 
@@ -259,7 +260,9 @@ func (p *Pool) Reboot() {
 		atomic.StoreInt32(&p.heartbeatDone, 0)
 		var ctx context.Context
 		ctx, p.stopHeartbeat = context.WithCancel(context.Background())
-		go p.purgePeriodically(ctx)
+		if !p.options.DisablePurge {
+			go p.purgePeriodically(ctx)
+		}
 	}
 }