From 94027eb4ad01c501c0778dfa0984366759ef0a9d Mon Sep 17 00:00:00 2001
From: Jordan Krage <jmank88@gmail.com>
Date: Fri, 3 Nov 2023 08:22:42 -0500
Subject: [PATCH] pkg/services: add StopChan & StopRChan from core (#213)

---
 pkg/services/stop.go | 50 ++++++++++++++++++++++++++++++++++++++++++++
 pkg/utils/utils.go   | 12 +++--------
 2 files changed, 53 insertions(+), 9 deletions(-)
 create mode 100644 pkg/services/stop.go

diff --git a/pkg/services/stop.go b/pkg/services/stop.go
new file mode 100644
index 0000000000..900ec6c846
--- /dev/null
+++ b/pkg/services/stop.go
@@ -0,0 +1,50 @@
+package services
+
+import "context"
+
+// A StopChan signals when some work should stop.
+// Use StopChanR if you already have a read only <-chan.
+type StopChan chan struct{}
+
+// NewCtx returns a background [context.Context] that is cancelled when StopChan is closed.
+func (s StopChan) NewCtx() (context.Context, context.CancelFunc) {
+	return StopRChan((<-chan struct{})(s)).NewCtx()
+}
+
+// Ctx cancels a [context.Context] when StopChan is closed.
+func (s StopChan) Ctx(ctx context.Context) (context.Context, context.CancelFunc) {
+	return StopRChan((<-chan struct{})(s)).Ctx(ctx)
+}
+
+// CtxCancel cancels a [context.Context] when StopChan is closed.
+// Returns ctx and cancel unmodified, for convenience.
+func (s StopChan) CtxCancel(ctx context.Context, cancel context.CancelFunc) (context.Context, context.CancelFunc) {
+	return StopRChan((<-chan struct{})(s)).CtxCancel(ctx, cancel)
+}
+
+// A StopRChan signals when some work should stop.
+// This is a receive-only version of StopChan, for casting an existing <-chan.
+type StopRChan <-chan struct{}
+
+// NewCtx returns a background [context.Context] that is cancelled when StopChan is closed.
+func (s StopRChan) NewCtx() (context.Context, context.CancelFunc) {
+	return s.Ctx(context.Background())
+}
+
+// Ctx cancels a [context.Context] when StopChan is closed.
+func (s StopRChan) Ctx(ctx context.Context) (context.Context, context.CancelFunc) {
+	return s.CtxCancel(context.WithCancel(ctx))
+}
+
+// CtxCancel cancels a [context.Context] when StopChan is closed.
+// Returns ctx and cancel unmodified, for convenience.
+func (s StopRChan) CtxCancel(ctx context.Context, cancel context.CancelFunc) (context.Context, context.CancelFunc) {
+	go func() {
+		select {
+		case <-s:
+			cancel()
+		case <-ctx.Done():
+		}
+	}()
+	return ctx, cancel
+}
diff --git a/pkg/utils/utils.go b/pkg/utils/utils.go
index aed521c621..4f17144e85 100644
--- a/pkg/utils/utils.go
+++ b/pkg/utils/utils.go
@@ -5,6 +5,8 @@ import (
 	"math"
 	mrand "math/rand"
 	"time"
+
+	"github.com/smartcontractkit/chainlink-relay/pkg/services"
 )
 
 // WithJitter adds +/- 10% to a duration
@@ -27,15 +29,7 @@ func WithJitter(d time.Duration) time.Duration {
 // NOTE: Spins up a goroutine that exits on cancellation.
 // REMEMBER TO CALL CANCEL OTHERWISE IT CAN LEAD TO MEMORY LEAKS
 func ContextFromChan(chStop <-chan struct{}) (context.Context, context.CancelFunc) {
-	ctx, cancel := context.WithCancel(context.Background())
-	go func() {
-		select {
-		case <-chStop:
-			cancel()
-		case <-ctx.Done():
-		}
-	}()
-	return ctx, cancel
+	return services.StopRChan(chStop).NewCtx()
 }
 
 // ContextWithDeadlineFn returns a copy of the parent context with the deadline modified by deadlineFn.