From a21a7b7d8efe5b594791153e7141b4e58246b299 Mon Sep 17 00:00:00 2001
From: Kostiantyn Masliuk <1pkg@protonmail.com>
Date: Mon, 19 Oct 2020 19:17:43 +0200
Subject: [PATCH] add retry throttler

---
 README.MD                    |  1 +
 runnables.go => executors.go |  0
 throttlers.go                | 23 +++++++++++++++++++++++
 throttlers_test.go           | 23 +++++++++++++++++++++--
 4 files changed, 45 insertions(+), 2 deletions(-)
 rename runnables.go => executors.go (100%)

diff --git a/README.MD b/README.MD
index 926ff5b..7d1e26f 100644
--- a/README.MD
+++ b/README.MD
@@ -159,6 +159,7 @@ thr := NewThrottlerAll( // throttles only if all children throttle
 | any | `func NewThrottlerAny(thrs ...Throttler) Throttler` | Throttles call if any of provided throttlers throttle. |
 | not | `func NewThrottlerNot(thr Throttler) Throttler` | Throttles call if provided throttler doesn't throttle. |
 | suppress | `func NewThrottlerSuppress(thr Throttler) Throttler` | Suppresses provided throttler to never throttle. |
+| retry | `func NewThrottlerRetry(thr Throttler, retries uint64) Throttler` | Retries provided throttler error up until the provided retries threshold.<br> Internally retry uses square throttler with `DefaultRetriedDuration` initial duration. |
 
 ## Integrations
 
diff --git a/runnables.go b/executors.go
similarity index 100%
rename from runnables.go
rename to executors.go
diff --git a/throttlers.go b/throttlers.go
index 726e098..563b3cb 100644
--- a/throttlers.go
+++ b/throttlers.go
@@ -770,3 +770,26 @@ func (thr tsuppress) Release(ctx context.Context) error {
 	_ = thr.thr.Release(ctx)
 	return nil
 }
+
+type tretry struct {
+	thr     Throttler
+	retries uint64
+}
+
+// NewThrottlerRetry creates new throttler instance that
+// retries provided throttler error up until the provided retries threshold.
+// Internally retry uses square throttler with `DefaultRetriedDuration` initial duration.
+func NewThrottlerRetry(thr Throttler, retries uint64) Throttler {
+	return tretry{thr: thr, retries: retries}
+}
+
+func (thr tretry) Acquire(ctx context.Context) error {
+	return retried(thr.retries, func(ctx context.Context) error {
+		return thr.thr.Acquire(ctx)
+	})(ctx)
+}
+
+func (thr tretry) Release(ctx context.Context) error {
+	_ = thr.thr.Release(ctx)
+	return nil
+}
diff --git a/throttlers_test.go b/throttlers_test.go
index 339379e..67f242e 100644
--- a/throttlers_test.go
+++ b/throttlers_test.go
@@ -102,6 +102,7 @@ func (t *tcase) result(index int) (dur time.Duration, err error) {
 }
 
 func TestThrottlers(t *testing.T) {
+	DefaultRetriedDuration = time.Millisecond
 	cctx, cancel := context.WithCancel(context.Background())
 	cancel()
 	table := map[string]tcase{
@@ -774,14 +775,32 @@ func TestThrottlers(t *testing.T) {
 				errors.New("throttler hasn't received any internal error"),
 			},
 		},
-		"Throttler suppress should not throttle on internal errors": {
+		"Throttler suppress should not throttle on internal error": {
 			tms: 3,
 			thr: NewThrottlerSuppress(NewThrottlerEcho(errors.New("test"))),
 		},
-		"Throttler suppress should throttle on non internal errors": {
+		"Throttler suppress should throttle on non internal error": {
 			tms: 3,
 			thr: NewThrottlerSuppress(NewThrottlerEcho(nil)),
 		},
+		"Throttler retry should throttle on recuring internal error": {
+			tms: 3,
+			thr: NewThrottlerRetry(NewThrottlerEcho(errors.New("test")), 2),
+			errs: []error{
+				errors.New("test"),
+				errors.New("test"),
+				errors.New("test"),
+			},
+		},
+		"Throttler retry should not throttle on retried recuring internal error": {
+			tms: 3,
+			thr: NewThrottlerRetry(NewThrottlerAfter(3), 2),
+			errs: []error{
+				errors.New("test"),
+				nil,
+				nil,
+			},
+		},
 	}
 	for tname, ptrtcase := range table {
 		t.Run(tname, func(t *testing.T) {