Replace two more backoff implementations with common one

Author: bboreham

pkg/alertmanager/multitenant.go

@@ -28,11 +28,13 @@ import (
 	"github.com/weaveworks/cortex/pkg/util"
 )
 
-const (
+var backoffConfig = util.BackoffConfig{
 	// Backoff for loading initial configuration set.
-	minBackoff = 100 * time.Millisecond
-	maxBackoff = 2 * time.Second
+	MinBackoff: 100 * time.Millisecond,
+	MaxBackoff: 2 * time.Second,
+}
 
+const (
 	// If a config sets the Slack URL to this, it will be rewritten to
 	// a URL derived from Config.AutoSlackRoot
 	autoSlackURL = "internal://monitor"
@@ -331,19 +333,15 @@ func (am *MultitenantAlertmanager) Stop() {
 // Load the full set of configurations from the server, retrying with backoff
 // until we can get them.
 func (am *MultitenantAlertmanager) loadAllConfigs() map[string]configs.View {
-	backoff := minBackoff
+	backoff := util.NewBackoff(backoffConfig, nil)
 	for {
 		cfgs, err := am.poll()
 		if err == nil {
 			level.Debug(util.Logger).Log("msg", "MultitenantAlertmanager: initial configuration load", "num_configs", len(cfgs))
 			return cfgs
 		}
 		level.Warn(util.Logger).Log("msg", "MultitenantAlertmanager: error fetching all configurations, backing off", "err", err)
-		time.Sleep(backoff)
-		backoff *= 2
-		if backoff > maxBackoff {
-			backoff = maxBackoff
-		}
+		backoff.Wait()
 	}
 }
 

pkg/ruler/scheduler.go

@@ -18,11 +18,13 @@ import (
 	"github.com/weaveworks/cortex/pkg/util"
 )
 
-const (
+var backoffConfig = util.BackoffConfig{
 	// Backoff for loading initial configuration set.
-	minBackoff = 100 * time.Millisecond
-	maxBackoff = 2 * time.Second
+	MinBackoff: 100 * time.Millisecond,
+	MaxBackoff: 2 * time.Second,
+}
 
+const (
 	timeLogFormat = "2006-01-02T15:04:05"
 )
 
@@ -136,19 +138,15 @@ func (s *scheduler) Stop() {
 // Load the full set of configurations from the server, retrying with backoff
 // until we can get them.
 func (s *scheduler) loadAllConfigs() map[string]configs.View {
-	backoff := minBackoff
+	backoff := util.NewBackoff(backoffConfig, nil)
 	for {
 		cfgs, err := s.poll()
 		if err == nil {
 			level.Debug(util.Logger).Log("msg", "scheduler: initial configuration load", "num_configs", len(cfgs))
 			return cfgs
 		}
 		level.Warn(util.Logger).Log("msg", "scheduler: error fetching all configurations, backing off", "err", err)
-		time.Sleep(backoff)
-		backoff *= 2
-		if backoff > maxBackoff {
-			backoff = maxBackoff
-		}
+		backoff.Wait()
 	}
 }