pkg/leakybucket: avoid busy loop

Author: mmetc

pkg/leakybucket/manager_run.go

@@ -76,18 +76,14 @@ func PourItemToBucket(
 
 	sigclosed := 0
 	failed_sent := 0
-	attempts := 0
 	start := time.Now().UTC()
 
-	for {
-		attempts += 1
-		/* Warn the user if we used more than a 100 ms to pour an event, it's at least an half lock*/
-		if attempts%100000 == 0 && start.Add(100*time.Millisecond).Before(time.Now().UTC()) {
-			holder.logger.Warningf("stuck for %s sending event to %s (sigclosed:%d failed_sent:%d attempts:%d)", time.Since(start),
-				buckey, sigclosed, failed_sent, attempts)
-		}
+	// Warn if we're stuck for too long trying to pour
+	warnTicker := time.NewTicker(100 * time.Millisecond)
+	defer warnTicker.Stop()
 
-		/* check if leak routine is up */
+	for {
+		// If bucket is dead, recreate and retry.
 		select {
 		case <-bucket.done:
 			// the bucket was found and dead, get a new one and continue
@@ -100,6 +96,8 @@ func PourItemToBucket(
 			}
 			continue
 			// holder.logger.Tracef("Signal exists, try to pour :)")
+		case <-ctx.Done():
+			return ctx.Err()
 		default:
 			// nothing to read, but not closed, try to pour
 			// holder.logger.Tracef("Signal exists but empty, try to pour :)")
@@ -131,7 +129,9 @@ func PourItemToBucket(
 				}
 			}
 		}
-		// the bucket seems to be up & running
+
+		// Block until we can send, or we learn it's dead/canceled, or we warn periodically.
+
 		select {
 		case bucket.In <- parsed:
 			// holder.logger.Tracef("Successfully sent !")
@@ -141,11 +141,23 @@ func PourItemToBucket(
 			}
 			holder.logger.Debugf("bucket '%s' is poured", holder.Spec.Name)
 			return nil
+		// XXX: bucket died while we were waiting to send.
+		// case <- bucket.done:
+
+		case <-ctx.Done():
+			return ctx.Err()
+
+		case <-warnTicker.C:
+			// We are blocked because bucket.In isn't being read fast enough (or at all).
+			holder.logger.Warningf(
+				"stuck for %s sending event to %s (sigclosed:%d failed_sent:%d",
+				time.Since(start),
+				buckey,
+				sigclosed,
+				failed_sent,
+			)
+			failed_sent++
 		default:
-			failed_sent += 1
-			// holder.logger.Tracef("Failed to send, try again")
-			continue
-
 		}
 	}
 }