pkg/cacheutil: Async op fix (#8044)

* Add test for AsyncOperationProcessor stop() behavior The existing implementation sometimes drops existing operations that are still on the queue when .stop() is called. If multiple communications in a select statement can proceed, one is chosen pseudo-randomly: https://go.dev/ref/spec#Select_statements This means that sometimes a processor worker will process a remaining operation, and sometimes it won't. Signed-off-by: Daniel Sabsay <[email protected]> * Fix async_op test regarding stop() behavior Signed-off-by: Daniel Sabsay <[email protected]> * add header to test file Signed-off-by: Daniel Sabsay <[email protected]> --------- Signed-off-by: Daniel Sabsay <[email protected]> Co-authored-by: Daniel Sabsay <[email protected]>
thanos-io · Jan 10, 2025 · 4ba0ba4 · 4ba0ba4
1 parent f250d68
commit 4ba0ba4
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diff --git a/pkg/cacheutil/async_op.go b/pkg/cacheutil/async_op.go
@@ -54,7 +54,14 @@ func (p *AsyncOperationProcessor) asyncQueueProcessLoop() {
 		case op := <-p.asyncQueue:
 			op()
 		case <-p.stop:
-			return
+			// Run all remaining operations before stopping
+			select {
+			case op := <-p.asyncQueue:
+				op()
+				continue
+			default:
+				return
+			}
 		}
 	}
 }

diff --git a/pkg/cacheutil/async_op_test.go b/pkg/cacheutil/async_op_test.go
@@ -0,0 +1,36 @@
+// Copyright (c) The Thanos Authors.
+// Licensed under the Apache License 2.0.
+
+package cacheutil
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/efficientgo/core/testutil"
+)
+
+// Ensure that the processor does not stop if there are still operations waiting in the queue.
+func TestAsyncOp(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		runTest(t)
+	}
+}
+
+func runTest(t *testing.T) {
+	p := NewAsyncOperationProcessor(100, 10)
+	mtx := sync.Mutex{}
+	var acc int = 0
+
+	for i := 0; i < 100; i++ {
+		err := p.EnqueueAsync(func() {
+			mtx.Lock()
+			defer mtx.Unlock()
+			acc += 1
+		})
+		testutil.Ok(t, err)
+	}
+
+	p.Stop()
+	testutil.Equals(t, 100, acc)
+}