fix: 修正异步运行时隔离并更新使用与迁移说明

async_runtime_test.go

@@ -0,0 +1,27 @@
+package starlog
+
+import "testing"
+
+func resetLoggerAsyncRuntimeForTest(t *testing.T, logger *StarLogger) *asyncRuntime {
+	t.Helper()
+	if logger == nil {
+		t.Fatal("logger is nil")
+	}
+	runtime := logger.asyncRuntime()
+	runtime.resetForTest()
+	t.Cleanup(runtime.resetForTest)
+	return runtime
+}
+
+func setAsyncRuntimeStateForTest(runtime *asyncRuntime, queue *starChanStack, started bool) {
+	if runtime == nil {
+		return
+	}
+	runtime.Stop()
+	runtime.mu.Lock()
+	runtime.queue = queue
+	runtime.started = started
+	runtime.stopChan = nil
+	runtime.doneChan = nil
+	runtime.mu.Unlock()
+}

core.go

@@ -578,7 +578,7 @@ func (logger *starlog) flushPendingWritesLocked(name string, colors []Attr) {
 		logger.pendingWrites = logger.pendingWrites[1:]
 		logger.signalPendingCondLocked()
 		if err := logger.writeDirect(logStr); err != nil {
-			reportWriteError(err, LogData{
+			logger.reportWriteError(err, LogData{
 				Name:   name,
 				Log:    logStr,
 				Colors: colors,
@@ -622,13 +622,13 @@ func (logger *starlog) enqueuePendingWriteLocked(logStr string, data LogData) bo
 		switch logger.pendingDropPolicy {
 		case PendingDropNewest:
 			atomic.AddUint64(&logger.pendingDropCount, 1)
-			reportWriteError(ErrPendingWriteDropped, data)
+			logger.reportWriteError(ErrPendingWriteDropped, data)
 			return true
 		case PendingBlock:
 			atomic.AddUint64(&logger.pendingBlockCount, 1)
 			if logger.pendingCond == nil {
 				atomic.AddUint64(&logger.pendingDropCount, 1)
-				reportWriteError(ErrPendingWriteDropped, data)
+				logger.reportWriteError(ErrPendingWriteDropped, data)
 				return true
 			}
 			logger.pendingCond.Wait()
@@ -638,7 +638,7 @@ func (logger *starlog) enqueuePendingWriteLocked(logStr string, data LogData) bo
 			dropData.Log = logger.pendingWrites[0]
 			logger.pendingWrites = logger.pendingWrites[1:]
 			logger.signalPendingCondLocked()
-			reportWriteError(ErrPendingWriteDropped, dropData)
+			logger.reportWriteError(ErrPendingWriteDropped, dropData)
 		}
 	}
 	if !logger.switching {
@@ -657,14 +657,15 @@ func (logger *starlog) invokeEntryHandler(handler Handler, timeout time.Duration
 	if handlerCtx == nil {
 		handlerCtx = context.Background()
 	}
+	handlerCtx = withAsyncRuntime(handlerCtx, logger.asyncRuntime())
 	run := func() {
 		defer func() {
 			if panicErr := recover(); panicErr != nil {
-				reportAsyncDrop(fmt.Errorf("%w: %v", ErrAsyncHandlerPanic, panicErr), data)
+				logger.reportAsyncDrop(fmt.Errorf("%w: %v", ErrAsyncHandlerPanic, panicErr), data)
 			}
 		}()
 		if err := handler.Handle(handlerCtx, entry); err != nil {
-			reportWriteError(err, data)
+			logger.reportWriteError(err, data)
 		}
 	}
 	if timeout <= 0 {
@@ -679,27 +680,29 @@ func (logger *starlog) invokeEntryHandler(handler Handler, timeout time.Duration
 	select {
 	case <-done:
 	case <-time.After(timeout):
-		reportAsyncDrop(ErrAsyncHandlerTimeout, data)
+		logger.reportAsyncDrop(ErrAsyncHandlerTimeout, data)
 	}
 }
 
 func (logger *starlog) enqueueAsyncTransfer(transfer logTransfer, fallbackSync bool) {
-	StartStacks()
-	if stacks == nil {
-		reportAsyncDrop(io.ErrClosedPipe, transfer.LogData)
-		if fallbackSync && GetAsyncFallbackToSync() {
-			invokeAsyncHandlerSafely(transfer.handlerFunc, transfer.LogData)
+	runtime := logger.asyncRuntime()
+	runtime.Start()
+	queue, _ := runtime.snapshot()
+	if queue == nil {
+		logger.reportAsyncDrop(io.ErrClosedPipe, transfer.LogData)
+		if fallbackSync && runtime.GetAsyncFallbackToSync() {
+			runtime.invokeAsyncHandlerSafely(transfer.handlerFunc, transfer.LogData)
 		}
 		return
 	}
-	if err := stacks.TryPush(transfer); err != nil {
+	if err := queue.TryPush(transfer); err != nil {
 		if errors.Is(err, errStackFull) {
-			reportAsyncDrop(ErrAsyncQueueFull, transfer.LogData)
+			logger.reportAsyncDrop(ErrAsyncQueueFull, transfer.LogData)
 		} else {
-			reportAsyncDrop(err, transfer.LogData)
+			logger.reportAsyncDrop(err, transfer.LogData)
 		}
-		if fallbackSync && GetAsyncFallbackToSync() {
-			invokeAsyncHandlerSafely(transfer.handlerFunc, transfer.LogData)
+		if fallbackSync && runtime.GetAsyncFallbackToSync() {
+			runtime.invokeAsyncHandlerSafely(transfer.handlerFunc, transfer.LogData)
 		}
 	}
 }
@@ -795,21 +798,21 @@ func (logger *starlog) build(thread string, isStd bool, isShow bool, handler fun
 		if level < snapshot.errOutputLevel {
 			if snapshot.showColor {
 				if _, err := fmt.Fprint(stdScreen, displayLine); err != nil {
-					reportWriteError(err, logData)
+					logger.reportWriteError(err, logData)
 				}
 			} else {
 				if _, err := fmt.Fprint(os.Stdout, displayLine); err != nil {
-					reportWriteError(err, logData)
+					logger.reportWriteError(err, logData)
 				}
 			}
 		} else {
 			if snapshot.showColor {
 				if _, err := fmt.Fprint(errScreen, displayLine); err != nil {
-					reportWriteError(err, logData)
+					logger.reportWriteError(err, logData)
 				}
 			} else {
 				if _, err := fmt.Fprint(os.Stderr, displayLine); err != nil {
-					reportWriteError(err, logData)
+					logger.reportWriteError(err, logData)
 				}
 			}
 		}
@@ -858,7 +861,7 @@ func (logger *starlog) writeWithData(logStr string, data LogData) {
 	}
 	logger.flushPendingWritesLocked(data.Name, data.Colors)
 	if err := logger.writeDirect(logStr); err != nil {
-		reportWriteError(err, data)
+		logger.reportWriteError(err, data)
 	}
 }
 

docs/MIGRATION.md

@@ -83,9 +83,17 @@ defer starlog.Shutdown(ctx)
 
 说明：
 
-- `Shutdown(ctx)` 会等待异步 handler drain，并统一关闭资源。
+- `Shutdown(ctx)` 会等待当前 logger 的异步 handler drain，并统一关闭资源。
 - `Close()` 仍可用，但不等待异步 handler 队列。
 
+如果项目里主要使用自定义 logger，推荐直接写成：
+
+```go
+ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+defer cancel()
+defer log.Shutdown(ctx)
+```
+
 ## 常见旧写法到推荐写法
 
 1. 配置项逐条 setter  
@@ -106,6 +114,9 @@ defer starlog.Shutdown(ctx)
 6. 旧 `StartArchive` 轮转启动  
 推荐：`StartRotatePolicy` / `StartManagedRotatePolicy`，模板场景可直接用 `StartRotateByTime/BySize/ByTimeSize`
 
+7. 包级异步观测/回调入口  
+推荐：自定义 logger 优先使用实例方法，例如 `log.SetAsyncErrorHandler(...)`、`log.SetWriteErrorHandler(...)`、`log.GetAsyncDropCount()`、`log.GetWriteErrorCount()`、`log.Shutdown(ctx)`
+
 ## 旧 API 仍可用（重要）
 
 以下旧/兼容路径当前仍可用：
@@ -114,6 +125,7 @@ defer starlog.Shutdown(ctx)
 - 历史错拼兼容名仍可用（如 `EnbaleWrite`、`IsWriteStoed`、`HookBeforArchive`）
 - `Archive` 旧模型仍可用（建议新代码优先 `RotatePolicy`）
 - 旧生命周期入口仍可用（如 `CloseStd`、`Close`），但建议新代码优先 `Shutdown(ctx)` / `CloseLogFile`
+- 包级异步/错误统计入口仍可用，但默认绑定全局 `Std` logger；自定义 logger 建议改用实例方法
 
 ## 升级后验证建议
 
@@ -123,7 +135,7 @@ defer starlog.Shutdown(ctx)
 4. 重点验证：
    - 级别过滤是否符合预期
    - 归档文件数量/保留策略
-   - 异步丢弃计数和写入错误计数
+   - 异步丢弃计数和写入错误计数是否落在预期 logger 上
 
 ## 何时需要进一步迁移
 
@@ -135,5 +147,5 @@ defer starlog.Shutdown(ctx)
 
 ---
 
-如果你希望，我可以基于你当前项目的实际日志初始化代码，给出一份“一次改完可落地”的迁移 patch 方案。
+自定义 logger 较多的项目，建议优先检查包级异步观测入口是否仍在使用，并逐步替换为实例方法。
 

docs/USAGE.md

@@ -421,9 +421,17 @@ log.SetPendingWriteLimit(1024)
 log.SetPendingDropPolicy(starlog.PendingDropOldest)
 ```
 
+说明：
+
+- 每个 `StarLogger` 都有独立的异步运行时。
+- `SetHandler`、`SetEntryHandler`、`SetAsyncErrorHandler`、`SetWriteErrorHandler`、`GetAsyncDropCount`、`GetWriteErrorCount`、`GetAsyncMetrics`、`Shutdown(ctx)` 都作用于当前 logger。
+- 包级入口（如 `starlog.SetAsyncErrorHandler`、`starlog.GetAsyncDropCount`、`starlog.Shutdown(ctx)`）保留兼容，默认作用于全局 `Std` logger。
+
 可观测项：
 
+- `GetAsyncMetrics()`
 - `GetAsyncDropCount()`
+- `GetWriteErrorCount()`
 - `GetPendingStats()`
 
 ## 11. 高频防爆（去重 / 采样 / 限流）
@@ -477,6 +485,8 @@ _ = snapshot
 
 常用统计：
 
+- `GetMetricsSnapshot()`
+- `GetAsyncMetrics()`
 - `GetPendingStats()`
 - `GetSamplingStats()`
 - `GetDedupStats()`
@@ -491,7 +501,7 @@ _ = snapshot
 - `Flush()`：刷写 pending
 - `Sync()`：`Flush + 底层 Sync()`（若支持）
 - `Close()`：关闭资源，不等待异步队列 drain
-- `Shutdown(ctx)`：等待异步 drain，再关闭资源
+- `Shutdown(ctx)`：等待当前 logger 的异步 drain，再关闭资源
 
 推荐：
 
@@ -501,7 +511,11 @@ defer cancel()
 defer log.Shutdown(ctx)
 ```
 
-全局 logger 可使用：`starlog.Shutdown(ctx)`。
+说明：
+
+- 自定义 logger 优先使用 `log.Shutdown(ctx)`。
+- 全局 logger 可使用 `starlog.Shutdown(ctx)`。
+- `WaitAsyncDrain(ctx)` 作为兼容入口保留，默认等待全局 `Std` logger 的异步队列；自定义 logger 退出时直接使用 `log.Shutdown(ctx)` 更明确。
 
 ## 15. 标准库桥接
 
@@ -678,6 +692,7 @@ func main() {
 
 - 显示回调链路：可能因超时或队列满发生丢弃，可通过计数观测
 - writer/sink 主写链路：只要未被过滤（级别/去重/采样/限流）且写入正常，会落盘
+- 多个自定义 logger 之间的异步丢弃计数、写入错误计数和关闭流程彼此独立
 
 ### Q3：新项目应该选 `Archive` 还是 `RotatePolicy`？
 

lifecycle.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"time"
 )
 
 type sinkSyncer interface {
@@ -15,6 +14,10 @@ type writerSyncer interface {
 	Sync() error
 }
 
+type contextualCloser interface {
+	CloseWithContext(context.Context) error
+}
+
 func mergeLifecycleError(current error, next error) error {
 	if next == nil {
 		return current
@@ -26,23 +29,7 @@ func mergeLifecycleError(current error, next error) error {
 }
 
 func WaitAsyncDrain(ctx context.Context) error {
-	if ctx == nil {
-		ctx = context.Background()
-	}
-	for {
-		stackMu.Lock()
-		current := stacks
-		started := stackStarted
-		stackMu.Unlock()
-		if !started || current == nil || current.Len() == 0 {
-			return nil
-		}
-		select {
-		case <-ctx.Done():
-			return ctx.Err()
-		case <-time.After(5 * time.Millisecond):
-		}
-	}
+	return defaultAsyncRuntime().WaitDrain(ctx)
 }
 
 func (logger *StarLogger) Flush() error {
@@ -112,7 +99,9 @@ func (logger *StarLogger) Close() error {
 		}
 	}
 	if entryHandler != nil {
-		if closer, ok := entryHandler.(interface{ Close() error }); ok {
+		if closer, ok := entryHandler.(contextualCloser); ok {
+			err = mergeLifecycleError(err, closer.CloseWithContext(withAsyncRuntime(context.Background(), logger.asyncRuntime())))
+		} else if closer, ok := entryHandler.(interface{ Close() error }); ok {
 			err = mergeLifecycleError(err, closer.Close())
 		}
 	}
@@ -126,8 +115,8 @@ func (logger *StarLogger) Shutdown(ctx context.Context) error {
 	}
 	var err error
 	err = mergeLifecycleError(err, logger.Flush())
-	err = mergeLifecycleError(err, WaitAsyncDrain(ctx))
-	StopStacks()
+	err = mergeLifecycleError(err, logger.asyncRuntime().WaitDrain(ctx))
+	logger.asyncRuntime().Stop()
 	err = mergeLifecycleError(err, logger.Close())
 	return err
 }

lifecycle_test.go

@@ -91,25 +91,13 @@ func TestCloseClosesSinkAndStopsWrite(t *testing.T) {
 }
 
 func TestWaitAsyncDrainContextTimeout(t *testing.T) {
-	stackMu.Lock()
-	stackStarted = true
-	stacks = newStarChanStack(1)
-	stackStopChan = nil
-	stackDoneChan = nil
-	stackMu.Unlock()
-	defer func() {
-		stackMu.Lock()
-		if stacks != nil {
-			_ = stacks.Close()
-		}
-		stackStarted = false
-		stacks = nil
-		stackStopChan = nil
-		stackDoneChan = nil
-		stackMu.Unlock()
-	}()
+	runtime := defaultAsyncRuntime()
+	runtime.resetForTest()
+	t.Cleanup(runtime.resetForTest)
 
-	if err := stacks.Push("x"); err != nil {
+	queue := newStarChanStack(1)
+	setAsyncRuntimeStateForTest(runtime, queue, true)
+	if err := queue.Push("x"); err != nil {
 		t.Fatalf("prepare queue failed: %v", err)
 	}
 	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Millisecond)
@@ -121,13 +109,8 @@ func TestWaitAsyncDrainContextTimeout(t *testing.T) {
 }
 
 func TestShutdownStopsAsyncStacks(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer func() {
-		resetAsyncMetricsForTest()
-		StopStacks()
-	}()
-
 	logger := NewStarlog(nil)
+	runtime := resetLoggerAsyncRuntimeForTest(t, logger)
 	logger.SetShowStd(false)
 	handled := make(chan struct{}, 1)
 	logger.SetHandler(func(LogData) {
@@ -149,11 +132,36 @@ func TestShutdownStopsAsyncStacks(t *testing.T) {
 		t.Fatalf("async handler should complete before shutdown")
 	}
 
-	stackMu.Lock()
-	started := stackStarted
-	stackMu.Unlock()
-	if started {
-		t.Fatalf("Shutdown should stop async stacks")
+	if runtime.Metrics().Started {
+		t.Fatalf("Shutdown should stop logger async runtime")
+	}
+}
+
+func TestShutdownDoesNotStopOtherLoggerAsyncRuntime(t *testing.T) {
+	loggerA := NewStarlog(nil)
+	runtimeA := resetLoggerAsyncRuntimeForTest(t, loggerA)
+	loggerA.SetShowStd(false)
+	loggerA.SetHandler(func(LogData) {})
+
+	loggerB := NewStarlog(nil)
+	runtimeB := resetLoggerAsyncRuntimeForTest(t, loggerB)
+	loggerB.SetShowStd(false)
+	loggerB.SetHandler(func(LogData) {})
+
+	if !runtimeA.Metrics().Started || !runtimeB.Metrics().Started {
+		t.Fatalf("both logger runtimes should be started")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	if err := loggerA.Shutdown(ctx); err != nil {
+		t.Fatalf("Shutdown failed: %v", err)
+	}
+	if runtimeA.Metrics().Started {
+		t.Fatalf("Shutdown should stop only the target logger runtime")
+	}
+	if !runtimeB.Metrics().Started {
+		t.Fatalf("Shutdown should not stop another logger runtime")
 	}
 }
 

metrics.go

@@ -35,42 +35,29 @@ type MetricsSnapshot struct {
 }
 
 func GetAsyncMetrics() AsyncMetrics {
-	stackMu.Lock()
-	started := stackStarted
-	current := stacks
-	stackMu.Unlock()
-
-	snapshot := AsyncMetrics{
-		Started:        started,
-		Dropped:        GetAsyncDropCount(),
-		FallbackToSync: GetAsyncFallbackToSync(),
-		HandlerTimeout: GetAsyncHandlerTimeout(),
-	}
-	if current != nil {
-		snapshot.QueueLength = current.Len()
-		snapshot.QueueCapacity = current.Cap()
-		snapshot.QueueFree = current.Free()
-	}
-	return snapshot
+	return defaultAsyncRuntime().Metrics()
 }
 
 func (logger *StarLogger) GetMetricsSnapshot() MetricsSnapshot {
 	snapshot := MetricsSnapshot{
 		Time: time.Now(),
-		Async: GetAsyncMetrics(),
 		Errors: ErrorMetrics{
-			WriteErrors: GetWriteErrorCount(),
+			WriteErrors: 0,
 		},
 	}
 	if logger == nil || logger.logcore == nil {
+		snapshot.Async = GetAsyncMetrics()
+		snapshot.Errors.WriteErrors = GetWriteErrorCount()
 		return snapshot
 	}
 
+	snapshot.Async = logger.GetAsyncMetrics()
 	snapshot.Pending = logger.GetPendingStats()
 	snapshot.Sampling = logger.GetSamplingStats()
 	snapshot.Dedup = logger.GetDedupStats()
 	snapshot.RateLimit = logger.GetRateLimitStats()
 	snapshot.Errors.RedactionErrors = logger.GetRedactErrorCount()
+	snapshot.Errors.WriteErrors = logger.GetWriteErrorCount()
 	snapshot.ArchiveRunning = IsArchiveRun(logger)
 
 	logger.logcore.mu.Lock()
@@ -90,6 +77,8 @@ func (logger *StarLogger) GetMetricsSnapshot() MetricsSnapshot {
 }
 
 func (logger *StarLogger) GetAsyncMetrics() AsyncMetrics {
-	_ = logger
+	if logger == nil {
 		return GetAsyncMetrics()
+	}
+	return logger.asyncRuntime().Metrics()
 }

metrics_test.go

@@ -1,6 +1,7 @@
 package starlog
 
 import (
+	"bytes"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -60,8 +61,8 @@ func TestMetricsSnapshotIncludesPendingAndMultiSink(t *testing.T) {
 	if snapshot.Pending.Policy != PendingDropOldest {
 		t.Fatalf("snapshot should include pending policy")
 	}
-	if snapshot.Errors.WriteErrors != GetWriteErrorCount() {
-		t.Fatalf("snapshot write error count should match global counter")
+	if snapshot.Errors.WriteErrors != logger.GetWriteErrorCount() {
+		t.Fatalf("snapshot write error count should match logger counter")
 	}
 	if !snapshot.Sampling.Enabled || snapshot.Sampling.Rate != 0.5 {
 		t.Fatalf("snapshot should include sampling stats, got %+v", snapshot.Sampling)
@@ -97,3 +98,27 @@ func TestMetricsSnapshotNilLogger(t *testing.T) {
 		t.Fatalf("snapshot should contain timestamp")
 	}
 }
+
+func TestMetricsSnapshotUsesLoggerRuntimeCounters(t *testing.T) {
+	loggerA := NewStarlog(&errWriter{})
+	resetLoggerAsyncRuntimeForTest(t, loggerA)
+	loggerA.SetShowStd(false)
+	loggerA.SetShowColor(false)
+	loggerA.SetShowOriginFile(false)
+	loggerA.SetShowFuncName(false)
+	loggerA.SetShowFlag(false)
+
+	loggerB := newStructuredTestLogger(&bytes.Buffer{})
+	resetLoggerAsyncRuntimeForTest(t, loggerB)
+
+	loggerA.Infoln("write error check")
+
+	snapshotA := loggerA.GetMetricsSnapshot()
+	snapshotB := loggerB.GetMetricsSnapshot()
+	if snapshotA.Errors.WriteErrors == 0 {
+		t.Fatalf("snapshot should include logger write errors")
+	}
+	if snapshotB.Errors.WriteErrors != 0 {
+		t.Fatalf("other logger snapshot should not inherit write errors, got %d", snapshotB.Errors.WriteErrors)
+	}
+}

observer_test.go

@@ -38,9 +38,9 @@ func waitObserverCondition(t *testing.T, timeout time.Duration, cond func() bool
 }
 
 func TestObserverCollectsEntries(t *testing.T) {
-	defer StopStacks()
 	var buf bytes.Buffer
 	logger := newStructuredTestLogger(&buf)
+	defer logger.asyncRuntime().Stop()
 	observer := NewObserver()
 	logger.AppendEntryHandler(observer)
 
@@ -61,9 +61,9 @@ func TestObserverCollectsEntries(t *testing.T) {
 }
 
 func TestObserverLimitAndDropped(t *testing.T) {
-	defer StopStacks()
 	observer := NewObserverWithLimit(2)
 	logger := newStructuredTestLogger(&bytes.Buffer{})
+	defer logger.asyncRuntime().Stop()
 	logger.AppendEntryHandler(observer)
 
 	logger.Info("one")
@@ -93,9 +93,9 @@ func TestObserverLimitAndDropped(t *testing.T) {
 }
 
 func TestObserverTakeAllAndReset(t *testing.T) {
-	defer StopStacks()
 	observer := NewObserver()
 	logger := newStructuredTestLogger(&bytes.Buffer{})
+	defer logger.asyncRuntime().Stop()
 	logger.AppendEntryHandler(observer)
 
 	logger.Info("a")
@@ -119,9 +119,9 @@ func TestObserverTakeAllAndReset(t *testing.T) {
 }
 
 func TestTestHookAttachAndRestore(t *testing.T) {
-	defer StopStacks()
 	var buf bytes.Buffer
 	logger := newStructuredTestLogger(&buf)
+	defer logger.asyncRuntime().Stop()
 	var previousCount uint64
 	logger.SetEntryHandler(HandlerFunc(func(_ context.Context, _ *Entry) error {
 		atomic.AddUint64(&previousCount, 1)
@@ -163,8 +163,8 @@ func TestTestHookAttachAndRestore(t *testing.T) {
 }
 
 func TestTestHookCloseWhenHandlerReplaced(t *testing.T) {
-	defer StopStacks()
 	logger := newStructuredTestLogger(&bytes.Buffer{})
+	defer logger.asyncRuntime().Stop()
 	hook := NewTestHook(logger)
 	logger.SetEntryHandler(nil)
 

p0_reliability_test.go

@@ -33,21 +33,8 @@ func TestWriteBufferFlushAfterSwitchingOff(t *testing.T) {
 }
 
 func TestAsyncQueuePushFailureFallsBackToSyncHandler(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer func() {
-		resetAsyncMetricsForTest()
-		stackMu.Lock()
-		if stacks != nil {
-			_ = stacks.Close()
-		}
-		stackStarted = false
-		stacks = nil
-		stackStopChan = nil
-		stackDoneChan = nil
-		stackMu.Unlock()
-	}()
-
 	logger := NewStarlog(nil)
+	runtime := resetLoggerAsyncRuntimeForTest(t, logger)
 	logger.SetShowStd(false)
 	var handled uint64
 	logger.handlerFunc = func(data LogData) {
@@ -55,26 +42,21 @@ func TestAsyncQueuePushFailureFallsBackToSyncHandler(t *testing.T) {
 	}
 
 	alertCalled := make(chan struct{}, 1)
-	SetAsyncErrorHandler(func(err error, data LogData) {
+	logger.SetAsyncErrorHandler(func(err error, data LogData) {
 		select {
 		case alertCalled <- struct{}{}:
 		default:
 		}
 	})
 
-	stackMu.Lock()
-	stackStarted = true
-	stacks = nil
-	stackStopChan = nil
-	stackDoneChan = nil
-	stackMu.Unlock()
+	setAsyncRuntimeStateForTest(runtime, nil, true)
 
 	logger.Infoln("trigger async fallback")
 
 	if atomic.LoadUint64(&handled) != 1 {
 		t.Fatalf("handler should be called once via sync fallback, got: %d", handled)
 	}
-	if GetAsyncDropCount() == 0 {
+	if logger.GetAsyncDropCount() == 0 {
 		t.Fatalf("async drop counter should increase on push failure")
 	}
 	select {
@@ -221,15 +203,13 @@ func (w *errWriter) Write(p []byte) (int, error) {
 }
 
 func TestWriteErrorObservable(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer resetAsyncMetricsForTest()
-
 	logger := NewStarlog(&errWriter{})
+	resetLoggerAsyncRuntimeForTest(t, logger)
 	logger.SetShowStd(false)
 	logger.SetShowColor(false)
 
 	observed := make(chan struct{}, 1)
-	SetWriteErrorHandler(func(err error, data LogData) {
+	logger.SetWriteErrorHandler(func(err error, data LogData) {
 		if err != nil {
 			select {
 			case observed <- struct{}{}:
@@ -240,7 +220,7 @@ func TestWriteErrorObservable(t *testing.T) {
 
 	logger.Infoln("write error check")
 
-	if GetWriteErrorCount() == 0 {
+	if logger.GetWriteErrorCount() == 0 {
 		t.Fatalf("write error count should increase")
 	}
 	select {
@@ -251,13 +231,8 @@ func TestWriteErrorObservable(t *testing.T) {
 }
 
 func TestAsyncHandlerPanicDoesNotCrash(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer func() {
-		resetAsyncMetricsForTest()
-		StopStacks()
-	}()
-
 	logger := NewStarlog(nil)
+	resetLoggerAsyncRuntimeForTest(t, logger)
 	logger.SetShowStd(false)
 	logger.SetHandler(func(LogData) {
 		panic("boom")
@@ -266,19 +241,14 @@ func TestAsyncHandlerPanicDoesNotCrash(t *testing.T) {
 	logger.Infoln("panic safe")
 	time.Sleep(20 * time.Millisecond)
 
-	if GetAsyncDropCount() == 0 {
+	if logger.GetAsyncDropCount() == 0 {
 		t.Fatalf("panic in async handler should be reported as drop")
 	}
 }
 
 func TestEntryHandlerTimeoutFallback(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer func() {
-		resetAsyncMetricsForTest()
-		StopStacks()
-	}()
-
 	logger := NewStarlog(nil)
+	resetLoggerAsyncRuntimeForTest(t, logger)
 	logger.SetShowStd(false)
 	logger.SetEntryHandler(HandlerFunc(func(context.Context, *Entry) error {
 		time.Sleep(80 * time.Millisecond)
@@ -295,7 +265,7 @@ func TestEntryHandlerTimeoutFallback(t *testing.T) {
 	}
 	deadline := time.Now().Add(300 * time.Millisecond)
 	for time.Now().Before(deadline) {
-		if GetAsyncDropCount() > 0 {
+		if logger.GetAsyncDropCount() > 0 {
 			return
 		}
 		time.Sleep(5 * time.Millisecond)
@@ -304,20 +274,9 @@ func TestEntryHandlerTimeoutFallback(t *testing.T) {
 }
 
 func TestEntryHandlerQueueFullNoFallbackDoesNotBlock(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer func() {
-		resetAsyncMetricsForTest()
-		stackMu.Lock()
-		stackStarted = false
-		stacks = nil
-		stackStopChan = nil
-		stackDoneChan = nil
-		stackMu.Unlock()
-	}()
-
-	SetAsyncFallbackToSync(false)
-
 	logger := NewStarlog(nil)
+	runtime := resetLoggerAsyncRuntimeForTest(t, logger)
+	logger.SetAsyncFallbackToSync(false)
 	logger.SetShowStd(false)
 	var handled uint64
 	logger.SetEntryHandler(HandlerFunc(func(context.Context, *Entry) error {
@@ -326,14 +285,10 @@ func TestEntryHandlerQueueFullNoFallbackDoesNotBlock(t *testing.T) {
 		return nil
 	}))
 
-	stackMu.Lock()
-	stackStarted = true
-	stacks = newStarChanStack(1)
-	stackStopChan = nil
-	stackDoneChan = nil
-	stackMu.Unlock()
+	queue := newStarChanStack(1)
+	setAsyncRuntimeStateForTest(runtime, queue, true)
 
-	if err := stacks.Push(logTransfer{
+	if err := queue.Push(logTransfer{
 		handlerFunc: func(LogData) {
 			time.Sleep(80 * time.Millisecond)
 		},
@@ -351,7 +306,7 @@ func TestEntryHandlerQueueFullNoFallbackDoesNotBlock(t *testing.T) {
 	if atomic.LoadUint64(&handled) != 0 {
 		t.Fatalf("entry handler should be dropped when queue is full and fallback disabled, got %d", handled)
 	}
-	if GetAsyncDropCount() == 0 {
+	if logger.GetAsyncDropCount() == 0 {
 		t.Fatalf("queue-full drop should be observable")
 	}
 }

redaction.go

@@ -65,7 +65,7 @@ func (logger *starlog) applyRedaction(snapshot *starlog, entry *Entry) bool {
 }
 
 func (logger *starlog) handleRedactionFailure(snapshot *starlog, entry *Entry, err error) bool {
-	reportWriteError(fmt.Errorf("%w: %v", ErrRedactionFailed, err), LogData{
+	logger.reportWriteError(fmt.Errorf("%w: %v", ErrRedactionFailed, err), LogData{
 		Name: snapshot.name,
 		Log:  entry.Message,
 	})

redaction_test.go

@@ -146,17 +146,15 @@ func TestSetRedactMaskToken(t *testing.T) {
 }
 
 func TestRedactionFailureReportsWriteError(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer resetAsyncMetricsForTest()
-
 	var buf bytes.Buffer
 	logger := newStructuredTestLogger(&buf)
+	resetLoggerAsyncRuntimeForTest(t, logger)
 	logger.SetRedactor(RedactorFunc(func(context.Context, *Entry) error {
 		return errors.New("redactor failed")
 	}))
 
 	observed := make(chan error, 1)
-	SetWriteErrorHandler(func(err error, data LogData) {
+	logger.SetWriteErrorHandler(func(err error, data LogData) {
 		if err == nil {
 			return
 		}
@@ -167,7 +165,7 @@ func TestRedactionFailureReportsWriteError(t *testing.T) {
 	})
 
 	logger.Info("check redaction error report")
-	if GetWriteErrorCount() == 0 {
+	if logger.GetWriteErrorCount() == 0 {
 		t.Fatalf("write error count should increase when redaction fails")
 	}
 	select {

route_handler.go

@@ -87,7 +87,7 @@ func (handler *RouteHandler) Handle(ctx context.Context, entry *Entry) error {
 		formatted, err := formatter.Format(entry)
 		if err != nil {
 			wrapErr := fmt.Errorf("route %s format failed: %w", route.name, err)
-			reportWriteError(wrapErr, LogData{
+			reportWriteErrorWithContext(ctx, wrapErr, LogData{
 				Name: route.name,
 				Log:  entry.Message,
 			})
@@ -101,7 +101,7 @@ func (handler *RouteHandler) Handle(ctx context.Context, entry *Entry) error {
 		}
 		if err = route.sink.Write(formatted); err != nil {
 			wrapErr := fmt.Errorf("route %s write failed: %w", route.name, err)
-			reportWriteError(wrapErr, LogData{
+			reportWriteErrorWithContext(ctx, wrapErr, LogData{
 				Name: route.name,
 				Log:  string(formatted),
 			})
@@ -115,6 +115,10 @@ func (handler *RouteHandler) Handle(ctx context.Context, entry *Entry) error {
 }
 
 func (handler *RouteHandler) Close() error {
+	return handler.CloseWithContext(nil)
+}
+
+func (handler *RouteHandler) CloseWithContext(ctx context.Context) error {
 	if handler == nil {
 		return nil
 	}
@@ -137,7 +141,7 @@ func (handler *RouteHandler) Close() error {
 		}
 		if err := route.sink.Close(); err != nil {
 			wrapErr := fmt.Errorf("route %s close failed: %w", route.name, err)
-			reportWriteError(wrapErr, LogData{
+			reportWriteErrorWithContext(ctx, wrapErr, LogData{
 				Name: route.name,
 			})
 			if firstErr == nil {
@@ -198,6 +202,10 @@ func (handler *chainedHandler) Handle(ctx context.Context, entry *Entry) error {
 }
 
 func (handler *chainedHandler) Close() error {
+	return handler.CloseWithContext(nil)
+}
+
+func (handler *chainedHandler) CloseWithContext(ctx context.Context) error {
 	if handler == nil {
 		return nil
 	}
@@ -206,14 +214,18 @@ func (handler *chainedHandler) Close() error {
 		if item == nil {
 			continue
 		}
-		closer, ok := item.(interface{ Close() error })
-		if !ok {
+		if closer, ok := item.(contextualCloser); ok {
+			if err := closer.CloseWithContext(ctx); err != nil && firstErr == nil {
+				firstErr = err
+			}
 			continue
 		}
+		if closer, ok := item.(interface{ Close() error }); ok {
 			if err := closer.Close(); err != nil && firstErr == nil {
 				firstErr = err
 			}
 		}
+	}
 	return firstErr
 }
 

route_handler_test.go

@@ -47,6 +47,17 @@ func (sink *closeCountSink) Close() error {
 	return nil
 }
 
+type closeFailSink struct{}
+
+func (sink *closeFailSink) Write(data []byte) error {
+	_ = data
+	return nil
+}
+
+func (sink *closeFailSink) Close() error {
+	return errors.New("route sink close failed")
+}
+
 type safeBuffer struct {
 	mu  sync.Mutex
 	buf bytes.Buffer
@@ -206,11 +217,9 @@ func TestChainHandlerRunsAll(t *testing.T) {
 }
 
 func TestRouteHandlerWriteErrorObservable(t *testing.T) {
-	resetAsyncMetricsForTest()
-	defer resetAsyncMetricsForTest()
-
 	var totalBuf safeBuffer
 	logger := newStructuredTestLogger(&totalBuf)
+	resetLoggerAsyncRuntimeForTest(t, logger)
 	logger.SetEntryHandler(NewRouteHandler(
 		Route{
 			Name:      "failed-route",
@@ -222,10 +231,50 @@ func TestRouteHandlerWriteErrorObservable(t *testing.T) {
 
 	logger.Info("route write error")
 	waitFor(t, 300*time.Millisecond, func() bool {
-		return GetWriteErrorCount() > 0
+		return logger.GetWriteErrorCount() > 0
 	}, "route sink write error observable")
 }
 
+func TestRouteHandlerCloseErrorUsesLoggerRuntime(t *testing.T) {
+	logger := newStructuredTestLogger(&bytes.Buffer{})
+	resetLoggerAsyncRuntimeForTest(t, logger)
+
+	observed := make(chan error, 1)
+	logger.SetWriteErrorHandler(func(err error, data LogData) {
+		if err == nil {
+			return
+		}
+		select {
+		case observed <- err:
+		default:
+		}
+	})
+	logger.SetEntryHandler(NewRouteHandler(
+		Route{
+			Name:      "failed-close",
+			Match:     MatchAllLevels(),
+			Formatter: &messageOnlyFormatter{},
+			Sink:      &closeFailSink{},
+		},
+	))
+
+	err := logger.Close()
+	if err == nil {
+		t.Fatalf("logger close should return route close error")
+	}
+	if logger.GetWriteErrorCount() == 0 {
+		t.Fatalf("route close error should increase logger write error count")
+	}
+	select {
+	case observedErr := <-observed:
+		if !strings.Contains(observedErr.Error(), "route sink close failed") {
+			t.Fatalf("unexpected observed error: %v", observedErr)
+		}
+	default:
+		t.Fatalf("route close error should invoke logger write error handler")
+	}
+}
+
 func TestRouteHandlerCloseDeduplicatesSameSink(t *testing.T) {
 	sink := &closeCountSink{}
 	handler := NewRouteHandler(
@@ -284,23 +333,31 @@ func TestRouteHandlerWithRotatingFileSink(t *testing.T) {
 		logger.Infof("debug payload %02d %s", idx, strings.Repeat("x", 24))
 		time.Sleep(3 * time.Millisecond)
 	}
-	waitFor(t, 2*time.Second, func() bool {
+
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	if err = logger.Shutdown(ctx); err != nil {
+		t.Fatalf("logger shutdown failed: %v", err)
+	}
+
+	paths := []string{debugPath}
 	matches, _ := filepath.Glob(filepath.Join(filepath.Dir(debugPath), "debug.*.log"))
-		return len(matches) > 0
-	}, "rotating route sink archive creation")
-
-	content, readErr := ioutil.ReadFile(debugPath)
+	paths = append(paths, matches...)
+	found := false
+	for _, path := range paths {
+		content, readErr := ioutil.ReadFile(path)
 		if readErr != nil {
-		t.Fatalf("read debug current log failed: %v", readErr)
+			t.Fatalf("read routed log %s failed: %v", path, readErr)
 		}
-	if len(content) == 0 {
-		t.Fatalf("debug log should contain routed logs")
+		if strings.Contains(string(content), "debug payload") {
+			found = true
+			break
 		}
-
-	if err = logger.Close(); err != nil {
-		t.Fatalf("logger close failed: %v", err)
+	}
+	if !found {
+		t.Fatalf("routed logs should exist in current or archived debug files")
 	}
 	if err = debugSink.Write([]byte("after close")); !errors.Is(err, ErrRotatingFileSinkClosed) {
-		t.Fatalf("rotating sink should be closed by logger close, got %v", err)
+		t.Fatalf("rotating sink should be closed by logger shutdown, got %v", err)
 	}
 }

starlog.go

@@ -107,7 +107,7 @@ func (logger *starlog) applyPendingLimitLocked(limit int) {
 		case PendingDropNewest:
 			keepEnd := len(logger.pendingWrites) - dropped
 			for idx := keepEnd; idx < len(logger.pendingWrites); idx++ {
-			reportWriteError(ErrPendingWriteDropped, LogData{
+				logger.reportWriteError(ErrPendingWriteDropped, LogData{
 					Name: logger.name,
 					Log:  logger.pendingWrites[idx],
 				})
@@ -115,7 +115,7 @@ func (logger *starlog) applyPendingLimitLocked(limit int) {
 		logger.pendingWrites = logger.pendingWrites[:keepEnd]
 		default:
 			for idx := 0; idx < dropped; idx++ {
-			reportWriteError(ErrPendingWriteDropped, LogData{
+				logger.reportWriteError(ErrPendingWriteDropped, LogData{
 					Name: logger.name,
 					Log:  logger.pendingWrites[idx],
 				})
@@ -464,7 +464,7 @@ func (logger *StarLogger) AppendEntryHandler(handler Handler) {
 
 func (logger *StarLogger) SetHandler(f func(LogData)) {
 	if f != nil {
-		StartStacks()
+		logger.asyncRuntime().Start()
 	}
 	logger.logcore.mu.Lock()
 	defer logger.logcore.mu.Unlock()
@@ -487,35 +487,35 @@ func (logger *StarLogger) SetSwitching(sw bool) {
 }
 
 func (logger *StarLogger) SetAsyncErrorHandler(alert func(error, LogData)) {
-	SetAsyncErrorHandler(alert)
+	logger.asyncRuntime().SetAsyncErrorHandler(alert)
 }
 
 func (logger *StarLogger) GetAsyncDropCount() uint64 {
-	return GetAsyncDropCount()
+	return logger.asyncRuntime().GetAsyncDropCount()
 }
 
 func (logger *StarLogger) SetAsyncFallbackToSync(enable bool) {
-	SetAsyncFallbackToSync(enable)
+	logger.asyncRuntime().SetAsyncFallbackToSync(enable)
 }
 
 func (logger *StarLogger) GetAsyncFallbackToSync() bool {
-	return GetAsyncFallbackToSync()
+	return logger.asyncRuntime().GetAsyncFallbackToSync()
 }
 
 func (logger *StarLogger) SetAsyncHandlerTimeout(timeout time.Duration) {
-	SetAsyncHandlerTimeout(timeout)
+	logger.asyncRuntime().SetAsyncHandlerTimeout(timeout)
 }
 
 func (logger *StarLogger) GetAsyncHandlerTimeout() time.Duration {
-	return GetAsyncHandlerTimeout()
+	return logger.asyncRuntime().GetAsyncHandlerTimeout()
 }
 
 func (logger *StarLogger) SetWriteErrorHandler(alert func(error, LogData)) {
-	SetWriteErrorHandler(alert)
+	logger.asyncRuntime().SetWriteErrorHandler(alert)
 }
 
 func (logger *StarLogger) GetWriteErrorCount() uint64 {
-	return GetWriteErrorCount()
+	return logger.asyncRuntime().GetWriteErrorCount()
 }
 
 func (logger *StarLogger) SetOnlyColorLevel(ocl bool) {

typed.go

@@ -59,6 +59,8 @@ const (
 	FieldTypeOther  = "other"
 )
 
+const defaultAsyncQueueCapacity uint64 = 1024
+
 var (
 	ErrAsyncHandlerPanic   = errors.New("async handler panic")
 	ErrAsyncHandlerTimeout = errors.New("async handler timeout")
@@ -90,27 +92,41 @@ var (
 		"panic":    LvPanic,
 		"fatal":    LvFatal,
 	}
-	stacks        *starChanStack
-	stackStarted  bool = false
-	stackStopChan chan struct{}
-	stackDoneChan chan struct{}
-	stackMu       sync.Mutex
-	stackDrop     uint64
-	stackAlert    func(error, LogData)
-	stackAlertMu  sync.RWMutex
-	stackFallback uint32 = 1
-	stackTimeout  int64
+
+	stdScreen io.Writer = colorable.NewColorableStdout()
+	errScreen io.Writer = colorable.NewColorableStderr()
+
+	defaultAsyncRuntimeOnce     sync.Once
+	defaultAsyncRuntimeFallback *asyncRuntime
+)
+
+type asyncRuntime struct {
+	mu sync.Mutex
+
+	queue    *starChanStack
+	started  bool
+	stopChan chan struct{}
+	doneChan chan struct{}
+
+	dropCount uint64
+
+	asyncAlert   func(error, LogData)
+	asyncAlertMu sync.RWMutex
+	fallbackSync uint32
+	timeout      int64
 
 	writeErrCount   uint64
 	writeErrHandler func(error, LogData)
 	writeErrMu      sync.RWMutex
 
-	stdScreen io.Writer = colorable.NewColorableStdout()
-	errScreen io.Writer = colorable.NewColorableStderr()
-)
+	queueCapacity uint64
+}
+
+type asyncRuntimeContextKey struct{}
 
 type starlog struct {
 	mu                  *sync.Mutex
+	runtime             *asyncRuntime
 	output              io.Writer
 	minLevel            int
 	errOutputLevel      int
@@ -240,9 +256,57 @@ type Config struct {
 	ContextFieldExtractor func(context.Context) Fields
 }
 
+func newAsyncRuntime(queueCapacity uint64) *asyncRuntime {
+	if queueCapacity == 0 {
+		queueCapacity = defaultAsyncQueueCapacity
+	}
+	runtime := &asyncRuntime{
+		queueCapacity: queueCapacity,
+	}
+	atomic.StoreUint32(&runtime.fallbackSync, 1)
+	return runtime
+}
+
+func defaultAsyncRuntime() *asyncRuntime {
+	if Std != nil && Std.logcore != nil && Std.logcore.runtime != nil {
+		return Std.logcore.runtime
+	}
+	defaultAsyncRuntimeOnce.Do(func() {
+		defaultAsyncRuntimeFallback = newAsyncRuntime(defaultAsyncQueueCapacity)
+	})
+	return defaultAsyncRuntimeFallback
+}
+
+func withAsyncRuntime(ctx context.Context, runtime *asyncRuntime) context.Context {
+	if runtime == nil {
+		return ctx
+	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, asyncRuntimeContextKey{}, runtime)
+}
+
+func runtimeFromContext(ctx context.Context) *asyncRuntime {
+	if ctx == nil {
+		return nil
+	}
+	runtime, _ := ctx.Value(asyncRuntimeContextKey{}).(*asyncRuntime)
+	return runtime
+}
+
+func reportWriteErrorWithContext(ctx context.Context, err error, data LogData) {
+	runtime := runtimeFromContext(ctx)
+	if runtime == nil {
+		runtime = defaultAsyncRuntime()
+	}
+	runtime.reportWriteError(err, data)
+}
+
 func newLogCore(out io.Writer) *starlog {
 	core := &starlog{
 		mu:             &sync.Mutex{},
+		runtime:        newAsyncRuntime(defaultAsyncQueueCapacity),
 		output:         out,
 		minLevel:       LvDebug,
 		errOutputLevel: LvError,
@@ -389,62 +453,98 @@ func generateId() string {
 	return fmt.Sprintf("%dstar%db612%d", time.Now().UnixNano(), rand.Intn(1000000), rand.Intn(1000000))
 }
 
-func StartStacks() {
-	stackMu.Lock()
-	if stackStarted {
-		stackMu.Unlock()
+func (logger *starlog) asyncRuntime() *asyncRuntime {
+	if logger == nil || logger.runtime == nil {
+		return defaultAsyncRuntime()
+	}
+	return logger.runtime
+}
+
+func (logger *StarLogger) asyncRuntime() *asyncRuntime {
+	if logger == nil || logger.logcore == nil {
+		return defaultAsyncRuntime()
+	}
+	return logger.logcore.asyncRuntime()
+}
+
+func (logger *starlog) reportAsyncDrop(err error, data LogData) {
+	logger.asyncRuntime().reportAsyncDrop(err, data)
+}
+
+func (logger *starlog) reportWriteError(err error, data LogData) {
+	logger.asyncRuntime().reportWriteError(err, data)
+}
+
+func (runtime *asyncRuntime) snapshot() (*starChanStack, bool) {
+	if runtime == nil {
+		return nil, false
+	}
+	runtime.mu.Lock()
+	defer runtime.mu.Unlock()
+	return runtime.queue, runtime.started
+}
+
+func (runtime *asyncRuntime) Start() {
+	if runtime == nil {
 		return
 	}
-	stackStarted = true
-	stackStopChan = make(chan struct{})
-	stackDoneChan = make(chan struct{})
-	stacks = newStarChanStack(1024)
-	stopChan := stackStopChan
-	doneChan := stackDoneChan
-	stackMu.Unlock()
-	go func(stop <-chan struct{}, done chan struct{}) {
+	runtime.mu.Lock()
+	if runtime.started {
+		runtime.mu.Unlock()
+		return
+	}
+	queue := newStarChanStack(runtime.queueCapacity)
+	stopChan := make(chan struct{})
+	doneChan := make(chan struct{})
+	runtime.queue = queue
+	runtime.stopChan = stopChan
+	runtime.doneChan = doneChan
+	runtime.started = true
+	runtime.mu.Unlock()
+
+	go func(queue *starChanStack, stop <-chan struct{}, done chan struct{}) {
 		defer close(done)
-		defer func() {
-			stackMu.Lock()
-			stackStarted = false
-			stackMu.Unlock()
-		}()
 		for {
 			select {
 			case <-stop:
 				return
 			default:
 			}
-			poped, err := stacks.Pop()
+			popped, err := queue.Pop()
 			if err != nil {
 				if errors.Is(err, io.EOF) {
 					return
 				}
 				return
 			}
-			val, ok := poped.(logTransfer)
+			val, ok := popped.(logTransfer)
 			if !ok {
 				continue
 			}
 			if val.handlerFunc != nil {
-				invokeAsyncHandlerSafely(val.handlerFunc, val.LogData)
+				runtime.invokeAsyncHandlerSafely(val.handlerFunc, val.LogData)
 			}
 		}
-	}(stopChan, doneChan)
+	}(queue, stopChan, doneChan)
 }
 
-func StopStacks() {
-	stackMu.Lock()
-	if !stackStarted {
-		stackMu.Unlock()
+func (runtime *asyncRuntime) Stop() {
+	if runtime == nil {
 		return
 	}
-	stopChan := stackStopChan
-	doneChan := stackDoneChan
-	current := stacks
-	stackStopChan = nil
-	stackDoneChan = nil
-	stackMu.Unlock()
+	runtime.mu.Lock()
+	if !runtime.started {
+		runtime.mu.Unlock()
+		return
+	}
+	stopChan := runtime.stopChan
+	doneChan := runtime.doneChan
+	queue := runtime.queue
+	runtime.queue = nil
+	runtime.stopChan = nil
+	runtime.doneChan = nil
+	runtime.started = false
+	runtime.mu.Unlock()
 
 	if stopChan != nil {
 		func() {
@@ -454,56 +554,106 @@ func StopStacks() {
 			close(stopChan)
 		}()
 	}
-	if current != nil {
-		_ = current.Close()
+	if queue != nil {
+		_ = queue.Close()
 	}
 	if doneChan != nil {
 		<-doneChan
 	}
 }
 
-func Stop() {
-	StopStacks()
+func (runtime *asyncRuntime) WaitDrain(ctx context.Context) error {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	for {
+		queue, started := runtime.snapshot()
+		if !started || queue == nil || queue.Len() == 0 {
+			return nil
+		}
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-time.After(5 * time.Millisecond):
+		}
+	}
 }
 
-func SetAsyncErrorHandler(alert func(error, LogData)) {
-	stackAlertMu.Lock()
-	defer stackAlertMu.Unlock()
-	stackAlert = alert
+func (runtime *asyncRuntime) Metrics() AsyncMetrics {
+	queue, started := runtime.snapshot()
+	snapshot := AsyncMetrics{
+		Started:        started,
+		Dropped:        runtime.GetAsyncDropCount(),
+		FallbackToSync: runtime.GetAsyncFallbackToSync(),
+		HandlerTimeout: runtime.GetAsyncHandlerTimeout(),
+	}
+	if queue != nil {
+		snapshot.QueueLength = queue.Len()
+		snapshot.QueueCapacity = queue.Cap()
+		snapshot.QueueFree = queue.Free()
+	}
+	return snapshot
 }
 
-func SetAsyncFallbackToSync(enable bool) {
-	if enable {
-		atomic.StoreUint32(&stackFallback, 1)
+func (runtime *asyncRuntime) SetAsyncErrorHandler(alert func(error, LogData)) {
+	if runtime == nil {
 		return
 	}
-	atomic.StoreUint32(&stackFallback, 0)
+	runtime.asyncAlertMu.Lock()
+	defer runtime.asyncAlertMu.Unlock()
+	runtime.asyncAlert = alert
 }
 
-func GetAsyncFallbackToSync() bool {
-	return atomic.LoadUint32(&stackFallback) == 1
+func (runtime *asyncRuntime) SetAsyncFallbackToSync(enable bool) {
+	if runtime == nil {
+		return
+	}
+	if enable {
+		atomic.StoreUint32(&runtime.fallbackSync, 1)
+		return
+	}
+	atomic.StoreUint32(&runtime.fallbackSync, 0)
 }
 
-func SetAsyncHandlerTimeout(timeout time.Duration) {
+func (runtime *asyncRuntime) GetAsyncFallbackToSync() bool {
+	if runtime == nil {
+		return true
+	}
+	return atomic.LoadUint32(&runtime.fallbackSync) == 1
+}
+
+func (runtime *asyncRuntime) SetAsyncHandlerTimeout(timeout time.Duration) {
+	if runtime == nil {
+		return
+	}
 	if timeout < 0 {
 		timeout = 0
 	}
-	atomic.StoreInt64(&stackTimeout, int64(timeout))
+	atomic.StoreInt64(&runtime.timeout, int64(timeout))
 }
 
-func GetAsyncHandlerTimeout() time.Duration {
-	return time.Duration(atomic.LoadInt64(&stackTimeout))
+func (runtime *asyncRuntime) GetAsyncHandlerTimeout() time.Duration {
+	if runtime == nil {
+		return 0
+	}
+	return time.Duration(atomic.LoadInt64(&runtime.timeout))
 }
 
-func GetAsyncDropCount() uint64 {
-	return atomic.LoadUint64(&stackDrop)
+func (runtime *asyncRuntime) GetAsyncDropCount() uint64 {
+	if runtime == nil {
+		return 0
+	}
+	return atomic.LoadUint64(&runtime.dropCount)
 }
 
-func reportAsyncDrop(err error, data LogData) {
-	atomic.AddUint64(&stackDrop, 1)
-	stackAlertMu.RLock()
-	alert := stackAlert
-	stackAlertMu.RUnlock()
+func (runtime *asyncRuntime) reportAsyncDrop(err error, data LogData) {
+	if runtime == nil {
+		return
+	}
+	atomic.AddUint64(&runtime.dropCount, 1)
+	runtime.asyncAlertMu.RLock()
+	alert := runtime.asyncAlert
+	runtime.asyncAlertMu.RUnlock()
 	if alert != nil {
 		func() {
 			defer func() {
@@ -514,31 +664,37 @@ func reportAsyncDrop(err error, data LogData) {
 	}
 }
 
-func invokeAsyncHandlerSafely(handler func(LogData), data LogData) bool {
+func (runtime *asyncRuntime) invokeAsyncHandlerSafely(handler func(LogData), data LogData) bool {
+	if runtime == nil {
+		return invokeAsyncHandlerDirect(defaultAsyncRuntime(), handler, data)
+	}
 	if handler == nil {
 		return true
 	}
-	timeout := GetAsyncHandlerTimeout()
+	timeout := runtime.GetAsyncHandlerTimeout()
 	if timeout <= 0 {
-		return invokeAsyncHandlerDirect(handler, data)
+		return invokeAsyncHandlerDirect(runtime, handler, data)
 	}
 	done := make(chan bool, 1)
 	go func() {
-		done <- invokeAsyncHandlerDirect(handler, data)
+		done <- invokeAsyncHandlerDirect(runtime, handler, data)
 	}()
 	select {
 	case ok := <-done:
 		return ok
 	case <-time.After(timeout):
-		reportAsyncDrop(ErrAsyncHandlerTimeout, data)
+		runtime.reportAsyncDrop(ErrAsyncHandlerTimeout, data)
 		return false
 	}
 }
 
-func invokeAsyncHandlerDirect(handler func(LogData), data LogData) (ok bool) {
+func invokeAsyncHandlerDirect(runtime *asyncRuntime, handler func(LogData), data LogData) (ok bool) {
 	defer func() {
 		if panicErr := recover(); panicErr != nil {
-			reportAsyncDrop(fmt.Errorf("%w: %v", ErrAsyncHandlerPanic, panicErr), data)
+			if runtime == nil {
+				runtime = defaultAsyncRuntime()
+			}
+			runtime.reportAsyncDrop(fmt.Errorf("%w: %v", ErrAsyncHandlerPanic, panicErr), data)
 			ok = false
 		}
 	}()
@@ -546,24 +702,30 @@ func invokeAsyncHandlerDirect(handler func(LogData), data LogData) (ok bool) {
 	return true
 }
 
-func SetWriteErrorHandler(alert func(error, LogData)) {
-	writeErrMu.Lock()
-	defer writeErrMu.Unlock()
-	writeErrHandler = alert
-}
-
-func GetWriteErrorCount() uint64 {
-	return atomic.LoadUint64(&writeErrCount)
-}
-
-func reportWriteError(err error, data LogData) {
-	if err == nil {
+func (runtime *asyncRuntime) SetWriteErrorHandler(alert func(error, LogData)) {
+	if runtime == nil {
 		return
 	}
-	atomic.AddUint64(&writeErrCount, 1)
-	writeErrMu.RLock()
-	alert := writeErrHandler
-	writeErrMu.RUnlock()
+	runtime.writeErrMu.Lock()
+	defer runtime.writeErrMu.Unlock()
+	runtime.writeErrHandler = alert
+}
+
+func (runtime *asyncRuntime) GetWriteErrorCount() uint64 {
+	if runtime == nil {
+		return 0
+	}
+	return atomic.LoadUint64(&runtime.writeErrCount)
+}
+
+func (runtime *asyncRuntime) reportWriteError(err error, data LogData) {
+	if runtime == nil || err == nil {
+		return
+	}
+	atomic.AddUint64(&runtime.writeErrCount, 1)
+	runtime.writeErrMu.RLock()
+	alert := runtime.writeErrHandler
+	runtime.writeErrMu.RUnlock()
 	if alert != nil {
 		func() {
 			defer func() {
@@ -574,11 +736,75 @@ func reportWriteError(err error, data LogData) {
 	}
 }
 
-func resetAsyncMetricsForTest() {
-	atomic.StoreUint64(&stackDrop, 0)
-	SetAsyncErrorHandler(nil)
-	SetAsyncFallbackToSync(true)
-	SetAsyncHandlerTimeout(0)
-	atomic.StoreUint64(&writeErrCount, 0)
-	SetWriteErrorHandler(nil)
+func (runtime *asyncRuntime) resetForTest() {
+	if runtime == nil {
+		return
+	}
+	runtime.Stop()
+	atomic.StoreUint64(&runtime.dropCount, 0)
+	runtime.SetAsyncErrorHandler(nil)
+	runtime.SetAsyncFallbackToSync(true)
+	runtime.SetAsyncHandlerTimeout(0)
+	atomic.StoreUint64(&runtime.writeErrCount, 0)
+	runtime.SetWriteErrorHandler(nil)
+}
+
+func StartStacks() {
+	defaultAsyncRuntime().Start()
+}
+
+func StopStacks() {
+	defaultAsyncRuntime().Stop()
+}
+
+func Stop() {
+	StopStacks()
+}
+
+func SetAsyncErrorHandler(alert func(error, LogData)) {
+	defaultAsyncRuntime().SetAsyncErrorHandler(alert)
+}
+
+func SetAsyncFallbackToSync(enable bool) {
+	defaultAsyncRuntime().SetAsyncFallbackToSync(enable)
+}
+
+func GetAsyncFallbackToSync() bool {
+	return defaultAsyncRuntime().GetAsyncFallbackToSync()
+}
+
+func SetAsyncHandlerTimeout(timeout time.Duration) {
+	defaultAsyncRuntime().SetAsyncHandlerTimeout(timeout)
+}
+
+func GetAsyncHandlerTimeout() time.Duration {
+	return defaultAsyncRuntime().GetAsyncHandlerTimeout()
+}
+
+func GetAsyncDropCount() uint64 {
+	return defaultAsyncRuntime().GetAsyncDropCount()
+}
+
+func reportAsyncDrop(err error, data LogData) {
+	defaultAsyncRuntime().reportAsyncDrop(err, data)
+}
+
+func invokeAsyncHandlerSafely(handler func(LogData), data LogData) bool {
+	return defaultAsyncRuntime().invokeAsyncHandlerSafely(handler, data)
+}
+
+func SetWriteErrorHandler(alert func(error, LogData)) {
+	defaultAsyncRuntime().SetWriteErrorHandler(alert)
+}
+
+func GetWriteErrorCount() uint64 {
+	return defaultAsyncRuntime().GetWriteErrorCount()
+}
+
+func reportWriteError(err error, data LogData) {
+	defaultAsyncRuntime().reportWriteError(err, data)
+}
+
+func resetAsyncMetricsForTest() {
+	defaultAsyncRuntime().resetForTest()
 }