Yiming1997 · Bury-Lee · Sep 2, 2026
diff --git a/context.go b/context.go
diff --git a/example/gin_example/README.md b/example/gin_example/README.md
@@ -0,0 +1,89 @@
+# Gin 集成示例
+
+这个示例展示如何使用 `UpdateTask` 将 Gin 请求的 `context.Context` 传递到 agilePool 的任务中，并使用非阻塞提交实现流量控制。
+
+## 运行
+
+```bash
+go run .
+```
+
+服务监听 `:8080`，提交请求：
+
+```bash
+curl -X POST http://localhost:8080/jobs
+```
+
+## 关键设计
+
+- `c.Request.Context()` 是请求级 Context，客户端断开或请求超时后会自动取消。
+- `agilepool.UpdateTask(ctx, task)` 将 Context 封装到 `contextTask` 中。
+- `TrySubmit` 配合 `NONBLOCK` 模式，在池已达到处理能力时立即返回 `false`。
+- 被拒绝的请求返回 `429 Too Many Requests`，由客户端稍后重试。
+- 任务只向带缓冲的 channel 写结果，不直接使用 `gin.Context`，避免请求结束后异步访问 Gin 对象。
+- 任务开始前如果 Context 已取消，`contextTask` 会跳过任务；执行中的任务需要像示例一样主动监听 Context。
+- 不要把 `*gin.Context` 直接放入异步任务。示例只复制 `request.Context()`、请求 ID 和客户端 IP，避免 Gin 请求对象被复用后发生数据竞争。
+
+## 其他用法
+
+### 请求超时
+
+为请求增加 deadline，任务和 handler 共享该 Context：
+
+```go
+ctx, cancel := context.WithTimeout(c.Request.Context(), 500*time.Millisecond)
+defer cancel()
+
+task := agilepool.UpdateTask(ctx, agilepool.TaskFunc(func() error {
+	select {
+	case <-time.After(time.Second):
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}))
+if !pool.TrySubmit(task) {
+	c.Status(http.StatusTooManyRequests)
+	return
+}
+```
+
+### 携带请求元数据
+
+将必要数据复制到标准 Context，而不是传递 Gin 对象：
+
+```go
+ctx := context.WithValue(c.Request.Context(), traceIDKey{}, c.GetHeader("X-Trace-ID"))
+pool.Submit(agilepool.UpdateTask(ctx, agilepool.TaskFunc(func() error {
+	traceID, _ := ctx.Value(traceIDKey{}).(string)
+	log.Printf("processing trace=%s", traceID)
+	return nil
+})))
+```
+
+### 等待异步结果
+
+使用带缓冲 channel 将结果安全地交回 handler。任务只写 channel，handler 负责写 HTTP 响应：
+
+```go
+resultCh := make(chan string, 1)
+ctx := c.Request.Context()
+if !pool.TrySubmit(agilepool.UpdateTask(ctx, agilepool.TaskFunc(func() error {
+	resultCh <- "ok"
+	return nil
+}))) {
+	c.Status(http.StatusTooManyRequests)
+	return
+}
+select {
+case value := <-resultCh:
+	c.JSON(http.StatusOK, gin.H{"result": value})
+case <-ctx.Done():
+	c.Status(http.StatusRequestTimeout)
+}
+
+可以用以下命令观察流量控制：
+
+```bash
+for /L %i in (1,1,100) do start /B curl -X POST http://localhost:8080/jobs
+```
diff --git a/example/gin_example/go.mod b/example/gin_example/go.mod
@@ -0,0 +1,39 @@
+module github.com/Yiming1997/agilePool/v2/example/gin
+
+go 1.23.4
+
+require (
+	github.com/Yiming1997/agilePool/v2 v2.0.0
+	github.com/gin-gonic/gin v1.10.0
+)
+
+require (
+	github.com/bytedance/sonic v1.11.6 // indirect
+	github.com/bytedance/sonic/loader v0.1.1 // indirect
+	github.com/cloudwego/base64x v0.1.4 // indirect
+	github.com/cloudwego/iasm v0.2.0 // indirect
+	github.com/gabriel-vasile/mimetype v1.4.3 // indirect
+	github.com/gin-contrib/sse v0.1.0 // indirect
+	github.com/go-playground/locales v0.14.1 // indirect
+	github.com/go-playground/universal-translator v0.18.1 // indirect
+	github.com/go-playground/validator/v10 v10.20.0 // indirect
+	github.com/goccy/go-json v0.10.2 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/cpuid/v2 v2.2.7 // indirect
+	github.com/leodido/go-urn v1.4.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.2 // indirect
+	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
+	github.com/ugorji/go/codec v1.2.12 // indirect
+	golang.org/x/arch v0.8.0 // indirect
+	golang.org/x/crypto v0.23.0 // indirect
+	golang.org/x/net v0.25.0 // indirect
+	golang.org/x/sys v0.20.0 // indirect
+	golang.org/x/text v0.15.0 // indirect
+	google.golang.org/protobuf v1.34.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
+
+replace github.com/Yiming1997/agilePool/v2 => ../..
diff --git a/example/gin_example/go.sum b/example/gin_example/go.sum
@@ -0,0 +1,90 @@
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diff --git a/example/gin_example/main.go b/example/gin_example/main.go
@@ -0,0 +1,107 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"math/rand/v2"
+	"net/http"
+	"sync"
+	"time"
+
+	agilepool "github.com/Yiming1997/agilePool/v2"
+	"github.com/gin-gonic/gin"
+)
+
+// This example keeps request work bounded. NONBLOCK makes TrySubmit return
+// immediately when both the handoff channel and overflow buffer are full.
+var pool = agilepool.NewPool(agilepool.NewConfig(
+	agilepool.WithBlockMode(agilepool.NONBLOCK),
+	agilepool.WithTaskQueueSize(32),
+	agilepool.WithWorkerNumCapacity(8),
+))
+
+// taskStartTimes associates each traceID with the time when its pool task
+// started. sync.Map is used because hooks run concurrently across workers.
+var taskStartTimes sync.Map
+
+func main() {
+	defer pool.Close()
+	// Register lifecycle hooks: the start hook records the timestamp, and the
+	// completion hook calculates the elapsed time for the same traceID.
+	pool.OnTaskStarted(DebugHook)
+	pool.OnTaskCompleted(DebugCompleteHook)
+	r := gin.Default()
+	r.Use(PoolMiddleware)
+	// This example shows how to limit concurrency for incoming requests.
+	r.POST("/jobs", anRouterFunc)
+	_ = r.Run("127.0.0.1:8080")
+}
+
+func DebugHook(ctx context.Context, task agilepool.Task) {
+	if c, ok := ctx.(*gin.Context); ok {
+		// UpdateTask preserves this Gin context, so the hook can read request
+		// metadata that was attached before the task was submitted.
+		traceID, _ := c.Get("traceID")
+		taskStartTimes.Store(traceID, time.Now())
+		fmt.Println("task started", traceID, c.ClientIP())
+	}
+}
+
+func DebugCompleteHook(ctx context.Context, task agilepool.Task, recovered any) {
+	if c, ok := ctx.(*gin.Context); ok {
+		traceID, _ := c.Get("traceID")
+		// LoadAndDelete both reads the start time and releases it after the
+		// task completes, preventing completed requests from accumulating.
+		if started, exists := taskStartTimes.LoadAndDelete(traceID); exists {
+			duration := time.Since(started.(time.Time))
+			// recovered is nil for normal completion and contains the panic
+			// value when the pool recovered a panic from the task.
+			log.Printf("task completed traceID=%v duration=%s recovered=%v", traceID, duration, recovered)
+		}
+	}
+}
+
+type Content struct {
+	Content string `json:"content"`
+}
+
+// PoolMiddleware runs the complete Gin handler chain in an agilePool task.
+// UpdateTask keeps the original Gin context available to the task and hooks.
+func PoolMiddleware(c *gin.Context) {
+	// done keeps the HTTP request open until the pool worker finishes the
+	// complete Gin handler chain and writes the response.
+	done := make(chan struct{})
+	// Set metadata before submission so the start hook can read it regardless
+	// of how long the task waits in the pool queue.
+	c.Set("traceID", rand.Int64())
+	// UpdateTask carries the Gin context through the pool. The worker executes
+	// c.Next(), so normal handlers can write responses in the usual way.
+	task := agilepool.UpdateTask(c, agilepool.TaskFunc(func() error {
+		defer close(done)
+		c.Next()
+		return nil
+	}))
+	if !pool.TrySubmit(task) {
+		// NONBLOCK rejects the request when the pool is saturated.
+		c.JSON(http.StatusTooManyRequests, gin.H{"error": "system busy"})
+		c.Abort()
+		return
+	}
+	// For this small example, assume the request is not cancelled and wait
+	// until the handler chain has completed.
+	<-done
+}
+
+func anRouterFunc(c *gin.Context) {
+	var content Content
+	if err := c.ShouldBindBodyWithJSON(&content); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	// The handler itself runs in the pool; no extra result channel is needed.
+	// It can write the response normally because PoolMiddleware waits for
+	// c.Next() to finish before returning to the HTTP server.
+	time.Sleep(10 * time.Second)
+	c.JSON(http.StatusOK, content)
+}