{"id":10021331,"date":"2026-03-30T15:40:15","date_gmt":"2026-03-30T07:40:15","guid":{"rendered":"https:\/\/itmax.cn\/?p=10021331"},"modified":"2026-03-30T15:40:15","modified_gmt":"2026-03-30T07:40:15","slug":"%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3-go-context%ef%bc%9a%e4%bb%8e%e5%8e%9f%e7%90%86%e5%88%b0%e5%ae%9e%e6%88%98%ef%bc%88%e5%9f%ba%e4%ba%8e-go-1-26%ef%bc%89","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10021331","title":{"rendered":"\u6df1\u5165\u7406\u89e3 Go Context\uff1a\u4ece\u539f\u7406\u5230\u5b9e\u6218\uff08\u57fa\u4e8e Go 1.26\uff09"},"content":{"rendered":"

\u524d\u8a00<\/h2>\n

\u5728 Go \u7684\u5e76\u53d1\u7f16\u7a0b\u4e2d\uff0ccontext<\/code> \u5305\u662f\u6700\u6838\u5fc3\u7684\u57fa\u7840\u8bbe\u65bd\u4e4b\u4e00\u3002\u5b83\u89e3\u51b3\u4e86\u4e00\u4e2a\u770b\u4f3c\u7b80\u5355\u5374\u6781\u5176\u91cd\u8981\u7684\u95ee\u9898\uff1a\u5982\u4f55\u4f18\u96c5\u5730\u63a7\u5236 goroutine \u7684\u751f\u547d\u5468\u671f\uff1f<\/strong><\/p>\n

\u5148\u770b\u4e00\u4e2a\u6ca1\u6709 context \u7684\u53cd\u9762\u4f8b\u5b50\uff1a<\/p>\n

\/\/ \u6a21\u62df\uff1a\u7528\u6237\u8bf7\u6c42\u4e00\u4e2a\u63a5\u53e3\uff0c\u540e\u7aef\u6d3e goroutine \u53bb\u67e5\u6570\u636e\u5e93\nfunc handleRequest() {\n    go queryDB("SELECT * FROM orders") \/\/ \u8017\u65f6 5 \u79d2\n    go callRPC("user-service")         \/\/ \u8017\u65f6 3 \u79d2\n    go fetchCache("hot-items")         \/\/ \u8017\u65f6 1 \u79d2\n}<\/code><\/pre>\n
\u5982\u679c\u7528\u6237\u5728\u7b2c 0.5 \u79d2\u5c31\u65ad\u5f00\u4e86\u8fde\u63a5\uff0c\u4f1a\u53d1\u751f\u4ec0\u4e48\uff1f<\/p>\n
func main() {\n    for i := 0; i < 100; i++ {\n        handleRequest() \/\/ \u6bcf\u4e2a\u8bf7\u6c42\u6d3e\u751f 3 \u4e2a goroutine\n        \/\/ \u5047\u8bbe\u7528\u6237\u5168\u90e8\u5728 0.5 \u79d2\u540e\u65ad\u5f00\n    }\n    time.Sleep(1 * time.Second)\n    fmt.Println("\u5f53\u524d goroutine \u6570:", runtime.NumGoroutine())\n    \/\/ \u8f93\u51fa: \u5f53\u524d goroutine \u6570: 301\n    \/\/ 300 \u4e2a goroutine \u5728\u505a\u65e0\u7528\u529f\uff0c\u6ca1\u4eba\u8981\u5b83\u4eec\u7684\u7ed3\u679c\u4e86\n}<\/code><\/pre>\n
\u8fd9 300 \u4e2a goroutine \u6bcf\u4e00\u4e2a\u90fd\u5728\u5360\u7528\u5185\u5b58\uff08\u6700\u5c11 2KB \u6808\u7a7a\u95f4\uff09\u3001\u53ef\u80fd\u6301\u6709\u6570\u636e\u5e93\u8fde\u63a5\u3001\u6d88\u8017 CPU \u65f6\u95f4\u7247\u2014\u2014\u800c\u5b83\u4eec\u7684\u7ed3\u679c\u5df2\u7ecf\u6ca1\u4eba\u9700\u8981\u4e86\u3002\u5728\u9ad8\u5e76\u53d1\u573a\u666f\u4e0b\uff0c\u8fd9\u79cd\u6cc4\u6f0f\u4f1a\u50cf\u6eda\u96ea\u7403\u4e00\u6837\u62d6\u57ae\u6574\u4e2a\u670d\u52a1\u3002<\/p>\n
\u6709\u4e86 context\uff0c\u4e00\u884c\u4ee3\u7801\u5c31\u80fd\u89e3\u51b3\uff1a<\/p>\n
func handleRequest(ctx context.Context) {\n    go queryDB(ctx, "SELECT * FROM orders")\n    go callRPC(ctx, "user-service")\n    go fetchCache(ctx, "hot-items")\n}\n\n\/\/ \u7528\u6237\u65ad\u5f00 \u2192 ctx \u88ab\u53d6\u6d88 \u2192 \u4e09\u4e2a goroutine \u6536\u5230\u4fe1\u53f7 \u2192 \u7acb\u5373\u9000\u51fa\n\/\/ goroutine \u6570: 1\uff08\u53ea\u5269 main\uff09<\/code><\/pre>\n
\u8fd9\u5c31\u662f context \u7684\u4ef7\u503c\uff1a\u5b83\u662f goroutine \u4e4b\u95f4\u7684”\u7d27\u6025\u53eb\u505c”\u673a\u5236<\/strong>\u3002\u6ca1\u6709\u5b83\uff0c\u4f60\u6d3e\u51fa\u53bb\u7684 goroutine \u5c31\u50cf\u65ad\u4e86\u7ebf\u7684\u98ce\u7b5d\uff0c\u518d\u4e5f\u6536\u4e0d\u56de\u6765\u3002<\/p>\n
\u4e00\u3001Context \u662f\u4ec0\u4e48<\/h2>\n
context.Context<\/code> \u662f\u4e00\u4e2a\u63a5\u53e3\uff0c\u5b9a\u4e49\u5728\u6807\u51c6\u5e93 context<\/code> \u5305\u4e2d\uff1a<\/p>\n
type Context interface {\n    \/\/ \u8fd4\u56de context \u7684\u622a\u6b62\u65f6\u95f4\u3002\u5982\u679c\u6ca1\u6709\u8bbe\u7f6e\u622a\u6b62\u65f6\u95f4\uff0cok \u4e3a false\n    Deadline() (deadline time.Time, ok bool)\n\n    \/\/ \u8fd4\u56de\u4e00\u4e2a channel\uff0c\u5f53 context \u88ab\u53d6\u6d88\u6216\u8d85\u65f6\u65f6\uff0c\u8be5 channel \u4f1a\u88ab\u5173\u95ed\n    Done() <-chan struct{}\n\n    \/\/ \u8fd4\u56de context \u88ab\u53d6\u6d88\u7684\u539f\u56e0\n    Err() error\n\n    \/\/ \u4ece context \u4e2d\u83b7\u53d6 key \u5bf9\u5e94\u7684\u503c\n    Value(key any) any\n}<\/code><\/pre>\n
\u56db\u4e2a\u65b9\u6cd5\uff0c\u5404\u53f8\u5176\u804c\uff1a<\/p>\n\n\n\n\n\n\n\n\n
\u65b9\u6cd5<\/th>\n\u4f5c\u7528<\/th>\n\u5178\u578b\u4f7f\u7528\u573a\u666f<\/th>\n<\/tr>\n<\/thead>\n
Deadline()<\/code><\/td>\n\u83b7\u53d6\u622a\u6b62\u65f6\u95f4<\/td>\n\u5224\u65ad\u5269\u4f59\u65f6\u95f4\u662f\u5426\u591f\u5b8c\u6210\u64cd\u4f5c<\/td>\n<\/tr>\n
Done()<\/code><\/td>\n\u83b7\u53d6\u53d6\u6d88\u4fe1\u53f7 channel<\/td>\n\u5728 select \u4e2d\u76d1\u542c\u53d6\u6d88\u4e8b\u4ef6<\/td>\n<\/tr>\n
Err()<\/code><\/td>\n\u83b7\u53d6\u53d6\u6d88\u539f\u56e0<\/td>\n\u533a\u5206\u662f\u4e3b\u52a8\u53d6\u6d88\u8fd8\u662f\u8d85\u65f6<\/td>\n<\/tr>\n
Value()<\/code><\/td>\n\u83b7\u53d6\u4f20\u9012\u7684\u503c<\/td>\n\u8bfb\u53d6 request-scoped \u6570\u636e\uff08\u5982 traceID\uff09<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u4e8c\u3001\u4e94\u79cd\u521b\u5efa\u65b9\u5f0f<\/h2>\n
1. context.Background() \u548c context.TODO()<\/h3>\n
\u8fd9\u4e24\u4e2a\u51fd\u6570\u8fd4\u56de\u7684\u90fd\u662f\u7a7a context\uff0c\u6c38\u8fdc\u4e0d\u4f1a\u88ab\u53d6\u6d88\uff0c\u6ca1\u6709\u622a\u6b62\u65f6\u95f4\uff0c\u6ca1\u6709\u503c\u3002<\/p>\n
\/\/ \u4f5c\u4e3a\u6574\u68f5 context \u6811\u7684\u6839\u8282\u70b9\uff0c\u901a\u5e38\u5728 main\u3001init \u6216\u9876\u5c42\u8bf7\u6c42\u5165\u53e3\u4f7f\u7528\nctx := context.Background()\n\n\/\/ \u5f53\u4f60\u8fd8\u4e0d\u786e\u5b9a\u8be5\u7528\u4ec0\u4e48 context \u65f6\u7684\u5360\u4f4d\u7b26\nctx := context.TODO()<\/code><\/pre>\n
\u5b83\u4eec\u7684\u533a\u522b\u7eaf\u7cb9\u662f\u8bed\u4e49\u4e0a\u7684\u2014\u2014TODO()<\/code> \u662f\u5728\u544a\u8bc9\u4ee3\u7801\u7684\u8bfb\u8005\uff1a”\u8fd9\u91cc\u4ee5\u540e\u8981\u6362\u6210\u771f\u6b63\u7684 context”\u3002<\/p>\n
2. context.WithCancel \u2014 \u624b\u52a8\u53d6\u6d88<\/h3>\n
func WithCancel(parent Context) (ctx Context, cancel CancelFunc)<\/code><\/pre>\n
\u8fd4\u56de\u4e00\u4e2a\u5b50 context \u548c\u4e00\u4e2a\u53d6\u6d88\u51fd\u6570\u3002\u8c03\u7528 cancel()<\/code> \u65f6\uff0c\u5b50 context \u7684 Done()<\/code> channel \u4f1a\u88ab\u5173\u95ed\uff0c\u6240\u6709\u76d1\u542c\u5b83\u7684 goroutine \u90fd\u4f1a\u6536\u5230\u4fe1\u53f7\u3002<\/p>\n
func main() {\n    ctx, cancel := context.WithCancel(context.Background())\n\n    go worker(ctx, "worker-1")\n    go worker(ctx, "worker-2")\n\n    time.Sleep(3 * time.Second)\n    fmt.Println("\u4e3b\u534f\u7a0b\uff1a\u901a\u77e5\u6240\u6709 worker \u505c\u6b62")\n    cancel() \/\/ \u624b\u52a8\u53d1\u51fa\u53d6\u6d88\u4fe1\u53f7\uff0c\u540c\u65f6\u91ca\u653e\u8d44\u6e90\n\n    time.Sleep(1 * time.Second) \/\/ \u7b49\u5f85 worker \u9000\u51fa\n}\n\nfunc worker(ctx context.Context, name string) {\n    for {\n        select {\n        case <-ctx.Done():\n            fmt.Printf("%s: \u6536\u5230\u53d6\u6d88\u4fe1\u53f7\uff0c\u9000\u51fa\u3002\u539f\u56e0: %v\/n", name, ctx.Err())\n            return\n        default:\n            fmt.Printf("%s: \u5de5\u4f5c\u4e2d...\/n", name)\n            time.Sleep(1 * time.Second)\n        }\n    }\n}<\/code><\/pre>\n
\u8f93\u51fa\uff1a<\/p>\n
worker-1: \u5de5\u4f5c\u4e2d...\nworker-2: \u5de5\u4f5c\u4e2d...\nworker-1: \u5de5\u4f5c\u4e2d...\nworker-2: \u5de5\u4f5c\u4e2d...\nworker-1: \u5de5\u4f5c\u4e2d...\nworker-2: \u5de5\u4f5c\u4e2d...\n\u4e3b\u534f\u7a0b\uff1a\u901a\u77e5\u6240\u6709 worker \u505c\u6b62\nworker-1: \u6536\u5230\u53d6\u6d88\u4fe1\u53f7\uff0c\u9000\u51fa\u3002\u539f\u56e0: context canceled\nworker-2: \u6536\u5230\u53d6\u6d88\u4fe1\u53f7\uff0c\u9000\u51fa\u3002\u539f\u56e0: context canceled<\/code><\/pre>\n
3. context.WithTimeout \u2014 \u8d85\u65f6\u81ea\u52a8\u53d6\u6d88<\/h3>\n
func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc)<\/code><\/pre>\n
\u5728\u6307\u5b9a\u65f6\u95f4\u540e\u81ea\u52a8\u53d6\u6d88\u3002\u8fd9\u662f HTTP \u5ba2\u6237\u7aef\u8c03\u7528\u3001\u6570\u636e\u5e93\u67e5\u8be2\u7b49\u573a\u666f\u7684\u6807\u914d\u3002<\/p>\n
func queryDatabase(ctx context.Context) (string, error) {\n    \/\/ \u6a21\u62df\u4e00\u4e2a\u53ef\u80fd\u5f88\u6162\u7684\u6570\u636e\u5e93\u67e5\u8be2\n    select {\n    case <-time.After(5 * time.Second): \/\/ \u67e5\u8be2\u9700\u8981 5 \u79d2\n        return "\u67e5\u8be2\u7ed3\u679c", nil\n    case <-ctx.Done():\n        return "", fmt.Errorf("\u67e5\u8be2\u88ab\u53d6\u6d88: %w", ctx.Err())\n    }\n}\n\nfunc main() {\n    \/\/ \u8bbe\u7f6e 2 \u79d2\u8d85\u65f6\n    ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)\n    defer cancel()\n\n    result, err := queryDatabase(ctx)\n    if err != nil {\n        fmt.Println("\u9519\u8bef:", err) \/\/ \u8f93\u51fa: \u9519\u8bef: \u67e5\u8be2\u88ab\u53d6\u6d88: context deadline exceeded\n        return\n    }\n    fmt.Println("\u7ed3\u679c:", result)\n}<\/code><\/pre>\n
4. context.WithDeadline \u2014 \u6307\u5b9a\u622a\u6b62\u65f6\u95f4<\/h3>\n
func WithDeadline(parent Context, d time.Time) (Context, CancelFunc)<\/code><\/pre>\n
\u548c WithTimeout<\/code> \u7c7b\u4f3c\uff0c\u4f46\u63a5\u53d7\u7684\u662f\u4e00\u4e2a\u7edd\u5bf9\u65f6\u95f4\u70b9\u800c\u975e\u76f8\u5bf9\u65f6\u957f\u3002\u5b9e\u9645\u4e0a WithTimeout<\/code> \u5185\u90e8\u5c31\u662f\u8c03\u7528\u7684 WithDeadline<\/code>\uff1a<\/p>\n
\/\/ \u6807\u51c6\u5e93\u6e90\u7801\nfunc WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {\n    return WithDeadline(parent, time.Now().Add(timeout))\n}<\/code><\/pre>\n
\u4f7f\u7528\u573a\u666f\uff1a\u5f53\u4f60\u9700\u8981\u8ba9\u591a\u4e2a\u64cd\u4f5c\u5171\u4eab\u540c\u4e00\u4e2a\u622a\u6b62\u65f6\u95f4\u65f6\uff0cWithDeadline<\/code> \u66f4\u76f4\u89c2\u3002<\/p>\n
func main() {\n    deadline := time.Now().Add(3 * time.Second)\n\n    ctx, cancel := context.WithDeadline(context.Background(), deadline)\n    defer cancel()\n\n    \/\/ \u68c0\u67e5\u8fd8\u5269\u591a\u5c11\u65f6\u95f4\n    if d, ok := ctx.Deadline(); ok {\n        fmt.Printf("\u622a\u6b62\u65f6\u95f4: %v, \u5269\u4f59: %v\/n", d, time.Until(d))\n    }\n}<\/code><\/pre>\n
5. context.WithValue \u2014 \u4f20\u9012\u8bf7\u6c42\u7ea7\u6570\u636e<\/h3>\n
func WithValue(parent Context, key, val any) Context<\/code><\/pre>\n
\u5728 context \u4e2d\u9644\u52a0\u4e00\u4e2a\u952e\u503c\u5bf9\u3002\u5e38\u7528\u4e8e\u4f20\u9012 traceID\u3001\u7528\u6237\u8ba4\u8bc1\u4fe1\u606f\u7b49 request-scoped \u6570\u636e\u3002<\/p>\n
\/\/ \u63a8\u8350\u4f7f\u7528\u81ea\u5b9a\u4e49\u7c7b\u578b\u4f5c\u4e3a key\uff0c\u907f\u514d\u51b2\u7a81\ntype contextKey string\n\nconst (\n    keyTraceID contextKey = "traceID"\n    keyUserID  contextKey = "userID"\n)\n\nfunc middleware(next http.HandlerFunc) http.HandlerFunc {\n    return func(w http.ResponseWriter, r *http.Request) {\n        \/\/ \u6ce8\u5165 traceID\n        traceID := generateTraceID()\n        ctx := context.WithValue(r.Context(), keyTraceID, traceID)\n\n        \/\/ \u6ce8\u5165\u7528\u6237\u4fe1\u606f\n        userID := authenticate(r)\n        ctx = context.WithValue(ctx, keyUserID, userID)\n\n        next(w, r.WithContext(ctx))\n    }\n}\n\nfunc handler(w http.ResponseWriter, r *http.Request) {\n    traceID, _ := r.Context().Value(keyTraceID).(string)\n    userID, _ := r.Context().Value(keyUserID).(string)\n    fmt.Fprintf(w, "trace=%s, user=%s", traceID, userID)\n}<\/code><\/pre>\n
\u4e09\u3001\u6a2a\u5411\u5bf9\u6bd4\uff1a\u5982\u4f55\u9009\u62e9\u6b63\u786e\u7684 Context<\/h2>\n
\u9762\u5bf9\u8fd9\u4e48\u591a\u521b\u5efa\u65b9\u5f0f\uff0c\u5b9e\u9645\u5f00\u53d1\u4e2d\u8be5\u600e\u4e48\u9009\uff1f\u4ee5\u4e0b\u4ece\u591a\u4e2a\u7ef4\u5ea6\u505a\u5bf9\u6bd4\u3002<\/p>\n
WithCancel vs WithTimeout vs WithDeadline<\/h3>\n\n\n\n\n\n\n\n\n
\u7ef4\u5ea6<\/th>\nWithCancel<\/th>\nWithTimeout<\/th>\nWithDeadline<\/th>\n<\/tr>\n<\/thead>\n
\u53d6\u6d88\u65b9\u5f0f<\/td>\n\u624b\u52a8\u8c03\u7528 cancel()<\/td>\n\u8d85\u65f6\u81ea\u52a8 + \u624b\u52a8<\/td>\n\u8d85\u65f6\u81ea\u52a8 + \u624b\u52a8<\/td>\n<\/tr>\n
\u65f6\u95f4\u53c2\u6570<\/td>\n\u65e0<\/td>\n\u76f8\u5bf9\u65f6\u957f (Duration)<\/td>\n\u7edd\u5bf9\u65f6\u95f4\u70b9 (Time)<\/td>\n<\/tr>\n
\u5e95\u5c42\u5b9e\u73b0<\/td>\ncancelCtx<\/td>\ntimerCtx\uff08\u5185\u90e8\u8c03 WithDeadline\uff09<\/td>\ntimerCtx<\/td>\n<\/tr>\n
\u5178\u578b\u573a\u666f<\/td>\n\u624b\u52a8\u63a7\u5236 goroutine \u751f\u547d\u5468\u671f<\/td>\n\u5355\u6b21\u64cd\u4f5c\u9650\u65f6\uff08DB \u67e5\u8be2\u3001HTTP \u8c03\u7528\uff09<\/td>\n\u591a\u4e2a\u64cd\u4f5c\u5171\u4eab\u540c\u4e00\u622a\u6b62\u65f6\u95f4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u9009\u62e9\u539f\u5219\uff1a<\/p>\n