{"id":208146,"date":"2025-07-08T17:01:48","date_gmt":"2025-07-08T09:01:48","guid":{"rendered":"https:\/\/server.hk\/cnblog\/208146\/"},"modified":"2025-07-08T17:01:48","modified_gmt":"2025-07-08T09:01:48","slug":"%e5%90%8c%e4%b8%80%e6%89%a7%e8%a1%8c%e7%ba%bf%e7%a8%8b%e4%b8%ad%e6%b2%a1%e6%9c%89%e9%80%9a%e9%81%93%e7%9a%84%e4%b8%8a%e4%b8%8b%e6%96%87","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/208146\/","title":{"rendered":"\u540c\u4e00\u6267\u884c\u7ebf\u7a0b\u4e2d\u6ca1\u6709\u901a\u9053\u7684\u4e0a\u4e0b\u6587"},"content":{"rendered":"

<\/b> <\/p>\n

\u5f53\u524d\u4f4d\u7f6e\uff1a ><\/span> ><\/span> ><\/span> ><\/span> \u540c\u4e00\u6267\u884c\u7ebf\u7a0b\u4e2d\u6ca1\u6709\u901a\u9053\u7684\u4e0a\u4e0b\u6587<\/span><\/p>\n

\u6765\u6e90\uff1astackoverflow<\/span>
\n2024-04-29 15:48:33<\/span>
\n<\/i>0\u6d4f\u89c8<\/span>
\n<\/i>\u6536\u85cf<\/span> <\/p>\n

\u6b22\u8fce\u5404\u4f4d\u5c0f\u4f19\u4f34\u6765\u5230\uff0c\u76f8\u805a\u4e8e\u6b64\u90fd\u662f\u7f18\u54c8\u54c8\u54c8\uff01\u4eca\u5929\u6211\u7ed9\u5927\u5bb6\u5e26\u6765\u300a\u540c\u4e00\u6267\u884c\u7ebf\u7a0b\u4e2d\u6ca1\u6709\u901a\u9053\u7684\u4e0a\u4e0b\u6587\u300b<\/span>\uff0c\u8fd9\u7bc7\u6587\u7ae0\u4e3b\u8981\u8bb2\u5230<\/span>\u7b49\u7b49\u77e5\u8bc6\uff0c\u5982\u679c\u4f60\u5bf9Golang<\/span>\u76f8\u5173\u7684\u77e5\u8bc6\u975e\u5e38\u611f\u5174\u8da3\u6216\u8005\u6b63\u5728\u81ea\u5b66\uff0c\u90fd\u53ef\u4ee5\u5173\u6ce8\u6211\uff0c\u6211\u4f1a\u6301\u7eed\u66f4\u65b0\u76f8\u5173\u6587\u7ae0\uff01\u5f53\u7136\uff0c\u6709\u4ec0\u4e48\u5efa\u8bae\u4e5f\u6b22\u8fce\u5728\u8bc4\u8bba\u7559\u8a00\u63d0\u51fa\uff01\u4e00\u8d77\u5b66\u4e60\uff01<\/p>\n

\u95ee\u9898\u5185\u5bb9
\n <\/p>\n

\u5982\u679c\u901a\u8fc7\u4e0a\u4e0b\u6587\u8bed\u4e49\u5728\u540c\u4e00\u6267\u884c\u7ebf\u7a0b\u4e2d\u8fdb\u884c\u5927\u91cf\u8ba1\u7b97\uff0c\u6211\u65e0\u6cd5\u5f04\u6e05\u695a\u5982\u4f55\u53d6\u6d88\u4efb\u52a1\uff1f <\/p>\n

\u6211\u4f7f\u7528\u8fd9\u4e2a\u4f8b\u5b50\u4f5c\u4e3a\u53c2\u8003\u70b9 https:\/\/golang.org\/src\/context\/context_test.go<\/p>\n

\u8fd9\u91cc\u7684\u76ee\u6807\u662f\u8c03\u7528\u4e00\u4e2adowork\uff0c\u5982\u679cdowork\u9700\u8981\u592a\u591a\u65f6\u95f4\u6765\u8ba1\u7b97\uff0cgetvaluewithdeadline\u5e94\u8be5\u5728\u8d85\u65f6\u540e\u8fd4\u56de0\uff0c\u6216\u8005\u5982\u679c\u8c03\u7528\u8005\u8c03\u7528cancel\u6765\u53d6\u6d88\u7b49\u5f85\uff0c\uff08\u8fd9\u91cc\u4e3b\u8981\u662f\u8c03\u7528\u8005\uff09\u6216in\u4e2d\u8fd4\u56de\u7684\u503c\u7ed9\u4e00\u4e2a\u65f6\u95f4\u7a97\u53e3\u3002 <\/p>\n

\u540c\u6837\u7684\u573a\u666f\u53ef\u4ee5\u7528\u4e0d\u540c\u7684\u65b9\u5f0f\u6765\u5b8c\u6210\u3002 \uff08\u5355\u72ec\u7684 goroutine \u7761\u7720\u3001\u5524\u9192\u68c0\u67e5\u503c\u7b49\u3001\u4e92\u65a5\u4f53\u6761\u4ef6\u7b49\uff09\u4f46\u6211\u771f\u7684\u60f3\u4e86\u89e3\u4f7f\u7528\u4e0a\u4e0b\u6587\u7684\u6b63\u786e\u65b9\u6cd5\u3002<\/p>\n

\u901a\u9053\u8bed\u4e49\u6211\u7406\u89e3\u4f46\u662f\u8fd9\u91cc\u8fbe\u4e0d\u5230\u60f3\u8981\u7684\u6548\u679c\uff0c\u9ed8\u8ba4\u60c5\u51b5 \u5728\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u8c03\u7528 dowork \u9519\u8bef\u5e76\u7761\u7720\u3002 <\/p>\n

package main\n\nimport (\n    \"context\"\n    \"fmt\"\n    \"log\"\n    \"math\/rand\"\n    \"sync\"\n    \"time\"\n)\n\ntype Server struct {\n    lock sync.Mutex\n}\n\nfunc NewServer() *Server {\n    s := new(Server)\n    return s\n}\n\nfunc (s *Server) doWork() int {\n    s.lock.Lock()\n    defer s.lock.Unlock()\n    r := rand.Intn(100)\n    log.Printf(\"Going to nap for %d\", r)\n    time.Sleep(time.Duration(r) * time.Millisecond)\n    return r\n}\n\n\/\/ I take an example from here and it very unclear where is do work executed\n\/\/ https:\/\/golang.org\/src\/context\/context_test.go\n\nfunc (s *Server)  GetValueWithDeadline(ctx context.Context) int {\n    val := 0\n    select {\n        case <- time.After(150 * time.Millisecond):\n                fmt.Println(\"overslept\")\n                return 0\n        case <- ctx.Done():\n                fmt.Println(ctx.Err())\n                return 0\n        default:\n                val = s.doWork()\n    }\n\n    return all\n}\n\nfunc main() {\n\n    rand.Seed(time.Now().UTC().UnixNano())\n    s := NewServer()\n    for i :=0; i < 10; i++ {\n        d := time.Now().Add(50 * time.Millisecond)\n        ctx, cancel := context.WithDeadline(context.Background(), d)\n        log.Print(s.GetValueWithDeadline(ctx))\n        cancel()\n    }\n}<\/pre>\n
\u8c22\u8c22<\/p>\n
 <\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
 <\/p>\n
\u60a8\u7684\u65b9\u6cd5\u5b58\u5728\u591a\u4e2a\u95ee\u9898\u3002<\/p>\n
\u4e0a\u4e0b\u6587\u89e3\u51b3\u4ec0\u4e48\u95ee\u9898<\/h3>\n
\u9996\u5148\uff0cgo \u4e2d\u53d1\u660e\u4e0a\u4e0b\u6587\u7684\u4e3b\u8981\u539f\u56e0\u662f\u5b83\u4eec\u5141\u8bb8\u7edf\u4e00\u53d6\u6d88\u4e00\u7ec4\u4efb\u52a1\u7684\u65b9\u6cd5\u3002<\/p>\n
\u4e3a\u4e86\u7528\u4e00\u4e2a\u7b80\u5355\u7684\u4f8b\u5b50\u6765\u89e3\u91ca\u8fd9\u4e2a\u6982\u5ff5\uff0c\u8003\u8651\u4e00\u4e2a\u5ba2\u6237\u7aef\u5bf9\u67d0\u4e2a\u670d\u52a1\u5668\u7684\u8bf7\u6c42\uff1b\u4e3a\u4e86\u8fdb\u4e00\u6b65\u7b80\u5316\uff0c\u8ba9\u5b83\u6210\u4e3a\u4e00\u4e2a http \u8bf7\u6c42\u3002 \u5ba2\u6237\u7aef\u8fde\u63a5\u5230\u670d\u52a1\u5668\uff0c\u53d1\u9001\u4e00\u4e9b\u6570\u636e\u544a\u8bc9\u670d\u52a1\u5668\u5982\u4f55\u5b8c\u6210\u8bf7\u6c42\uff0c\u7136\u540e\u7b49\u5f85\u670d\u52a1\u5668\u54cd\u5e94\u3002
 \u73b0\u5728\u5047\u8bbe\u8be5\u8bf7\u6c42\u9700\u8981\u5728\u670d\u52a1\u5668\u4e0a\u8fdb\u884c\u590d\u6742\u4e14\u8017\u65f6\u7684\u5904\u7406 – \u4f8b\u5982\uff0c\u5047\u8bbe\u5b83\u9700\u8981\u5bf9\u591a\u4e2a\u8fdc\u7a0b\u6570\u636e\u5e93\u5f15\u64ce\u6267\u884c\u591a\u4e2a\u590d\u6742\u67e5\u8be2\uff0c\u5bf9\u5916\u90e8\u670d\u52a1\u6267\u884c\u591a\u4e2a http \u8bf7\u6c42\uff0c\u7136\u540e\u5904\u7406\u83b7\u53d6\u7684\u7ed3\u679c\u4ee5\u5b9e\u9645\u751f\u6210\u5ba2\u6237\u60f3\u8981\u7684\u6570\u636e\u3002<\/p>\n
\u56e0\u6b64\uff0c\u5ba2\u6237\u7aef\u5f00\u59cb\u5176\u8bf7\u6c42\uff0c\u670d\u52a1\u5668\u7ee7\u7eed\u5904\u7406\u6240\u6709\u8fd9\u4e9b\u8bf7\u6c42\u3002
 \u4e3a\u4e86\u9690\u85cf\u670d\u52a1\u5668\u4e3a\u6ee1\u8db3\u8bf7\u6c42\u800c\u5fc5\u987b\u6267\u884c\u7684\u5404\u4e2a\u4efb\u52a1\u7684\u5ef6\u8fdf\uff0c\u5b83\u5728\u5355\u72ec\u7684 goroutine \u4e2d\u8fd0\u884c\u5b83\u4eec\u3002 \u4e00\u65e6\u6bcf\u4e2a goroutine \u5b8c\u6210\u5206\u914d\u7684\u4efb\u52a1\uff0c\u5b83\u4f1a\u5c06\u5176\u7ed3\u679c\uff08\u548c\/\u6216\u9519\u8bef\uff09\u4f20\u56de\u5904\u7406\u5ba2\u6237\u7aef\u8bf7\u6c42\u7684 goroutine\uff0c\u4f9d\u6b64\u7c7b\u63a8\u3002<\/p>\n
\u73b0\u5728\u5047\u8bbe\u5ba2\u6237\u7aef\u7531\u4e8e\u67d0\u79cd\u539f\u56e0\u672a\u80fd\u7b49\u5f85\u5bf9\u5176\u8bf7\u6c42\u7684\u54cd\u5e94 – \u7f51\u7edc\u4e2d\u65ad\u3001\u5ba2\u6237\u7aef\u8f6f\u4ef6\u4e2d\u7684\u663e\u5f0f\u8d85\u65f6\u3001\u7528\u6237\u7ec8\u6b62\u53d1\u8d77\u8bf7\u6c42\u7684\u5e94\u7528\u7a0b\u5e8f\u7b49 – \u6709\u5f88\u591a\u53ef\u80fd\u6027.<\/p>\n
\u6b63\u5982\u60a8\u6240\u770b\u5230\u7684\uff0c\u670d\u52a1\u5668\u7ee7\u7eed\u82b1\u8d39\u8d44\u6e90\u6765\u5b8c\u6210\u903b\u8f91\u4e0a\u4e0e\u73b0\u5df2\u5931\u6548\u7684\u8bf7\u6c42\u7ed1\u5b9a\u7684\u4efb\u52a1\u6ca1\u6709\u4ec0\u4e48\u610f\u4e49\uff1a\u65e0\u8bba\u5982\u4f55\u90fd\u6ca1\u6709\u4eba\u542c\u5230\u7ed3\u679c\u3002
 \u56e0\u6b64\uff0c\u4e00\u65e6\u6211\u4eec\u77e5\u9053\u8bf7\u6c42\u4e0d\u4f1a\u5b8c\u6210\uff0c\u5c31\u53ef\u4ee5\u83b7\u53d6\u8fd9\u4e9b\u4efb\u52a1\uff0c\u8fd9\u5c31\u662f\u4e0a\u4e0b\u6587\u53d1\u6325\u4f5c\u7528\u7684\u5730\u65b9\uff1a\u60a8\u53ef\u4ee5\u5c06\u6bcf\u4e2a\u4f20\u5165\u8bf7\u6c42\u4e0e\u5355\u4e2a\u4e0a\u4e0b\u6587\u76f8\u5173\u8054\uff0c\u7136\u540e\u5c06\u5176\u672c\u8eab\u4f20\u9012\u7ed9\u751f\u6210\u7684\u4efb\u4f55 goroutine \u6765\u627f\u8f7d\u8f93\u51fa\u6ee1\u8db3\u8bf7\u6c42\u6240\u9700\u5b8c\u6210\u7684\u5355\u4e2a\u4efb\u52a1\uff0c\u6216\u8005\u4ece\u4e2d\u6d3e\u751f\u53e6\u4e00\u4e2a\u4e0a\u4e0b\u6587\u5e76\u4f20\u9012\u5b83\u3002 \u7136\u540e\uff0c\u4e00\u65e6\u60a8\u53d6\u6d88<\/em>\u201c\u6839\u201d\u4e0a\u4e0b\u6587\uff0c\u8be5\u4fe1\u53f7\u5c31\u4f1a\u901a\u8fc7\u4ece\u6839\u4e0a\u4e0b\u6587\u6d3e\u751f\u7684\u6574\u4e2a\u4e0a\u4e0b\u6587\u6811\u4f20\u64ad\u3002
 \u73b0\u5728\uff0c\u6bcf\u4e2a\u88ab\u8d4b\u4e88\u4e0a\u4e0b\u6587\u7684 goroutine \u90fd\u5e94\u8be5\u201c\u76d1\u542c\u201d\u5b83\uff0c\u4ee5\u4fbf\u5728\u53d1\u9001\u53d6\u6d88\u4fe1\u53f7\u65f6\u6536\u5230\u901a\u77e5\uff0c\u5e76\u4e14\u4e00\u65e6 goroutine \u6ce8\u610f\u5230\u5b83\u53ef\u80fd\u4f1a\u653e\u5f03\u6b63\u5728\u6267\u884c\u7684\u4efb\u4f55\u64cd\u4f5c\u5e76\u9000\u51fa\u3002<\/p>\n
\u5c31\u5b9e\u9645\u7684 context.context<\/code> \u7c7b\u578b\u800c\u8a00\uff0c\u8be5\u4fe1\u53f7\u88ab\u79f0\u4e3a\u201c\u5b8c\u6210\u201d\u2014\u2014\u5c31\u50cf\u201c\u6211\u4eec\u5df2\u7ecf\u5b8c\u6210\u4e86\u4e0e\u4e0a\u4e0b\u6587\u76f8\u5173\u7684\u4efb\u4f55\u4e8b\u60c5\u201d\u2014\u2014\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u60f3\u8981\u77e5\u9053\u5b83\u7684 goroutine \u5e94\u8be5\u505c\u6b62\u6267\u884c\u5b83\u7684\u64cd\u4f5cwork \u76d1\u542c\u4e0a\u4e0b\u6587\u65b9\u6cd5 done<\/code> \u8fd4\u56de\u7684\u7279\u6b8a\u901a\u9053\u3002<\/p>\n
\u56de\u5230\u4f60\u7684\u4f8b\u5b50<\/h3>\n
\u8981\u4f7f\u5176\u6b63\u5e38\u5de5\u4f5c\uff0c\u60a8\u9700\u8981\u6267\u884c\u4ee5\u4e0b\u64cd\u4f5c\uff1a<\/p>\n
func (s *Server) doWork(ctx context.Context) int {\n    s.lock.Lock()\n    defer s.lock.Unlock()\n\n    r := rand.Intn(100)\n    log.Printf(\"Going to nap for %d\", r)\n    select {\n    case <- time.After(time.Duration(r) * time.Millisecond):\n        return r\n    case <- ctx.Done():\n        return -1\n    }\n}\n\nfunc (s *Server)  GetValueWithTimeout(ctx context.Context, maxTime time.Duration) int {\n    d := time.Now().Add(maxTime)\n    ctx, cancel := context.WithDeadline(ctx, d)\n    defer cancel()\n\n    return s.doWork(ctx)\n}\n\nfunc main() {\n    const maxTime = 50 * time.Millisecond\n\n    rand.Seed(time.Now().UTC().UnixNano())\n\n    s := NewServer()\n    for i :=0; i < 10; i++ {\n        v := s.GetValueWithTimeout(context.Background(), maxTime)\n        log.Print(v)\n    }\n}\n<\/pre>\n
\uff08\uff09\u3002<\/p>\n
\u90a3\u4e48\u8fd9\u91cc\u4f1a\u53d1\u751f\u4ec0\u4e48\uff1f<\/p>\n
getvaluewithtimeout<\/code> \u65b9\u6cd5\u63a5\u53d7 dowork<\/code> \u65b9\u6cd5\u751f\u6210\u503c\u6240\u9700\u7684\u6700\u957f\u65f6\u95f4\uff0c\u8ba1\u7b97\u622a\u6b62\u65e5\u671f\uff0c\u6d3e\u751f\u4e00\u4e2a\u4e0a\u4e0b\u6587\uff0c\u4e00\u65e6\u622a\u6b62\u65e5\u671f\u4ece\u4f20\u9012\u7ed9\u8be5\u65b9\u6cd5\u7684\u4e0a\u4e0b\u6587\u8fc7\u53bb\uff0c\u8be5\u4e0a\u4e0b\u6587\u5c31\u4f1a\u81ea\u884c\u53d6\u6d88\uff0c\u5e76\u4f7f\u7528\u65b0\u7684\u4e0a\u4e0b\u6587\u5bf9\u8c61\u8c03\u7528 dowork<\/code> .<\/p>\n
dowork<\/code> \u65b9\u6cd5\u5c06\u5176\u81ea\u5df1\u7684\u8ba1\u65f6\u5668\u8bbe\u7f6e\u4e3a\u5728\u968f\u673a\u65f6\u95f4\u95f4\u9694\u540e\u5173\u95ed\uff0c\u7136\u540e\u76d1\u542c\u4e0a\u4e0b\u6587\u548c\u8ba1\u65f6\u5668\u3002<\/em>
 \u8fd9\u4e00\u70b9\u662f\u5173\u952e\u70b9\uff1a\u6267\u884c\u67d0\u4e9b\u5e94\u8be5\u53ef\u53d6\u6d88\u7684\u5de5\u4f5c\u5355\u5143\u7684\u4ee3\u7801\u5fc5\u987b\u68c0\u67e5\u4e0a\u4e0b\u6587\uff0c\u4f7f\u5176\u4e3b\u52a8\u5730<\/em>\u81ea\u884c\u201c\u5b8c\u6210\u201d\u3002
 \u56e0\u6b64\uff0c\u5728\u6211\u4eec\u7684\u73a9\u5177\u793a\u4f8b\u4e2d\uff0c\u8981\u4e48 dowork<\/code> \u81ea\u5df1\u7684\u8ba1\u65f6\u5668\u9996\u5148\u89e6\u53d1\uff0c\u8981\u4e48\u9996\u5148\u8fbe\u5230\u751f\u6210\u7684\u4e0a\u4e0b\u6587\u7684\u622a\u6b62\u65e5\u671f\uff1b\u65e0\u8bba\u5148\u53d1\u751f\u4ec0\u4e48\uff0c\u90fd\u4f1a\u4f7f select<\/code> \u8bed\u53e5\u89e3\u9501\u5e76\u7ee7\u7eed\u3002<\/p>\n
\u8bf7\u6ce8\u610f\uff0c\u5982\u679c\u4f60\u7684\u201c\u505a\u5de5\u4f5c\u201d\u4ee3\u7801\u4f1a\u66f4\u52a0\u590d\u6742\u2014\u2014\u5b83\u5b9e\u9645\u4e0a\u4f1a\u505a\u4e00\u4e9b\u4e8b\u60c5\u800c\u4e0d\u662f\u7761\u89c9\u2014\u2014\u4f60\u5f88\u53ef\u80fd\u9700\u8981\u5b9a\u671f\u68c0\u67e5\u4e0a\u4e0b\u6587\u7684\u72b6\u6001\uff0c\u901a\u5e38\u662f\u5728\u6267\u884c\u8be5\u5de5\u4f5c\u7684\u5404\u4e2a\u90e8\u5206\u4e4b\u540e\u3002 <\/p>\n
\u4eca\u5929\u5e26\u5927\u5bb6\u4e86\u89e3\u4e86\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u5e0c\u671b\u5bf9\u4f60\u6709\u6240\u5e2e\u52a9\uff1b\u5173\u4e8eGolang\u7684\u6280\u672f\u77e5\u8bc6\u6211\u4eec\u4f1a\u4e00\u70b9\u70b9\u6df1\u5165\u4ecb\u7ecd\uff0c\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u516c\u4f17\u53f7\uff0c\u4e00\u8d77\u5b66\u4e60\u7f16\u7a0b~<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f53\u524d\u4f4d\u7f6e\uff1a > > ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-208146","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208146","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=208146"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208146\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=208146"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=208146"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=208146"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}