{"id":44918,"date":"2024-01-21T02:07:06","date_gmt":"2024-02-17T18:27:19","guid":{"rendered":"https:\/\/www.silicloud.com\/zh\/blog\/44918-2\/"},"modified":"2024-05-04T19:22:49","modified_gmt":"2024-05-04T11:22:49","slug":"44918-2","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/zh\/blog\/44918-2\/","title":{"rendered":""},"content":{"rendered":"

\u300eGo\u8a00\u8a9e\u306b\u3088\u308b\u4e26\u884c\u51e6\u7406\u300f\u3092\u8aad\u3093\u3067Context\u30c1\u30e7\u30c3\u30c8\u30ef\u30ab\u30eb\u3088\u3046\u306b\u306a\u3063\u305f\u306e\u3067\u8a18\u9332\u306b\u6b8b\u3057\u307e\u3059\u3002<\/p>\n

Context\u306e\u89e3\u6c7a\u3057\u305f\u3044\u554f\u984c<\/h1>\n
    \n
  1. \n
      Go\u306f\u4e26\u884c\u51e6\u7406\u306e\u305f\u3081\u306b\u30b4\u30eb\u30fc\u30c1\u30f3\u3092\u7c21\u5358\u306b\u751f\u6210\u3067\u304d\u308b<\/ol>\n<\/li>\n<\/ol>\n

       <\/p>\n

        \n
      1. \n
          \u591a\u304f\u306e\u5834\u5408\u30b4\u30eb\u30fc\u30c1\u30f3\u306f\u4ed6\u306e\u30b4\u30eb\u30fc\u30c1\u30f3\u3068\u9023\u643a\u3057\u3066\u304a\u308a\u3001\u5b50\u306e\u30b4\u30eb\u30fc\u30c1\u30f3\u304c\u51e6\u7406\u3092\u7d9a\u3051\u308b\u3079\u304d\u304b\u3092\u77e5\u308b\u3053\u3068\u3067\u30ea\u30bd\u30fc\u30b9\u3092\u52b9\u7387\u7684\u306b\u5229\u7528\u3067\u304d\u308b<\/ol>\n<\/li>\n<\/ol>\n

           <\/p>\n

            \u305d\u308c\u3092\u5b9f\u73fe\u3059\u308b\u6a19\u6e96\u7684\u306a\u30d1\u30bf\u30fc\u30f3\u304c\u5fc5\u8981\u3068\u306a\u308aContext\u30d1\u30c3\u30b1\u30fc\u30b8\u304c\u3067\u304d\u305f<\/ol>\n

            \u4f7f\u3046\u6642\u306b\u3069\u3046\u3059\u308b\u306e\u304c\u826f\u3044\u306e\u304b<\/h2>\n

            \u5b9f\u969b\u306b\u78ba\u304b\u3081\u3066\u307f\u307e\u3057\u305f\u3002
            \n\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u306fgithub\u306b\u3042\u3052\u3066\u307e\u3059\u3002<\/p>\n

            structure image on mermaid<\/p>\n

            Proxy<\/h3>\n

            \u5225\u306e\u5834\u6240\u304b\u3089\u30ea\u30af\u30a8\u30b9\u30c8\u3092\u53d7\u3051\u53d6\u3063\u3066\u6b21\u306e\u30b5\u30fc\u30d0\u30fc\u6d41\u3059\u5834\u5408\u3002
            \nProxy\u81ea\u8eab\u3082\u500b\u5225\u306b\u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u8a2d\u5b9a\u3092\u6301\u3063\u3066\u304a\u308a\u6e21\u3057\u305f\u5148\u3067\u4e00\u5b9a\u6642\u9593\u306b\u7d42\u308f\u3089\u306a\u3044\u5834\u5408\u306b\u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u3092\u3055\u305b\u307e\u3059\u3002
            \nchildCtx, cancel := context.WithCancel(ctx)\u3067cancel\u95a2\u6570\u3068\u305d\u308c\u3068\u3064\u306a\u304c\u3063\u305fContext\u3092\u751f\u6210\u3057\u305d\u308c\u3092\u6b21\u306e\u30b5\u30fc\u30d0\u30fc\u306b\u6e21\u3057\u3001Proxy\u304ctimeout\u3060\u3068\u5224\u65ad\u3057\u305f\u3089cancel()\u3092\u547c\u3073\u307e\u3059\u3002<\/p>\n

            childCtx<\/span>,<\/span> cancel<\/span> :=<\/span> context<\/span>.<\/span>WithCancel<\/span>(<\/span>ctx<\/span>)<\/span>\r\ndefer<\/span> cancel<\/span>()<\/span>\r\ngo<\/span> func<\/span>()<\/span> {<\/span>\r\n  \/\/ Call server's method with cancelable context by proxy<\/span>\r\n  res<\/span>,<\/span> err<\/span> :=<\/span> p<\/span>.<\/span>Server<\/span>.<\/span>Call<\/span>(<\/span>childCtx<\/span>,<\/span> task<\/span>)<\/span>\r\n  ch<\/span> <-<\/span> ProxiedResponce<\/span>{<\/span>\r\n    Responce<\/span>:<\/span> res<\/span>,<\/span>\r\n    Error<\/span>:<\/span>    err<\/span>,<\/span>\r\n  }<\/span>\r\n}()<\/span>\r\ngo<\/span> func<\/span>()<\/span> {<\/span>\r\n  \/\/ Call cancel after proxy timeout<\/span>\r\n  <-<\/span>time<\/span>.<\/span>After<\/span>(<\/span>p<\/span>.<\/span>Timeout<\/span>)<\/span>\r\n  cancel<\/span>()<\/span>\r\n}()<\/span>\r\n<\/code><\/pre>\n
            \u30b5\u30f3\u30d7\u30eb\u306e\u7d50\u679c\u306f\u4ee5\u4e0b\u306e\u3068\u304a\u308a\u3067\u3059\u3002<\/p>\n
            # Responce\u8868\u793a\u306f[(\u8a08\u6e2c\u6642\u9593)\/(Task\u306eTimeout\u8a2d\u5b9a)]<\/span>\r\n# Client\u306f`70ms`\u3067Timeout\u3059\u308bContext\u3092\u6e21\u3059<\/span>\r\n\r\n# Proxy\u306etimeout\u306f45ms<\/span>\r\n# 30ms\u3067\u5b8c\u4e86\u3059\u308b`Fast`Server\u306b\u30ea\u30af\u30a8\u30b9\u30c8\u3092\u6e21\u3057\u305f\u5834\u5408<\/span>\r\nProxy: through[TO:45ms] Fast: Timeout [<\/span>20.1622ms\/20ms] Timeout by Server # time 20ms\u306a\u306e\u3067Server\u306b\u3066Timeout<\/span>\r\nProxy: through[TO:45ms] Fast: Complete [<\/span>30.9573ms\/60ms] <nil>\r\nProxy: through[TO:45ms] Fast: Complete [<\/span>30.9573ms\/40ms] <nil>\r\nProxy: through[TO:45ms] Fast: Complete [<\/span>30.9573ms\/80ms] <nil>\r\n\r\n# 90ms\u3067\u5b8c\u4e86\u3059\u308b`Slow`Server\u306b\u30ea\u30af\u30a8\u30b9\u30c8\u3092\u6e21\u3057\u305f\u5834\u5408<\/span>\r\nProxy: through[TO:45ms] Slow: Timeout [<\/span>20.1622ms\/20ms] Timeout by Server\r\nProxy: through[TO:45ms] Slow: Timeout [<\/span>40.8834ms\/40ms] Timeout by Server\r\nProxy: through[TO:45ms] Slow: Cancel [<\/span>45.0796ms\/80ms] context canceled # Proxy\u306b\u3088\u308bCancel<\/span>\r\nProxy: through[TO:45ms] Slow: Cancel [<\/span>45.0796ms\/60ms] context canceled # Proxy\u306b\u3088\u308bCancel<\/span>\r\n\r\n# Proxy\u306etimeout\u309275ms\u306b\u5909\u66f4<\/span>\r\n# 30ms\u3067\u5b8c\u4e86\u3059\u308b`Fast`Server\u306b\u30ea\u30af\u30a8\u30b9\u30c8\u3092\u6e21\u3057\u305f\u5834\u5408<\/span>\r\nProxy: through[TO:75ms] Fast: Timeout [<\/span>20.1622ms\/20ms] Timeout by Server # time 20ms\u306a\u306e\u3067Server\u306b\u3066Timeout<\/span>\r\nProxy: through[TO:75ms] Fast: Complete [<\/span>30.9573ms\/60ms] <nil>\r\nProxy: through[TO:75ms] Fast: Complete [<\/span>30.9573ms\/80ms] <nil>\r\nProxy: through[TO:75ms] Fast: Complete [<\/span>30.9573ms\/40ms] <nil>\r\n\r\n# 90ms\u3067\u5b8c\u4e86\u3059\u308b`Slow`Server\u306b\u30ea\u30af\u30a8\u30b9\u30c8\u3092\u6e21\u3057\u305f\u5834\u5408<\/span>\r\nProxy: through[TO:75ms] Slow: Timeout [<\/span>20.1622ms\/20ms] Timeout by Server\r\nProxy: through[TO:75ms] Slow: Timeout [<\/span>40.8041ms\/40ms] Timeout by Server\r\nProxy: through[TO:75ms] Slow: Timeout [<\/span>61.0672ms\/60ms] Timeout by Server\r\nProxy: through[TO:75ms] Slow: Cancel [<\/span>70.9447ms\/80ms] context deadline exceeded # Client\u306e\u6307\u5b9a\u3057\u305fTimeout\u306b\u3088\u308bCancel<\/span>\r\n<\/code><\/pre>\n
            \u30b3\u30fc\u30c9\u5168\u4f53\u3092\u793a\u3057\u307e\u3059\u3002Client\u306b\u8fd4\u3059\u306e\u306b\u30b5\u30fc\u30d0\u30fc\u304b\u3089\u306e\u623b\u308a\u5024\u3092\u53d7\u3051\u3066\u3044\u307e\u3059\u304c\u30d7\u30ed\u30ad\u30b7\u81ea\u8eab\u304c\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u3092\u751f\u6210\u3057\u3066\u623b\u3057\u305f\u308aWithTimeout\u3067\u3088\u308a\u77ed\u3044\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u3092\u751f\u6210\u3057\u306a\u304a\u3059\u3068\u3044\u3046\u30d1\u30bf\u30fc\u30f3\u3082\u3042\u308a\u305d\u3046\u3067\u3059\u3002
            \n\u30ad\u30e3\u30f3\u30bb\u30eb\u6642\u306eRollback\u5b8c\u4e86\u307e\u3067\u78ba\u8a8d\u304c\u5fc5\u8981\u304b\u3001\u8ab0\u304c\u30ad\u30e3\u30f3\u30bb\u30eb\u3092\u3057\u305f\u306e\u304b\u660e\u793a\u304c\u5fc5\u8981\u304b\u3001\u306a\u3069\u306b\u3088\u3063\u3066\u305d\u306e\u3042\u305f\u308a\u5909\u308f\u308a\u305d\u3046\u3067\u3059\u306d\u3002<\/p>\n
            \/\/ ProxyProcessWithTimeout pass the request to the next process<\/span>\r\n\/\/ and interrupts the request by its own time out setting<\/span>\r\ntype<\/span> ProxyProcessWithTimeout<\/span> struct<\/span> {<\/span>\r\n    Name<\/span>    string<\/span>\r\n    Server<\/span>  Process<\/span>\r\n    Timeout<\/span> time<\/span>.<\/span>Duration<\/span>\r\n}<\/span>\r\n\r\nfunc<\/span> (<\/span>p<\/span> *<\/span>ProxyProcessWithTimeout<\/span>)<\/span> Call<\/span>(<\/span>ctx<\/span> context<\/span>.<\/span>Context<\/span>,<\/span> task<\/span> Task<\/span>)<\/span> (<\/span>Responce<\/span>,<\/span> error<\/span>)<\/span> {<\/span>\r\n    type<\/span> ProxiedResponce<\/span> struct<\/span> {<\/span>\r\n        Responce<\/span> Responce<\/span>\r\n        Error<\/span>    error<\/span>\r\n    }<\/span>\r\n    \/\/ Generate goroutine<\/span>\r\n    ch<\/span> :=<\/span> make<\/span>(<\/span>chan<\/span> ProxiedResponce<\/span>)<\/span>\r\n\r\n    \/\/ Get a cancel function to cancel by proxy<\/span>\r\n    childCtx<\/span>,<\/span> cancel<\/span> :=<\/span> context<\/span>.<\/span>WithCancel<\/span>(<\/span>ctx<\/span>)<\/span>\r\n    defer<\/span> cancel<\/span>()<\/span>\r\n    go<\/span> func<\/span>()<\/span> {<\/span>\r\n        \/\/ Call server's method with cancelable context by proxy<\/span>\r\n        res<\/span>,<\/span> err<\/span> :=<\/span> p<\/span>.<\/span>Server<\/span>.<\/span>Call<\/span>(<\/span>childCtx<\/span>,<\/span> task<\/span>)<\/span>\r\n        ch<\/span> <-<\/span> ProxiedResponce<\/span>{<\/span>\r\n            Responce<\/span>:<\/span> res<\/span>,<\/span>\r\n            Error<\/span>:<\/span>    err<\/span>,<\/span>\r\n        }<\/span>\r\n    }()<\/span>\r\n    go<\/span> func<\/span>()<\/span> {<\/span>\r\n        \/\/ Call cancel after proxy timeout<\/span>\r\n        <-<\/span>time<\/span>.<\/span>After<\/span>(<\/span>p<\/span>.<\/span>Timeout<\/span>)<\/span>\r\n        cancel<\/span>()<\/span>\r\n    }()<\/span>\r\n\r\n    \/\/ wait responce<\/span>\r\n    pres<\/span> :=<\/span> <-<\/span>ch<\/span>\r\n    res<\/span> :=<\/span> Responce<\/span>(<\/span>fmt<\/span>.<\/span>Sprintf<\/span>(<\/span>\"%s: through[TO:%s] %s\"<\/span>,<\/span> p<\/span>.<\/span>Name<\/span>,<\/span> p<\/span>.<\/span>Timeout<\/span>,<\/span> string<\/span>(<\/span>pres<\/span>.<\/span>Responce<\/span>)))<\/span>\r\n    return<\/span> res<\/span>,<\/span> pres<\/span>.<\/span>Error<\/span>\r\n}<\/span>\r\n<\/code><\/pre>\n
            Process<\/h2>\n
            \u91cd\u3044\u51e6\u7406\u3092\u884c\u3046\u5834\u5408\u306f\u53d7\u3051\u53d6\u3063\u305fContext\u304b\u3089\u5272\u308a\u8fbc\u307f\u3092\u9069\u5207\u306b\u53d7\u3051\u308b\u306e\u304c\u826f\u3044\u3067\u3059\u3002
            \n\u4e00\u5b9a\u306e\u77ed\u3044\u30eb\u30fc\u30d7\u306b\u5206\u89e3\u3067\u304d\u308b\u306e\u3067\u3042\u308c\u3070\u9014\u4e2d\u3067<-ctx.Done()\u3092\u78ba\u8a8d\u3057\u3066\u4e2d\u65ad\u3092\u3059\u3079\u304d\u304b\u3092\u5224\u65ad\u3055\u305b\u307e\u3059\u3002<\/p>\n
            for<\/span> {<\/span>\r\n  \/\/ \u4f55\u3089\u304b\u306e\u51e6\u7406...<\/span>\r\n  \/\/ ...<\/span>\r\n  \/\/<\/span>\r\n  select<\/span> {<\/span>\r\n      \/\/ Cancel, Time<\/span>\r\n      case<\/span> <-<\/span>ctx<\/span>.<\/span>Done<\/span>()<\/span>:<\/span>\r\n        \/\/ rollback <\/span>\r\n        return<\/span> \r\n      default<\/span>:<\/span>\r\n        \/\/ \u7d42\u4e86\u6761\u4ef6<\/span>\r\n  }<\/span>\r\n}<\/span>\r\n<\/code><\/pre>\n
            \u30b5\u30f3\u30d7\u30eb\u306e\u7d50\u679c\u306f\u4ee5\u4e0b\u306e\u3068\u304a\u308a\u3067\u3059\u3002<\/p>\n
            # Timeout [(\u8a08\u6e2c\u6642\u9593)\/(Task\u306eTimeout\u8a2d\u5b9a)]<\/span>\r\n# Client\u306f`70ms`\u3067Timeout\u3059\u308bContext\u3092\u6e21\u3059<\/span>\r\n# Proxy\u306f`75ms`\u3067Context\u3092Cancel\u3059\u308b<\/span>\r\n\r\nProxy: through[TO:75ms] l:1ms: Complete [<\/span>loop: 20] [<\/span>33.804ms\/40ms] <nil>\r\nProxy: through[TO:75ms] l:1ms: Timeout [<\/span>41.9723ms\/40ms] Timeout by Simulation\r\nProxy: through[TO:75ms] l:1ms: Cancel [<\/span>70.7212ms\/80ms] context deadline exceeded # Context\u306e\u30b7\u30b0\u30ca\u30eb\u3092\u53d7\u3051\u3066\u4e2d\u65ad\u3067\u304d\u3066\u3044\u308b<\/span>\r\nProxy: through[TO:75ms] l:1ms: Cancel [<\/span>70.7212ms\/80ms] context deadline exceeded\r\n<\/code><\/pre>\n
            \u30b5\u30f3\u30d7\u30eb\u306e\u5168\u4f53\u306f\u4ee5\u4e0b\u306e\u3068\u304a\u308a\u3067\u3059\u3002
            \nTick\u6642\u9593\u304b\u304b\u308b\u51e6\u7406\u3092n\u56de\u884c\u3046(task.Value\u304b\u3089\u53d6\u308b)\u3068\u3057\u3001\u30eb\u30fc\u30d7\u306e\u305f\u3073\u306bcontext\u3092\u78ba\u8a8d\u3057\u307e\u3059\u3002
            \n\u4f8b\u3067\u306f1tick=1ms\u3067\u52d5\u304b\u3057\u3066\u307e\u3059\u304c20loop\u306e\u5b9f\u884c\u306b30ms\u304b\u304b\u3063\u3066\u307e\u3059\u306d\u3002\u3069\u3053\u306b\u6642\u9593\u304c\u304b\u304b\u3063\u3066\u308b\u304b\u307e\u305f\u8abf\u3079\u307e\u3059\u3002<\/p>\n
            \/\/ ProcessSimulation simurate the real process.<\/span>\r\n\/\/ This is an example of a process that can be suspended from Context<\/span>\r\ntype<\/span> ProcessSimulation<\/span> struct<\/span> {<\/span>\r\n    Name<\/span> string<\/span>\r\n    Tick<\/span> time<\/span>.<\/span>Duration<\/span>\r\n}<\/span>\r\n\r\nfunc<\/span> (<\/span>p<\/span> *<\/span>ProcessSimulation<\/span>)<\/span> Call<\/span>(<\/span>ctx<\/span> context<\/span>.<\/span>Context<\/span>,<\/span> task<\/span> Task<\/span>)<\/span> (<\/span>Responce<\/span>,<\/span> error<\/span>)<\/span> {<\/span>\r\n    start<\/span> :=<\/span> time<\/span>.<\/span>Now<\/span>()<\/span>\r\n    loopMax<\/span>,<\/span> ok<\/span> :=<\/span> task<\/span>.<\/span>Value<\/span>.<\/span>(<\/span>int<\/span>)<\/span>\r\n    if<\/span> !<\/span>ok<\/span> {<\/span>\r\n        return<\/span> Responce<\/span>(<\/span>\"\"<\/span>),<\/span> errors<\/span>.<\/span>Errorf<\/span>(<\/span>\"Task Value is not int\"<\/span>)<\/span>\r\n    }<\/span>\r\n    if<\/span> loopMax<\/span> <<\/span> 1<\/span> {<\/span>\r\n        return<\/span> Responce<\/span>(<\/span>\"\"<\/span>),<\/span> errors<\/span>.<\/span>Errorf<\/span>(<\/span>\"Task.Value must int type and 1 or more\"<\/span>)<\/span>\r\n    }<\/span>\r\n\r\n    \/\/ Heavy loop process<\/span>\r\n    var<\/span> counter<\/span> int<\/span>\r\n    timeout<\/span> :=<\/span> time<\/span>.<\/span>After<\/span>(<\/span>task<\/span>.<\/span>Timeout<\/span>)<\/span>\r\n    for<\/span> {<\/span>\r\n        if<\/span> counter<\/span> >=<\/span> loopMax<\/span> {<\/span>\r\n            return<\/span> Responce<\/span>(<\/span>fmt<\/span>.<\/span>Sprintf<\/span>(<\/span>\"%s: Complete [loop: %d] [%s\/%s]\"<\/span>,<\/span> p<\/span>.<\/span>Name<\/span>,<\/span> counter<\/span>,<\/span> time<\/span>.<\/span>Since<\/span>(<\/span>start<\/span>),<\/span> task<\/span>.<\/span>Timeout<\/span>)),<\/span> nil<\/span>\r\n        }<\/span>\r\n        counter<\/span>++<\/span>\r\n\r\n        \/\/ Here is check Context and time out setting.<\/span>\r\n        select<\/span> {<\/span>\r\n        case<\/span> <-<\/span>ctx<\/span>.<\/span>Done<\/span>()<\/span>:<\/span>\r\n            \/\/ Add Rollback process when need<\/span>\r\n            return<\/span> Responce<\/span>(<\/span>fmt<\/span>.<\/span>Sprintf<\/span>(<\/span>\"%s: Cancel [%s\/%s]\"<\/span>,<\/span> p<\/span>.<\/span>Name<\/span>,<\/span> time<\/span>.<\/span>Since<\/span>(<\/span>start<\/span>),<\/span> task<\/span>.<\/span>Timeout<\/span>)),<\/span> ctx<\/span>.<\/span>Err<\/span>()<\/span>\r\n        case<\/span> <-<\/span>timeout<\/span>:<\/span>\r\n            \/\/ Add Rollback process when need<\/span>\r\n            return<\/span> Responce<\/span>(<\/span>fmt<\/span>.<\/span>Sprintf<\/span>(<\/span>\"%s: Timeout [%s\/%s]\"<\/span>,<\/span> p<\/span>.<\/span>Name<\/span>,<\/span> time<\/span>.<\/span>Since<\/span>(<\/span>start<\/span>),<\/span> task<\/span>.<\/span>Timeout<\/span>)),<\/span> errors<\/span>.<\/span>Errorf<\/span>(<\/span>\"Timeout by Simulation\"<\/span>)<\/span>\r\n        case<\/span> <-<\/span>time<\/span>.<\/span>After<\/span>(<\/span>p<\/span>.<\/span>Tick<\/span>)<\/span>:<\/span>\r\n        }<\/span>\r\n    }<\/span>\r\n}<\/span>\r\n<\/code><\/pre>\n
            \u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u3092\u8aad\u3080<\/h2>\n
            \u6b21\u306f\u306a\u305cWith***\u3067\u8a2d\u5b9a\u3092\u3059\u308b\u306e\u304b\u3001\u8907\u6570\u56deWithTimeout()\u3092\u547c\u3093\u3060\u3089\u3069\u3046\u306a\u308b\u306e\u304b\u77e5\u308b\u305f\u3081\u306b\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9(context.go)\u3092\u8aad\u3093\u3067\u307f\u307e\u3057\u305f\u3002<\/p>\n
              \n
            • \n
                Context\u306fWith***(ctx,args)\u306e\u305f\u3073\u306b\u65b0\u3057\u3044\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u751f\u6210\u3057\u3066\u3044\u308b<\/ul>\n<\/li>\n<\/ul>\n
                 <\/p>\n
                  \n
                • \n
                    \u305d\u308c\u3089\u306fContext\u5185\u3067\u5ba3\u8a00\u3055\u308c\u305f*emptyCtx\u3092\u7d42\u7aef\u306b\u6301\u3064\u9023\u7d50\u30ea\u30b9\u30c8\u306e\u5b50\u5b6b\u3067\u3042\u308b<\/ul>\n<\/li>\n<\/ul>\n
                     <\/p>\n
                      \n
                    • \n
                        Cancel\u306f\u5e38\u306b\u89aa\u304b\u3089\u5b50\u306b\u4f1d\u64ad\u3057\u89aa\u306f\u5f71\u97ff\u3092\u53d7\u3051\u306a\u3044<\/ul>\n<\/li>\n<\/ul>\n
                         <\/p>\n
                          Value\u306f\u5b50\u304b\u3089\u89aa\u306b\u5411\u304b\u3063\u3066\u306e\u307f\u53c2\u7167\u3059\u308b<\/ul>\n
                          \u3068\u3044\u3046\u5b9f\u88c5\u306b\u306a\u3063\u3066\u3044\u307e\u3057\u305f\u3002\u3053\u308c\u3067\u5b89\u5fc3\u3057\u3066\u30ad\u30e3\u30f3\u30bb\u30eb\u3067\u304d\u307e\u3059\u306d\u3002<\/p>\n
                          Cancel\u306e\u5b9f\u88c5<\/h3>\n
                          Context\u306e\u30ad\u30e3\u30f3\u30bb\u30eb\u306e\u5b9f\u88c5\u306fcancelCtx\u306b\u3042\u308a\u307e\u3059\u3002Timeout,Deadline\u3082cancelCtx\u3092\u57cb\u3081\u8fbc\u3093\u3067\u3042\u308a\u6307\u5b9a\u306e\u6642\u9593\u304c\u6765\u305f\u3089\u30ad\u30e3\u30f3\u30bb\u30eb\u3092\u3059\u308b\u3060\u3051\u3067\u3059\u3002
                          \n\u305d\u306e\u30ad\u30e3\u30f3\u30bb\u30eb\u306e\u5b9f\u88c5\u304c\u6b21\u306e\u90e8\u5206\u3067\u3059<\/p>\n
                            func (c *cancelCtx) cancel(removeFromParent bool, err error)<\/ul>\n
                            \u81ea\u8eab\u306e\u72b6\u614b\u3092\u898b\u3066\u30ad\u30e3\u30f3\u30bb\u30eb\u3055\u308c\u3066\u3044\u306a\u3044\u5834\u5408\u306f\u72b6\u614b\u3092\u5909\u66f4\u3057(err field\u3092non-nil\u306b\u3059\u308b)\u5b50\u306b\u3082\u540c\u3058error\u3092\u4f1d\u3048\u3001\u5b50\u3092\u9023\u7d50\u30ea\u30b9\u30c8\u304b\u3089\u53d6\u308a\u9664\u304d\u307e\u3059\u3002
                            \n\u307e\u305f\u81ea\u8eab\u3092\u89aa\u306e\u6301\u3064\u5b50\u306e\u30ea\u30b9\u30c8\u53d6\u308a\u9664\u304d\u307e\u3059\u3002<\/p>\n
                            \u89aa\u5b50\u95a2\u4fc2\u306e\u8a2d\u5b9a\u306fWith***\u306e\u969b\u306bfunc propagateCancel(parent Context, child canceler)\u3092\u547c\u3076\u3053\u3068\u3067\u884c\u308f\u308c\u307e\u3059\u3002<\/p>\n
                              func propagateCancel(parent Context, child canceler)<\/ul>\n
                              Value\u306e\u5b9f\u88c5<\/h3>\n
                              WithValue(ctx, key, value)\u306f\u6307\u5b9a\u3055\u308c\u305fkey\u3068value\u3068ctx\u3078\u306e\u53c2\u7167\u3092\u6301\u3064*valueCtx\u3092\u8fd4\u3057\u307e\u3059\u3002
                              \nValue(key)\u304c\u547c\u3070\u308c\u308b\u3068key\u304c\u4e00\u81f4\u3059\u308b\u307e\u3067\u89aa\u306e\u65b9\u5411\u3092\u305f\u3069\u308a\u307e\u3059\u3002
                              \n\u3059\u3079\u3066\u306e\u89aa\u306fbackground *emptyCtx\u3067\u3042\u308a\u5e38\u306bnil\u3092\u8fd4\u3059\u306e\u3067key\u304c\u4e00\u81f4\u3059\u308b\u6700\u3082\u8fd1\u3044*valueCtx\u306e\u5024\u304bnil\u306e\u3069\u3061\u3089\u304b\u304c\u8fd4\u3063\u3066\u304d\u307e\u3059\u3002<\/p>\n
                                func WithValue<\/ul>\n
                                Done()\u304b\u3089\u5f97\u3089\u308c\u308b\u5024<\/h3>\n
                                Done\u306e\u623b\u308a\u5024\u306f<-chan struct{}\u3067\u3059\u3002
                                \n\u30af\u30ed\u30fc\u30ba\u3057\u3066\u3042\u308b\u30c1\u30e3\u30f3\u30cd\u30eb\u306f\u305d\u306e\u578b\u306e\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3068true\u3092\u8fd4\u3057\u307e\u3059\u3002
                                \n\u6545\u306b\u3069\u3053\u3067\u3069\u308c\u3060\u3051Done()\u3067\u5f85\u3063\u3066\u3044\u3066\u3082\u30c1\u30e3\u30f3\u30cd\u30eb\u9589\u3058\u3089\u308c\u305f\u306a\u3089\u51e6\u7406\u306f\u6b21\u306b\u9032\u307f\u307e\u3059\u3002<\/p>\n
                                \u307e\u3068\u3081<\/h1>\n
                                \u4ee5\u4e0aContext\u306e\u30ad\u30e3\u30f3\u30bb\u30eb\u51e6\u7406\u306b\u3064\u3044\u3066\u8a66\u3057\u307e\u3057\u305f\u3002
                                \n\u4eca\u601d\u3046\u3068\u4e0a\u8a18\u30b5\u30f3\u30d7\u30eb\u306eResponce\u306b\u306ferror\u3092\u542b\u3093\u3060\u307b\u3046\u304c\u826f\u304b\u3063\u305f\u6c17\u304c\u3057\u307e\u3059\u3002
                                \n\u3053\u3046\u3044\u3046\u306e\u3092\u8003\u3048\u308b\u306e\u306f\u697d\u3057\u3044\u3067\u3059\u306d\u3002<\/p>\n
                                Context\u3092http.Request\u306a\u3069\u304b\u3089\u6e21\u3055\u308c\u308b\u3068\u3053\u308d\u304b\u3089\u5165\u308b\u3068\u5358\u306a\u308b\u30ad\u30e3\u30ea\u30a2\u306e\u3088\u3046\u306b\u611f\u3058\u307e\u3059\u304c(\u79c1\u304c\u305d\u3046\u3067\u3057\u305f)\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u51fa\u3059\u305f\u3081\u306b\u88cf\u5074\u3067\u30b4\u30eb\u30fc\u30c1\u30f3\u304c\u52d5\u3044\u3066\u304a\u308a\u305d\u306e\u80cc\u666f\u304b\u3089Context\u3092\u5f15\u304d\u7d99\u3044\u3067\u3044\u308b\u306e\u3060\u3068\u3044\u3046\u3053\u3068\u3067\u3044\u308d\u3044\u308d\u7d0d\u5f97\u3092\u3057\u307e\u3057\u305f\u3002
                                \n\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u51fa\u3059\u3046\u3048\u3067\u30b4\u30eb\u30fc\u30c1\u30f3\u3067\u4e26\u884c\u51e6\u7406\u3092\u3059\u308b\u3068\u601d\u3046\u306e\u3067\u305d\u306e\u969b\u306f\u4ee5\u4e0b\u306b\u6ce8\u610f\u3057\u3066\u4f5c\u308b\u3068\u826f\u3055\u305d\u3046\u3067\u3059\u3002<\/p>\n
                                Context\u3092\u5f15\u6570\u306b\u3068\u3063\u3066\u5272\u308a\u8fbc\u307f\u53ef\u80fd\u306b\u4f5c\u308b
                                \n\u91cd\u3044\u51e6\u7406\u306f\u3069\u3053\u3067\u5272\u308a\u8fbc\u307e\u305b\u308b\u306e\u304b\u3001Rollback\u51e6\u7406\u3001\u30a8\u30e9\u30fc\u306e\u4f1d\u64ad\u3092\u8a2d\u8a08\u6642\u306b\u8003\u3048\u3066\u304a\u304f<\/p>\n","protected":false},"excerpt":{"rendered":"
                                \u300eGo\u8a00\u8a9e\u306b\u3088\u308b\u4e26\u884c\u51e6\u7406\u300f\u3092\u8aad\u3093\u3067Context\u30c1\u30e7\u30c3\u30c8\u30ef\u30ab\u30eb\u3088\u3046\u306b\u306a\u3063\u305f\u306e\u3067\u8a18\u9332\u306b\u6b8b\u3057\u307e\u3059\u3002 Context […]<\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-44918","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"\n- Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/zh\/blog\/44918-2\/\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:description\" content=\"\u300eGo\u8a00\u8a9e\u306b\u3088\u308b\u4e26\u884c\u51e6\u7406\u300f\u3092\u8aad\u3093\u3067Context\u30c1\u30e7\u30c3\u30c8\u30ef\u30ab\u30eb\u3088\u3046\u306b\u306a\u3063\u305f\u306e\u3067\u8a18\u9332\u306b\u6b8b\u3057\u307e\u3059\u3002 Context […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/zh\/blog\/44918-2\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - 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