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如何在golang中处理HTTP超时错误和访问状态代码

运维开发网 https://www.qedev.com 2020-05-19 20:38 出处:网络 作者:运维开发网整理
我有一些用Go编写的代码(见下文),它应该“扇出”HTTP请求,然后整理/聚合细节. I’m new to golang and so expect me to be a nOOb and my knowledge to be limited 该程序的输出目前是这样的: { "Status":"success", "Components":[ {"Id":"foo"
我有一些用Go编写的代码(见下文),它应该“扇出”HTTP请求,然后整理/聚合细节.

I’m new to golang and so expect me to be a nOOb and my knowledge to be limited

该程序的输出目前是这样的:

{
    "Status":"success",
    "Components":[
        {"Id":"foo","Status":200,"Body":"..."},
        {"Id":"bar","Status":200,"Body":"..."}, 
        {"Id":"baz","Status":404,"Body":"..."}, 
        ...
    ]
}

运行的本地服务器特意慢(睡眠5秒然后返回响应).但我列出了其他网站(见下面的代码),有时也会触发错误(如果它们出错,那就没关系).

我目前遇到的问题是如何最好地处理这些错误,特别是“超时”相关的错误;因为我不知道如何识别故障是超时还是其他错误?

目前我总是得到一揽子错误:

Get http://localhost:8080/pugs: read tcp 127.0.0.1:8080: use of closed network connection

http:// localhost:8080 / pugs通常是失败的URL(希望超时!).但正如你从代码中看到的那样(下图),我不确定如何确定错误代码与超时有关,也不确定如何访问响应的状态代码(我目前只是将其设置为404但是显然这是不对的 – 如果服务器出错了,我会期待类似500状态代码的东西,显然我想在我发回的聚合响应中反映出来.

完整的代码如下所示.任何帮助赞赏.

package main

    import (
            "encoding/json"
            "fmt"
            "io/ioutil"
            "net/http"
            "sync"
            "time"
    )

    type Component struct {
            Id  string `json:"id"`
            Url string `json:"url"`
    }

    type ComponentsList struct {
            Components []Component `json:"components"`
    }

    type ComponentResponse struct {
            Id     string
            Status int
            Body   string
    }

    type Result struct {
            Status     string
            Components []ComponentResponse
    }

    var overallStatus string = "success"

    func main() {
            var cr []ComponentResponse
            var c ComponentsList

            b := []byte(`{"components":[{"id":"local","url":"http://localhost:8080/pugs"},{"id":"google","url":"http://google.com/"},{"id":"integralist","url":"http://integralist.co.uk/"},{"id":"sloooow","url":"http://stevesouders.com/cuzillion/?c0=hj1hfff30_5_f&t=1439194716962"}]}`)

            json.Unmarshal(b, &c)

            var wg sync.WaitGroup

            timeout := time.Duration(1 * time.Second)
            client := http.Client{
                    Timeout: timeout,
            }

            for i, v := range c.Components {
                    wg.Add(1)

                    go func(i int, v Component) {
                            defer wg.Done()

                            resp, err := client.Get(v.Url)

                            if err != nil {
                                fmt.Printf("Problem getting the response: %s\n", err)

                                cr = append(cr, ComponentResponse{
                                    v.Id,
                                    404,
                                    err.Error(),
                                })
                            } else {
                                    defer resp.Body.Close()
                                    contents, err := ioutil.ReadAll(resp.Body)
                                    if err != nil {
                                            fmt.Printf("Problem reading the body: %s\n", err)
                                    }

                                    cr = append(cr, ComponentResponse{
                                            v.Id,
                                            resp.StatusCode,
                                            string(contents),
                                    })
                            }
                    }(i, v)
            }
            wg.Wait()

            j, err := json.Marshal(Result{overallStatus, cr})
            if err != nil {
                    fmt.Printf("Problem converting to JSON: %s\n", err)
                    return
            }

            fmt.Println(string(j))
    }
如果你想散开然后聚合结果,并且你想要net / http包没有给你特定的超时行为,那么你可能想要使用goroutines和channel.

我今天刚观看了这个视频,它将使用Go的并发功能引导您完成这些场景.另外,扬声器Rob Pike非常有权威 – 他解释得比我更好.

https://www.youtube.com/watch?v=f6kdp27TYZs

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