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goexceptionhttpclientpanic

How to catch panic when HTTP client make request to unavailable url?


I need to make request to some URLs. It is possible, that someone of them is unavailable. It is OK for me, and I want just ignore these URLs.

My problem is I cannot catch error, which is occurs. I get a error message:

2018/01/13 18:46:24 Get http://fakesite.com: dial tcp [::1]:8084: connectex: No connection could be made because the target machine actively refused it.

My sample code is:

package main

import (
    "fmt"
    "log"
    "net/http"
    "io/ioutil"
)

func main() {
    c := make(chan string, 1)

    go func() {
        defer func() {
            if r := recover(); r != nil {
                fmt.Println("try to catch error1", r)
            }
        }()

        resp, err := http.Get("http://fakesite.com")
        if err != nil {
            log.Fatal(err)
            c <- ""
            return
        }

        defer resp.Body.Close()
        body, err := ioutil.ReadAll(resp.Body)
        if err != nil {
            log.Fatal(err)
            c <- ""
            return
        }

        c <- string(body)
    }()


    defer func() {
        if r := recover(); r != nil {
            fmt.Println("try to catch error2", r)
        }
    }()

    msg := <-c
    fmt.Println(msg)
}

Solution

  • The problem is:

    log.Fatal(err)
    

    This function performs two things. Firstly, it logs. But this function exits too.

    // Fatal is equivalent to Print() followed by a call to os.Exit(1).
    func Fatal(v ...interface{}) {
        std.Output(2, fmt.Sprint(v...))
        os.Exit(1)
    }