How to catch errors from Goroutines?

user_12371730 0
Viewed 3676

I've created function which needs to run in goroutine, the code is working(this is just simple sample to illustrate the issue) 

go rze(ftFilePath, 2)


func rze(ftDataPath,duration time.Duration) error {

}

I want to do something like this 

errs := make(chan error, 1)
err := go rze(ftFilePath, 2)
if err != nil{
    r <- Result{result, errs}
}

but not sure how to it, most of the examples show how you do it when you using func https://tour.golang.org/concurrency/5

go
3 Answers

You cannot use the return value of a function that is executed with the go keyword. Use an anonymous function instead:

errs := make(chan error, 1)
go func() {
    errs <- rze(ftFilePath, 2)
}()

// later:
if err := <-errs; err != nil {
    // handle error
}
user_6033160

You can use golang errgroup pkg.

var eg errgroup.Group
eg.Go(func() error {
  return rze(ftFilePath, 2)
})
if err := g.Wait(); err != nil {
    r <- Result{result, errs}
}
user_63997210

You can handle error from go routines using a separate channel for errors. Create a separate channel specifically for errors. Each child go routine must pass corresponding errors into this channel.

This is one of the ways how it can be done:

func main() {
    type err error

    items := []string{"1", "2", "3"}

    ch := make(chan err, len(items))
    for _, f := range items {
        go func(f string) {
            var e err
            e = testFunc(f)
            ch <- e
        }(f)
    }
    for range items {
        e := <-ch
        fmt.Println("Error: ", e)
        if e != nil {
            // DO Something
        }
    }
}

func testFunc(item string) error {
    if item == "1" {
        return errors.New("err")
    }
    return nil
}
user_25361120
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