Go Routine for cmd exec but with errorcode

Question

I am a beginner in Go.

I would like to use the code snippet from : How would you define a pool of goroutines to be executed at once in Golang? (this answer)

I need to check the error for each cmd executed as in :

out, err := exec.Command(cmd,params).Output()

But, in the snippet there is no error checking:

tasks <- exec.Command("zenity", "--info", "--text='Hello from iteration n."+strconv.Itoa(i)+"'")

How can check for errors when the cmd executes ?

Answer 1

That line:

tasks <- exec.Command("zenity", "--info", "--text='Hello from iteration n."+strconv.Itoa(i)+"'")

is adding a Cmd object into the channel, from where it will be pulled later and executed by this code:

    for cmd := range tasks {
        cmd.Run()
    }

so it is here that you need to check the error code. Since you suggested you wanted to use Cmd.Output instead of Run, it would look like this:

    for cmd := range tasks {
        out, err := Cmd().Output()
    }

You see, exec.Command creates and initializes an object, and .Output or .Run tells that object to do its stuff.

Answer 2

exec.Command doesn't execute the command, it creates a *Cmd only.

You would check the err in the go func()

    go func() {
        for cmd := range tasks {
            err := cmd.Run()
            // do the test here
        }
        wg.Done()
    }()