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| package main | |
| import ( | |
| "os" | |
| "os/exec" | |
| ) | |
| func Start(args ...string) (p *os.Process, err error) { | |
| if args[0], err = exec.LookPath(args[0]); err == nil { | |
| var procAttr os.ProcAttr | |
| procAttr.Files = []*os.File{os.Stdin, | |
| os.Stdout, os.Stderr} | |
| p, err := os.StartProcess(args[0], args, &procAttr) | |
| if err == nil { | |
| return p, nil | |
| } | |
| } | |
| return nil, err | |
| } | |
| func main() { | |
| if proc, err := Start("ping", "-c 3", "www.google.com"); err == nil { | |
| proc.Wait() | |
| } | |
| if proc, err := Start("zsh"); err == nil { | |
| proc.Wait() | |
| } | |
| } |
I just came across some code for this today... but I don't understand why would you use os.StartProcess instead of exec.Command. What's the advantage?
I just came across some code for this today... but I don't understand why would you use
os.StartProcessinstead ofexec.Command. What's the advantage?* https://golang.org/pkg/os/exec/
os/Exec is a higher level implementation of the os.Process, with os.StartProcess, you can get the ProcessState with which you can get more control over the process than os/exec. For example, I had to run a commandline process which locks and when it crashes golang hangs until the lock is removed, but with processState.Release option I was able to release the process resources thereby allowing my code to run to completion. I could have used the os/exec.Start and os/exec.Wait() but it did not work for me.
Hi, thank you for sharing.
Do you know how i can capture the output stream from the StartProcess command in realtime?
Thank you @lee8oi
I've tried using io pipes, MultiReader and bufio.NewScanner, but with no luck
For anyone reading, im trying to do something like this, but using os.StartProcess instead of exec.Command
multi := io.MultiReader(stdout, stderr)
if err := cmd.Start(); err != nil {
return err
}
in := bufio.NewScanner(multi)
for in.Scan() {
log.Printf(in.Text()) // write each line to the log or anything else
}
[Update] This bug will not occur, because line 18 will always return an err != nil, which is picked up by your main function.
Hello lee,
Thanks for this code, a good way to wrap around the low level os.Process* call.
There is a potential bug with the code however, in the event that exec.LookPath fails, the start function will return *os.Process = nil (line 18) , this will cause problems in your main function as a nil pointer dereference issue at proc.Wait, this should be removed.
Regards,
Jeff J