Hi Peter, You might find the Wait4 idea useful; here for example is what I use to monitor (and restart) dependent processes
https://github.com/glycerine/bark See in particular the syscall to Wait4 here https://github.com/glycerine/bark/blob/master/start.go#L114 Best, Jason On Wednesday, August 13, 2025 at 6:59:37 PM UTC+1 Peter Bočan wrote: > Hello all, > > I am running into a little nifty problem. I have a program which can run > an arbitrary command, and in a separate goroutine it awaits the termination > of the subprocess. This works nicely, but not as nicely as I would want to. > If my program terminates, the Wait() will error out with "signal: killed", > which is fine, if it's intended to be terminated alongside with my program. > However, if that's not the case and the subprocess is terminated for other > reasons, the observing the channel as outlined below blocks the goroutine > indefinitely, which is not something I want. > > c := exec.CommandContext(ctx, ...) > c.Start() > go func() { > log.Debug().Msg("waiting for a program...") > err := c.Wait() > select { > case <- ctx.Done(): > // it's ever done, if the process terminates early > } > if err != nil { > // Prints out that the program received the > signal, which is not something I want to do. > log.Fatal().Err(err).Msg("failed to run the program") > } > }() > > I could get around it other ways (using WaitGroup), but do you think there > is a slightly nicer way, if we could include a method on the Context > interface called "Cancelled() bool" which would simply return a boolean > value if the context was somewhere somehow cancelled? Or maybe it should be > done on the exec.Cmd object itself? > > c := exec.CommandContext(ctx, ...) > c.Start() > go func() { > log.Debug().Msg("waiting for a program...") > // no more Wait() necessary. > select { > case <- c.Done(): > // done, if the process terminates early > case <- c.Cancelled() > // done, if the execution context has been > cancelled > } > }() > > Just a food for thought, > Peter Bocan. > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/golang-nuts/72c1c43b-307d-4d6b-8745-1692386aa3ean%40googlegroups.com.
