I want to implement a "process wrapper" in Go. Basically what it will do, is launch a process (lets say a node server) and monitor it (catch signals like SIGKILL, SIGTERM ...)
I think the way to do is to launch the node server in a go routine using syscall.Exec
:
func launchCmd(path string, args []string) {
err := syscall.Exec(path, args, os.Environ())
if err != nil {
panic(err)
}
}
Then I'd like to catch every possible signals generated by the command executed by syscall
. I'm pretty new to Go, any help would be appreciated.
There are three ways of executing a program in Go:
syscall
package with syscall.Exec, syscall.ForkExec, syscall.StartProcessos
package with os.StartProcessos/exec
package with exec.Commandsyscall.StartProcess is low level. It returns a uintptr
as a handle.
os.StartProcess
gives you a nice os.Process
struct that you can call Signal on. os/exec
gives you io.ReaderWriter
to use on a pipe. Both use syscall
internally.
Reading signals sent from a process other than your own seems a bit tricky. If it was possible, syscall
would be able to do it. I don't see anything obvious in the higher level packages.
To receive a signal you can use signal.Notify like this:
sigc := make(chan os.Signal, 1)
signal.Notify(sigc,
syscall.SIGHUP,
syscall.SIGINT,
syscall.SIGTERM,
syscall.SIGQUIT)
go func() {
s := <-sigc
// ... do something ...
}()
You just need to change the signals you're interested in listening to. If you don't specify a signal, it'll catch all the signals that can be captured.
You would use syscall.Kill or Process.Signal to map the signal. You can get the pid from Process.Pid
or as a result from syscall.StartProcess.