package externalcmd import ( "time" ) const ( restartPause = 5 * time.Second ) // Environment is a Cmd environment. type Environment struct { Path string Port string } // Cmd is an external command. type Cmd struct { cmdstr string restart bool env Environment // in terminate chan struct{} // out done chan struct{} } // New allocates an Cmd. func New(cmdstr string, restart bool, env Environment) *Cmd { e := &Cmd{ cmdstr: cmdstr, restart: restart, env: env, terminate: make(chan struct{}), done: make(chan struct{}), } go e.run() return e } // Close closes an Cmd. func (e *Cmd) Close() { close(e.terminate) <-e.done } func (e *Cmd) run() { defer close(e.done) for { ok := func() bool { ok := e.runInner() if !ok { return false } if !e.restart { <-e.terminate return false } select { case <-time.After(restartPause): return true case <-e.terminate: return false } }() if !ok { break } } }