Support installation as a service

vendor/github.com/kardianos/service/service_unix.go

@@ -0,0 +1,88 @@
+// Copyright 2015 Daniel Theophanes.
+// Use of this source code is governed by a zlib-style
+// license that can be found in the LICENSE file.
+
+// +build linux darwin
+
+package service
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log/syslog"
+	"os/exec"
+)
+
+func newSysLogger(name string, errs chan<- error) (Logger, error) {
+	w, err := syslog.New(syslog.LOG_INFO, name)
+	if err != nil {
+		return nil, err
+	}
+	return sysLogger{w, errs}, nil
+}
+
+type sysLogger struct {
+	*syslog.Writer
+	errs chan<- error
+}
+
+func (s sysLogger) send(err error) error {
+	if err != nil && s.errs != nil {
+		s.errs <- err
+	}
+	return err
+}
+
+func (s sysLogger) Error(v ...interface{}) error {
+	return s.send(s.Writer.Err(fmt.Sprint(v...)))
+}
+func (s sysLogger) Warning(v ...interface{}) error {
+	return s.send(s.Writer.Warning(fmt.Sprint(v...)))
+}
+func (s sysLogger) Info(v ...interface{}) error {
+	return s.send(s.Writer.Info(fmt.Sprint(v...)))
+}
+func (s sysLogger) Errorf(format string, a ...interface{}) error {
+	return s.send(s.Writer.Err(fmt.Sprintf(format, a...)))
+}
+func (s sysLogger) Warningf(format string, a ...interface{}) error {
+	return s.send(s.Writer.Warning(fmt.Sprintf(format, a...)))
+}
+func (s sysLogger) Infof(format string, a ...interface{}) error {
+	return s.send(s.Writer.Info(fmt.Sprintf(format, a...)))
+}
+
+func run(command string, arguments ...string) error {
+	cmd := exec.Command(command, arguments...)
+
+	// Connect pipe to read Stderr
+	stderr, err := cmd.StderrPipe()
+
+	if err != nil {
+		// Failed to connect pipe
+		return fmt.Errorf("%q failed to connect stderr pipe: %v", command, err)
+	}
+
+	// Do not use cmd.Run()
+	if err := cmd.Start(); err != nil {
+		// Problem while copying stdin, stdout, or stderr
+		return fmt.Errorf("%q failed: %v", command, err)
+	}
+
+	// Zero exit status
+	// Darwin: launchctl can fail with a zero exit status,
+	// so check for emtpy stderr
+	if command == "launchctl" {
+		slurp, _ := ioutil.ReadAll(stderr)
+		if len(slurp) > 0 {
+			return fmt.Errorf("%q failed with stderr: %s", command, slurp)
+		}
+	}
+
+	if err := cmd.Wait(); err != nil {
+		// Command didn't exit with a zero exit status.
+		return fmt.Errorf("%q failed: %v", command, err)
+	}
+
+	return nil
+}