monitor.go

// Copyright 2015 Google Inc. All rights reserved.

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

// +build linux darwin freebsd

package main

import (
	"fmt"
	"io/ioutil"
	"net"
	"os"
	"time"

	"github.com/google/cloud-print-connector/lib"
	"github.com/urfave/cli"
)

func monitorConnector(context *cli.Context) error {
	config, filename, err := lib.GetConfig(context)
	if err != nil {
		return fmt.Errorf("Failed to read config file: %s", err)
	}
	if filename == "" {
		fmt.Println("No config file was found, so using defaults")
	}

	if _, err := os.Stat(config.MonitorSocketFilename); err != nil {
		if !os.IsNotExist(err) {
			return err
		}
		return fmt.Errorf(
			"No connector is running, or the monitoring socket %s is mis-configured",
			config.MonitorSocketFilename)
	}

	timer := time.AfterFunc(context.Duration("monitor-timeout"), func() {
		fmt.Fprintf(os.Stderr, "Monitor check timed out after %s", context.Duration("monitor-timeout").String())
		os.Exit(1)
	})

	conn, err := net.DialTimeout("unix", config.MonitorSocketFilename, time.Second)
	if err != nil {
		return fmt.Errorf(
			"No connector is running, or it is not listening to socket %s",
			config.MonitorSocketFilename)
	}
	defer conn.Close()

	buf, err := ioutil.ReadAll(conn)
	if err != nil {
		return err
	}

	timer.Stop()

	fmt.Printf(string(buf))
	return nil
}