Ruby1.9スクリプト(Twitterbot)をLinuxデーモン化する方法

Ruby 1.9系からRubyスクリプトをデーモン化するのが1行できるようになりました。

3分でわかる RubyでつぶやくTwitter botを拡張してTwitterbotをデーモン化します。

実際にRuby 1.9系のスクリプトをデーモン化させようとすると。

Process.daemon

この1行を追加するだけ。なんということでしょう！

/home/hirocaster/tweet.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-
require "rubygems"
require "twitter"
require 'logger'
Process.daemon
pid = File.open("/var/run/tweet.rb.pid", "w")
pid.write Process.pid
pid.close
LOG = Logger.new('tweet.log')
CONSUMER_KEY = 'XXXXXXXXXXXXX'
CONSUMER_SECRET = 'XXXXXXXXXXXXXXXXXXXXXX'
ACCESS_TOKEN = 'XXXXXXXXXXXXXXXXXXXXXX'
ACCESS_SECRET = 'XXXXXXXXXXXXXXXXXXXXXX'
Twitter.configure do |config|
  config.consumer_key = CONSUMER_KEY
  config.consumer_secret = CONSUMER_SECRET
  config.oauth_token = ACCESS_TOKEN
  config.oauth_token_secret = ACCESS_SECRET
end
tweet = ['つぶやきA', 'つぶやきB', 'つぶやきC', 'つぶやきD', 'つぶやきE',
         'つぶやきF', 'つぶやきG', 'つぶやきH', 'つぶやきI', 'つぶやきJ',
         'つぶやきシロー']
client = Twitter::Client.new
while true
  begin
    client.update(tweet[rand(tweet.length)])
  rescue => ex
    LOG.warn ex
    sleep 5
    retry
  end
end

デーモン化するスクリプトには実行権限をつけておきます。

$ chmod 755 /home/hirocaster/tweet.rb

/etc/init.d/tweet

#! /bin/sh
PATH=/home/hirocaster/.rvm/rubies/ruby-1.9.2-p136/bin:/sbin:/usr/sbin:/bin:/usr/bin
DESC="twitterbot"
NAME=tweet.rb
DAEMON=/home/hirocaster/tweet.rb
DAEMON_ARGS=""
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME
GEM_HOME=/home/hirocaster/.rvm/gems/ruby-1.9.2-p136
export GEM_HOME
# Exit if the package is not installed
[ -x "$DAEMON" ] || exit 0
# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME
# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh
# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions
#
# Function that starts the daemon/service
#
do_start()
{
    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON -- \
        $DAEMON_ARGS \
        || return 2
    # Add code here, if necessary, that waits for the process to be ready
    # to handle requests from services started subsequently which depend
    # on this one.  As a last resort, sleep for some time.
}
#
# Function that stops the daemon/service
#
do_stop()
{
    # Return
    #   0 if daemon has been stopped
    #   1 if daemon was already stopped
    #   2 if daemon could not be stopped
    #   other if a failure occurred
    start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE
    RETVAL="$?"
    [ "$RETVAL" = 2 ] && return 2
    # Wait for children to finish too if this is a daemon that forks
    # and if the daemon is only ever run from this initscript.
    # If the above conditions are not satisfied then add some other code
    # that waits for the process to drop all resources that could be
    # needed by services started subsequently.  A last resort is to
    # sleep for some time.
    # start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON
    # [ "$?" = 2 ] && return 2
    # Many daemons don't delete their pidfiles when they exit.
    rm -f $PIDFILE
    return "$RETVAL"
}
#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
    #
    # If the daemon can reload its configuration without
    # restarting (for example, when it is sent a SIGHUP),
    # then implement that here.
    #
    start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE --name $NAME
    return 0
}
case "$1" in
  start)
    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
    do_start
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  stop)
    [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
    do_stop
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  status)
       status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
       ;;
  #reload|force-reload)
    #
    # If do_reload() is not implemented then leave this commented out
    # and leave 'force-reload' as an alias for 'restart'.
    #
    #log_daemon_msg "Reloading $DESC" "$NAME"
    #do_reload
    #log_end_msg $?
    #;;
  restart|force-reload)
    #
    # If the "reload" option is implemented then remove the
    # 'force-reload' alias
    #
    log_daemon_msg "Restarting $DESC" "$NAME"
    do_stop
    case "$?" in
      0|1)
        do_start
        case "$?" in
            0) log_end_msg 0 ;;
            1) log_end_msg 1 ;; # Old process is still running
            *) log_end_msg 1 ;; # Failed to start
        esac
        ;;
      *)
        # Failed to stop
        log_end_msg 1
        ;;
    esac
    ;;
  *)
    #echo "Usage: $SCRIPTNAME {start|stop|restart|reload|force-reload}" >&2
    echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
    exit 3
    ;;
esac
:

rvmで導入された ruby-1.9.2-p136 を使用するため必要なPATHや環境変数を設定しています。

Ubuntuの/etc/init.d/skeletonを参考に修正を加えています。

$ chmod 775 /etc/init.d/tweet
$ chown root:root /etc/init.d/tweet

実行権限をつけて、所有者なども変更しておきます。

$ sudo /etc/init.d/tweet start
$ sudo /etc/init.d/tweet stop

この時点でこんな風に起動と停止ができます。

あとは、Linuxが起動停止するときに自動でやってもらえるように

$ sudo update-rc tweet defaults

Rubyスクリプトかあっという間にTwitterbotデーモンになりました。

workerをRubyでサクッとつくったりもできそうです。