RExec::Daemon::Controller

This module contains functionality related to starting and stopping the daemon, and code for processing command line input.

Public Class Methods

daemonize(daemon) click to toggle source

This function is called from the daemon executable. It processes ARGV and checks whether the user is asking for `start`, `stop`, `restart`, `status`.

# File lib/rexec/daemon/controller.rb, line 34
def self.daemonize(daemon)
        case ARGV.shift
        when 'start'
                start(daemon)
                status(daemon)
        when 'stop'
                stop(daemon)
                status(daemon)
                ProcessFile.cleanup(daemon)
        when 'restart'
                stop(daemon)
                ProcessFile.cleanup(daemon)
                start(daemon)
                status(daemon)
        when 'status'
                status(daemon)
        else
                puts "Invalid command. Please specify start, restart, stop or status."
                exit
        end
end
start(daemon) click to toggle source

This function starts the supplied daemon

# File lib/rexec/daemon/controller.rb, line 57
def self.start(daemon)
        puts "Starting daemon...".color(:blue)

        case ProcessFile.status(daemon)
        when :running
                $stderr.puts "Daemon already running!".color(:blue)
                return
        when :stopped
                # We are good to go...
        else
                $stderr.puts "Daemon in unknown state! Will clear previous state and continue.".color(:red)
                status(daemon)
                ProcessFile.clear(daemon)
        end

        daemon.prefork
        daemon.mark_log

        fork do
                Process.setsid
                exit if fork

                ProcessFile.store(daemon, Process.pid)

                File.umask 0000
                Dir.chdir daemon.working_directory

                $stdin.reopen "/dev/null"
                $stdout.reopen daemon.log_file_path, "a"
                $stdout.sync = true
                
                $stderr.reopen $stdout
                $stderr.sync = true

                begin
                        daemon.run
                        
                        trap("INT") do
                                daemon.shutdown
                        end
                rescue
                        $stderr.puts "=== Daemon Exception Backtrace @ #{Time.now.to_s} ==="
                        $stderr.puts "#{$!.class}: #{$!.message}"
                        $!.backtrace.each { |at| $stderr.puts at }
                        $stderr.puts "=== Daemon Crashed ==="
                        $stderr.flush
                ensure
                        $stderr.puts "=== Daemon Stopping @ #{Time.now.to_s} ==="
                        $stderr.flush
                end
        end

        puts "Waiting for daemon to start...".color(:blue)
        sleep 0.1
        timer = TIMEOUT
        pid = ProcessFile.recall(daemon)

        while pid == nil and timer > 0
                # Wait a moment for the forking to finish...
                puts "Waiting for daemon to start (#{timer}/#{TIMEOUT})".color(:blue)
                sleep 1

                # If the daemon has crashed, it is never going to start...
                break if daemon.crashed?

                pid = ProcessFile.recall(daemon)

                timer -= 1
        end
end
status(daemon) click to toggle source

Prints out the status of the daemon

# File lib/rexec/daemon/controller.rb, line 129
def self.status(daemon)
        case ProcessFile.status(daemon)
        when :running
                puts "Daemon status: running pid=#{ProcessFile.recall(daemon)}".color(:green)
        when :unknown
                if daemon.crashed?
                        puts "Daemon status: crashed".color(:red)

                        $stdout.flush
                        $stderr.puts "Dumping daemon crash log:".color(:red)
                        daemon.tail_log($stderr)
                else
                        puts "Daemon status: unknown".color(:red)
                end
        when :stopped
                puts "Daemon status: stopped".color(:blue)
        end
end
stop(daemon) click to toggle source

Stops the daemon process.

# File lib/rexec/daemon/controller.rb, line 149
def self.stop(daemon)
        puts "Stopping daemon...".color(:blue)

        # Check if the pid file exists...
        unless File.file?(daemon.process_file_path)
                puts "Pid file not found. Is the daemon running?".color(:red)
                return
        end

        pid = ProcessFile.recall(daemon)

        # Check if the daemon is already stopped...
        unless ProcessFile.running(daemon)
                puts "Pid #{pid} is not running. Has daemon crashed?".color(:red)
                return
        end

        pgid = -Process.getpgid(pid)
        Process.kill("INT", pgid)
        sleep 0.1

        sleep 1 if ProcessFile.running(daemon)

        # Kill/Term loop - if the daemon didn't die easily, shoot
        # it a few more times.
        attempts = 5
        while ProcessFile.running(daemon) and attempts > 0
                sig = (attempts >= 2) ? "KILL" : "TERM"

                puts "Sending #{sig} to process group #{pgid}...".color(:red)
                Process.kill(sig, pgid)

                attempts -= 1
                sleep 1
        end

        # If after doing our best the daemon is still running (pretty odd)...
        if ProcessFile.running(daemon)
                puts "Daemon appears to be still running!".color(:red)
                return
        end

        # Otherwise the daemon has been stopped.
        ProcessFile.clear(daemon)
end

[Validate]

Generated with the Darkfish Rdoc Generator 2.