Schedule commands using "at" from ruby.

README.md

Ex Ordo Scheduler

What?

Ex Ordo Scheduler is a wrapper written around the at command on Linux:

at, batch, atq, atrm - queue, examine or delete jobs for later execution

It doesn't support all of at's functions but as it is will allow you to queue, dequeue and list scheduled commands. Feel free to change it as you need so :)

How?

You can schedule any command or you can use the shortcut provided to run rake tasks, here're some examples:

ExOrdo::Scheduler::At.schedule(Time.now, 'ls')

ExOrdo::Scheduler::At.schedule(Time.now, {:rake => {:task => 'my:task', :args => [1,4]}})

NOTE. On Mac you'll have to enable atrun for at to work as follows:

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.atrun.plist

Who's using this?

We're heavily using it on Ex Ordo our software to help academic conferences run smoothly around the globe and save conference organisers loads of time. :)

Enjoy!

exordo_scheduler.rb

# Ex Ordo Scheduler
# https://gist.github.com/1566114
# (c) 2012 Darío Javier Cravero

require 'tempfile'

module ExOrdo
  module Scheduler
    # Schedule commands with 'at'.
    #
    # Mac's note
    # ----------
    #   You'll need to run this: 
    #
    #     sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.atrun.plist
    #
    #   in order to enable atrun (the utility runs commands queued by at). 
    #
    # http://linuxmanpages.com/man1/at.1.php
    module At
      # Schedule a job
      #
      # @param time     Date/Time     When do you want to queue the job?
      # @param command  String/Hash        Whatever you want to run
      def self.schedule(time, command='')
        res=`at -t #{parse_time(time)} -f #{encapsulate_command(command)} 2>&1`
        sp=res.split(' ')
        $?.success? ? sp[sp.index('job')+1] : false
      end

      # Cancel a job
      #
      # @param id   String  The id of the job you'd like to cancel
      def self.cancel(id)
        if self.pending.map {|p| p[:id]}.include?(id.to_s)
          `at -r #{id} 2>&1`
          $?.success?
        else
          false
        end
      end

      # List all the pending jobs
      def self.pending
        `at -l 2>&1`.split("\n").map do |job|
          data = job.split("\t")
          {:id => data[0], :date => Time.parse(data[1])}
        end
      end

      # Shortcut to a rake task
      #
      # @param task String The task to run
      # @param args Array The task's params
      # @param log String The log's path
      def self.rake(task, args=[], log="#{PADRINO_ROOT}/log/rake.log")
        params = args.empty? ? '' : "[#{args.join(',')}]"
        "bash -l -c 'cd #{PADRINO_ROOT} && bundle exec /usr/local/bin/rake #{task}#{params} --trace 2>&1 >> #{log}'"
      end

      private
        # Parse a time into the format 'at' is expecting
        # @param time   Date/Time   When do you want to queue the job?
        def self.parse_time(time)
          time.strftime('%Y%m%d%H%M.%S')
        end

        # Create a temporary file to embed the command 'at' will run. 
        #
        # @param command  String/Hash  Whatever you want to run
        def self.encapsulate_command(command)
          file = Tempfile.new('exordo')
          file.write(parse_command(command))
          file.close
          file.path
        end

        def self.parse_command(command)
          if command.is_a?(Hash)
            if command.keys.include?(:rake)
              return rake(command[:rake][:task],
                          command[:rake][:args] || [],
                          command[:rake][:log] || "#{PADRINO_ROOT}/log/rake.log")
            end
          end
          command
        end
    end
  end
end

LICENSE

# Copyright (c) 2012 - Darío Javier Cravero
#
# Permission is hereby granted, free of charge, to any
# person obtaining a copy of this software and associated
# documentation files (the "Software"), to deal in the
# Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the
# Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice
# shall be included in all copies or substantial portions of
# the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

@DAddYE Thanks!! :) Hope you had a great start of the year!! Please, let me know if it can be improved on any way :)