# Process::Daemon `Process::Daemon` is a stable and helpful base class for long running tasks and daemons. Provides standard `start`, `stop`, `restart`, `status` operations. [![Build Status](https://travis-ci.org/ioquatix/process-daemon.svg)](https://travis-ci.org/ioquatix/process-daemon) [![Code Climate](https://codeclimate.com/github/ioquatix/process-daemon.svg)](https://codeclimate.com/github/ioquatix/process-daemon) [![Coverage Status](https://coveralls.io/repos/ioquatix/process-daemon/badge.svg)](https://coveralls.io/r/ioquatix/process-daemon) [![Documentation](http://img.shields.io/badge/yard-docs-blue.svg)](http://www.rubydoc.info/gems/process-daemon) [![Code](http://img.shields.io/badge/github-code-blue.svg)](https://github.com/ioquatix/process-daemon) ## Installation Add this line to your application's Gemfile: gem 'process-daemon' And then execute: $ bundle Or install it yourself as: $ gem install process-daemon ## Usage A process daemon has a specific structure: class MyDaemon < Process::Daemon def startup # Called when the daemon is initialized in it's own process. Should return quickly. end def run # Do the actual work. Does not need to be implemented, e.g. if using threads or other background processing mechanisms which were kicked off in #startup. end def shutdown # Stop everything that was setup in startup. Called as part of main daemon thread/process, not in trap context (e.g. SIGINT). # Asynchronous code can call self.request_shutdown from a trap context to interrupt the main process, provided you aren't doing work in #run. end end # Make this file executable and have a command line interface: MyDaemon.daemonize ### Working directory By default, daemons run in the current working directory. They setup paths according to the following logic: working_directory = "." log_directory = #{working_directory}/log log_file_path = #{log_directory}/#{name}.log runtime_directory = #{working_directory}/run process_file_path = #{runtime_directory}/#{name}.pid After calling `prefork`, the working directory is expanded to a full path and should not be changed. ### WEBRick Server Some servers must run on the main process thread. In this case, the normal interrupt mechanism won't be used and we will handle signals directly. Create a file for your daemon, e.g. `daemon.rb`: #!/usr/bin/env ruby require 'process/daemon' # Very simple XMLRPC daemon class XMLRPCDaemon < Process::Daemon def startup @rpc_server = WEBrick::HTTPServer.new( :Port => 31337, :BindAddress => "0.0.0.0" ) @listener = XMLRPC::WEBrickServlet.new @listener.add_handler("fourty-two") do |amount| "Hello World" end @rpc_server.mount("/RPC2", @listener) end def run # This is the correct way to cleanly shutdown the server: trap(:INT) do @rpc_server.shutdown end @rpc_server.start ensure @rpc_server.shutdown end end XMLRPCDaemon.daemonize Then run `daemon.rb start`. To stop the daemon, run `daemon.rb stop`. ### Celluloid Actor `Process::Daemon` is the perfect place to spawn your [celluloid](https://celluloid.io) actors. require 'celluloid' require 'process/daemon' class MyActor include Celluloid::Actor def long_running sleep 1000 end end class MyDaemon < Process::Daemon def startup @actor = MyActor.new @actor.async.long_running_process end def shutdown @actor.terminate end end MyDaemon.daemonize ## Contributing 1. Fork it 2. Create your feature branch (`git checkout -b my-new-feature`) 3. Commit your changes (`git commit -am 'Add some feature'`) 4. Push to the branch (`git push origin my-new-feature`) 5. Create new Pull Request ## License Released under the MIT license. Copyright, 2015, by [Samuel G. D. Williams](http://www.codeotaku.com/samuel-williams). 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.