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https://github.com/chetan/daemons


https://github.com/chetan/daemons

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README 

        
= Daemons Version 1.1.9



(See Releases for release-specific information)



== What is Daemons?



Daemons provides an easy way to wrap existing ruby scripts (for example a self-written server) 

to be run as a daemon and to be controlled by simple start/stop/restart commands.



If you want, you can also use daemons to run blocks of ruby code in a daemon process and to control

these processes from the main application.



Besides this basic functionality, daemons offers many advanced features like exception backtracing 

and logging (in case your ruby script crashes) and monitoring and automatic restarting of your processes

if they crash.



== Basic Usage



You can use Daemons in four different ways:



=== 1. Create wrapper scripts for your server scripts or applications



Layout: suppose you have your self-written server myserver.rb:



  # this is myserver.rb

  # it does nothing really useful at the moment

  

  loop do

    sleep(5)

  end

  

To use myserver.rb in a production environment, you need to be able to

run myserver.rb in the _background_ (this means detach it from the console, fork it

in the background, release all directories and file descriptors).



Just create myserver_control.rb like this:



  # this is myserver_control.rb

  

  require 'rubygems'        # if you use RubyGems

  require 'daemons'

  

  Daemons.run('myserver.rb')

  

And use it like this from the console:



  $ ruby myserver_control.rb start

      (myserver.rb is now running in the background)

  $ ruby myserver_control.rb restart

      (...)

  $ ruby myserver_control.rb stop

  

For testing purposes you can even run myserver.rb without forking in the background:



  $ ruby myserver_control.rb run



An additional nice feature of Daemons is that you can pass additional arguments to the script that 

should be daemonized by seperating them by two _hyphens_:

  

  $ ruby myserver_control.rb start -- --file=anyfile --a_switch another_argument

  



=== 2. Create wrapper scripts that include your server procs



Layout: suppose you have some code you want to run in the background and control that background process

from a script:



  # this is your code

  # it does nothing really useful at the moment

  

  loop do

    sleep(5)

  end

  

To run this code as a daemon create myproc_control.rb like this and include your code:



  # this is myproc_control.rb

  

  require 'rubygems'        # if you use RubyGems

  require 'daemons'

  

  Daemons.run_proc('myproc.rb') do

    loop do

      sleep(5)

    end

  end

  

And use it like this from the console:



  $ ruby myproc_control.rb start

      (myproc.rb is now running in the background)

  $ ruby myproc_control.rb restart

      (...)

  $ ruby myproc_control.rb stop

  

For testing purposes you can even run myproc.rb without forking in the background:



  $ ruby myproc_control.rb run

  

=== 3. Control a bunch of daemons from another application



Layout: you have an application my_app.rb that wants to run a bunch of 

server tasks as daemon processes.



  # this is my_app.rb

  

  require 'rubygems'        # if you use RubyGems

  require 'daemons'

  

  task1 = Daemons.call(:multiple => true) do

    # first server task

    

    loop {

      conn = accept_conn()

      serve(conn)

    }

  end

  

  task2 = Daemons.call do

    # second server task

    

    loop {

      something_different()

    }

  end

  

  # the parent process continues to run

  

  # we can even control our tasks, for example stop them

  task1.stop

  task2.stop

  

  exit

  

=== 4. Daemonize the currently running process



Layout: you have an application my_daemon.rb that wants to run as a daemon

(but without the ability to be controlled by daemons via start/stop commands)



  # this is my_daemons.rb

  

  require 'rubygems'        # if you use RubyGems

  require 'daemons'

  

  # Initialize the app while we're not a daemon

  init()

  

  # Become a daemon

  Daemons.daemonize

  

  # The server loop

  loop {

    conn = accept_conn()

    serve(conn)

  }



  

For further documentation, refer to the module documentation of Daemons.



  

== Download and Installation



*Download*: just go to http://rubyforge.org/projects/daemons/



Installation *with* RubyGems:

  $ su

  # gem install daemons

  

Installation *without* RubyGems:

  $ tar xfz daemons-x.x.x.tar.gz

  $ cd daemons-x.x.x

  $ su

  # ruby setup.rb

  

== Documentation



For further documentation, refer to the module documentation of Daemons (click on Daemons).



The RDoc documentation is also online at http://daemons.rubyforge.org



== Author



Written 2005-2010 by Thomas Uehlinger .

Anonymous SVN checkout is available with "svn checkout http://daemons.rubyforge.org/svn/".



== License



Copyright (c) 2005-2012 Thomas Uehlinger



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.



== Feedback and other resources



At http://rubyforge.org/projects/daemons.