application_procfile Cookbook

This cookbook installs initscripts and monitrc files for the different process types specified in your application's Procfile.

Requirements

cookbooks

• application - application_procfile needs the application cookbook to discover a Procfile.
• monit - application_procfile needs the monit cookbook to configure services under monit.

gems

• foreman - application_procfile uses the foreman gem's Procfile parser.

Usage

<cookbook>/metadata.rb:

depends 'application_procfile'

<cookbook>/recipes/default.rb:

include_recipe 'application_procfile'

application 'someapp' do
  ...
  procfile do
    web node[:someapp][:processes][:web] || 1, :reload => 'USR2', :health_check => { :path => '/system/status', :timeout => 10, :unhealthy => 10, :action => :alert }, :limit => { :totalmem => '512 MB', :unhealthy => 10 }
    worker node[:someapp][:processes][:worker] || 2, :limit => { :totalmem => '192 MB' }
  end
end

This will run a default of 1 web and 2 workers for a Procfile that looks like:

web: bundle exec unicorn -c ./config/unicorn.rb
worker: bundle exec rake resque:work

If you provide a port number via a node attribute node[:app][:port] then it will be incremented automatically and made available to your Procfile commands:

web: bundle exec thin start -p $PORT

Any output to stderr or stdout from your processes will be logged to files like:

/var/log/someapp/web.log
/var/log/someapp/worker.log

To restart your workers:

touch /var/local/someapp/worker.restart

The reload option specifies an optional signal that can be sent to processes to gracefully reload them by doing:

touch /var/local/someapp/web.reload

If the process is unicorn a HUP and USR2 combination will be used automatically, with no need for the reload option.

To properly support reloads for unicorn processes, a unicorn.rb with before_fork, correct paths and worker numbers will be installed in the shared directory and will include your config/unicorn.rb if you have one.

You can specify resource limits with the :limit option, such as :mem, :totalmem, :cpu, :totalcpu, or :children.

For :mem and :totalmem the value is the maximum allowable memory for the process or the process and all it's children, respectively, as B, KB, MB, GB, or %. (eg. :limit => { :totalmem => '512 MB' })

For :cpu, and :totalcpu the value is the maxmimum allowable CPU usage for the process or the process and all it's children, respectively, as %. (eg. :limit => { :totalcpu => '90%' })

For :children the value is the maximum number of child processes allowed for the process. (eg. :limit => { :children => 10 })

Within :limit you can specify the action to be taken :alert, :restart, or :stop when any of the limits are exceeded. (eg. :limit => { :cpu => '25%', :action => :alert })

You can also specify the number of times the limits must exceed their values before taking action using :unhealthy. (eg. :limit => { :mem => '10%', :unhealthy => 10 })

You can specify a health check with the :health_check option as long as the port your service is listening on is accessible via node attribute as node[:app][:port] or you specify a :port in your health check. (eg. :health_check => { :port => 8080, :path => '/system/status', :timeout => 10, :unhealthy => 10, :action => :alert })

Contributing

1. Fork the repository on Github
2. Create a named feature branch (like add_component_x)
3. Write your change
4. Write tests for your change (if applicable)
5. Run the tests, ensuring they all pass
6. Submit a Pull Request using Github

License and Authors

Author:: Javier Muniz javier@granicus.com
Author:: Matt Kasa mattk@granicus.com

Copyright 2013, Granicus Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.