Magistrate

gem install magistrate

Magistrate is a manager for workers that is cluster and network aware.
It interacts with a centralized server to get its management and marching orders. It's designed to be a process manager that runs entirely in userspace: no root access needed.

The magistrate command line tool utilizes the following from the filesystem:

• config/magistrate.yml - The configuration file (override the path with the --config option)
• tmp/pids - stores the pids of itself and all managed workers

These are meant to coincide with easy running from a Rails app root (so that the worker config can be kept together with the app) If you're using capistrano, then the tmp/pids directory is persisted across deploys, so Magistrate will continue to run (with an updated config) even after a deploy.

Your user-space cron job should look like this:

• 0 0 0 0 magistrate run --config ~/my_app/current/config/magistrate.yml

The magistrate request will time out after 30 seconds and then use its previously stored target_states.yml file

--config path/to/config.yml

Sets the config file path. See example_config.yml for an example config

magistrate run

run is the primary command used. It's intended to be run as a cron job periodically. Each time it's run it'll:

• Download the target state for each worker from the server
• Check each worker
• Try to get it to its target state
• POST back to the server its state

magistrate list

Will return a string like:

{:test1=>{:state=>:unmonitored, :target_state=>:running}}

This is the status string that is sent to the remote server during a run

magistrate start WORKER_NAME magistrate stop WORKER_NAME

Allows you to manually start/stop a worker process. This has the side effect of writing the new target_state to the cached target state. It will then continue to use this requested state UNTIL it next gets a different state from the server.

Copyright (C) 2011 by Drew Blas drew.blas@gmail.com

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

Inspiration and thanks to:

• foreman
• resque
• god