activerain-mongrel_runit

README for mongrel_runit

This is a mongrel_cluster replacement using runit to control a set of mongrel instances. It provides all of the features inherent in services being managed by runit, and knows how to check each running mongrel for status.

Debt of Gratitude

Mongrel Runit was greatly inspired by mongrel_cluster, and some portions of it are taken verbatim: particularly the code to construct a mongrel's command line arguments.

Requirements

1. Mongrel (gem install mongrel)
2. runit (http://smarden.org/runit/)

You will need to have runit installed, and the permissions on /etc/sv and /var/service (or equivalents) be correct. (You will need to allow the user running 'mongrel_runit create' to create the right directories)

Usage

You will need to have the proper service directories created in order to have them managed by mongrel_runit. We handle that for you through:

mongrel_runit create

This will read the configuration and create the proper number of mongrel services. If you change the configuration, either to alter the number of running mongrels or anything else, simply run mongrel_runit create again. It knows what "should" be there, and will clean up after you.

Once that is done, you should be able to do:

mongrel_runit stop|start|restart

For a full list of options, run mongrel_runit -h

Configuration

We look for the configuration file in a number of different places. With no arguments at all, we assume that we are in a Rails applications base directory already, with a:

./config/mongrel_runit.yml

        or

./config/mongrel_cluster.yml

File. If we find one, we will load it and go to town. If you are reusing a mongrel_cluster.yml file, you will likely need to specify the "-a appname" argument.

YAML file options are identical to mongrel_cluster, and represent options to mongrel_rails:

environment port address log_file cwd timeout mime_map docroot debug config_script user group prefix

Additional, mongrel_runit specific options are:

application_name: This is the "name" of your rails app. We use it to construct the actual name of the service directory. So "foo" becomes "mongrel-foo-port"

runit_sv_dir: Where to create the service directories. Defaults to /etc/sv

runit_service_dir: Where to create the symlinks for runsvdir to pick up. Defaults to /var/service

check: A block of code that will become the check file. By default, it is:

#!/usr/bin/env ruby

require 'net/http'

http = Net::HTTP.new('#{address}', #{@config["port"].to_i})
begin
  response = http.options('/')
  if [Net::HTTPSuccess, Net::HTTPRedirection].any? {|klass| response = klass}
    exit 0
  else 
    exit 1
  end
rescue Errno::ECONNREFUSED
  exit 1
end

This will be created for each service, and used to report the final
status when running "mongrel_runit start"

svlogd_config: Another code block, which sets up the log configuration. See the svlogd manpage for options.

base_log_directory: By default, your logs will wind up under each service directory in "log/main/current". You can override this directory here. If you do, each log will wind up in a subdirectory named after the service. For example, setting base_log_directory to "/tmp" would create:

    /tmp/mongrel-appname-port/current

For your logs.  Not a bad idea to set this to your applications "log"
directory.