# freebsd-unicorn A robust init script for running unicorn on FreeBSD This rc script works with either RVM and RBENV installed in your deploy user's directory, or with a globally installed ruby. It correctly handle's Unicorn+Bundler [idiosyncrasies][unicorn-sandboxing]. Simply place the `unicorn` script in your `/usr/local/etc/rc.d` directory, modify it if necessary, and configure your application via variables in `/etc/rc.conf` This has been tested on **FreeBSD 9.0 and 9.1** ## Make sure unicorn starts after your database launches! The only thing you might need to configure in the rc script is to change the `REQUIRE` line to specify your database (I use PostreSQL so that's what's in the repo) For example, if you were using MySQL, you would change # REQUIRE: LOGIN postgresql to # REQUIRE: LOGIN mysql-server You might need to add other services to this list if your Rails application requires them. ## Quick Setup To get up and running quickly, adjust the `REQUIRE` line like above, and add edit your `/etc/rc.conf`: For Capistrano or Capistrano-like directory layouts: unicorn_enable="YES" # this is the path to where your application is deployed via Capistrano # (the parent directory of the `current` directory) unicorn_directory="/u/application" For Non-Capistrano-like layouts: unicorn_enable="YES" unicorn_command="/u/application/bin/unicorn_rails" unicorn_rackup="/u/application/config.ru" unicorn_pidfile="/u/application/tmp/pids/unicorn.pid" unicorn_old_pidfile="/u/application/tmp/pids/unicorn.oldbin" unicorn_listen="/u/application/tmp/sockets/unicorn.sock" unicorn_config="/u/application/config/unicorn.rb" unicorn_chdir="/u/application" unicorn_user="deploy" # Uncomment this if using a different RAILS_ENV/RACK_ENV than production #unicorn_env="production" ## Starting/Stopping/Restarting and Upgrading Unicorn You can now start Unicorn like any other FreeBSD service: /usr/local/etc/rc.d/unicorn start There's also a handy `show` command to look at your final Unicorn configuration: /usr/local/etc/rc.d/unicorn show You can do an old-fashioned restart, or a [zero-downtime upgrade][unicorn-0-downtime] with these commands: /usr/local/etc/rc.d/unicorn restart /usr/local/etc/rc.d/unicorn upgrade And when you're done riding Unicorns, you can shut it down /usr/local/etc/rc.d/unicorn stop ## `/etc/rc.conf` Details ### Using a Capistrano directory layout The rc script does as much as possible to help you out. If you are using Capistrano, or a Capistrano-like directory structure, then you can just specify the directory of your application (the parent directory of `current`): unicorn_enable="YES" unicorn_directory="/u/application" This infers all sorts of information about your app (you can always run `/usr/local/etc/rc.d/unicorn show` to see what your configuration is. **Note** the variable names listed here are without the leading `unicorn_` prefix that you would need to specify in `/etc/rc.conf`): # # Unicorn Configuration for application # command: /u/application/current/bin/unicorn_rails command_args: /u/application/current/config.ru rackup: /u/application/current/config.ru pidfile: /u/application/shared/tmp/pids/unicorn.pid old_pidfile: /u/application/shared/tmp/pids/unicorn.pid.oldbin listen: config: /u/application/current/config/unicorn.conf.rb init_config: bundle_gemfile: /u/application/current/Gemfile chdir: /u/application/current user: deploy nice: env: production flags: -E production -c /u/application/current/config/unicorn.conf.rb -D start_command: su -l deploy -c "export BUNDLE_GEMFILE=/u/application/current/Gemfile && cd /u/application && /u/application/current/bin/unicorn_rails -E production -c /u/application/current/config/unicorn.conf.rb -D /u/application/current/config.ru" Let's look at these settings one by one: `command`: By default, it uses the `current/bin/unicorn_rails` [bundler binstub][binstub] located in your project to ensure your gems are loaded. `command` comes from FreeBSD's `rc.subr` init system functions. `command_args`: This is the standard FreeBSD's `rc.subr` variable that holds the arguments to the above `command`. The `rackup` setting is prepended to the beginning of this setting. Typically you don't need to set this. `rackup`: This is the `rackup` file that unicorn uses. By default this is set to `current/config.ru` for capistrano projects. `pidfile`: This is also part of FreeBSD's `rc.subr` system. This is where the built in functions will look for the pid of the process. By default, this rc script looks in the `shared/tmp/pids/unicorn.pid` file. `old_pidfile`: This is the pidfile used by unicorn to perform zero-downtime upgrades. [Procedure to replace a running unicorn executable][unicorn-0-downtime]. This rc script uses Unicorn's default convention of appending `.oldbin` to the end of the `pidfile` `listen`: This is the port or socket for Unicorn to listen on. This rc script assumes that you will specify it in your project's Unicorn config file (see the next variable). e.g. listen "#{app}/shared/sockets/unicorn.sock", :backlog => 64 `config`: This is the path to Unicorn's config file where unicorn will find it's settings. By default this rc script looks for a file called `current/conf/unicorn.conf.rb` `init_config`: This is a shell script file that is included in the environment before Unicorn is executed. In this file you can include `export VAR=value` statements to pass environment variables into your rails app. By default, this init script looks for a file called `current/.env` and uses that. If that file doesn't exist, this rc script will skip this functionality (as seen in the above example). This could be used in conjunction with [dotenv][dotenv] in development since dotenv accepts lines beginning with `export` `bundle_gemfile`: This is the path to the `Gemfile` of your project. This rc script sets the `BUNDLE_GEMFILE` environment variable to this value. By default it looks to `current/Gemfile`. This is required so that Unicorn uses the most current `Gemfile` (rather than the one in the specific deployment directory) when an upgrade is performed. See [Unicorn Sandboxing][unicorn-sandboxing]. This is a safeguard, you should really put this in your unicorn.conf.rb: before_exec do |server| ENV["BUNDLE_GEMFILE"] = "/path/to/app/current/Gemfile" end `chdir`: This is the directory we `cd` into before running Unicorn. By default it's the currently deployed version of your application "`current/`" `user`: This is the user that Unicorn will be run as. By default we do like [Passenger][passenger] and use the owner of the `unicorn_directory`. `nice`: The `nice` level to run unicorn at. Usually you'll leave this alone. `flags`: This is a variable defined by FreeBSD's `/etc/rc.subr` init system, and contains the flags passed to the command (Unicorn in this case) when run. This variable is built up from the variables above, but you could manually specify `unicorn_flags` in your `/etc/rc.conf` to override them. `start_command`: Here you can see the full command that will be run when you start this service. It's a beaut' isn't it? You can override any of these parameter in your `/etc/rc.conf` by simply specifying the variables like you see below (you can pick and choose which to override). ### Using a custom directory layout Using your own layout is easy, you can just leave the `unicorn_directory` variable out of your `/etc/rc.conf` and specify all of the above variables manually. Here's a list of those variables for your convenience: unicorn_command: The path to the unicorn command unicorn_command_args: The non-flag arguments passed to the above command. This is usually the path to the Rack config.ru file, and the rackup parameter is prepended to the beginning of this setting. Typically you do not need to set this. unicorn_rackup: This is the path to the Rack config file (typically called `config.ru`). This setting is prepended to the `command_args` parameter unicorn_pidfile: The path where Unicorn will put its pid file unicorn_old_pidfile: The path where Unicorn will put its `old` pid file (usually the same as the sbove with `.oldbin` appended) unicorn_listen: The path to the socket or port to listen on. You can leave this blank to specify where to listen in the Unicorn config unicorn_config: The path to the Unicorn config file unicorn_chdir: The path where this script will `cd` to before starting unicorn unicorn_user: The user to run Unicorn as unicorn_nice: The `nice` level to run Unicorn as. Leave blank to run un-niced unicorn_env: The RAILS_ENV (or RACK_ENV) to run your application as. (default: production) unicorn_flags: The flags passed in to Unicorn when starting (not counting the unicorn_command_args specified above). Override this for complete control of how to start Unicorn. ### Deploying multiple applications This is all find and dandy, but some of you might have multiple applications running on the same server (even if it's just a staging and production version of your app). This rc script can work with multiple applications. It works similarly to how postgresql's rc script works on FreeBSD. You simply specify your profiles in your `/etc/rc.conf` with the `unicorn_profiles` variable. This is a space separated list of application names. Then you can customize each application by specifying variables in this form: unicorn__variable=VALUE Here's a simple example (I can leave the _env variable out of the production declaration since it's the default value) unicorn_enable="YES" unicorn_profiles="application_staging application_production" unicorn_application_staging_enable="YES" unicorn_application_staging_directory="/u/application_staging" unicorn_application_staging_env="staging" unicorn_application_production_enable="YES" unicorn_application_production_directory="/u/application_production" You can use the simplified Capistrano `directory`-based configuration like above, or you can specify all of the variable's separately, for a fully custom setup ### Customizing the script If you want to customize the default, calculated values you want to look in the `_setup_directory()` function. This is what is called when you specify that you want to use a Capistrano-like directory layout by specifying `unicorn_directory` or `unicorn__directory` in your `/etc/rc.conf`. If you use a different deployment strategy than Capistrano, you could adjust the default values to work with your system. [passenger]: https://www.phusionpassenger.com [unicorn-sandboxing]: http://unicorn.bogomips.org/Sandbox.html [dotenv]: https://github.com/bkeepers/dotenv [unicorn-0-downtime]: http://unicorn.bogomips.org/SIGNALS.html [binstub]: https://github.com/sstephenson/rbenv/wiki/Understanding-binstubs