Union Station Ruby on Rails hooks

Union Station is a web application monitoring and performance analytics platform for Ruby. In order for Union Station to analyze your application, your application must send data to Union Station. This gem allows you to do that.

union_station_hooks_rails is a gem that automatically hooks into various parts of Rails, so that the right information is sent to Union Station. Under the hood, it makes use of the APIs provided by union_station_hooks_core.

Resources: About Union Station | Github

Table of contents

• Installation
  • Using with Passenger
  • Overriding Passenger's version
  • Using without Passenger
• Legacy code
• Contributing

Note: This documentation section only applies to Passenger 5.0.20 or later!

If you use Passenger, then you do not need to install the union_station_hooks_rails gem. union_station_hooks_rails is bundled with Passenger.

The only thing you need to do is to create a file config/initializers/union_station.rb in which you call this code:

if defined?(UnionStationHooks)
  UnionStationHooks.initialize!
end

(Are you already calling PhusionPassenger.install_framework_extensions! from somewhere in your codebase? Please read Legacy code for important information.)

When you have this call in place, enable Union Station support in Passenger. Here are some examples:

• Passenger with Nginx integration mode
  

  Insert the following config in your virtual host configuration, then restart Nginx:

   union_station_support on;
   union_station_key <YOUR KEY HERE>;
  

• Passenger with Apache integration mode
  

  Insert the following config in your virtual host configuration, then restart Apache:

   UnionStationSupport on
   UnionStationKey <YOUR KEY HERE>
  

• Passenger Standalone
  

  Start Passenger with the --union-station-key parameter:

   $ passenger start --union-station-key <YOUR KEY HERE>
  

  Or set the union_station_key configuration option in Passengerfile.json:

   {
       "union_station_key": "<YOUR KEY HERE>"
   }
  

Each version of Passenger bundles its own version of the union_station_hooks_rails gem (and the union_station_hooks_core gem, which is a dependency). The Passenger maintainers regularly update their bundled versions with the latest version. Sometimes, you may wish to use a specific version of union_station_hooks_rails and union_station_hooks_core, overriding the versions that came bundled with Passenger. For example, we have may published a new version of union_station_hooks_rails with some bug fixes, even though Passenger hasn't been updated yet.

You can override Passenger's bundled versions as follows.

1. Add the gems you want to override to your Gemfile, like this:

   # Uncomment the following line if you want to override Passenger's
   # bundled version
   #gem 'union_station_hooks_core'
   
   gem 'union_station_hooks_rails'
   

2. Install your gem bundle:

   bundle install
   

It is currently not possible to use Union Station without Passenger. If you would like to have this feature, please let us know.

Before Passenger 5.0.20, the Union Station setup instructions used to tell you to create a config/initializers/passenger.rb in which you call the following code:

PhusionPassenger.install_framework_extensions! if defined?(PhusionPassenger)

Since Passenger 5.0.20, PhusionPassenger.install_framework_extensions! has become an alias for UnionStationHooks.initialize!, but the former is considered deprecated. Please replace the above code with:

if defined?(UnionStationHooks)
  UnionStationHooks.initialize!
end

And please also rename config/initializers/passenger.rb to config/initializers/union_station.rb.

Looking to contribute to this gem? Please read the documentation in the hacking/ directory.