README.md

Rack::RequestIDPassthrough

Rack middleware which will take incoming headers (such as request id) and ensure that they are passed along to outgoing http requests. This can be used to track a request throughout your architecture by ensuring that all networks calls will recieve the same request id as the request originator. An example of such an envrionment would be as follows:

Installation

Add this line to your application's Gemfile:

gem 'rack-request-id-passthrough', require: 'rack/request-id-passthrough'

And then execute:

bundle install

Or install it yourself as:

gem install rack-request-id-passthrough

Sinatra (or any rack based stack)

# config.ru
class MyApp < Sinatra::Base
  use Rack::RequestIDPassthrough
end

Rails

# ./config/application.rb
module MyApp
  class Application < Rails::Application
    # ...
    # warning! Make sure that you insert this middleware early so that you can capture all relevant network calls
    config.middleware.insert_after Rack::Runtime, Rack::RequestIDPassthrough
  end
end

Configuration Example

Create an initializer file:

# ./config/initializers/rack-request-id-passthrough.rb

RackRequestIDPassthrough.source_headers = %w(HTTP_FUNKY_TOWN HTTP_LESS_IMPORTANT) # List of source headers to look for request ids in
RackRequestIDPassthrough.response_headers = %w(OUTGOING) # Controls the response headers sent back to the browser
RackRequestIDPassthrough.http_headers = %w(OUTGOING_CALL) # Name of http headers that will be appended to all outgoing http calls

# ./config/application.rb

config.middleware.insert_after Rack::RequestIDPassthrough

There are three main configuration options

• source_headers: An array of headers to look for incoming request id values
• outgoing_headers: An array of headers which will be appended to all outgoing http/https requests
• http_headers: An array of http headers that will be appended to all outgoing http calls, if you don't want to append then set this to []

So in the example above ridp would check the HTTP headers FUNKY_TOWN and LESS_IMPORTANT for a value (in that order). If it found one it would add it Thread.current[:request_id_passthrough] for usage. It would also add an HTTP header called OUTGOING to all http requests going thru net/http that contains the request id.

Contributing

See here