NewRelic::Rack middleware not exposing Sinatra::Base settings

Question

I have a modular Sinatra app, where I use

run Rack::URLMap

to add various services, where each service is a Sinatra::Base

I've added a middleware in one of the services that uses the settings method. It seems that the NewRelic rack middlewares are not exposing this method.

class MyService < Sinatra::Base
  configure do
    set :optional_auth, [
      { method: :get, path: ''},
      { method: :get, path: '/:id'},
      { method: :get, path: '/:id/attachments'},
      { method: :get, path: '/:id/comments'}
    ]
    mime_type :json, 'application/json'
    use Rack::PostBodyContentTypeParser
    use MyMiddleware
  end

  get '/' ....

Locally, things work fine, however, when deployed, it seems that MyMiddleware is being added after NewRelic::Rack, so when the middleware is invoked, the @app is no longer MyService, it's NewRelic::Rack without the exposed settings method.

Has anyone else experienced this? I'm running the application with bundle exec puma

Answer 1

I was able to work around this by updating my middleware

    def initialize app, &block
      @app = app
      @block = block
    end

    def call env
      @block.call(env)
      do_something(env[:my_middleware_option])
      ...
      @app.call(env)
    end

And initializing my middleware with

    use MyMiddleware do |env|
      env[:my_middleware_option] = "any data type"
    end