Grape support (#562)

* Foundations for Grape support

* Only instrument endpoint_run and pass app to Grape.start

* Test Grape.start

* Remove Grape app constant after test

* Add documentation for app parameter to Grape.start

* Add documentation for getting started with Grape

* Add documentation for configuring Grape

* Test passing config values to Grape.start

* Resolve rubocop complaints

* Add Grape.start documentation to API docs

* Make method name clearer

* Grape should be tested as a framework in Jenkins

* Fix spacing

* Correct documentation of config options order

* Support installing and testing against multiple frameworks

* Update framework info in transaction context for Grape

* Add rails and grape spec

* Grape github repo name has a different pattern than the other frameworks

* Only test grape master on newest ruby

* Add message that grape test is skipped

* Test Grape and Rails together

* No need for SpecLogger in rails-grape spec

* Fix formatting

* Remove unncessary test settings

* Move requiring gemspec in Gemfile so framework modules are required automatically

* Remove one more unnecessary require

* Revert docs change about order that config options are applied

* Move changelog entry to asciidoc file

* Be explicit that scenario is grape and rack without rails

Author: estolfo

.ci/.jenkins_exclude.yml

@@ -61,3 +61,40 @@ exclude:
   - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.1-7-jdk
     FRAMEWORK: sinatra-master
 
+  - RUBY_VERSION: ruby:2.5
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: ruby:2.4
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: ruby:2.3
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: jruby:9.2
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: jruby:9.1
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.2-12-jdk
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.2-11-jdk
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.2-8-jdk
+    FRAMEWORK: grape-master
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.1-7-jdk
+    FRAMEWORK: grape-master
+
+  - RUBY_VERSION: ruby:2.5
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: ruby:2.4
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: ruby:2.3
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: jruby:9.2
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: jruby:9.1
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.2-12-jdk
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.2-11-jdk
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.2-8-jdk
+    FRAMEWORK: grape-1.2,rails-6.0
+  - RUBY_VERSION: docker.elastic.co/observability-ci/jruby:9.1-7-jdk
+    FRAMEWORK: grape-1.2,rails-6.0

.ci/.jenkins_framework.yml

@@ -7,3 +7,7 @@ FRAMEWORK:
 
   - sinatra-2.0
   - sinatra-1.4
+
+  - grape-1.2
+
+  - grape-1.2,rails-6.0

.ci/.jenkins_master_framework.yml

@@ -1,3 +1,4 @@
 FRAMEWORK:
   - rails-master
   - sinatra-master
+  - grape-master

CHANGELOG.asciidoc

@@ -17,7 +17,7 @@ endif::[]
 
 [float]
 ===== Added
-- Feature {pull}2526[#2526]
+- Add Grape support ([#562](https://github.com/elastic/apm-agent-ruby/pull/562))
 
 [float]
 ===== Changed

Gemfile

@@ -4,8 +4,6 @@ source 'https://rubygems.org'
 
 git_source(:github) { |repo_name| "https://github.com/#{repo_name}" }
 
-gemspec
-
 gem 'rack-test'
 gem 'rspec'
 gem 'rspec-its'
@@ -33,25 +31,37 @@ else
   gem 'sqlite3'
 end
 
-framework, *version = ENV.fetch('FRAMEWORK', 'rails').split('-')
-version = version.join('-')
+## Install Framework
+GITHUB_REPOS = { 'grape' => 'ruby-grape/grape'}
 
-case version
-when 'master'
-  gem framework, github: "#{framework}/#{framework}"
-when /.+/
-  gem framework, "~> #{version}.0"
-else
-  gem framework
+frameworks = ENV.fetch('FRAMEWORK', 'rails').split(',')
+frameworks_versions = frameworks.inject({}) do |frameworks, str|
+  framework, *version = str.split('-')
+  frameworks.merge(framework => version.join('-'))
 end
 
-gem 'activerecord-jdbcsqlite3-adapter', platform: :jruby
+frameworks_versions.each do |framework, version|
+  case version
+  when 'master'
+    gem framework, github: (GITHUB_REPOS[framework] || "#{framework}/#{framework}")
+  when /.+/
+    gem framework, "~> #{version}.0"
+  else
+    gem framework
+  end
+end
 
-unless version =~ /^(master|6)/
-  gem 'delayed_job', require: nil
+if frameworks_versions.key?('rails')
+  unless frameworks_versions['rails'] =~ /^(master|6)/
+    gem 'delayed_job', require: nil
+  end
 end
 
+gem 'activerecord-jdbcsqlite3-adapter', platform: :jruby
+
 group :bench do
   gem 'ruby-prof', require: nil, platforms: %i[ruby]
   gem 'stackprof', require: nil, platforms: %i[ruby]
 end
+
+gemspec

docs/api.asciidoc

@@ -193,9 +193,9 @@ Returns the built context.
 
 [float]
 [[rails-start]]
-=== Manually hooking into Rails
+=== Rails
 
-Start the agent and hook into Rails explicitly. This is useful if you skip requiring
+Start the agent and hook into Rails manually. This is useful if you skip requiring
 the gem and using the `Railtie`.
 
 [source,ruby]
@@ -212,6 +212,16 @@ Start the agent and hook into Sinatra.
 [source,ruby]
 ----
 ElasticAPM::Sinatra.start(MySinatraApp, server_url: 'http://localhost:8200')
+
+[float]
+[[grape-start]]
+=== Grape
+
+Start the agent and hook into Grape.
+
+[source,ruby]
+----
+ElasticAPM::Grape.start(MyGrapeApp, server_url: 'http://localhost:8200')
 ----
 
 [float]

docs/configuration.asciidoc

@@ -66,6 +66,23 @@ ElasticAPM::Sinatra.start(
 
 See <<getting-started-rack>>.
 
+[float]
+=== Grape and Rack
+
+When using APM with Grape and Rack (without Rails), you can configure it when starting
+the agent:
+
+[source,ruby]
+----
+# config.ru or similar
+ElasticAPM::Grape.start(
+  MyApp,
+  service_name: 'SomeOtherName'
+)
+----
+
+See <<getting-started-rack>>.
+
 [float]
 === Options
 

docs/getting-started-rack.asciidoc

@@ -72,3 +72,27 @@ run MySinatraApp
 at_exit { ElasticAPM.stop }
 ----
 
+[float]
+[[getting-started-grape]]
+==== Grape example
+
+[source,ruby]
+----
+# Example config.ru
+
+require 'grape'
+
+module Twitter
+  class API < Grape::API
+    use ElasticAPM::Middleware
+
+  # ...
+  end
+end
+
+# Start the agent and hook in your app
+ElasticAPM::Grape.start(Twitter::API, config)
+
+run Twitter::API
+
+----

lib/elastic_apm.rb

@@ -15,6 +15,7 @@
 
 require 'elastic_apm/railtie' if defined?(::Rails::Railtie)
 require 'elastic_apm/sinatra' if defined?(::Sinatra)
+require 'elastic_apm/grape' if defined?(::Grape)
 
 # ElasticAPM
 module ElasticAPM # rubocop:disable Metrics/ModuleLength

lib/elastic_apm/grape.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require 'elastic_apm/subscriber'
+require 'elastic_apm/normalizers/grape'
+
+module ElasticAPM
+  # Module for starting the ElasticAPM agent and hooking into Grape.
+  module Grape
+    extend self
+    # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
+    # Start the ElasticAPM agent and hook into Grape.
+    #
+    # @param app [Grape::API] A Grape app.
+    # @param config [Config, Hash] An instance of Config or a Hash config.
+    # @return [true, nil] true if the agent was started, nil otherwise.
+    def start(app, config = {})
+      config = Config.new(config) unless config.is_a?(Config)
+      configure_app(app, config)
+
+      ElasticAPM.start(config).tap do |agent|
+        attach_subscriber(agent)
+      end
+      ElasticAPM.running?
+    rescue StandardError => e
+      config.logger.error format('Failed to start: %s', e.message)
+      config.logger.debug "Backtrace:\n" + e.backtrace.join("\n")
+    end
+    # rubocop:enable Metrics/MethodLength, Metrics/AbcSize
+
+    private
+
+    def configure_app(app, config)
+      config.service_name ||= app.name
+      config.framework_name ||= 'Grape'
+      config.framework_version ||= ::Grape::VERSION
+      config.logger ||= app.logger
+      config.__root_path ||= Dir.pwd
+    end
+
+    def attach_subscriber(agent)
+      return unless agent
+
+      agent.instrumenter.subscriber = ElasticAPM::Subscriber.new(agent)
+    end
+  end
+end

lib/elastic_apm/middleware.rb

@@ -13,7 +13,7 @@ def initialize(app)
     # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
     def call(env)
       begin
-        if running? && !path_ignored?(env)
+        if running? && !path_ignored?(env) && !ElasticAPM.current_transaction
           transaction = start_transaction(env)
         end
 

lib/elastic_apm/normalizers/grape.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+%w[endpoint_run].each do |lib|
+  require "elastic_apm/normalizers/grape/#{lib}"
+end

lib/elastic_apm/normalizers/grape/endpoint_run.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module ElasticAPM
+  module Normalizers
+    module Grape
+      # @api private
+      class EndpointRun < Normalizer
+        register 'endpoint_run.grape'
+
+        TYPE = 'app'
+        SUBTYPE = 'resource'
+
+        FRAMEWORK_NAME = 'Grape'
+
+        def normalize(transaction, _name, payload)
+          transaction.name = endpoint(payload[:env])
+          unless transaction.config.framework_name == FRAMEWORK_NAME
+            transaction.context.set_service(framework_name: FRAMEWORK_NAME,
+                                            framework_version: ::Grape::VERSION)
+          end
+          [transaction.name, TYPE, SUBTYPE, nil, nil]
+        end
+
+        private
+
+        def endpoint(env)
+          route_name = env['api.endpoint']&.routes&.first&.pattern&.origin ||
+            env['REQUEST_PATH']
+          [env['REQUEST_METHOD'], route_name].join(' ')
+        end
+      end
+    end
+  end
+end

spec/elastic_apm/grape_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+if defined?(Grape)
+  RSpec.describe Grape do
+    describe '.start' do
+      before do
+        class GrapeTestApp < ::Grape::API
+          use ElasticAPM::Middleware
+        end
+        ElasticAPM::Grape.start(GrapeTestApp, config)
+      end
+
+      after do
+        ElasticAPM.stop
+        Object.send(:remove_const, :GrapeTestApp)
+      end
+
+      context 'with no overridden config settings' do
+        let(:config) { {} }
+        it 'starts the agent' do
+          expect(ElasticAPM::Agent).to be_running
+        end
+      end
+
+      context 'a config with settings' do
+        let(:config) { { service_name: 'Other Name' } }
+
+        it 'sets the options' do
+          expect(ElasticAPM.agent.config.options[:service_name].value)
+            .to eq('Other Name')
+        end
+      end
+    end
+  end
+end