feat: OTel Railtie (#1111)

* feat: OTel Railtie

This gem provides a minimal Railtie to use in lieu of manual configuration.

Operators may customize SDK settings using environment variables but this gem will provide some defaults:

Sets a minimal set of values for OTEL_SERVICE_NAME and OTEL_RESOURCE_ATTRIBUTES when left unset
Users may override SDK configurations using standard OTel SDK environment variables
Users may override Instrumentation libraries are configurable using OTEL_RUBY_*_CONFIG_OPTS

.gitignore

@@ -23,3 +23,5 @@ instrumentation/active_record/db
 
 # rbenv configuration
 .ruby-version
+
+tags

instrumentation/rails/.rubocop.yml

@@ -1,7 +1,15 @@
 inherit_from: ../.rubocop-examples.yml
 
+AllCops:
+  Exclude:
+    - test/railtie/dummy/**/*
+    - gemfiles/*.gemfilqe
+
 Metrics/BlockLength:
   Enabled: false
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-instrumentation-rails.rb"
+Style/ClassAndModuleChildren:
+  Exclude:
+    - test/railtie/**/*

instrumentation/rails/Appraisals

@@ -11,16 +11,22 @@ if RUBY_VERSION < '3'
   end
 end
 
-appraise 'rails-6.0' do
-  gem 'rails', '~> 6.0.0'
-end
+if Gem::Requirement.new('>= 2.7.0', '< 3.1').satisfied_by?(Gem::Version.new(RUBY_VERSION))
+  appraise 'rails-6.0' do
+    gem 'rails', '~> 6.0.0'
+  end
 
-appraise 'rails-6.1' do
-  gem 'rails', '~> 6.1.0'
-end
+  appraise 'rails-6.1' do
+    gem 'rails', '~> 6.1.0'
+  end
 
-if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.7.0')
   appraise 'rails-7.0' do
     gem 'rails', '~> 7.0.0'
   end
 end
+
+if Gem::Requirement.new('>= 3.1').satisfied_by?(Gem::Version.new(RUBY_VERSION))
+  appraise 'rails-7.0.ruby.3.1' do
+    gem 'rails', '~> 7.0.1'
+  end
+end

instrumentation/rails/Rakefile

@@ -11,12 +11,23 @@ require 'rubocop/rake_task'
 
 RuboCop::RakeTask.new
 
-Rake::TestTask.new :test do |t|
-  t.libs << 'test'
-  t.libs << 'lib'
-  t.test_files = FileList['test/**/*_test.rb']
+namespace :test do
+  Rake::TestTask.new :instrumentation do |t|
+    t.libs << 'lib'
+    t.libs << 'test/instrumentation'
+    t.test_files = FileList['test/instrumentation/**/*_test.rb']
+  end
+
+  Rake::TestTask.new :railtie do |t|
+    t.libs << 'lib'
+    t.libs << 'test/railtie'
+    t.test_files = FileList['test/railtie/**/*_test.rb']
+  end
 end
 
+desc 'Run all tests'
+task test: %i[test:instrumentation test:railtie]
+
 YARD::Rake::YardocTask.new do |t|
   t.stats_options = ['--list-undoc']
 end

instrumentation/rails/gemfiles/rails_5.2.gemfile

@@ -12,6 +12,7 @@ group :test do
   gem "opentelemetry-instrumentation-action_pack", path: "../../../instrumentation/action_pack"
   gem "opentelemetry-instrumentation-action_view", path: "../../../instrumentation/action_view"
   gem "opentelemetry-instrumentation-active_record", path: "../../../instrumentation/active_record"
+  gem "opentelemetry-instrumentation-active_support", path: "../../../instrumentation/active_support"
   gem "opentelemetry-instrumentation-rack", path: "../../../instrumentation/rack"
   gem "opentelemetry-sdk", path: "../../../sdk"
   gem "opentelemetry-semantic_conventions", path: "../../../semantic_conventions"

instrumentation/rails/gemfiles/rails_6.0.gemfile

@@ -12,6 +12,7 @@ group :test do
   gem "opentelemetry-instrumentation-action_pack", path: "../../../instrumentation/action_pack"
   gem "opentelemetry-instrumentation-action_view", path: "../../../instrumentation/action_view"
   gem "opentelemetry-instrumentation-active_record", path: "../../../instrumentation/active_record"
+  gem "opentelemetry-instrumentation-active_support", path: "../../../instrumentation/active_support"
   gem "opentelemetry-instrumentation-rack", path: "../../../instrumentation/rack"
   gem "opentelemetry-sdk", path: "../../../sdk"
   gem "opentelemetry-semantic_conventions", path: "../../../semantic_conventions"

instrumentation/rails/gemfiles/rails_6.1.gemfile

@@ -12,6 +12,7 @@ group :test do
   gem "opentelemetry-instrumentation-action_pack", path: "../../../instrumentation/action_pack"
   gem "opentelemetry-instrumentation-action_view", path: "../../../instrumentation/action_view"
   gem "opentelemetry-instrumentation-active_record", path: "../../../instrumentation/active_record"
+  gem "opentelemetry-instrumentation-active_support", path: "../../../instrumentation/active_support"
   gem "opentelemetry-instrumentation-rack", path: "../../../instrumentation/rack"
   gem "opentelemetry-sdk", path: "../../../sdk"
   gem "opentelemetry-semantic_conventions", path: "../../../semantic_conventions"

instrumentation/rails/gemfiles/rails_7.0.gemfile

@@ -4,14 +4,15 @@ source "https://rubygems.org"
 
 gem "opentelemetry-api", path: "../../../api"
 gem "opentelemetry-instrumentation-base", path: "../../base"
-gem "rails", "~> 7.0.0.alpha2"
+gem "rails", "~> 7.0.0"
 
 group :test do
   gem "byebug"
   gem "opentelemetry-common", path: "../../../common"
   gem "opentelemetry-instrumentation-action_pack", path: "../../../instrumentation/action_pack"
   gem "opentelemetry-instrumentation-action_view", path: "../../../instrumentation/action_view"
   gem "opentelemetry-instrumentation-active_record", path: "../../../instrumentation/active_record"
+  gem "opentelemetry-instrumentation-active_support", path: "../../../instrumentation/active_support"
   gem "opentelemetry-instrumentation-rack", path: "../../../instrumentation/rack"
   gem "opentelemetry-sdk", path: "../../../sdk"
   gem "opentelemetry-semantic_conventions", path: "../../../semantic_conventions"

instrumentation/rails/gemfiles/rails_7.0.ruby.3.1.gemfile

@@ -0,0 +1,22 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "opentelemetry-api", path: "../../../api"
+gem "opentelemetry-instrumentation-base", path: "../../base"
+gem "rails", "~> 7.0.1"
+
+group :test do
+  gem "byebug"
+  gem "opentelemetry-common", path: "../../../common"
+  gem "opentelemetry-instrumentation-action_pack", path: "../../../instrumentation/action_pack"
+  gem "opentelemetry-instrumentation-action_view", path: "../../../instrumentation/action_view"
+  gem "opentelemetry-instrumentation-active_record", path: "../../../instrumentation/active_record"
+  gem "opentelemetry-instrumentation-active_support", path: "../../../instrumentation/active_support"
+  gem "opentelemetry-instrumentation-rack", path: "../../../instrumentation/rack"
+  gem "opentelemetry-sdk", path: "../../../sdk"
+  gem "opentelemetry-semantic_conventions", path: "../../../semantic_conventions"
+  gem "pry-byebug"
+end
+
+gemspec path: "../"

instrumentation/rails/lib/opentelemetry/instrumentation/rails/railtie.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+# Copyright The OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+module OpenTelemetry
+  module Instrumentation
+    module Rails
+      # Railtie automatically configure the OpentTelemetry SDK
+      #
+      # This railtie will set defaults for the following environment variables:
+      # `OTEL_SERVICE_NAME` - if unset, will default to the Rails application name
+      # `OTEL_RESOURCE_ATTRIBUTES` - if unset, will set the deployment environment to the current Rails environment
+      #
+      # This will also set the `OpenTelemetry.logger` to the Rails logger.
+      class Railtie < ::Rails::Railtie
+        railtie_name :opentelemetry
+        initializer 'opentelemetry.configure' do |app|
+          # See https://api.rubyonrails.org/classes/Rails/Generators/NamedBase.html#method-i-application_name
+          ENV['OTEL_SERVICE_NAME'] ||= app.class.name.split('::').first.underscore
+
+          ::OpenTelemetry::SDK.configure do |c|
+            c.logger = ::Rails.logger
+            c.use_all
+          end
+        end
+      end
+    end
+  end
+end

instrumentation/rails/test/test_helper.rb → instrumentation/rails/test/instrumentation/test_helper.rb

@@ -13,13 +13,14 @@
 require 'rack/test'
 require 'test_helpers/app_config.rb'
 
-require_relative '../lib/opentelemetry/instrumentation'
+require_relative '../../lib/opentelemetry/instrumentation'
 
 # Global opentelemetry-sdk setup
 EXPORTER = OpenTelemetry::SDK::Trace::Export::InMemorySpanExporter.new
 span_processor = OpenTelemetry::SDK::Trace::Export::SimpleSpanProcessor.new(EXPORTER)
 
 OpenTelemetry::SDK.configure do |c|
+  c.logger = ::Logger.new(File::NULL)
   c.use_all
   c.add_span_processor span_processor
 end

instrumentation/rails/test/railtie/dummy/Rakefile

@@ -0,0 +1,6 @@
+# Add your own tasks in files placed in lib/tasks ending in .rake,
+# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.
+
+require_relative "config/application"
+
+Rails.application.load_tasks

instrumentation/rails/test/railtie/dummy/app/controllers/application_controller.rb

@@ -0,0 +1,2 @@
+class ApplicationController < ActionController::API
+end

instrumentation/rails/test/railtie/dummy/bin/rails

@@ -0,0 +1,4 @@
+#!/usr/bin/env ruby
+APP_PATH = File.expand_path("../config/application", __dir__)
+require_relative "../config/boot"
+require "rails/commands"

instrumentation/rails/test/railtie/dummy/bin/rake

@@ -0,0 +1,4 @@
+#!/usr/bin/env ruby
+require_relative "../config/boot"
+require "rake"
+Rake.application.run

instrumentation/rails/test/railtie/dummy/bin/setup

@@ -0,0 +1,33 @@
+#!/usr/bin/env ruby
+require "fileutils"
+
+# path to your application root.
+APP_ROOT = File.expand_path("..", __dir__)
+
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+FileUtils.chdir APP_ROOT do
+  # This script is a way to set up or update your development environment automatically.
+  # This script is idempotent, so that you can run it at any time and get an expectable outcome.
+  # Add necessary setup steps to this file.
+
+  puts "== Installing dependencies =="
+  system! "gem install bundler --conservative"
+  system("bundle check") || system!("bundle install")
+
+  # puts "\n== Copying sample files =="
+  # unless File.exist?("config/database.yml")
+  #   FileUtils.cp "config/database.yml.sample", "config/database.yml"
+  # end
+
+  puts "\n== Preparing database =="
+  system! "bin/rails db:prepare"
+
+  puts "\n== Removing old logs and tempfiles =="
+  system! "bin/rails log:clear tmp:clear"
+
+  puts "\n== Restarting application server =="
+  system! "bin/rails restart"
+end

instrumentation/rails/test/railtie/dummy/config.ru

@@ -0,0 +1,6 @@
+# This file is used by Rack-based servers to start the application.
+
+require_relative "config/environment"
+
+run Rails.application
+Rails.application.load_server

instrumentation/rails/test/railtie/dummy/config/application.rb

@@ -0,0 +1,37 @@
+require_relative "boot"
+
+require "rails"
+# Pick the frameworks you want:
+require "active_model/railtie"
+require "active_job/railtie"
+# require "active_record/railtie"
+# require "active_storage/engine"
+require "action_controller/railtie"
+# require "action_mailer/railtie"
+# require "action_mailbox/engine"
+# require "action_text/engine"
+require "action_view/railtie"
+# require "action_cable/engine"
+# require "sprockets/railtie"
+require "rails/test_unit/railtie"
+
+# Require the gems listed in Gemfile, including any gems
+# you've limited to :test, :development, or :production.
+Bundler.require(*Rails.groups)
+require "opentelemetry/instrumentation/rails/railtie"
+
+module Dummy
+  class Application < Rails::Application
+    config.load_defaults Rails::VERSION::STRING.to_f
+
+    # Configuration for the application, engines, and railties goes here.
+    #
+    # These settings can be overridden in specific environments using the files
+    # in config/environments, which are processed later.
+    #
+    # config.time_zone = "Central Time (US & Canada)"
+    # config.eager_load_paths << Rails.root.join("extras")
+    config.logger    = ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(File::NULL))
+    config.api_only = true
+  end
+end

instrumentation/rails/test/railtie/dummy/config/boot.rb

@@ -0,0 +1,5 @@
+# Set up gems listed in the Gemfile.
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../../Gemfile", __dir__)
+
+require "bundler/setup" if File.exist?(ENV["BUNDLE_GEMFILE"])
+$LOAD_PATH.unshift File.expand_path("../../../lib", __dir__)

instrumentation/rails/test/railtie/dummy/config/environment.rb

@@ -0,0 +1,5 @@
+# Load the Rails application.
+require_relative "application"
+
+# Initialize the Rails application.
+Rails.application.initialize!

instrumentation/rails/test/railtie/dummy/config/environments/development.rb

@@ -0,0 +1,68 @@
+require "active_support/core_ext/integer/time"
+
+Rails.application.configure do
+  # Settings specified here will take precedence over those in config/application.rb.
+
+  # In the development environment your application's code is reloaded any time
+  # it changes. This slows down response time but is perfect for development
+  # since you don't have to restart the web server when you make code changes.
+  config.cache_classes = false
+
+  # Do not eager load code on boot.
+  config.eager_load = false
+
+  # Show full error reports.
+  config.consider_all_requests_local = true
+
+  # Enable server timing
+  config.server_timing = true
+
+  # Enable/disable caching. By default caching is disabled.
+  # Run rails dev:cache to toggle caching.
+  if Rails.root.join("tmp/caching-dev.txt").exist?
+    config.action_controller.perform_caching = true
+    config.action_controller.enable_fragment_cache_logging = true
+
+    config.cache_store = :memory_store
+    config.public_file_server.headers = {
+      "Cache-Control" => "public, max-age=#{2.days.to_i}"
+    }
+  else
+    config.action_controller.perform_caching = false
+
+    config.cache_store = :null_store
+  end
+
+  # Store uploaded files on the local file system (see config/storage.yml for options).
+  config.active_storage.service = :local
+
+  # Don't care if the mailer can't send.
+  config.action_mailer.raise_delivery_errors = false
+
+  config.action_mailer.perform_caching = false
+
+  # Print deprecation notices to the Rails logger.
+  config.active_support.deprecation = :log
+
+  # Raise exceptions for disallowed deprecations.
+  config.active_support.disallowed_deprecation = :raise
+
+  # Tell Active Support which deprecation messages to disallow.
+  config.active_support.disallowed_deprecation_warnings = []
+
+  # Raise an error on page load if there are pending migrations.
+  config.active_record.migration_error = :page_load
+
+  # Highlight code that triggered database queries in logs.
+  config.active_record.verbose_query_logs = true
+
+
+  # Raises error for missing translations.
+  # config.i18n.raise_on_missing_translations = true
+
+  # Annotate rendered view with file names.
+  # config.action_view.annotate_rendered_view_with_filenames = true
+
+  # Uncomment if you wish to allow Action Cable access from any origin.
+  # config.action_cable.disable_request_forgery_protection = true
+end