Add Net:HTTP instrumentation adapter (#187)

Add `Net::HTTP` instrumentation adapter
based on other HTTP client adapters and the related `ddtrace` code.

.circleci/config.yml

@@ -68,6 +68,14 @@ commands:
             bundle install --jobs=3 --retry=3
             bundle exec appraisal install
             bundle exec appraisal rake test
+      - run:
+          name: Bundle + CI (Adapters - Net::HTTP)
+          command: |
+            cd adapters/net_http
+            gem uninstall -aIx bundler
+            gem install --no-document bundler -v '~> 2.0.2'
+            bundle install --jobs=3 --retry=3
+            bundle exec rake test
       - run:
           name: Bundle + CI (Adapters - Redis)
           command: |

Rakefile

@@ -69,6 +69,12 @@ GEM_INFO = {
       OpenTelemetry::Adapters::Faraday::VERSION
     }
   },
+  "opentelemetry-adapters-net_http" => {
+    version_getter: ->() {
+      require './lib/opentelemetry/adapters/net/http/version.rb'
+      OpenTelemetry::Adapters::Net::HTTP::VERSION
+    }
+  },
   "opentelemetry-adapters-redis" => {
     version_getter: ->() {
       require './lib/opentelemetry/adapters/redis/version.rb'

adapters/net_http/.rubocop.yml

@@ -0,0 +1,27 @@
+AllCops:
+  TargetRubyVersion: '2.4.0'
+
+Bundler/OrderedGems:
+  Exclude:
+    - gemfiles/**/*
+Lint/UnusedMethodArgument:
+  Enabled: false
+Metrics/AbcSize:
+  Max: 18
+Metrics/LineLength:
+  Enabled: false
+Metrics/MethodLength:
+  Max: 20
+Metrics/ParameterLists:
+  Enabled: false
+Naming/FileName:
+  Exclude:
+    - "lib/opentelemetry-adapters-net-http.rb"
+Style/FrozenStringLiteralComment:
+  Exclude:
+    - gemfiles/**/*
+Style/ModuleFunction:
+  Enabled: false
+Style/StringLiterals:
+  Exclude:
+    - gemfiles/**/*

adapters/net_http/Gemfile

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+source 'https://rubygems.org'
+
+gemspec
+
+gem 'opentelemetry-api', path: '../../api'
+
+group :test do
+  gem 'opentelemetry-sdk', path: '../../sdk'
+end

adapters/net_http/Rakefile

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'bundler/gem_tasks'
+require 'rake/testtask'
+require 'yard'
+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']
+end
+
+YARD::Rake::YardocTask.new do |t|
+  t.stats_options = ['--list-undoc']
+end
+
+if RUBY_ENGINE == 'truffleruby'
+  task default: %i[test]
+else
+  task default: %i[test rubocop yard]
+end

adapters/net_http/example/Gemfile

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+source 'https://rubygems.org'
+
+gem 'opentelemetry-adapters-net-http', path: '../../../adapters/net_http'
+gem 'opentelemetry-api', path: '../../../api'
+gem 'opentelemetry-sdk', path: '../../../sdk'

adapters/net_http/example/net_http.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require 'rubygems'
+require 'bundler/setup'
+require 'net/http'
+
+Bundler.require
+
+OpenTelemetry::SDK.configure do |c|
+  c.use 'OpenTelemetry::Adapters::Net::HTTP'
+end
+
+Net::HTTP.get(URI('http://example.com'))

adapters/net_http/lib/opentelemetry-adapters-net-http.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require_relative './opentelemetry/adapters'

adapters/net_http/lib/opentelemetry/adapters.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  # "Instrumentation adapters" are specified by
+  # https://github.com/open-telemetry/opentelemetry-specification/blob/57714f7547fe4dcb342ad0ad10a80d86118431c7/specification/overview.md#instrumentation-adapters
+  #
+  # Adapters should be able to handle the case when the library is not installed on a user's system.
+  module Adapters
+  end
+end
+
+require_relative './adapters/net/http'

adapters/net_http/lib/opentelemetry/adapters/net/http.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'opentelemetry'
+
+module OpenTelemetry
+  module Adapters
+    module Net
+      # Contains the OpenTelemetry adapter for the Net::HTTP gem
+      module HTTP
+      end
+    end
+  end
+end
+
+require_relative './http/adapter'
+require_relative './http/version'

adapters/net_http/lib/opentelemetry/adapters/net/http/adapter.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Net
+      module HTTP
+        # The Adapter class contains logic to detect and install the Net::HTTP
+        # instrumentation adapter
+        class Adapter < OpenTelemetry::Instrumentation::Adapter
+          install do |_config|
+            require_dependencies
+            patch
+          end
+
+          present do
+            defined?(::Net::HTTP)
+          end
+
+          private
+
+          def require_dependencies
+            require_relative 'patches/instrumentation'
+          end
+
+          def patch
+            ::Net::HTTP.prepend(Patches::Instrumentation)
+          end
+        end
+      end
+    end
+  end
+end

adapters/net_http/lib/opentelemetry/adapters/net/http/patches/instrumentation.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Net
+      module HTTP
+        module Patches
+          # Module to prepend to Net::HTTP for instrumentation
+          module Instrumentation
+            HTTP_METHODS_TO_SPAN_NAMES = Hash.new { |h, k| h[k] = "HTTP #{k}" }
+            USE_SSL_TO_SCHEME = { false => 'http', true => 'https' }.freeze
+
+            def request(req, body = nil, &block)
+              # Do not trace recursive call for starting the connection
+              return super(req, body, &block) unless started?
+
+              tracer.in_span(
+                HTTP_METHODS_TO_SPAN_NAMES[req.method],
+                attributes: {
+                  'component' => 'http',
+                  'http.method' => req.method,
+                  'http.scheme' => USE_SSL_TO_SCHEME[use_ssl?],
+                  'http.target' => req.path,
+                  'peer.hostname' => @address,
+                  'peer.port' => @port
+                },
+                kind: :client
+              ) do |span|
+                OpenTelemetry.propagation.inject(req)
+
+                super(req, body, &block).tap do |response|
+                  annotate_span_with_response!(span, response)
+                end
+              end
+            end
+
+            private
+
+            def annotate_span_with_response!(span, response)
+              return unless response&.code
+
+              status_code = response.code.to_i
+
+              span.set_attribute('http.status_code', status_code)
+              span.status = OpenTelemetry::Trace::Status.http_to_status(
+                status_code
+              )
+            end
+
+            def tracer
+              Net::HTTP::Adapter.instance.tracer
+            end
+          end
+        end
+      end
+    end
+  end
+end

adapters/net_http/lib/opentelemetry/adapters/net/http/version.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Net
+      module HTTP
+        VERSION = '0.0.0'
+      end
+    end
+  end
+end

adapters/net_http/opentelemetry-adapters-net-http.gemspec

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+lib = File.expand_path('lib', __dir__)
+$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
+require 'opentelemetry/adapters/net/http/version'
+
+Gem::Specification.new do |spec|
+  spec.name        = 'opentelemetry-adapters-net-http'
+  spec.version     = OpenTelemetry::Adapters::Net::HTTP::VERSION
+  spec.authors     = ['OpenTelemetry Authors']
+  spec.email       = ['[email protected]']
+
+  spec.summary     = 'Net::HTTP instrumentation adapter for the OpenTelemetry framework'
+  spec.description = 'Net::HTTP instrumentation adapter for the OpenTelemetry framework'
+  spec.homepage    = 'https://github.com/open-telemetry/opentelemetry-ruby'
+  spec.license     = 'Apache-2.0'
+
+  spec.files = ::Dir.glob('lib/**/*.rb') +
+               ::Dir.glob('*.md') +
+               ['LICENSE']
+  spec.require_paths = ['lib']
+  spec.required_ruby_version = '>= 2.4.0'
+
+  spec.add_dependency 'opentelemetry-api', '~> 0.0'
+
+  spec.add_development_dependency 'bundler', '>= 1.17'
+  spec.add_development_dependency 'minitest', '~> 5.0'
+  spec.add_development_dependency 'opentelemetry-sdk', '~> 0.0'
+  spec.add_development_dependency 'rake', '~> 13.0.1'
+  spec.add_development_dependency 'rubocop', '~> 0.73.0'
+  spec.add_development_dependency 'simplecov', '~> 0.17.1'
+  spec.add_development_dependency 'webmock', '~> 3.7.6'
+  spec.add_development_dependency 'yard', '~> 0.9'
+  spec.add_development_dependency 'yard-doctest', '~> 0.1.6'
+end

adapters/net_http/test/.rubocop.yml

@@ -0,0 +1,4 @@
+inherit_from: ../.rubocop.yml
+
+Metrics/BlockLength:
+  Enabled: false