Add redis instrumentation adapter (#176)

grantbdev · web-flow · commit ba8b7b6aac87 · 2020-02-28T10:38:37.000-08:00
Add `redis` instrumentation adapter based on the adapter for `rest-client` and the `dd-trace-rb` code for `redis`, including its utilites. The `fakeredis` gem is used in the tests to have a fake server. The Docker container for the example includes a real Redis server. Related to #67
diff --git a/.circleci/config.yml b/.circleci/config.yml
@@ -68,6 +68,15 @@ commands:
             bundle install --jobs=3 --retry=3
             bundle exec appraisal install
             bundle exec appraisal rake test
+      - run:
+          name: Bundle + CI (Adapters - Redis)
+          command: |
+            cd adapters/redis
+            gem uninstall -aIx bundler
+            gem install --no-document bundler -v '~> 2.0.2'
+            bundle install --jobs=3 --retry=3
+            bundle exec appraisal install
+            bundle exec appraisal rake test
       - run:
           name: Bundle + CI (Adapters - REST Client)
           command: |
diff --git a/Rakefile b/Rakefile
@@ -69,6 +69,12 @@ GEM_INFO = {
       OpenTelemetry::Adapters::Faraday::VERSION
     }
   },
+  "opentelemetry-adapters-redis" => {
+    version_getter: ->() {
+      require './lib/opentelemetry/adapters/redis/version.rb'
+      OpenTelemetry::Adapters::Redis::VERSION
+    }
+  },
   "opentelemetry-adapters-restclient" => {
     version_getter: ->() {
       require './lib/opentelemetry/adapters/restclient/version.rb'
diff --git a/adapters/redis/.rubocop.yml b/adapters/redis/.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-redis.rb"
+Style/FrozenStringLiteralComment:
+  Exclude:
+    - gemfiles/**/*
+Style/ModuleFunction:
+  Enabled: false
+Style/StringLiterals:
+  Exclude:
+    - gemfiles/**/*
diff --git a/adapters/redis/Appraisals b/adapters/redis/Appraisals
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+appraise 'redis-4.1' do
+  gem 'redis', '~> 4.1.0'
+end
+
+appraise 'redis-4.0' do
+  gem 'redis', '~> 4.0.0'
+end
diff --git a/adapters/redis/Gemfile b/adapters/redis/Gemfile
@@ -0,0 +1,16 @@
+# 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 'fakeredis', require: 'fakeredis/minitest'
+  gem 'opentelemetry-sdk', path: '../../sdk'
+end
diff --git a/adapters/redis/Rakefile b/adapters/redis/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
diff --git a/adapters/redis/example/Gemfile b/adapters/redis/example/Gemfile
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+source 'https://rubygems.org'
+
+gem 'opentelemetry-adapters-redis', path: '../../../adapters/redis'
+gem 'opentelemetry-api', path: '../../../api'
+gem 'opentelemetry-sdk', path: '../../../sdk'
+gem 'redis'
diff --git a/adapters/redis/example/redis.rb b/adapters/redis/example/redis.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require 'rubygems'
+require 'bundler/setup'
+
+Bundler.require
+
+OpenTelemetry::SDK.configure do |c|
+  c.use 'OpenTelemetry::Adapters::Redis'
+end
+
+Redis.new.set('mykey', 'hello world')
diff --git a/adapters/redis/gemfiles/redis_4.0.gemfile b/adapters/redis/gemfiles/redis_4.0.gemfile
@@ -0,0 +1,13 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "opentelemetry-api", path: "../../../api"
+gem "redis", "~> 4.0.0"
+
+group :test do
+  gem "opentelemetry-sdk", path: "../../../sdk"
+  gem "fakeredis", require: "fakeredis/minitest"
+end
+
+gemspec path: "../"
diff --git a/adapters/redis/gemfiles/redis_4.1.gemfile b/adapters/redis/gemfiles/redis_4.1.gemfile
@@ -0,0 +1,13 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "opentelemetry-api", path: "../../../api"
+gem "redis", "~> 4.1.0"
+
+group :test do
+  gem "opentelemetry-sdk", path: "../../../sdk"
+  gem "fakeredis", require: "fakeredis/minitest"
+end
+
+gemspec path: "../"
diff --git a/adapters/redis/lib/opentelemetry-adapters-redis.rb b/adapters/redis/lib/opentelemetry-adapters-redis.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require_relative './opentelemetry/adapters'
diff --git a/adapters/redis/lib/opentelemetry/adapters.rb b/adapters/redis/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/redis'
diff --git a/adapters/redis/lib/opentelemetry/adapters/redis.rb b/adapters/redis/lib/opentelemetry/adapters/redis.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'opentelemetry'
+
+module OpenTelemetry
+  module Adapters
+    # Contains the OpenTelemetry adapter for the Redis gem
+    module Redis
+    end
+  end
+end
+
+require_relative './redis/adapter'
+require_relative './redis/version'
diff --git a/adapters/redis/lib/opentelemetry/adapters/redis/adapter.rb b/adapters/redis/lib/opentelemetry/adapters/redis/adapter.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Redis
+      # The Adapter class contains logic to detect and install the Redis
+      # instrumentation adapter
+      class Adapter < OpenTelemetry::Instrumentation::Adapter
+        install do |_config|
+          require_dependencies
+          patch_client
+        end
+
+        present do
+          defined?(::Redis)
+        end
+
+        private
+
+        def require_dependencies
+          require_relative 'utils'
+          require_relative 'patches/client'
+        end
+
+        def patch_client
+          ::Redis::Client.prepend(Patches::Client)
+        end
+      end
+    end
+  end
+end
diff --git a/adapters/redis/lib/opentelemetry/adapters/redis/patches/client.rb b/adapters/redis/lib/opentelemetry/adapters/redis/patches/client.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Redis
+      module Patches
+        # Module to prepend to Redis::Client for instrumentation
+        module Client
+          def call(*args, &block)
+            response = nil
+
+            tracer.in_span(
+              Utils.format_command(args),
+              attributes: client_attributes.merge(
+                'db.statement' => Utils.format_statement(args)
+              ),
+              kind: :client
+            ) do |span|
+              response = super(*args, &block)
+            end
+
+            response
+          end
+
+          def call_pipeline(*args, &block)
+            response = nil
+
+            tracer.in_span(
+              'pipeline',
+              attributes: client_attributes.merge(
+                'db.statement' => Utils.format_pipeline_statement(args)
+              ),
+              kind: :client
+            ) do |span|
+              response = super(*args, &block)
+            end
+
+            response
+          end
+
+          private
+
+          def client_attributes
+            host = options[:host]
+            port = options[:port]
+
+            {
+              'component' => 'redis',
+              'db.type' => 'redis',
+              'db.instance' => options[:db].to_s,
+              'db.url' => "redis://#{host}:#{port}",
+              'net.peer.name' => host,
+              'net.peer.port' => port
+            }
+          end
+
+          def tracer
+            Redis::Adapter.instance.tracer
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/adapters/redis/lib/opentelemetry/adapters/redis/utils.rb b/adapters/redis/lib/opentelemetry/adapters/redis/utils.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+# Copyright 2020 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Redis
+      # Utility functions
+      module Utils
+        extend self
+
+        STRING_PLACEHOLDER = ''.encode(::Encoding::UTF_8).freeze
+        PLACEHOLDER = '?'
+        VALUE_MAX_LEN = 50
+        CMD_MAX_LEN = 500
+
+        def format_command(command_args)
+          format_arg(resolve_command_args(command_args).first)
+        end
+
+        def format_pipeline_statement(command_args)
+          command_args[0].commands.map do |args|
+            format_statement(args)
+          end.join("\n")
+        end
+
+        def format_statement(command_args)
+          command_args = resolve_command_args(command_args)
+          return 'AUTH ?' if auth_command?(command_args)
+
+          cmd = command_args.map { |x| format_arg(x) }.join(' ')
+          truncate(cmd, CMD_MAX_LEN)
+        end
+
+        def format_arg(arg)
+          str = arg.is_a?(Symbol) ? arg.to_s.upcase : arg.to_s
+          str = utf8_encode(str, binary: true, placeholder: PLACEHOLDER)
+          truncate(str, VALUE_MAX_LEN)
+        rescue StandardError => e
+          OpenTelemetry.logger.debug("non formattable Redis arg #{str}: #{e}")
+          PLACEHOLDER
+        end
+
+        def auth_command?(command_args)
+          return false unless command_args.is_a?(Array) && !command_args.empty?
+
+          command_args.first.to_sym == :auth
+        end
+
+        # Unwraps command array when Redis is called with the following syntax:
+        #   redis.call([:cmd, 'arg1', ...])
+        def resolve_command_args(command_args)
+          return command_args.first if command_args.is_a?(Array) && command_args.first.is_a?(Array)
+
+          command_args
+        end
+
+        def truncate(string, size)
+          string.size > size ? "#{string[0...size - 3]}..." : string
+        end
+
+        def utf8_encode(str, options = {})
+          str = str.to_s
+
+          if options[:binary]
+            # This option is useful for "gracefully" displaying binary data that
+            # often contains text such as marshalled objects
+            str.encode('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')
+          elsif str.encoding == ::Encoding::UTF_8
+            str
+          else
+            str.encode(::Encoding::UTF_8)
+          end
+        rescue StandardError => e
+          OpenTelemetry.logger.debug("Error encoding string in UTF-8: #{e}")
+
+          options.fetch(:placeholder, STRING_PLACEHOLDER)
+        end
+      end
+    end
+  end
+end
diff --git a/adapters/redis/lib/opentelemetry/adapters/redis/version.rb b/adapters/redis/lib/opentelemetry/adapters/redis/version.rb
diff --git a/adapters/redis/opentelemetry-adapters-redis.gemspec b/adapters/redis/opentelemetry-adapters-redis.gemspec
diff --git a/adapters/redis/test/.rubocop.yml b/adapters/redis/test/.rubocop.yml
diff --git a/adapters/redis/test/opentelemetry/adapters/redis/adapter_test.rb b/adapters/redis/test/opentelemetry/adapters/redis/adapter_test.rb
diff --git a/adapters/redis/test/opentelemetry/adapters/redis/utils_test.rb b/adapters/redis/test/opentelemetry/adapters/redis/utils_test.rb
diff --git a/adapters/redis/test/test_helper.rb b/adapters/redis/test/test_helper.rb
diff --git a/docker-compose.yml b/docker-compose.yml
