Refactored: Redis to use Datadog::Contrib::Integration.

lib/ddtrace.rb

@@ -64,7 +64,7 @@ def configure(target = configuration, opts = {})
 require 'ddtrace/contrib/rack/integration'
 require 'ddtrace/contrib/rails/integration'
 require 'ddtrace/contrib/rake/patcher'
-require 'ddtrace/contrib/redis/patcher'
+require 'ddtrace/contrib/redis/integration'
 require 'ddtrace/contrib/resque/integration'
 require 'ddtrace/contrib/rest_client/integration'
 require 'ddtrace/contrib/sequel/integration'

lib/ddtrace/contrib/rails/core_extensions.rb

@@ -335,7 +335,7 @@ def delete(*args, &block)
 
     def self.reload_cache_store
       redis = Datadog.registry[:redis]
-      return unless redis && redis.patched?
+      return unless redis && redis.patcher.patched?
 
       return unless defined?(::ActiveSupport::Cache::RedisStore) &&
                     defined?(::Rails.cache) &&

lib/ddtrace/contrib/redis/configuration/settings.rb

@@ -0,0 +1,16 @@
+require 'ddtrace/contrib/configuration/settings'
+require 'ddtrace/contrib/redis/ext'
+
+module Datadog
+  module Contrib
+    module Redis
+      module Configuration
+        # Custom settings for the Redis integration
+        class Settings < Contrib::Configuration::Settings
+          option :service_name, default: Ext::SERVICE_NAME
+          option :tracer, default: Datadog.tracer
+        end
+      end
+    end
+  end
+end

lib/ddtrace/contrib/redis/ext.rb

@@ -0,0 +1,13 @@
+module Datadog
+  module Contrib
+    module Redis
+      # Redis integration constants
+      module Ext
+        APP = 'redis'.freeze
+        SERVICE_NAME = 'redis'.freeze
+
+        SPAN_NAME = 'redis.command'.freeze
+      end
+    end
+  end
+end

lib/ddtrace/contrib/redis/integration.rb

@@ -0,0 +1,36 @@
+require 'ddtrace/contrib/integration'
+require 'ddtrace/contrib/redis/configuration/settings'
+require 'ddtrace/contrib/redis/patcher'
+
+module Datadog
+  module Contrib
+    module Redis
+      # Description of Redis integration
+      class Integration
+        include Contrib::Integration
+
+        register_as :redis, auto_patch: true
+
+        def self.version
+          Gem.loaded_specs['redis'] && Gem.loaded_specs['redis'].version
+        end
+
+        def self.present?
+          super && defined?(::Redis)
+        end
+
+        def self.compatible?
+          !version.nil? && version >= Gem::Version.new('3.0.0')
+        end
+
+        def default_configuration
+          Configuration::Settings.new
+        end
+
+        def patcher
+          Patcher
+        end
+      end
+    end
+  end
+end

lib/ddtrace/contrib/redis/patcher.rb

@@ -1,43 +1,35 @@
-# requirements should be kept minimal as Patcher is a shared requirement.
+require 'ddtrace/contrib/patcher'
+require 'ddtrace/contrib/redis/ext'
 
 module Datadog
   module Contrib
     module Redis
-      SERVICE = 'redis'.freeze
-      DRIVER = 'redis.driver'.freeze
-
       # Patcher enables patching of 'redis' module.
       module Patcher
-        include Base
-        register_as :redis, auto_patch: true
-        option :service_name, default: SERVICE
-        option :tracer, default: Datadog.tracer
-
-        @patched = false
+        include Contrib::Patcher
 
         module_function
 
+        def patched?
+          done?(:redis)
+        end
+
         # patch applies our patch if needed
         def patch
-          if !@patched && compatible?
+          do_once(:redis) do
             begin
               # do not require these by default, but only when actually patching
+              require 'redis'
               require 'ddtrace/ext/app_types'
               require 'ddtrace/contrib/redis/tags'
               require 'ddtrace/contrib/redis/quantize'
 
               patch_redis_client
-              @patched = true
               RailsCachePatcher.reload_cache_store if Datadog.registry[:rails].patcher.patched?
             rescue StandardError => e
               Datadog::Tracer.log.error("Unable to apply Redis integration: #{e}")
             end
           end
-          @patched
-        end
-
-        def compatible?
-          defined?(::Redis::VERSION) && Gem::Version.new(::Redis::VERSION) >= Gem::Version.new('3.0.0')
         end
 
         # rubocop:disable Metrics/MethodLength
@@ -52,7 +44,12 @@ def patch_redis_client
             def initialize(*args)
               service = Datadog.configuration[:redis][:service_name]
               tracer = Datadog.configuration[:redis][:tracer]
-              pin = Datadog::Pin.new(service, app: 'redis', app_type: Datadog::Ext::AppTypes::DB, tracer: tracer)
+              pin = Datadog::Pin.new(
+                service,
+                app: Ext::APP,
+                app_type: Datadog::Ext::AppTypes::DB,
+                tracer: tracer
+              )
               pin.onto(self)
               initialize_without_datadog(*args)
             end
@@ -64,7 +61,7 @@ def call(*args, &block)
               return call_without_datadog(*args, &block) unless pin && pin.tracer
 
               response = nil
-              pin.tracer.trace('redis.command') do |span|
+              pin.tracer.trace(Datadog::Contrib::Redis::Ext::SPAN_NAME) do |span|
                 span.service = pin.service
                 span.span_type = Datadog::Ext::Redis::TYPE
                 span.resource = Datadog::Contrib::Redis::Quantize.format_command_args(*args)
@@ -83,7 +80,7 @@ def call_pipeline(*args, &block)
               return call_pipeline_without_datadog(*args, &block) unless pin && pin.tracer
 
               response = nil
-              pin.tracer.trace('redis.command') do |span|
+              pin.tracer.trace(Datadog::Contrib::Redis::Ext::SPAN_NAME) do |span|
                 span.service = pin.service
                 span.span_type = Datadog::Ext::Redis::TYPE
                 commands = args[0].commands.map { |c| Datadog::Contrib::Redis::Quantize.format_command_args(c) }
@@ -98,11 +95,6 @@ def call_pipeline(*args, &block)
             end
           end
         end
-
-        # patched? tells wether patch has been successfully applied
-        def patched?
-          @patched
-        end
       end
     end
   end