Refactor:Move distributed propagation to Contrib

lib/datadog/core/utils/refinement.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+# typed: false
+
+module Datadog
+  module Core
+    module Utils
+      # A collection of refinements for core Ruby features.
+      # Backports future features to old rubies.
+      module Refinement
+        # rubocop:disable Style/Documentation
+        module Regexp
+          refine ::Regexp do
+            # `Regexp::match?` is measurably the most performant
+            # way to check if a String matches a regular expression.
+            #
+            # Introduced in Ruby 2.4.
+            def match?(*args)
+              !match(*args).nil?
+            end
+          end
+        end
+
+        module String
+          refine ::String do
+            # When not sure if a String is mutable and but it's necessary to perform
+            # changes to it, `+@` is measurable faster than a possibly unnecessary `.dup`.
+            #
+            # Introduced in Ruby 2.3.
+            def +@
+              frozen? ? dup : self
+            end
+          end
+        end
+        # rubocop:enable Style/Documentation
+      end
+    end
+  end
+end

lib/datadog/opentracer/distributed_headers.rb

@@ -1,14 +1,14 @@
 # typed: true
 
 require_relative '../tracing/span'
-require_relative '../tracing/distributed/headers/ext'
+require_relative '../tracing/distributed/ext'
 
 module Datadog
   module OpenTracer
     # DistributedHeaders provides easy access and validation to headers
     # @public_api
     class DistributedHeaders
-      include Tracing::Distributed::Headers::Ext
+      include Tracing::Distributed::Ext
 
       def initialize(carrier)
         @carrier = carrier

lib/datadog/opentracer/rack_propagator.rb

@@ -1,7 +1,7 @@
 # typed: true
 
 require_relative '../tracing/context'
-require_relative '../tracing/distributed/headers/ext'
+require_relative '../tracing/distributed/ext'
 require_relative '../tracing/propagation/http'
 require_relative '../tracing/trace_operation'
 require_relative 'propagator'
@@ -11,8 +11,8 @@ module OpenTracer
     # OpenTracing propagator for Datadog::OpenTracer::Tracer
     module RackPropagator
       extend Propagator
-      extend Tracing::Distributed::Headers::Ext
-      include Tracing::Distributed::Headers::Ext
+      extend Tracing::Distributed::Ext
+      include Tracing::Distributed::Ext
 
       BAGGAGE_PREFIX = 'ot-baggage-'.freeze
       BAGGAGE_PREFIX_FORMATTED = 'HTTP_OT_BAGGAGE_'.freeze

lib/datadog/opentracer/text_map_propagator.rb

@@ -1,7 +1,7 @@
 # typed: true
 
 require_relative '../tracing/context'
-require_relative '../tracing/distributed/headers/ext'
+require_relative '../tracing/distributed/ext'
 require_relative '../tracing/trace_operation'
 require_relative 'propagator'
 
@@ -10,8 +10,8 @@ module OpenTracer
     # OpenTracing propagator for Datadog::OpenTracer::Tracer
     module TextMapPropagator
       extend Propagator
-      extend Tracing::Distributed::Headers::Ext
-      include Tracing::Distributed::Headers::Ext
+      extend Tracing::Distributed::Ext
+      include Tracing::Distributed::Ext
 
       BAGGAGE_PREFIX = 'ot-baggage-'.freeze
 

lib/datadog/tracing/contrib/grpc/datadog_interceptor/client.rb

@@ -2,6 +2,7 @@
 
 require_relative '../../../../tracing'
 require_relative '../../../metadata/ext'
+require_relative '../distributed/propagation'
 require_relative '../../analytics'
 require_relative '../ext'
 require_relative '../../ext'
@@ -55,7 +56,7 @@ def annotate!(trace, span, metadata, call)
               # Set analytics sample rate
               Contrib::Analytics.set_sample_rate(span, analytics_sample_rate) if analytics_enabled?
 
-              Tracing::Propagation::GRPC.inject!(trace, metadata) if distributed_tracing?
+              Distributed::Propagation::INSTANCE.inject!(trace, metadata) if distributed_tracing?
             rescue StandardError => e
               Datadog.logger.debug("GRPC client trace failed: #{e}")
             end

lib/datadog/tracing/contrib/grpc/datadog_interceptor/server.rb

@@ -1,9 +1,9 @@
 # typed: ignore
 
 require_relative '../../../../tracing'
-require_relative '../../../distributed/headers/ext'
+require_relative '../../../distributed/ext'
 require_relative '../../../metadata/ext'
-require_relative '../../../propagation/grpc'
+require_relative '../distributed/propagation'
 require_relative '../../analytics'
 require_relative '../ext'
 require_relative '../../ext'
@@ -45,7 +45,7 @@ def trace(keywords)
             private
 
             def set_distributed_context!(metadata)
-              Tracing.continue_trace!(Tracing::Propagation::GRPC.extract(metadata))
+              Tracing.continue_trace!(Distributed::Propagation::INSTANCE.extract(metadata))
             rescue StandardError => e
               Datadog.logger.debug(
                 "unable to propagate GRPC metadata to context: #{e}"
@@ -54,7 +54,8 @@ def set_distributed_context!(metadata)
 
             def annotate!(span, metadata)
               metadata.each do |header, value|
-                next if reserved_headers.include?(header)
+                # Datadog propagation headers are considered internal implementation detail.
+                next if header.to_s.start_with?(Tracing::Distributed::Ext::DATADOG_PREFIX)
 
                 span.set_tag(header, value)
               end
@@ -71,14 +72,6 @@ def annotate!(span, metadata)
               Datadog.logger.debug("GRPC client trace failed: #{e}")
             end
 
-            def reserved_headers
-              [
-                Tracing::Distributed::Headers::Ext::GRPC_METADATA_TRACE_ID,
-                Tracing::Distributed::Headers::Ext::GRPC_METADATA_PARENT_ID,
-                Tracing::Distributed::Headers::Ext::GRPC_METADATA_SAMPLING_PRIORITY
-              ]
-            end
-
             def format_resource(proto_method)
               proto_method
                 .owner

lib/datadog/tracing/contrib/grpc/distributed/b3.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/b3'
+require_relative 'fetcher'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module GRPC
+        module Distributed
+          # B3-style trace propagation through gRPC metadata.
+          # @see https://github.com/openzipkin/b3-propagation#multiple-headers
+          # @see https://github.com/grpc/grpc-go/blob/v1.50.1/Documentation/grpc-metadata.md gRPC metadata
+          class B3 < Tracing::Distributed::B3
+            def initialize
+              super(fetcher: Fetcher)
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/grpc/distributed/b3_single.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/b3_single'
+require_relative 'fetcher'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module GRPC
+        module Distributed
+          # B3 single header-style trace propagation through gRPC metadata.
+          # @see https://github.com/openzipkin/b3-propagation#single-header
+          # @see https://github.com/grpc/grpc-go/blob/v1.50.1/Documentation/grpc-metadata.md gRPC metadata
+          class B3Single < Tracing::Distributed::B3Single
+            def initialize
+              super(fetcher: Fetcher)
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/grpc/distributed/datadog.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/datadog'
+require_relative 'fetcher'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module GRPC
+        module Distributed
+          # Datadog-style trace propagation through gRPC metadata.
+          # @see https://github.com/grpc/grpc-go/blob/v1.50.1/Documentation/grpc-metadata.md gRPC metadata
+          class Datadog < Tracing::Distributed::Datadog
+            def initialize
+              super(fetcher: Fetcher)
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/grpc/distributed/fetcher.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/fetcher'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module GRPC
+        module Distributed
+          # Retrieves values from the gRPC metadata.
+          class Fetcher < Tracing::Distributed::Fetcher
+            def [](key)
+              # Metadata values can be arrays (multiple values for the same key)
+              value = super(key)
+              value.is_a?(::Array) ? value[0] : value
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/grpc/distributed/propagation.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/propagation'
+require_relative 'b3'
+require_relative 'b3_single'
+require_relative 'datadog'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module GRPC
+        module Distributed
+          # Extracts and injects propagation through gRPC metadata.
+          class Propagation < Tracing::Distributed::Propagation
+            def initialize
+              super(
+                propagation_styles: {
+                  Tracing::Configuration::Ext::Distributed::PROPAGATION_STYLE_B3 => B3.new,
+                  Tracing::Configuration::Ext::Distributed::PROPAGATION_STYLE_B3_SINGLE_HEADER => B3Single.new,
+                  Tracing::Configuration::Ext::Distributed::PROPAGATION_STYLE_DATADOG => Datadog.new,
+                })
+            end
+
+            # DEV: Singleton kept until a larger refactor is performed.
+            # DEV: See {Datadog::Tracing::Distributed::Propagation#initialize} for more information.
+            INSTANCE = Propagation.new
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/grpc/patcher.rb

@@ -19,8 +19,6 @@ def target_version
           end
 
           def patch
-            require_relative '../../propagation/grpc'
-            require_relative 'datadog_interceptor'
             require_relative 'intercept_with_datadog'
 
             prepend_interceptor

lib/datadog/tracing/contrib/http/distributed/b3.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/b3'
+require_relative 'fetcher'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module HTTP
+        module Distributed
+          # B3-style trace propagation through HTTP headers.
+          # @see https://github.com/openzipkin/b3-propagation#multiple-headers
+          class B3 < Tracing::Distributed::B3
+            def initialize
+              super(fetcher: Fetcher)
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/http/distributed/b3_single.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/b3_single'
+require_relative 'fetcher'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module HTTP
+        module Distributed
+          # B3 single header-style trace propagation through HTTP headers.
+          # @see https://github.com/openzipkin/b3-propagation#single-header
+          class B3Single < Tracing::Distributed::B3Single
+            def initialize
+              super(fetcher: Fetcher)
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/tracing/contrib/http/distributed/datadog.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+# typed: true
+
+require_relative '../../../distributed/datadog'
+require_relative 'fetcher'
+
+module Datadog
+  module Tracing
+    module Contrib
+      module HTTP
+        module Distributed
+          # Datadog-style trace propagation through HTTP headers.
+          class Datadog < Tracing::Distributed::Datadog
+            def initialize
+              super(fetcher: Fetcher)
+            end
+          end
+        end
+      end
+    end
+  end
+end