allow overriding global configurations

lib/ddtrace/contrib/grpc/datadog_interceptor.rb

@@ -5,6 +5,12 @@ module GRPC
       module DatadogInterceptor
         # :nodoc:
         class Base < ::GRPC::Interceptor
+          attr_accessor :datadog_pin
+
+          def initialize(options = {})
+            datadog_pin_configuration { |c| yield(c) if block_given? }
+          end
+
           def request_response(**keywords)
             trace(keywords) { yield }
           end
@@ -23,12 +29,31 @@ def bidi_streamer(**keywords)
 
           private
 
-          def pin
+          def datadog_pin_configuration
+            pin = default_datadog_pin
+
+            if block_given?
+              pin = Pin.new(
+                pin.service_name,
+                app: pin.app,
+                app_type: pin.app_type,
+                tracer: pin.tracer
+              )
+
+              yield(pin)
+            end
+
+            pin.onto(self)
+
+            pin
+          end
+
+          def default_datadog_pin
             Pin.get_from(::GRPC)
           end
 
           def tracer
-            pin.tracer
+            datadog_pin.tracer
           end
         end
 

lib/ddtrace/contrib/grpc/datadog_interceptor/client.rb

@@ -12,7 +12,7 @@ def trace(keywords)
 
             options = {
               span_type: Datadog::Ext::GRPC::TYPE,
-              service: pin.service_name,
+              service: datadog_pin.service_name,
               resource: format_resource(keywords[:method])
             }
 

lib/ddtrace/contrib/grpc/datadog_interceptor/server.rb

@@ -11,7 +11,7 @@ class Server < Base
           def trace(keywords)
             options = {
               span_type: Datadog::Ext::GRPC::TYPE,
-              service: pin.service_name,
+              service: datadog_pin.service_name,
               resource: format_resource(keywords[:method])
             }
             metadata = keywords[:call].metadata

lib/ddtrace/contrib/grpc/interception_context.rb

@@ -8,7 +8,7 @@ class InterceptionContext
     # our tracing middleware into the head of the call chain.
     module InterceptWithDatadog
       def intercept!(type, args = {})
-        unless defined?(@trace_started) && @trace_started
+        if should_prepend?
           datadog_interceptor = choose_datadog_interceptor(args)
 
           @interceptors.unshift(datadog_interceptor.new) if datadog_interceptor
@@ -21,6 +21,20 @@ def intercept!(type, args = {})
 
       private
 
+      def should_prepend?
+        !trace_started? && !already_prepended?
+      end
+
+      def trace_started?
+        defined?(@trace_started) && @trace_started
+      end
+
+      def already_prepended?
+        @interceptors.any? do |interceptor|
+          interceptor.class.ancestors.include?(Datadog::Contrib::GRPC::DatadogInterceptor::Base)
+        end
+      end
+
       def choose_datadog_interceptor(args)
         if args.key?(:metadata)
           Datadog::Contrib::GRPC::DatadogInterceptor::Client

spec/ddtrace/contrib/grpc/datadog_interceptor/client_spec.rb

@@ -5,7 +5,7 @@
 RSpec.describe 'tracing on the client connection' do
   subject { Datadog::Contrib::GRPC::DatadogInterceptor::Client.new }
 
-  let(:span) { Datadog::Pin.get_from(::GRPC).tracer.writer.spans.first }
+  let(:span) { subject.datadog_pin.tracer.writer.spans.first }
 
   before do
     Datadog.configure do |c|
@@ -15,6 +15,35 @@
     end
   end
 
+  context 'using client-specific configurations' do
+    let(:keywords) do
+      { request: instance_double(Object),
+        call: instance_double('GRPC::ActiveCall'),
+        method: 'MyService.Endpoint',
+        metadata: { some: 'datum' } }
+    end
+
+    let(:default_client_interceptor) do
+      Datadog::Contrib::GRPC::DatadogInterceptor::Client.new
+    end
+
+    let(:configured_client_interceptor) do
+      Datadog::Contrib::GRPC::DatadogInterceptor::Client.new do |c|
+        c.service_name = 'cepsr'
+      end
+    end
+
+    it 'replaces default service name' do
+      default_client_interceptor.request_response(keywords) {}
+      span = default_client_interceptor.datadog_pin.tracer.writer.spans.first
+      expect(span.service).to eq 'rspec'
+
+      configured_client_interceptor.request_response(keywords) {}
+      span = configured_client_interceptor.datadog_pin.tracer.writer.spans.first
+      expect(span.service).to eq 'cepsr'
+    end
+  end
+
   shared_examples 'span data contents' do
     specify { expect(span.name).to eq 'grpc.client' }
     specify { expect(span.span_type).to eq 'grpc' }

spec/ddtrace/contrib/grpc/integration_spec.rb

@@ -15,6 +15,31 @@
     end
   end
 
+  context 'multiple client configurations' do
+    let(:configured_interceptor) do
+      Datadog::Contrib::GRPC::DatadogInterceptor::Client.new do |c|
+        c.service_name = 'awesome sauce'
+      end
+    end
+    let(:alternate_client) do
+      GRPCHelper::TestService.rpc_stub_class.new(
+        '0.0.0.0:50051',
+        :this_channel_is_insecure,
+        interceptors: [configured_interceptor]
+      )
+    end
+
+    it 'uses the correct configuration information' do
+      run_request_reply
+      span = spans.first
+      expect(span.service).to eq 'rspec'
+
+      run_request_reply('0.0.0.0:50051', alternate_client)
+      span = configured_interceptor.datadog_pin.tracer.writer.spans.first
+      expect(span.service).to eq 'awesome sauce'
+    end
+  end
+
   shared_examples 'associates child spans with the parent' do
     let(:parent_span) { spans.first }
     let(:child_span) { spans.last }

spec/ddtrace/contrib/grpc/support/grpc_helper.rb

@@ -1,31 +1,33 @@
 require 'grpc'
 
 module GRPCHelper
-  def run_request_reply
-    runner('0.0.0.0:50052') { |c| c.basic(TestMessage.new) }
+  def run_request_reply(address = '0.0.0.0:50052', client = nil)
+    runner(address, client) { |c| c.basic(TestMessage.new) }
   end
 
-  def run_client_streamer
-    runner('0.0.0.0:50053') { |c| c.stream_from_client([TestMessage.new]) }
+  def run_client_streamer(address = '0.0.0.0:50053', client = nil)
+    runner(address, client) { |c| c.stream_from_client([TestMessage.new]) }
   end
 
-  def run_server_streamer
-    runner('0.0.0.0:50054') { |c| c.stream_from_server(TestMessage.new) }
+  def run_server_streamer(address = '0.0.0.0:50054', client = nil)
+    runner(address, client) { |c| c.stream_from_server(TestMessage.new) }
   end
 
-  def run_bidi_streamer
-    runner('0.0.0.0:50055') { |c| c.stream_both_ways([TestMessage.new]) }
+  def run_bidi_streamer(address = '0.0.0.0:50055', client = nil)
+    runner(address, client) { |c| c.stream_both_ways([TestMessage.new]) }
   end
 
-  def runner(address)
+  def runner(address, client)
     server = GRPC::RpcServer.new
     server.add_http2_port(address, :this_port_is_insecure)
     server.handle(TestService)
 
     t = Thread.new { server.run }
     server.wait_till_running
 
-    yield TestService.rpc_stub_class.new(address, :this_channel_is_insecure)
+    client ||= TestService.rpc_stub_class.new(address, :this_channel_is_insecure)
+
+    yield client
 
     server.stop
     until server.stopped?; end