fix(grpc): allow custom error_handler for client interceptor

lib/datadog/tracing/contrib/grpc/configuration/settings.rb

@@ -49,6 +49,26 @@ class Settings < Contrib::Configuration::Settings
             option :error_handler do |o|
               o.type :proc
               o.default_proc(&Tracing::SpanOperation::Events::DEFAULT_ON_ERROR)
+              o.on_set do |value|
+                if value != Tracing::SpanOperation::Events::DEFAULT_ON_ERROR
+                  Datadog.logger.warn(
+                    'The gRPC `error_handler` setting has been deprecated for removal. Please replace ' \
+                    'it with `server_error_handler` which is explicit about only handling errors from ' \
+                    'server interceptors. Alternatively, to handle errors from client interceptors use ' \
+                    'the `client_error_handler` setting instead.'
+                  )
+                end
+              end
+            end
+
+            option :server_error_handler do |o|
+              o.type :proc
+              o.default_proc(&Tracing::SpanOperation::Events::DEFAULT_ON_ERROR)
+            end
+
+            option :client_error_handler do |o|
+              o.type :proc
+              o.default_proc(&Tracing::SpanOperation::Events::DEFAULT_ON_ERROR)
             end
           end
         end

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

@@ -58,10 +58,6 @@ def analytics_sample_rate
               datadog_configuration[:analytics_sample_rate]
             end
 
-            def error_handler
-              Datadog.configuration_for(self, :error_handler) || datadog_configuration[:error_handler]
-            end
-
             # Allows interceptors to define settings using methods instead of `[]`
             class PinAdapter
               OPTIONS = Configuration::Settings.instance_methods(false).freeze

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

@@ -102,6 +102,10 @@ def find_host_port(call)
               Datadog.logger.debug { "Could not parse host:port from #{call}: #{e}" }
               nil
             end
+
+            def error_handler
+              Datadog.configuration_for(self, :error_handler) || datadog_configuration[:client_error_handler]
+            end
           end
         end
       end

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

@@ -81,6 +81,19 @@ def annotate!(span, metadata, formatter)
             rescue StandardError => e
               Datadog.logger.debug("GRPC server trace failed: #{e}")
             end
+
+            def error_handler
+              self_handler = Datadog.configuration_for(self, :error_handler)
+              return self_handler if self_handler
+
+              unless datadog_configuration.using_default?(:server_error_handler)
+                return datadog_configuration[:server_error_handler]
+              end
+
+              # As a last resort, fallback to the deprecated error_handler
+              # configuration option.
+              datadog_configuration[:error_handler]
+            end
           end
         end
       end

spec/datadog/tracing/contrib/grpc/datadog_interceptor/client_spec.rb

@@ -5,6 +5,8 @@
 require 'datadog/tracing/contrib/span_attribute_schema_examples'
 require 'datadog/tracing/contrib/peer_service_configuration_examples'
 
+require_relative 'shared_examples'
+
 require 'grpc'
 require 'ddtrace'
 
@@ -150,6 +152,7 @@
       end
 
       let(:error_class) { stub_const('TestError', Class.new(StandardError)) }
+      let(:span_kind) { 'client' }
 
       context 'without an error handler' do
         it do
@@ -165,20 +168,25 @@
       end
 
       context 'with an error handler' do
-        let(:configuration_options) { { service_name: 'rspec', error_handler: error_handler } }
+        subject(:server) do
+          Datadog::Tracing::Contrib::GRPC::DatadogInterceptor::Client.new { |c| c.error_handler = error_handler }
+        end
 
         let(:error_handler) do
-          ->(span, error) { span.set_tag('custom.handler', "Got error #{error}, but ignored it") }
+          ->(span, error) { span.set_tag('custom.handler', "Got error #{error}, but ignored it from interceptor") }
         end
 
-        it do
-          expect { request_response }.to raise_error('test error')
+        it_behaves_like 'it handles the error', 'Got error test error, but ignored it from interceptor'
+      end
 
-          expect(span).not_to have_error
-          expect(span.get_tag('custom.handler')).to eq('Got error test error, but ignored it')
-          expect(span.get_tag('rpc.system')).to eq('grpc')
-          expect(span.get_tag('span.kind')).to eq('client')
+      context 'with an error handler defined in the configuration options' do
+        let(:configuration_options) { { service_name: 'rspec', client_error_handler: error_handler } }
+
+        let(:error_handler) do
+          ->(span, error) { span.set_tag('custom.handler', "Got error #{error}, but ignored it from configuration") }
         end
+
+        it_behaves_like 'it handles the error', 'Got error test error, but ignored it from configuration'
       end
     end
   end

spec/datadog/tracing/contrib/grpc/datadog_interceptor/server_spec.rb

@@ -4,6 +4,8 @@
 require 'datadog/tracing/contrib/environment_service_name_examples'
 require 'datadog/tracing/contrib/span_attribute_schema_examples'
 
+require_relative 'shared_examples'
+
 require 'grpc'
 require 'ddtrace'
 
@@ -70,11 +72,12 @@
     end
 
     context 'with an error' do
-      subject(:request_response) do
+      let(:request_response) do
         server.request_response(**keywords) { raise error_class, 'test error' }
       end
 
       let(:error_class) { stub_const('TestError', Class.new(StandardError)) }
+      let(:span_kind) { 'server' }
 
       context 'without an error handler' do
         it do
@@ -90,21 +93,35 @@
       end
 
       context 'with an error handler' do
-        let(:configuration_options) { { service_name: 'rspec', error_handler: error_handler } }
+        subject(:server) do
+          Datadog::Tracing::Contrib::GRPC::DatadogInterceptor::Server.new { |c| c.error_handler = error_handler }
+        end
+
         let(:error_handler) do
-          lambda do |span, error|
-            span.set_tag('custom.handler', "Got error #{error}, but ignored it")
-          end
+          ->(span, error) { span.set_tag('custom.handler', "Got error #{error}, but ignored it from interceptor") }
         end
 
-        it do
-          expect { request_response }.to raise_error('test error')
+        it_behaves_like 'it handles the error', 'Got error test error, but ignored it from interceptor'
+      end
 
-          expect(span).to_not have_error
-          expect(span.get_tag('custom.handler')).to eq('Got error test error, but ignored it')
-          expect(span.get_tag('rpc.system')).to eq('grpc')
-          expect(span.get_tag('span.kind')).to eq('server')
+      context 'with an error handler defined in the configuration_options' do
+        let(:configuration_options) { { service_name: 'rspec', server_error_handler: error_handler } }
+
+        let(:error_handler) do
+          ->(span, error) { span.set_tag('custom.handler', "Got error #{error}, but ignored it from configuration") }
         end
+
+        it_behaves_like 'it handles the error', 'Got error test error, but ignored it from configuration'
+      end
+
+      context 'with an error handler defined with the deprecated error_handler option' do
+        let(:configuration_options) { { service_name: 'rspec', error_handler: error_handler } }
+
+        let(:error_handler) do
+          ->(span, error) { span.set_tag('custom.handler', "Got error #{error}, but ignored it from deprecated config") }
+        end
+
+        it_behaves_like 'it handles the error', 'Got error test error, but ignored it from deprecated config'
       end
     end
   end

spec/datadog/tracing/contrib/grpc/datadog_interceptor/shared_examples.rb

@@ -0,0 +1,10 @@
+RSpec.shared_examples_for 'it handles the error' do |expected_error|
+  it do
+    expect { request_response }.to raise_error('test error')
+
+    expect(span).to_not have_error
+    expect(span.get_tag('custom.handler')).to eq(expected_error)
+    expect(span.get_tag('rpc.system')).to eq('grpc')
+    expect(span.get_tag('span.kind')).to eq(span_kind)
+  end
+end