Add config support for "on_error" in Elasticsearch tracing

docs/GettingStarted.md

@@ -677,6 +677,7 @@ Datadog.configure_onto(client.transport, **options)
 | `service_name` | `DD_TRACE_ELASTICSEARCH_SERVICE_NAME` | `String` | Name of application running the `elasticsearch` instrumentation. May be overridden by `global_default_service_name`. [See _Additional Configuration_ for more details](#additional-configuration) | `elasticsearch` |
 | `peer_service` | `DD_TRACE_ELASTICSEARCH_PEER_SERVICE` | `String` | Name of external service the application connects to                                                                                                                                              | `nil`           |
 | `quantize`     |                                       | `Hash`   | Hash containing options for quantization. May include `:show` with an Array of keys to not quantize (or `:all` to skip quantization), or `:exclude` with Array of keys to exclude entirely.       | `{}`            |
+| `on_error` | | `Proc` | Custom error handler invoked when a request raises an error. Provided `span` and `error` as arguments. Sets error on the span by default. Useful for ignoring transient errors. | `proc { \|span, error\| span.set_error(error) unless span.nil? }` |
 
 ### Ethon
 

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

@@ -49,6 +49,10 @@ class Settings < Contrib::Configuration::Settings
               o.type :string, nilable: true
               o.env Ext::ENV_PEER_SERVICE
             end
+
+            option :on_error do |o|
+              o.type :proc, nilable: true
+            end
           end
         end
       end

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

@@ -40,6 +40,7 @@ def perform_request(*args)
               # `Client#transport` is the most convenient object both for this integration and the library
               # as users have shared access to it across all `elasticsearch` versions.
               service ||= Datadog.configuration_for(transport, :service_name) || datadog_configuration[:service_name]
+              on_error = Datadog.configuration_for(transport, :on_error) || datadog_configuration[:on_error]
 
               method = args[0]
               path = args[1]
@@ -49,7 +50,11 @@ def perform_request(*args)
               url = full_url.path
               response = nil
 
-              Tracing.trace(Datadog::Tracing::Contrib::Elasticsearch::Ext::SPAN_QUERY, service: service) do |span|
+              Tracing.trace(
+                Datadog::Tracing::Contrib::Elasticsearch::Ext::SPAN_QUERY,
+                service: service,
+                on_error: on_error
+              ) do |span|
                 begin
                   connection = transport.connections.first
                   host = connection.host[:host] if connection

spec/datadog/tracing/contrib/elasticsearch/patcher_spec.rb

@@ -97,6 +97,36 @@
     end
   end
 
+  describe 'get request' do
+    context 'when requesting a document that does not exist' do
+      let(:index_name) { 'some_index' }
+      let(:document_id) { 999 }
+      let(:exception_class) do
+        if defined?(Elastic::Transport) # version >= 8
+          Elastic::Transport::Transport::Errors::NotFound
+        else # version < 8
+          Elasticsearch::Transport::Transport::Errors::NotFound
+        end
+      end
+
+      subject(:request) { client.perform_request 'GET', "#{index_name}/_doc/#{document_id}" }
+
+      it 'marks span with error' do
+        expect { request }.to raise_error(exception_class)
+        expect(span).to have_error
+      end
+
+      context 'when configured_with `on_error`' do
+        let(:configuration_options) { { on_error: ->(_span, _error) { false } } }
+
+        it 'does not mark span with error' do
+          expect { request }.to raise_error(exception_class)
+          expect(span).not_to have_error
+        end
+      end
+    end
+  end
+
   describe 'indexing request' do
     let(:document_body) do
       {