feat: Support including host name in faraday span names

Author: joshwestbrook

instrumentation/faraday/lib/opentelemetry/instrumentation/faraday/instrumentation.rb

@@ -28,6 +28,7 @@ class Instrumentation < OpenTelemetry::Instrumentation::Base
 
         option :span_kind, default: :client, validate: %i[client internal]
         option :peer_service, default: nil, validate: :string
+        option :span_naming, default: :http_method, validate: %i[http_method host]
 
         private
 

instrumentation/faraday/lib/opentelemetry/instrumentation/faraday/middlewares/tracer_middleware.rb

@@ -35,9 +35,14 @@ def call(env)
             )
 
             OpenTelemetry::Common::HTTP::ClientContext.with_attributes(attributes) do |attrs, _|
-              tracer.in_span(
-                "HTTP #{http_method}", attributes: attrs, kind: config.fetch(:span_kind)
-              ) do |span|
+              span_name = case config.fetch(:span_naming)
+                          when :host
+                            ['HTTP', http_method, env.url.host].compact.join(' ')
+                          else
+                            "HTTP #{http_method}"
+                          end
+
+              tracer.in_span(span_name, attributes: attrs, kind: config.fetch(:span_kind)) do |span|
                 OpenTelemetry.propagation.inject(env.request_headers)
 
                 app.call(env).on_complete { |resp| trace_response(span, resp.status) }

instrumentation/faraday/test/opentelemetry/instrumentation/faraday/middlewares/tracer_middleware_test.rb

@@ -121,6 +121,24 @@
         _(span.attributes['peer.service']).must_equal 'example:faraday'
       end
 
+      it 'defaults to span naming by http method' do
+        instrumentation.instance_variable_set(:@installed, false)
+        instrumentation.install
+
+        client.get('/success')
+
+        _(span.name).must_equal 'HTTP GET'
+      end
+
+      it 'allows including the host in the span name' do
+        instrumentation.instance_variable_set(:@installed, false)
+        instrumentation.install(span_naming: :host)
+
+        client.get('/success')
+
+        _(span.name).must_equal 'HTTP GET example.com'
+      end
+
       it 'defaults to span kind client' do
         instrumentation.instance_variable_set(:@installed, false)
         instrumentation.install