server.address

.env

@@ -21,7 +21,7 @@ TEST_MEMCACHED_PORT=11211
 TEST_MONGODB_HOST=127.0.0.1
 TEST_MONGODB_PORT=27017
 TEST_MYSQL_DB=mysql
-TEST_MYSQL_HOST=127.0.0.1
+TEST_MYSQL_HOST=localhost
 TEST_MYSQL_PASSWORD=mysql
 TEST_MYSQL_PORT=3306
 TEST_MYSQL_ROOT_PASSWORD=root

.rspec

@@ -1 +1,2 @@
 --require spec_helper
+--backtrace

Gemfile

@@ -93,3 +93,8 @@ end
 #
 # TODO: Remove this once the issue is resolved: https://github.com/ffi/ffi/issues/1107
 gem 'ffi', '~> 1.16.3', require: false
+
+gem 'mongo', '>= 2.8.0', '< 2.15.0' # TODO: FIX TEST BREAKAGES ON >= 2.15 https://github.com/DataDog/dd-trace-rb/issues/1596
+
+gem 'rails', '~> 6'
+gem 'mysql2'

lib/datadog/tracing/contrib/propagation/sql_comment.rb

@@ -52,7 +52,7 @@ def self.prepend_comment(sql, span_op, trace_op, mode)
               end
             end
 
-            "#{Comment.new(tags)} #{sql}"
+            "#{sql} #{Comment.new(tags)}"
           end
 
           def self.datadog_configuration

lib/datadog/tracing/metadata/ext.rb

@@ -22,6 +22,13 @@ module Ext
         # Name of external service that performed the work
         TAG_PEER_SERVICE = 'peer.service'
 
+        # The server domain name that the network client is talking to,
+        # before DNS resolution (e.g. what the user provided in the client's initializer/configuration);
+        # otherwise, IP address or Unix domain socket name.
+        #
+        # @see https://opentelemetry.io/docs/specs/semconv/general/attributes/#server-attributes
+        TAG_SERVER_ADDRESS = 'server.address'
+
         TAG_KIND = 'span.kind'
 
         # Set this tag to `1.0` if the span is a Service Entry span.

spec/datadog/tracing/contrib/active_record/multi_db_spec.rb

@@ -70,7 +70,7 @@
   let(:mysql) do
     {
       database: ENV.fetch('TEST_MYSQL_DB', 'mysql'),
-      host: ENV.fetch('TEST_MYSQL_HOST', '127.0.0.1'),
+      host: ENV.fetch('TEST_MYSQL_HOST', 'localhost'),
       password: ENV.fetch('TEST_MYSQL_ROOT_PASSWORD', 'root'),
       port: ENV.fetch('TEST_MYSQL_PORT', '3306')
     }

spec/datadog/tracing/contrib/active_record/tracer_spec.rb

@@ -51,7 +51,14 @@
       expect(span.get_tag('db.instance')).to eq('mysql')
       expect(span.get_tag('active_record.db.name')).to eq('mysql')
       expect(span.get_tag('active_record.db.cached')).to eq(nil)
+      # TODO: MYSQL is correct CONTINUE WITH OTHERS
       expect(span.get_tag('out.host')).to eq(ENV.fetch('TEST_MYSQL_HOST', '127.0.0.1'))
+      expect(span.get_tag('out.host')).to satisfy('not be an IP') do |host|
+        IPAddr.new host
+        false
+      rescue InvalidAddressError
+        true
+      end if PlatformHelpers.ci? # This test is hard to run locally because mysql considers `localhost` as a unix socket
       expect(span.get_tag('out.port')).to eq(ENV.fetch('TEST_MYSQL_PORT', 3306).to_f)
       expect(span.get_tag('sql.query')).to eq(nil)
       expect(span.get_tag(Datadog::Tracing::Metadata::Ext::TAG_COMPONENT)).to eq('active_record')

spec/datadog/tracing/contrib/active_record/utils_spec.rb

@@ -9,7 +9,7 @@
     context 'when connected to mysql' do
       it 'returns `mysql2`' do
         root_pw = ENV.fetch('TEST_MYSQL_ROOT_PASSWORD', 'root')
-        host = ENV.fetch('TEST_MYSQL_HOST', '127.0.0.1')
+        host = ENV.fetch('TEST_MYSQL_HOST', 'localhost')
         port = ENV.fetch('TEST_MYSQL_PORT', '3306')
         db = ENV.fetch('TEST_MYSQL_DB', 'mysql')
 
@@ -23,7 +23,7 @@
   describe 'regression: retrieving database without an active connection does not raise an error' do
     before do
       root_pw = ENV.fetch('TEST_MYSQL_ROOT_PASSWORD', 'root')
-      host = ENV.fetch('TEST_MYSQL_HOST', '127.0.0.1')
+      host = ENV.fetch('TEST_MYSQL_HOST', 'localhost')
       port = ENV.fetch('TEST_MYSQL_PORT', '3306')
       db = ENV.fetch('TEST_MYSQL_DB', 'mysql')
       ActiveRecord::Base.establish_connection("mysql2://root:#{root_pw}@#{host}:#{port}/#{db}")
@@ -32,7 +32,7 @@
 
     after do
       root_pw = ENV.fetch('TEST_MYSQL_ROOT_PASSWORD', 'root')
-      host = ENV.fetch('TEST_MYSQL_HOST', '127.0.0.1')
+      host = ENV.fetch('TEST_MYSQL_HOST', 'localhost')
       port = ENV.fetch('TEST_MYSQL_PORT', '3306')
       db = ENV.fetch('TEST_MYSQL_DB', 'mysql')
       ActiveRecord::Base.establish_connection("mysql2://root:#{root_pw}@#{host}:#{port}/#{db}")

spec/datadog/tracing/contrib/mongodb/client_spec.rb

@@ -125,6 +125,11 @@
           expect(spans.first.service).to eq(secondary_service)
         end
 
+        it 'captures the unresolved host name' do
+          subject
+          expect(spans.first.get_tag('out.host')).to eq('localhost')
+        end
+
         it_behaves_like 'a peer service span' do
           let(:peer_service_val) {  database }
           let(:peer_service_source) { 'mongodb.db' }

spec/datadog/tracing/contrib/rails/support/database.rb

@@ -58,7 +58,7 @@ def mysql_url(protocol = 'mysql2')
             def mysql_hash
               {
                 database: ENV.fetch('TEST_MYSQL_DB', 'mysql'),
-                host: ENV.fetch('TEST_MYSQL_HOST', '127.0.0.1'),
+                host: ENV.fetch('TEST_MYSQL_HOST', 'localhost'),
                 password: ENV.fetch('TEST_MYSQL_ROOT_PASSWORD', 'root'),
                 port: ENV.fetch('TEST_MYSQL_PORT', '3306')
               }

spec/datadog/tracing/contrib/sequel/instrumentation_spec.rb

@@ -230,7 +230,7 @@
       db = ENV.fetch('TEST_MYSQL_DB', 'mysql')
       "#{adapter}://#{host}:#{port}/#{db}?user=#{user}&password=#{password}"
     end
-    let(:host) { ENV.fetch('TEST_MYSQL_HOST', '127.0.0.1') }
+    let(:host) { ENV.fetch('TEST_MYSQL_HOST', 'localhost') }
     let(:adapter) do
       if PlatformHelpers.jruby?
         'mysql'