Support :source_location tag option for query log tags

Author: fatkodima

activerecord/CHANGELOG.md

@@ -1,3 +1,15 @@
+*   Support `:source_location` tag option for query log tags
+
+    ```ruby
+    config.active_record.query_log_tags << :source_location
+    ```
+
+    Calculating the caller location is a costly operation and should be used primarily in development
+    (note, there is also a `config.active_record.verbose_query_logs` that serves the same purpose)
+    or occasionally on production for debugging purposes.
+
+    *fatkodima*
+
 *   Add an option to `ActiveRecord::Encryption::Encryptor` to disable compression
 
     Allow compression to be disabled by setting `compress: false`

activerecord/lib/active_record/query_logs.rb

@@ -26,6 +26,7 @@ module ActiveRecord
   # * +socket+
   # * +db_host+
   # * +database+
+  # * +source_location+
   #
   # Action Controller adds default tags when loaded:
   #
@@ -108,6 +109,20 @@ def update_formatter(format)
           end
       end
 
+      if Thread.respond_to?(:each_caller_location)
+        def query_source_location # :nodoc:
+          Thread.each_caller_location do |location|
+            frame = LogSubscriber.backtrace_cleaner.clean_frame(location.path)
+            return frame if frame
+          end
+          nil
+        end
+      else
+        def query_source_location # :nodoc:
+          LogSubscriber.backtrace_cleaner.clean(caller_locations(1).each).first
+        end
+      end
+
       ActiveSupport::ExecutionContext.after_change { ActiveRecord::QueryLogs.clear_cache }
 
       private

activerecord/lib/active_record/railtie.rb

@@ -415,7 +415,8 @@ class Railtie < Rails::Railtie # :nodoc:
             pid:          -> { Process.pid.to_s },
             socket:       ->(context) { context[:connection].pool.db_config.socket },
             db_host:      ->(context) { context[:connection].pool.db_config.host },
-            database:     ->(context) { context[:connection].pool.db_config.database }
+            database:     ->(context) { context[:connection].pool.db_config.database },
+            source_location: -> { QueryLogs.query_source_location }
           )
           ActiveRecord.disable_prepared_statements = true
 

guides/source/configuring.md

@@ -1411,9 +1411,9 @@ NOTE: When this is set to `true` database prepared statements will be automatica
 
 #### `config.active_record.query_log_tags`
 
-Define an `Array` specifying the key/value tags to be inserted in an SQL
-comment. Defaults to `[ :application ]`, a predefined tag returning the
-application name.
+Define an `Array` specifying the key/value tags to be inserted in an SQL comment. Defaults to
+`[ :application, :controller, :action, :job ]`. The available tags are: `:application`, `:controller`,
+`:namespaced_controller`, `:action`, `:job`, and `:source_location`.
 
 #### `config.active_record.query_log_tags_format`
 

railties/test/application/query_logs_test.rb

@@ -149,6 +149,23 @@ def app
       assert_equal("/*action='index',controller='users',database='storage%2Fproduction_animals.sqlite3'*/", comment)
     end
 
+    test "source_location information is added if enabled" do
+      add_to_config <<~RUBY
+        config.active_record.query_log_tags_enabled = true
+        config.active_record.query_log_tags = [ :source_location ]
+
+        # Remove silencers, so we won't get all backtrace lines filtered.
+        Rails.backtrace_cleaner.remove_silencers!
+      RUBY
+
+      boot_app
+
+      get "/", {}, { "HTTPS" => "on" }
+      comment = last_response.body.strip
+
+      assert_match(/source_location='.*'/, comment)
+    end
+
     test "controller tags are not doubled up if already configured" do
       add_to_config "config.active_record.query_log_tags_enabled = true"
       add_to_config "config.active_record.query_log_tags = [ :action, :job, :controller, :pid ]"