Merge branch 'an-opentracing-active-record-tracing' into 'master'

Adds tracing support for ActiveRecord notifications

See merge request gitlab-org/gitlab-ce!24604

2 files changed, 49 insertions, 1 deletions

diff --git a/lib/gitlab/tracing/common.rb b/lib/gitlab/tracing/common.rb
index 5e2b12e3f90..3a08ede8138 100644
--- a/lib/gitlab/tracing/common.rb
+++ b/lib/gitlab/tracing/common.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'opentracing'
+
 module Gitlab
   module Tracing
     module Common
@@ -32,6 +34,14 @@ module Gitlab
         end
       end
 
+      def postnotify_span(operation_name, start_time, end_time, tags: nil, child_of: nil, exception: nil)
+        span = OpenTracing.start_span(operation_name, start_time: start_time, tags: tags, child_of: child_of)
+
+        log_exception_on_span(span, exception) if exception
+
+        span.finish(end_time: end_time)
+      end
+
       def log_exception_on_span(span, exception)
         span.set_tag('error', true)
         span.log_kv(kv_tags_for_exception(exception))
@@ -44,7 +54,7 @@ module Gitlab
             'event':      'error',
             'error.kind': exception.class.to_s,
             'message':    Gitlab::UrlSanitizer.sanitize(exception.message),
-            'stack':      exception.backtrace.join("\n")
+            'stack':      exception.backtrace&.join("\n")
           }
         else
           {
diff --git a/lib/gitlab/tracing/rails/active_record_subscriber.rb b/lib/gitlab/tracing/rails/active_record_subscriber.rb
new file mode 100644
index 00000000000..214eac47e14
--- /dev/null
+++ b/lib/gitlab/tracing/rails/active_record_subscriber.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Tracing
+    module Rails
+      class ActiveRecordSubscriber
+        include Gitlab::Tracing::Common
+
+        ACTIVE_RECORD_NOTIFICATION_TOPIC = 'sql.active_record'
+        DEFAULT_OPERATION_NAME = "sqlquery"
+
+        def self.instrument
+          subscriber = new
+
+          ActiveSupport::Notifications.subscribe(ACTIVE_RECORD_NOTIFICATION_TOPIC) do |_, start, finish, _, payload|
+            subscriber.notify(start, finish, payload)
+          end
+        end
+
+        # For more information on the payloads: https://guides.rubyonrails.org/active_support_instrumentation.html
+        def notify(start, finish, payload)
+          operation_name = payload[:name].presence || DEFAULT_OPERATION_NAME
+          exception = payload[:exception]
+          tags = {
+            'component' =>        'ActiveRecord',
+            'span.kind' =>        'client',
+            'db.type' =>          'sql',
+            'db.connection_id' => payload[:connection_id],
+            'db.cached' =>        payload[:cached] || false,
+            'db.statement' =>     payload[:sql]
+          }
+
+          postnotify_span("active_record:#{operation_name}", start, finish, tags: tags, exception: exception)
+        end
+      end
+    end
+  end
+end