1 files changed, 85 insertions, 0 deletions
diff --git a/lib/gitlab/sherlock/transaction.rb b/lib/gitlab/sherlock/transaction.rb
new file mode 100644
index 00000000000..5cb3e86aa4e
--- /dev/null
+++ b/lib/gitlab/sherlock/transaction.rb
@@ -0,0 +1,85 @@
+module Gitlab
+  module Sherlock
+    class Transaction
+      attr_reader :id, :type, :path, :queries, :file_samples, :started_at,
+        :finished_at
+
+      def initialize(type, path)
+        @id = SecureRandom.uuid
+        @type = type
+        @path = path
+        @duration = 0
+        @queries = []
+        @file_samples = []
+        @started_at = nil
+        @finished_at = nil
+        @thread = Thread.current
+      end
+
+      def run
+        @started_at = Time.now
+
+        subscriber = subscribe_to_active_record
+
+        retval = profile_lines { yield }
+
+        @finished_at = Time.now
+
+        ActiveSupport::Notifications.unsubscribe(subscriber)
+
+        retval
+      end
+
+      def duration
+        @started_at && @finished_at ? @finished_at - @started_at : 0
+      end
+
+      def to_param
+        @id
+      end
+
+      def sorted_queries
+        @queries.sort { |a, b| b.duration <=> a.duration }
+      end
+
+      def sorted_file_samples
+        @file_samples.sort { |a, b| b.duration <=> a.duration }
+      end
+
+      def find_query(id)
+        @queries.find { |query| query.id == id }
+      end
+
+      def find_file_sample(id)
+        @file_samples.find { |sample| sample.id == id }
+      end
+
+      def track_query(query, bindings, start, finish)
+        @queries << Query.new_with_bindings(query, bindings, start, finish)
+      end
+
+      def profile_lines
+        retval = nil
+
+        if Sherlock.enable_line_profiler?
+          retval, @file_samples = LineProfiler.new.profile { yield }
+        else
+          retval = yield
+        end
+
+        retval
+      end
+
+      def subscribe_to_active_record
+        ActiveSupport::Notifications.subscribe('sql.active_record') do |_, start, finish, _, data|
+          # In case somebody uses a multi-threaded server locally (e.g. Puma) we
+          # _only_ want to track queries that originate from the transaction
+          # thread.
+          next unless Thread.current == @thread
+
+          track_query(data[:sql].strip, data[:binds], start, finish)
+        end
+      end
+    end
+  end
+end