Log queue duration for Grape API calls

This mimics the same thing the RailsQueueDuration does for Rails controller
requests and will help diagnose issues with API delays.

Closes #46601

1 files changed, 35 insertions, 0 deletions

diff --git a/spec/lib/gitlab/grape_logging/loggers/queue_duration_logger_spec.rb b/spec/lib/gitlab/grape_logging/loggers/queue_duration_logger_spec.rb
new file mode 100644
index 00000000000..f47b9dd3498
--- /dev/null
+++ b/spec/lib/gitlab/grape_logging/loggers/queue_duration_logger_spec.rb
@@ -0,0 +1,35 @@
+require 'spec_helper'
+
+describe Gitlab::GrapeLogging::Loggers::QueueDurationLogger do
+  subject { described_class.new }
+
+  describe ".parameters" do
+    let(:start_time) { Time.new(2018, 01, 01) }
+
+    describe 'when no proxy time is available' do
+      let(:mock_request) { OpenStruct.new(env: {}) }
+
+      it 'returns an empty hash' do
+        expect(subject.parameters(mock_request, nil)).to eq({})
+      end
+    end
+
+    describe 'when a proxy time is available' do
+      let(:mock_request) do
+        OpenStruct.new(
+          env: {
+            'HTTP_GITLAB_WORKHORSE_PROXY_START' => (start_time - 1.hour).to_i * (10**9)
+          }
+        )
+      end
+
+      it 'returns the correct duration in ms' do
+        Timecop.freeze(start_time) do
+          subject.before
+
+          expect(subject.parameters(mock_request, nil)).to eq( { 'queue_duration': 1.hour.to_f * 1000 })
+        end
+      end
+    end
+  end
+end