1 files changed, 61 insertions, 0 deletions
diff --git a/spec/lib/gitlab/metrics/redis_rack_middleware_spec.rb b/spec/lib/gitlab/metrics/redis_rack_middleware_spec.rb
new file mode 100644
index 00000000000..f2f36ccad20
--- /dev/null
+++ b/spec/lib/gitlab/metrics/redis_rack_middleware_spec.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Metrics::RedisRackMiddleware do
+  let(:app) { double(:app) }
+  let(:middleware) { described_class.new(app) }
+  let(:env) { {} }
+  let(:transaction) { Gitlab::Metrics::WebTransaction.new(env) }
+
+  before do
+    allow(app).to receive(:call).with(env).and_return('wub wub')
+  end
+
+  describe '#call' do
+    let(:counter) { double(Prometheus::Client::Counter, increment: nil) }
+    let(:histogram) { double(Prometheus::Client::Histogram, observe: nil) }
+    let(:redis_query_time) { 0.1 }
+    let(:redis_requests_count) { 2 }
+
+    before do
+      allow(Gitlab::Instrumentation::Redis).to receive(:query_time) { redis_query_time }
+      allow(Gitlab::Instrumentation::Redis).to receive(:get_request_count) { redis_requests_count }
+
+      allow(Gitlab::Metrics).to receive(:counter)
+        .with(:http_redis_requests_total,
+              an_instance_of(String),
+              Gitlab::Metrics::Transaction::BASE_LABELS)
+        .and_return(counter)
+
+      allow(Gitlab::Metrics).to receive(:histogram)
+        .with(:http_redis_requests_duration_seconds,
+              an_instance_of(String),
+              Gitlab::Metrics::Transaction::BASE_LABELS,
+              Gitlab::Instrumentation::Redis::QUERY_TIME_BUCKETS)
+        .and_return(histogram)
+
+      allow(Gitlab::Metrics).to receive(:current_transaction).and_return(transaction)
+    end
+
+    it 'calls the app' do
+      expect(middleware.call(env)).to eq('wub wub')
+    end
+
+    it 'records redis metrics' do
+      expect(counter).to receive(:increment).with(transaction.labels, redis_requests_count)
+      expect(histogram).to receive(:observe).with(transaction.labels, redis_query_time)
+
+      middleware.call(env)
+    end
+
+    it 'records redis metrics if an error is raised' do
+      expect(counter).to receive(:increment).with(transaction.labels, redis_requests_count)
+      expect(histogram).to receive(:observe).with(transaction.labels, redis_query_time)
+
+      allow(app).to receive(:call).with(env).and_raise(StandardError)
+
+      expect { middleware.call(env) }.to raise_error(StandardError)
+    end
+  end
+end