1 files changed, 136 insertions, 0 deletions
diff --git a/spec/lib/gitlab/instrumentation/redis_helper_spec.rb b/spec/lib/gitlab/instrumentation/redis_helper_spec.rb
new file mode 100644
index 00000000000..54659ca2c02
--- /dev/null
+++ b/spec/lib/gitlab/instrumentation/redis_helper_spec.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Instrumentation::RedisHelper, :request_store, feature_category: :scalability do
+  include RedisHelpers
+
+  let(:minimal_test_class) do
+    Class.new do
+      include Gitlab::Instrumentation::RedisHelper
+      def initialize
+        @instrumentation_class = Gitlab::Instrumentation::Redis::Cache
+      end
+
+      def check_command(commands, pipelined)
+        instrument_call(commands, @instrumentation_class, pipelined) { 'empty block' }
+      end
+
+      def test_read(result)
+        measure_read_size(result, @instrumentation_class)
+      end
+
+      def test_write(command)
+        measure_write_size(command, @instrumentation_class)
+      end
+
+      def test_exclusion(commands)
+        exclude_from_apdex?(commands)
+      end
+    end
+  end
+
+  before do
+    stub_const("MinimalTestClass", minimal_test_class)
+  end
+
+  subject(:minimal_test_class_instance) { MinimalTestClass.new }
+
+  describe '.instrument_call' do
+    it 'instruments request count' do
+      expect(Gitlab::Instrumentation::Redis::Cache).to receive(:instance_count_request).with(1)
+      expect(Gitlab::Instrumentation::Redis::Cache).not_to receive(:instance_count_pipelined_request)
+
+      minimal_test_class_instance.check_command([[:set, 'foo', 'bar']], false)
+    end
+
+    it 'performs cluster validation' do
+      expect(Gitlab::Instrumentation::Redis::Cache).to receive(:redis_cluster_validate!).once
+
+      minimal_test_class_instance.check_command([[:set, 'foo', 'bar']], false)
+    end
+
+    context 'when command is not valid for Redis Cluster' do
+      before do
+        allow(Gitlab::Instrumentation::Redis::Cache).to receive(:redis_cluster_validate!).and_return(false)
+      end
+
+      it 'reports cross slot request' do
+        expect(Gitlab::Instrumentation::Redis::Cache).to receive(:increment_cross_slot_request_count).once
+
+        minimal_test_class_instance.check_command([[:mget, 'foo', 'bar']], false)
+      end
+    end
+
+    context 'when an error is raised' do
+      # specific error behaviours are tested in spec/lib/gitlab/instrumentation/redis_client_middleware_spec.rb
+      # this spec tests for the generic behaviour to verify that `ensure` works for any general error types
+      before do
+        allow(Gitlab::Instrumentation::Redis::Cache).to receive(:instance_count_request)
+          .and_raise(StandardError)
+      end
+
+      it 'ensures duration is tracked' do
+        commands = [[:set, 'foo', 'bar']]
+        allow(Gitlab::Instrumentation::Redis::Cache).to receive(:instance_observe_duration).once
+        allow(Gitlab::Instrumentation::Redis::Cache).to receive(:increment_request_count).with(1).once
+        allow(Gitlab::Instrumentation::Redis::Cache).to receive(:add_duration).once
+        allow(Gitlab::Instrumentation::Redis::Cache).to receive(:add_call_details).with(anything, commands).once
+
+        expect { minimal_test_class_instance.check_command(commands, false) }.to raise_error(StandardError)
+      end
+    end
+
+    context 'when pipelined' do
+      it 'instruments pipelined request count' do
+        expect(Gitlab::Instrumentation::Redis::Cache).to receive(:instance_count_pipelined_request)
+
+        minimal_test_class_instance.check_command([[:get, '{user1}:bar'], [:get, '{user1}:foo']], true)
+      end
+    end
+  end
+
+  describe '.measure_read_size' do
+    it 'reads array' do
+      expect(Gitlab::Instrumentation::Redis::Cache).to receive(:increment_read_bytes).with(3).exactly(3).times
+
+      minimal_test_class_instance.test_read(%w[bar foo buz])
+    end
+
+    it 'reads Integer' do
+      expect(Gitlab::Instrumentation::Redis::Cache).to receive(:increment_read_bytes).with(4)
+
+      minimal_test_class_instance.test_read(1234)
+    end
+
+    it 'reads String' do
+      expect(Gitlab::Instrumentation::Redis::Cache).to receive(:increment_read_bytes).with(3)
+
+      minimal_test_class_instance.test_read('bar')
+    end
+  end
+
+  describe '.measure_write_size' do
+    it 'measures command size' do
+      expect(Gitlab::Instrumentation::Redis::Cache).to receive(:increment_write_bytes).with(9)
+
+      minimal_test_class_instance.test_write([:set, 'foo', 'bar'])
+    end
+
+    it 'accept array input' do
+      expect(Gitlab::Instrumentation::Redis::Cache).to receive(:increment_write_bytes).with((9 + 12))
+
+      minimal_test_class_instance.test_write([[:set, 'foo', 'bar'], [:lpush, 'que', 'item']])
+    end
+  end
+
+  describe '.exclude_from_apdex?' do
+    it 'returns false if all commands are allowed' do
+      expect(minimal_test_class_instance.test_exclusion([[:set, 'foo', 'bar'], [:lpush, 'que', 'item']])).to eq(false)
+    end
+
+    it 'returns true if any commands are banned' do
+      expect(minimal_test_class_instance.test_exclusion([[:brpop, 'foo', 2], [:lpush, 'que', 'item']])).to eq(true)
+    end
+  end
+end