require 'spec_helper' describe Gitlab::Metrics::Instrumentation do let(:transaction) { Gitlab::Metrics::Transaction.new } before do @dummy = Class.new do def self.foo(text = 'foo') text end def bar(text = 'bar') text end end allow(@dummy).to receive(:name).and_return('Dummy') end describe '.configure' do it 'yields self' do described_class.configure do |c| expect(c).to eq(described_class) end end end describe '.instrument_method' do describe 'with metrics enabled' do before do allow(Gitlab::Metrics).to receive(:enabled?).and_return(true) described_class.instrument_method(@dummy, :foo) end it 'renames the original method' do expect(@dummy).to respond_to(:_original_foo) end it 'calls the instrumented method with the correct arguments' do expect(@dummy.foo).to eq('foo') end it 'tracks the call duration upon calling the method' do allow(Gitlab::Metrics).to receive(:method_call_threshold). and_return(0) allow(described_class).to receive(:transaction). and_return(transaction) expect(transaction).to receive(:increment). with(:method_duration, a_kind_of(Numeric)) expect(transaction).to receive(:add_metric). with(described_class::SERIES, an_instance_of(Hash), method: 'Dummy.foo') @dummy.foo end it 'does not track method calls below a given duration threshold' do allow(Gitlab::Metrics).to receive(:method_call_threshold). and_return(100) expect(transaction).to_not receive(:add_metric) @dummy.foo end it 'generates a method with the correct arity when using methods without arguments' do dummy = Class.new do def self.test; end end described_class.instrument_method(dummy, :test) expect(dummy.method(:test).arity).to eq(0) end end describe 'with metrics disabled' do before do allow(Gitlab::Metrics).to receive(:enabled?).and_return(false) end it 'does not instrument the method' do described_class.instrument_method(@dummy, :foo) expect(@dummy).to_not respond_to(:_original_foo) end end end describe '.instrument_instance_method' do describe 'with metrics enabled' do before do allow(Gitlab::Metrics).to receive(:enabled?).and_return(true) described_class. instrument_instance_method(@dummy, :bar) end it 'renames the original method' do expect(@dummy.method_defined?(:_original_bar)).to eq(true) end it 'calls the instrumented method with the correct arguments' do expect(@dummy.new.bar).to eq('bar') end it 'tracks the call duration upon calling the method' do allow(Gitlab::Metrics).to receive(:method_call_threshold). and_return(0) allow(described_class).to receive(:transaction). and_return(transaction) expect(transaction).to receive(:increment). with(:method_duration, a_kind_of(Numeric)) expect(transaction).to receive(:add_metric). with(described_class::SERIES, an_instance_of(Hash), method: 'Dummy#bar') @dummy.new.bar end it 'does not track method calls below a given duration threshold' do allow(Gitlab::Metrics).to receive(:method_call_threshold). and_return(100) expect(transaction).to_not receive(:add_metric) @dummy.new.bar end end describe 'with metrics disabled' do before do allow(Gitlab::Metrics).to receive(:enabled?).and_return(false) end it 'does not instrument the method' do described_class. instrument_instance_method(@dummy, :bar) expect(@dummy.method_defined?(:_original_bar)).to eq(false) end end end describe '.instrument_class_hierarchy' do before do allow(Gitlab::Metrics).to receive(:enabled?).and_return(true) @child1 = Class.new(@dummy) do def self.child1_foo; end def child1_bar; end end @child2 = Class.new(@child1) do def self.child2_foo; end def child2_bar; end end end it 'recursively instruments a class hierarchy' do described_class.instrument_class_hierarchy(@dummy) expect(@child1).to respond_to(:_original_child1_foo) expect(@child2).to respond_to(:_original_child2_foo) expect(@child1.method_defined?(:_original_child1_bar)).to eq(true) expect(@child2.method_defined?(:_original_child2_bar)).to eq(true) end it 'does not instrument the root module' do described_class.instrument_class_hierarchy(@dummy) expect(@dummy).to_not respond_to(:_original_foo) expect(@dummy.method_defined?(:_original_bar)).to eq(false) end end describe '.instrument_methods' do before do allow(Gitlab::Metrics).to receive(:enabled?).and_return(true) end it 'instruments all public class methods' do described_class.instrument_methods(@dummy) expect(@dummy).to respond_to(:_original_foo) end it 'only instruments methods directly defined in the module' do mod = Module.new do def kittens end end @dummy.extend(mod) described_class.instrument_methods(@dummy) expect(@dummy).to_not respond_to(:_original_kittens) end it 'can take a block to determine if a method should be instrumented' do described_class.instrument_methods(@dummy) do false end expect(@dummy).to_not respond_to(:_original_foo) end end describe '.instrument_instance_methods' do before do allow(Gitlab::Metrics).to receive(:enabled?).and_return(true) end it 'instruments all public instance methods' do described_class.instrument_instance_methods(@dummy) expect(@dummy.method_defined?(:_original_bar)).to eq(true) end it 'only instruments methods directly defined in the module' do mod = Module.new do def kittens end end @dummy.include(mod) described_class.instrument_instance_methods(@dummy) expect(@dummy.method_defined?(:_original_kittens)).to eq(false) end it 'can take a block to determine if a method should be instrumented' do described_class.instrument_instance_methods(@dummy) do false end expect(@dummy.method_defined?(:_original_bar)).to eq(false) end end end