gitlab-org--gitlab-foss/spec/lib/gitlab/metrics_spec.rb
Yorick Peterse 905f8d763a
Reduce instrumentation overhead
This reduces the overhead of the method instrumentation code primarily
by reducing the number of method calls. There are also some other small
optimisations such as not casting timing values to Floats (there's no
particular need for this), using Symbols for method call metric names,
and reducing the number of Hash lookups for instrumented methods.

The exact impact depends on the code being executed. For example, for a
method that's only called once the difference won't be very noticeable.
However, for methods that are called many times the difference can be
more significant.

For example, the loading time of a large commit
(nrclark/dummy_project@81ebdea5df)
was reduced from around 19 seconds to around 15 seconds using these
changes.
2016-07-28 16:56:17 +02:00

156 lines
4.1 KiB
Ruby

require 'spec_helper'
describe Gitlab::Metrics do
describe '.settings' do
it 'returns a Hash' do
expect(described_class.settings).to be_an_instance_of(Hash)
end
end
describe '.enabled?' do
it 'returns a boolean' do
expect([true, false].include?(described_class.enabled?)).to eq(true)
end
end
describe '.submit_metrics' do
it 'prepares and writes the metrics to InfluxDB' do
connection = double(:connection)
pool = double(:pool)
expect(pool).to receive(:with).and_yield(connection)
expect(connection).to receive(:write_points).with(an_instance_of(Array))
expect(Gitlab::Metrics).to receive(:pool).and_return(pool)
described_class.submit_metrics([{ 'series' => 'kittens', 'tags' => {} }])
end
end
describe '.prepare_metrics' do
it 'returns a Hash with the keys as Symbols' do
metrics = described_class.
prepare_metrics([{ 'values' => {}, 'tags' => {} }])
expect(metrics).to eq([{ values: {}, tags: {} }])
end
it 'escapes tag values' do
metrics = described_class.prepare_metrics([
{ 'values' => {}, 'tags' => { 'foo' => 'bar=' } }
])
expect(metrics).to eq([{ values: {}, tags: { 'foo' => 'bar\\=' } }])
end
it 'drops empty tags' do
metrics = described_class.prepare_metrics([
{ 'values' => {}, 'tags' => { 'cats' => '', 'dogs' => nil } }
])
expect(metrics).to eq([{ values: {}, tags: {} }])
end
end
describe '.escape_value' do
it 'escapes an equals sign' do
expect(described_class.escape_value('foo=')).to eq('foo\\=')
end
it 'casts values to Strings' do
expect(described_class.escape_value(10)).to eq('10')
end
end
describe '.measure' do
context 'without a transaction' do
it 'returns the return value of the block' do
val = Gitlab::Metrics.measure(:foo) { 10 }
expect(val).to eq(10)
end
end
context 'with a transaction' do
let(:transaction) { Gitlab::Metrics::Transaction.new }
before do
allow(Gitlab::Metrics).to receive(:current_transaction).
and_return(transaction)
end
it 'adds a metric to the current transaction' do
expect(transaction).to receive(:increment).
with('foo_real_time', a_kind_of(Numeric))
expect(transaction).to receive(:increment).
with('foo_cpu_time', a_kind_of(Numeric))
expect(transaction).to receive(:increment).
with('foo_call_count', 1)
Gitlab::Metrics.measure(:foo) { 10 }
end
it 'returns the return value of the block' do
val = Gitlab::Metrics.measure(:foo) { 10 }
expect(val).to eq(10)
end
end
end
describe '.tag_transaction' do
context 'without a transaction' do
it 'does nothing' do
expect_any_instance_of(Gitlab::Metrics::Transaction).
not_to receive(:add_tag)
Gitlab::Metrics.tag_transaction(:foo, 'bar')
end
end
context 'with a transaction' do
let(:transaction) { Gitlab::Metrics::Transaction.new }
it 'adds the tag to the transaction' do
expect(Gitlab::Metrics).to receive(:current_transaction).
and_return(transaction)
expect(transaction).to receive(:add_tag).
with(:foo, 'bar')
Gitlab::Metrics.tag_transaction(:foo, 'bar')
end
end
end
describe '.action=' do
context 'without a transaction' do
it 'does nothing' do
expect_any_instance_of(Gitlab::Metrics::Transaction).
not_to receive(:action=)
Gitlab::Metrics.action = 'foo'
end
end
context 'with a transaction' do
it 'sets the action of a transaction' do
trans = Gitlab::Metrics::Transaction.new
expect(Gitlab::Metrics).to receive(:current_transaction).
and_return(trans)
expect(trans).to receive(:action=).with('foo')
Gitlab::Metrics.action = 'foo'
end
end
end
describe '#series_prefix' do
it 'returns a String' do
expect(described_class.series_prefix).to be_an_instance_of(String)
end
end
end