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# frozen_string_literal: true
require 'fast_spec_helper'
require_relative '../../metrics_server/metrics_server'
require_relative '../support/helpers/next_instance_of'
RSpec.describe MetricsServer do # rubocop:disable RSpec/FilePath
include NextInstanceOf
let(:prometheus_config) { ::Prometheus::Client.configuration }
let(:metrics_dir) { Dir.mktmpdir }
# Prometheus::Client is a singleton, i.e. shared global state, so
# we need to reset it after testing.
let!(:old_multiprocess_files_dir) { prometheus_config.multiprocess_files_dir }
before do
# We do not want this to have knock-on effects on the test process.
allow(Gitlab::ProcessManagement).to receive(:modify_signals)
end
after do
Gitlab::Metrics.reset_registry!
prometheus_config.multiprocess_files_dir = old_multiprocess_files_dir
FileUtils.rm_rf(metrics_dir, secure: true)
end
describe '.spawn' do
context 'when in parent process' do
it 'forks into a new process and detaches it' do
expect(Process).to receive(:fork).and_return(99)
expect(Process).to receive(:detach).with(99)
described_class.spawn('sidekiq', metrics_dir: metrics_dir)
end
end
context 'when in child process' do
before do
# This signals the process that it's "inside" the fork
expect(Process).to receive(:fork).and_return(nil)
expect(Process).not_to receive(:detach)
end
it 'starts the metrics server with the given arguments' do
expect_next_instance_of(MetricsServer) do |server|
expect(server).to receive(:start)
end
described_class.spawn('sidekiq', metrics_dir: metrics_dir)
end
it 'resets signal handlers from parent process' do
expect(Gitlab::ProcessManagement).to receive(:modify_signals).with(%i[A B], 'DEFAULT')
described_class.spawn('sidekiq', metrics_dir: metrics_dir, trapped_signals: %i[A B])
end
end
end
describe '#start' do
let(:exporter_class) { Class.new(Gitlab::Metrics::Exporter::BaseExporter) }
let(:exporter_double) { double('fake_exporter', start: true) }
let(:settings) { { "fake_exporter" => { "enabled" => true } } }
let(:ruby_sampler_double) { double(Gitlab::Metrics::Samplers::RubySampler) }
subject(:metrics_server) { described_class.new('fake', metrics_dir, true)}
before do
stub_const('Gitlab::Metrics::Exporter::FakeExporter', exporter_class)
expect(exporter_class).to receive(:instance).with(
settings['fake_exporter'], gc_requests: true, synchronous: true
).and_return(exporter_double)
expect(Settings).to receive(:monitoring).and_return(settings)
allow(Gitlab::Metrics::Samplers::RubySampler).to receive(:initialize_instance).and_return(ruby_sampler_double)
allow(ruby_sampler_double).to receive(:start)
end
it 'configures ::Prometheus::Client' do
metrics_server.start
expect(prometheus_config.multiprocess_files_dir).to eq metrics_dir
expect(::Prometheus::Client.configuration.pid_provider.call).to eq 'fake_exporter'
end
it 'ensures that metrics directory exists in correct mode (0700)' do
expect(FileUtils).to receive(:mkdir_p).with(metrics_dir, mode: 0700)
metrics_server.start
end
context 'when wipe_metrics_dir is true' do
subject(:metrics_server) { described_class.new('fake', metrics_dir, true)}
it 'removes any old metrics files' do
FileUtils.touch("#{metrics_dir}/remove_this.db")
expect { metrics_server.start }.to change { Dir.empty?(metrics_dir) }.from(false).to(true)
end
end
context 'when wipe_metrics_dir is false' do
subject(:metrics_server) { described_class.new('fake', metrics_dir, false)}
it 'does not remove any old metrics files' do
FileUtils.touch("#{metrics_dir}/remove_this.db")
expect { metrics_server.start }.not_to change { Dir.empty?(metrics_dir) }.from(false)
end
end
it 'starts a metrics server' do
expect(exporter_double).to receive(:start)
metrics_server.start
end
it 'starts a RubySampler instance' do
expect(ruby_sampler_double).to receive(:start)
subject.start
end
end
end
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