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|
# frozen_string_literal: true
require 'spec_helper'
require_relative '../../../../lib/gitlab/cluster/lifecycle_events'
RSpec.describe Gitlab::Memory::Watchdog, :aggregate_failures, :prometheus do
context 'watchdog' do
let(:logger) { instance_double(::Logger) }
let(:handler) { instance_double(described_class::NullHandler) }
let(:heap_frag_limit_gauge) { instance_double(::Prometheus::Client::Gauge) }
let(:violations_counter) { instance_double(::Prometheus::Client::Counter) }
let(:violations_handled_counter) { instance_double(::Prometheus::Client::Counter) }
let(:sleep_time) { 0.1 }
let(:max_heap_fragmentation) { 0.2 }
let(:max_mem_growth) { 2 }
# Defaults that will not trigger any events.
let(:fragmentation) { 0 }
let(:worker_memory) { 0 }
let(:primary_memory) { 0 }
let(:max_strikes) { 0 }
# Tests should set this to control the number of loop iterations in `call`.
let(:watchdog_iterations) { 1 }
subject(:watchdog) do
described_class.new(handler: handler, logger: logger, sleep_time_seconds: sleep_time,
max_strikes: max_strikes, max_mem_growth: max_mem_growth,
max_heap_fragmentation: max_heap_fragmentation).tap do |instance|
# We need to defuse `sleep` and stop the internal loop after N iterations.
iterations = 0
allow(instance).to receive(:sleep) do
instance.stop if (iterations += 1) > watchdog_iterations
end
end
end
def stub_prometheus_metrics
allow(Gitlab::Metrics).to receive(:gauge)
.with(:gitlab_memwd_heap_frag_limit, anything)
.and_return(heap_frag_limit_gauge)
allow(Gitlab::Metrics).to receive(:counter)
.with(:gitlab_memwd_violations_total, anything, anything)
.and_return(violations_counter)
allow(Gitlab::Metrics).to receive(:counter)
.with(:gitlab_memwd_violations_handled_total, anything, anything)
.and_return(violations_handled_counter)
allow(heap_frag_limit_gauge).to receive(:set)
allow(violations_counter).to receive(:increment)
allow(violations_handled_counter).to receive(:increment)
end
before do
stub_prometheus_metrics
allow(handler).to receive(:call).and_return(true)
allow(logger).to receive(:warn)
allow(logger).to receive(:info)
allow(Gitlab::Metrics::Memory).to receive(:gc_heap_fragmentation).and_return(fragmentation)
allow(Gitlab::Metrics::System).to receive(:memory_usage_uss_pss).and_return({ uss: worker_memory })
allow(Gitlab::Metrics::System).to receive(:memory_usage_uss_pss).with(
pid: Gitlab::Cluster::PRIMARY_PID
).and_return({ uss: primary_memory })
allow(::Prometheus::PidProvider).to receive(:worker_id).and_return('worker_1')
end
context 'when created' do
it 'sets the heap fragmentation limit gauge' do
expect(heap_frag_limit_gauge).to receive(:set).with({}, max_heap_fragmentation)
watchdog
end
context 'when no settings are set in the environment' do
it 'initializes with defaults' do
watchdog = described_class.new(handler: handler, logger: logger)
expect(watchdog.max_heap_fragmentation).to eq(described_class::DEFAULT_MAX_HEAP_FRAG)
expect(watchdog.max_mem_growth).to eq(described_class::DEFAULT_MAX_MEM_GROWTH)
expect(watchdog.max_strikes).to eq(described_class::DEFAULT_MAX_STRIKES)
expect(watchdog.sleep_time_seconds).to eq(described_class::DEFAULT_SLEEP_TIME_SECONDS)
end
end
context 'when settings are passed through the environment' do
before do
stub_env('GITLAB_MEMWD_MAX_HEAP_FRAG', 1)
stub_env('GITLAB_MEMWD_MAX_STRIKES', 2)
stub_env('GITLAB_MEMWD_SLEEP_TIME_SEC', 3)
stub_env('GITLAB_MEMWD_MAX_MEM_GROWTH', 4)
end
it 'initializes with these settings' do
watchdog = described_class.new(handler: handler, logger: logger)
expect(watchdog.max_heap_fragmentation).to eq(1)
expect(watchdog.max_strikes).to eq(2)
expect(watchdog.sleep_time_seconds).to eq(3)
expect(watchdog.max_mem_growth).to eq(4)
end
end
end
shared_examples 'has strikes left' do |stat|
context 'when process has not exceeded allowed number of strikes' do
let(:watchdog_iterations) { max_strikes }
it 'does not signal the handler' do
expect(handler).not_to receive(:call)
watchdog.call
end
it 'does not log any events' do
expect(logger).not_to receive(:warn)
watchdog.call
end
it 'increments the violations counter' do
expect(violations_counter).to receive(:increment).with(reason: stat).exactly(watchdog_iterations)
watchdog.call
end
it 'does not increment violations handled counter' do
expect(violations_handled_counter).not_to receive(:increment)
watchdog.call
end
end
end
shared_examples 'no strikes left' do |stat|
it 'signals the handler and resets strike counter' do
expect(handler).to receive(:call).and_return(true)
watchdog.call
expect(watchdog.strikes(stat.to_sym)).to eq(0)
end
it 'increments both the violations and violations handled counters' do
expect(violations_counter).to receive(:increment).with(reason: stat).exactly(watchdog_iterations)
expect(violations_handled_counter).to receive(:increment).with(reason: stat)
watchdog.call
end
context 'when enforce_memory_watchdog ops toggle is off' do
before do
stub_feature_flags(enforce_memory_watchdog: false)
end
it 'always uses the NullHandler' do
expect(handler).not_to receive(:call)
expect(described_class::NullHandler.instance).to receive(:call).and_return(true)
watchdog.call
end
end
context 'when handler result is true' do
it 'considers the event handled and stops itself' do
expect(handler).to receive(:call).once.and_return(true)
expect(logger).to receive(:info).with(hash_including(message: 'stopped'))
watchdog.call
end
end
context 'when handler result is false' do
let(:max_strikes) { 0 } # to make sure the handler fires each iteration
let(:watchdog_iterations) { 3 }
it 'keeps running' do
expect(violations_counter).to receive(:increment).exactly(watchdog_iterations)
expect(violations_handled_counter).to receive(:increment).exactly(watchdog_iterations)
# Return true the third time to terminate the daemon.
expect(handler).to receive(:call).and_return(false, false, true)
watchdog.call
end
end
end
context 'when monitoring memory growth' do
let(:primary_memory) { 2048 }
context 'when process does not exceed threshold' do
let(:worker_memory) { max_mem_growth * primary_memory - 1 }
it 'does not signal the handler' do
expect(handler).not_to receive(:call)
watchdog.call
end
end
context 'when process exceeds threshold permanently' do
let(:worker_memory) { max_mem_growth * primary_memory + 1 }
let(:max_strikes) { 3 }
it_behaves_like 'has strikes left', 'mem_growth'
context 'when process exceeds the allowed number of strikes' do
let(:watchdog_iterations) { max_strikes + 1 }
it_behaves_like 'no strikes left', 'mem_growth'
it 'only reads reference memory once' do
expect(Gitlab::Metrics::System).to receive(:memory_usage_uss_pss)
.with(pid: Gitlab::Cluster::PRIMARY_PID)
.once
watchdog.call
end
it 'logs the event' do
expect(Gitlab::Metrics::System).to receive(:memory_usage_rss).at_least(:once).and_return(1024)
expect(logger).to receive(:warn).with({
message: 'memory limit exceeded',
pid: Process.pid,
worker_id: 'worker_1',
memwd_handler_class: 'RSpec::Mocks::InstanceVerifyingDouble',
memwd_sleep_time_s: sleep_time,
memwd_max_uss_bytes: max_mem_growth * primary_memory,
memwd_ref_uss_bytes: primary_memory,
memwd_uss_bytes: worker_memory,
memwd_rss_bytes: 1024,
memwd_max_strikes: max_strikes,
memwd_cur_strikes: max_strikes + 1
})
watchdog.call
end
end
end
context 'when process exceeds threshold temporarily' do
let(:worker_memory) { max_mem_growth * primary_memory }
let(:max_strikes) { 1 }
let(:watchdog_iterations) { 4 }
before do
allow(Gitlab::Metrics::System).to receive(:memory_usage_uss_pss).and_return(
{ uss: worker_memory - 0.1 },
{ uss: worker_memory + 0.2 },
{ uss: worker_memory - 0.1 },
{ uss: worker_memory + 0.1 }
)
allow(Gitlab::Metrics::System).to receive(:memory_usage_uss_pss).with(
pid: Gitlab::Cluster::PRIMARY_PID
).and_return({ uss: primary_memory })
end
it 'does not signal the handler' do
expect(handler).not_to receive(:call)
watchdog.call
end
end
end
context 'when monitoring heap fragmentation' do
context 'when process does not exceed threshold' do
let(:fragmentation) { max_heap_fragmentation - 0.1 }
it 'does not signal the handler' do
expect(handler).not_to receive(:call)
watchdog.call
end
end
context 'when process exceeds threshold permanently' do
let(:fragmentation) { max_heap_fragmentation + 0.1 }
let(:max_strikes) { 3 }
it_behaves_like 'has strikes left', 'heap_frag'
context 'when process exceeds the allowed number of strikes' do
let(:watchdog_iterations) { max_strikes + 1 }
it_behaves_like 'no strikes left', 'heap_frag'
it 'logs the event' do
expect(Gitlab::Metrics::System).to receive(:memory_usage_rss).at_least(:once).and_return(1024)
expect(logger).to receive(:warn).with({
message: 'heap fragmentation limit exceeded',
pid: Process.pid,
worker_id: 'worker_1',
memwd_handler_class: 'RSpec::Mocks::InstanceVerifyingDouble',
memwd_sleep_time_s: sleep_time,
memwd_max_heap_frag: max_heap_fragmentation,
memwd_cur_heap_frag: fragmentation,
memwd_max_strikes: max_strikes,
memwd_cur_strikes: max_strikes + 1,
memwd_rss_bytes: 1024
})
watchdog.call
end
end
end
context 'when process exceeds threshold temporarily' do
let(:fragmentation) { max_heap_fragmentation }
let(:max_strikes) { 1 }
let(:watchdog_iterations) { 4 }
before do
allow(Gitlab::Metrics::Memory).to receive(:gc_heap_fragmentation).and_return(
fragmentation - 0.1,
fragmentation + 0.2,
fragmentation - 0.1,
fragmentation + 0.1
)
end
it 'does not signal the handler' do
expect(handler).not_to receive(:call)
watchdog.call
end
end
end
context 'when both memory fragmentation and growth exceed thresholds' do
let(:fragmentation) { max_heap_fragmentation + 0.1 }
let(:primary_memory) { 2048 }
let(:worker_memory) { max_mem_growth * primary_memory + 1 }
let(:watchdog_iterations) { max_strikes + 1 }
it 'only calls the handler once' do
expect(handler).to receive(:call).once.and_return(true)
watchdog.call
end
end
context 'when gitlab_memory_watchdog ops toggle is off' do
before do
stub_feature_flags(gitlab_memory_watchdog: false)
end
it 'does not monitor heap fragmentation' do
expect(Gitlab::Metrics::Memory).not_to receive(:gc_heap_fragmentation)
watchdog.call
end
it 'does not monitor memory growth' do
expect(Gitlab::Metrics::System).not_to receive(:memory_usage_uss_pss)
watchdog.call
end
end
end
context 'handlers' do
context 'NullHandler' do
subject(:handler) { described_class::NullHandler.instance }
describe '#call' do
it 'does nothing' do
expect(handler.call).to be(false)
end
end
end
context 'TermProcessHandler' do
subject(:handler) { described_class::TermProcessHandler.new(42) }
describe '#call' do
it 'sends SIGTERM to the current process' do
expect(Process).to receive(:kill).with(:TERM, 42)
expect(handler.call).to be(true)
end
end
end
context 'PumaHandler' do
# rubocop: disable RSpec/VerifiedDoubles
# In tests, the Puma constant is not loaded so we cannot make this an instance_double.
let(:puma_worker_handle_class) { double('Puma::Cluster::WorkerHandle') }
let(:puma_worker_handle) { double('worker') }
# rubocop: enable RSpec/VerifiedDoubles
subject(:handler) { described_class::PumaHandler.new({}) }
before do
stub_const('::Puma::Cluster::WorkerHandle', puma_worker_handle_class)
end
describe '#call' do
it 'invokes orderly termination via Puma API' do
expect(puma_worker_handle_class).to receive(:new).and_return(puma_worker_handle)
expect(puma_worker_handle).to receive(:term)
expect(handler.call).to be(true)
end
end
end
end
end
|