462 lines
13 KiB
Ruby
462 lines
13 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
require 'spec_helper'
|
|
|
|
RSpec.describe Gitlab::Database::LoadBalancing::LoadBalancer, :request_store do
|
|
let(:conflict_error) { Class.new(RuntimeError) }
|
|
let(:db_host) { ActiveRecord::Base.connection_pool.db_config.host }
|
|
let(:config) do
|
|
Gitlab::Database::LoadBalancing::Configuration
|
|
.new(ActiveRecord::Base, [db_host, db_host])
|
|
end
|
|
|
|
let(:lb) { described_class.new(config) }
|
|
let(:request_cache) { lb.send(:request_cache) }
|
|
|
|
before do
|
|
stub_const(
|
|
'Gitlab::Database::LoadBalancing::LoadBalancer::PG::TRSerializationFailure',
|
|
conflict_error
|
|
)
|
|
end
|
|
|
|
after do |example|
|
|
lb.disconnect!(timeout: 0) unless example.metadata[:skip_disconnect]
|
|
end
|
|
|
|
def raise_and_wrap(wrapper, original)
|
|
raise original
|
|
rescue original.class
|
|
raise wrapper, 'boop'
|
|
end
|
|
|
|
def wrapped_exception(wrapper, original)
|
|
raise_and_wrap(wrapper, original.new)
|
|
rescue wrapper => error
|
|
error
|
|
end
|
|
|
|
def twice_wrapped_exception(top, middle, original)
|
|
begin
|
|
raise_and_wrap(middle, original.new)
|
|
rescue middle => middle_error
|
|
raise_and_wrap(top, middle_error)
|
|
end
|
|
rescue top => top_error
|
|
top_error
|
|
end
|
|
|
|
describe '#initialize' do
|
|
it 'ignores the hosts when load balancing is disabled' do
|
|
config = Gitlab::Database::LoadBalancing::Configuration
|
|
.new(ActiveRecord::Base, [db_host])
|
|
|
|
allow(config).to receive(:load_balancing_enabled?).and_return(false)
|
|
|
|
lb = described_class.new(config)
|
|
hosts = lb.host_list.hosts
|
|
|
|
expect(hosts.length).to eq(1)
|
|
expect(hosts.first)
|
|
.to be_instance_of(Gitlab::Database::LoadBalancing::PrimaryHost)
|
|
end
|
|
|
|
it 'sets the name of the connection that is used' do
|
|
config =
|
|
Gitlab::Database::LoadBalancing::Configuration.new(ActiveRecord::Base)
|
|
lb = described_class.new(config)
|
|
|
|
expect(lb.name).to eq(:main)
|
|
end
|
|
end
|
|
|
|
describe '#read' do
|
|
it 'yields a connection for a read' do
|
|
connection = double(:connection)
|
|
host = double(:host)
|
|
|
|
allow(lb).to receive(:host).and_return(host)
|
|
allow(host).to receive(:query_cache_enabled).and_return(true)
|
|
|
|
expect(host).to receive(:connection).and_return(connection)
|
|
|
|
expect { |b| lb.read(&b) }.to yield_with_args(connection)
|
|
end
|
|
|
|
it 'ensures that query cache is enabled' do
|
|
connection = double(:connection)
|
|
host = double(:host)
|
|
|
|
allow(lb).to receive(:host).and_return(host)
|
|
allow(host).to receive(:query_cache_enabled).and_return(false)
|
|
allow(host).to receive(:connection).and_return(connection)
|
|
|
|
expect(host).to receive(:enable_query_cache!).once
|
|
|
|
lb.read { 10 }
|
|
end
|
|
|
|
it 'marks hosts that are offline' do
|
|
allow(lb).to receive(:connection_error?).and_return(true)
|
|
|
|
expect(lb.host_list.hosts[0]).to receive(:offline!)
|
|
expect(lb).to receive(:release_host)
|
|
|
|
raised = false
|
|
|
|
returned = lb.read do
|
|
unless raised
|
|
raised = true
|
|
raise
|
|
end
|
|
|
|
10
|
|
end
|
|
|
|
expect(returned).to eq(10)
|
|
end
|
|
|
|
it 'retries a query in the event of a serialization failure' do
|
|
raised = false
|
|
|
|
expect(lb).to receive(:release_host)
|
|
|
|
returned = lb.read do
|
|
unless raised
|
|
raised = true
|
|
raise conflict_error
|
|
end
|
|
|
|
10
|
|
end
|
|
|
|
expect(returned).to eq(10)
|
|
end
|
|
|
|
it 'retries every host at most 3 times when a query conflict is raised' do
|
|
expect(lb).to receive(:release_host).exactly(6).times
|
|
expect(lb).to receive(:read_write)
|
|
|
|
lb.read { raise conflict_error }
|
|
end
|
|
|
|
context 'only primary is configured' do
|
|
let(:lb) do
|
|
config = Gitlab::Database::LoadBalancing::Configuration.new(ActiveRecord::Base)
|
|
allow(config).to receive(:load_balancing_enabled?).and_return(false)
|
|
|
|
described_class.new(config)
|
|
end
|
|
|
|
it 'does not retry a query on connection error if only the primary is configured' do
|
|
host = double(:host, query_cache_enabled: true)
|
|
|
|
allow(lb).to receive(:host).and_return(host)
|
|
allow(host).to receive(:connection).and_raise(PG::UnableToSend)
|
|
|
|
expect { lb.read }.to raise_error(PG::UnableToSend)
|
|
end
|
|
end
|
|
|
|
it 'uses the primary if no secondaries are available' do
|
|
allow(lb).to receive(:connection_error?).and_return(true)
|
|
|
|
expect(lb.host_list.hosts).to all(receive(:online?).and_return(false))
|
|
|
|
expect(lb).to receive(:read_write).and_call_original
|
|
|
|
expect { |b| lb.read(&b) }
|
|
.to yield_with_args(ActiveRecord::Base.retrieve_connection)
|
|
end
|
|
|
|
it 'uses the primary when load balancing is disabled' do
|
|
config = Gitlab::Database::LoadBalancing::Configuration
|
|
.new(ActiveRecord::Base)
|
|
|
|
allow(config).to receive(:load_balancing_enabled?).and_return(false)
|
|
|
|
lb = described_class.new(config)
|
|
|
|
# When no hosts are configured, we don't want to produce any warnings, as
|
|
# they aren't useful/too noisy.
|
|
expect(Gitlab::Database::LoadBalancing::Logger).not_to receive(:warn)
|
|
|
|
expect { |b| lb.read(&b) }
|
|
.to yield_with_args(ActiveRecord::Base.retrieve_connection)
|
|
end
|
|
end
|
|
|
|
describe '#read_write' do
|
|
it 'yields a connection for a write' do
|
|
connection = ActiveRecord::Base.connection_pool.connection
|
|
|
|
expect { |b| lb.read_write(&b) }.to yield_with_args(connection)
|
|
end
|
|
|
|
it 'uses a retry with exponential backoffs' do
|
|
expect(lb).to receive(:retry_with_backoff).and_yield
|
|
|
|
lb.read_write { 10 }
|
|
end
|
|
end
|
|
|
|
describe '#host' do
|
|
it 'returns the secondary host to use' do
|
|
expect(lb.host).to be_an_instance_of(Gitlab::Database::LoadBalancing::Host)
|
|
end
|
|
|
|
it 'stores the host in a thread-local variable' do
|
|
request_cache.delete(described_class::CACHE_KEY)
|
|
|
|
expect(lb.host_list).to receive(:next).once.and_call_original
|
|
|
|
lb.host
|
|
lb.host
|
|
end
|
|
|
|
it 'does not create conflicts with other load balancers when caching hosts' do
|
|
ci_config = Gitlab::Database::LoadBalancing::Configuration
|
|
.new(Ci::CiDatabaseRecord, [db_host, db_host])
|
|
|
|
lb1 = described_class.new(config)
|
|
lb2 = described_class.new(ci_config)
|
|
|
|
host1 = lb1.host
|
|
host2 = lb2.host
|
|
|
|
expect(lb1.send(:request_cache)[described_class::CACHE_KEY]).to eq(host1)
|
|
expect(lb2.send(:request_cache)[described_class::CACHE_KEY]).to eq(host2)
|
|
end
|
|
end
|
|
|
|
describe '#release_host' do
|
|
it 'releases the host and its connection' do
|
|
host = lb.host
|
|
|
|
expect(host).to receive(:disable_query_cache!)
|
|
|
|
lb.release_host
|
|
|
|
expect(request_cache[described_class::CACHE_KEY]).to be_nil
|
|
end
|
|
end
|
|
|
|
describe '#release_primary_connection' do
|
|
it 'releases the connection to the primary' do
|
|
expect(ActiveRecord::Base.connection_pool).to receive(:release_connection)
|
|
|
|
lb.release_primary_connection
|
|
end
|
|
end
|
|
|
|
describe '#primary_write_location' do
|
|
it 'returns a String in the right format' do
|
|
expect(lb.primary_write_location).to match(%r{[A-F0-9]{1,8}/[A-F0-9]{1,8}})
|
|
end
|
|
|
|
it 'raises an error if the write location could not be retrieved' do
|
|
connection = double(:connection)
|
|
|
|
allow(lb).to receive(:read_write).and_yield(connection)
|
|
allow(connection).to receive(:select_all).and_return([])
|
|
|
|
expect { lb.primary_write_location }.to raise_error(RuntimeError)
|
|
end
|
|
end
|
|
|
|
describe '#retry_with_backoff' do
|
|
it 'returns the value returned by the block' do
|
|
value = lb.retry_with_backoff { 10 }
|
|
|
|
expect(value).to eq(10)
|
|
end
|
|
|
|
it 're-raises errors not related to database connections' do
|
|
expect(lb).not_to receive(:sleep) # to make sure we're not retrying
|
|
|
|
expect { lb.retry_with_backoff { raise 'boop' } }
|
|
.to raise_error(RuntimeError)
|
|
end
|
|
|
|
it 'retries the block when a connection error is raised' do
|
|
allow(lb).to receive(:connection_error?).and_return(true)
|
|
expect(lb).to receive(:sleep).with(2)
|
|
expect(lb).to receive(:release_primary_connection)
|
|
|
|
raised = false
|
|
returned = lb.retry_with_backoff do
|
|
unless raised
|
|
raised = true
|
|
raise
|
|
end
|
|
|
|
10
|
|
end
|
|
|
|
expect(returned).to eq(10)
|
|
end
|
|
|
|
it 're-raises the connection error if the retries did not succeed' do
|
|
allow(lb).to receive(:connection_error?).and_return(true)
|
|
expect(lb).to receive(:sleep).with(2).ordered
|
|
expect(lb).to receive(:sleep).with(4).ordered
|
|
expect(lb).to receive(:sleep).with(16).ordered
|
|
|
|
expect(lb).to receive(:release_primary_connection).exactly(3).times
|
|
|
|
expect { lb.retry_with_backoff { raise } }.to raise_error(RuntimeError)
|
|
end
|
|
|
|
it 'skips retries when only the primary is used' do
|
|
allow(lb).to receive(:primary_only?).and_return(true)
|
|
|
|
expect(lb).not_to receive(:sleep)
|
|
|
|
expect { lb.retry_with_backoff { raise } }.to raise_error(RuntimeError)
|
|
end
|
|
end
|
|
|
|
describe '#connection_error?' do
|
|
it 'returns true for a connection error' do
|
|
error = ActiveRecord::ConnectionNotEstablished.new
|
|
|
|
expect(lb.connection_error?(error)).to eq(true)
|
|
end
|
|
|
|
it 'returns false for a missing database error' do
|
|
error = ActiveRecord::NoDatabaseError.new
|
|
|
|
expect(lb.connection_error?(error)).to eq(false)
|
|
end
|
|
|
|
it 'returns true for a wrapped connection error' do
|
|
wrapped = wrapped_exception(ActiveRecord::StatementInvalid, ActiveRecord::ConnectionNotEstablished)
|
|
|
|
expect(lb.connection_error?(wrapped)).to eq(true)
|
|
end
|
|
|
|
it 'returns true for a wrapped connection error from a view' do
|
|
wrapped = wrapped_exception(ActionView::Template::Error, ActiveRecord::ConnectionNotEstablished)
|
|
|
|
expect(lb.connection_error?(wrapped)).to eq(true)
|
|
end
|
|
|
|
it 'returns true for deeply wrapped/nested errors' do
|
|
top = twice_wrapped_exception(ActionView::Template::Error, ActiveRecord::StatementInvalid, ActiveRecord::ConnectionNotEstablished)
|
|
|
|
expect(lb.connection_error?(top)).to eq(true)
|
|
end
|
|
|
|
it 'returns true for an invalid encoding error' do
|
|
error = RuntimeError.new('invalid encoding name: unicode')
|
|
|
|
expect(lb.connection_error?(error)).to eq(true)
|
|
end
|
|
|
|
it 'returns false for errors not related to database connections' do
|
|
error = RuntimeError.new
|
|
|
|
expect(lb.connection_error?(error)).to eq(false)
|
|
end
|
|
|
|
it 'returns false for ActiveRecord errors without a cause' do
|
|
error = ActiveRecord::RecordNotUnique.new
|
|
|
|
expect(lb.connection_error?(error)).to eq(false)
|
|
end
|
|
end
|
|
|
|
describe '#serialization_failure?' do
|
|
let(:conflict_error) { Class.new(RuntimeError) }
|
|
|
|
before do
|
|
stub_const(
|
|
'Gitlab::Database::LoadBalancing::LoadBalancer::PG::TRSerializationFailure',
|
|
conflict_error
|
|
)
|
|
end
|
|
|
|
it 'returns for a serialization error' do
|
|
expect(lb.serialization_failure?(conflict_error.new)).to eq(true)
|
|
end
|
|
|
|
it 'returns true for a wrapped error' do
|
|
wrapped = wrapped_exception(ActionView::Template::Error, conflict_error)
|
|
|
|
expect(lb.serialization_failure?(wrapped)).to eq(true)
|
|
end
|
|
end
|
|
|
|
describe '#select_up_to_date_host' do
|
|
let(:location) { 'AB/12345'}
|
|
let(:hosts) { lb.host_list.hosts }
|
|
let(:set_host) { request_cache[described_class::CACHE_KEY] }
|
|
|
|
subject { lb.select_up_to_date_host(location) }
|
|
|
|
context 'when none of the replicas are caught up' do
|
|
before do
|
|
expect(hosts).to all(receive(:caught_up?).with(location).and_return(false))
|
|
end
|
|
|
|
it 'returns false and does not update the host thread-local variable' do
|
|
expect(subject).to be false
|
|
expect(set_host).to be_nil
|
|
end
|
|
end
|
|
|
|
context 'when any of the replicas is caught up' do
|
|
before do
|
|
# `allow` for non-caught up host, because we may not even check it, if will find the caught up one earlier
|
|
allow(hosts[0]).to receive(:caught_up?).with(location).and_return(false)
|
|
expect(hosts[1]).to receive(:caught_up?).with(location).and_return(true)
|
|
end
|
|
|
|
it 'returns true and sets host thread-local variable' do
|
|
expect(subject).to be true
|
|
expect(set_host).to eq(hosts[1])
|
|
end
|
|
end
|
|
end
|
|
|
|
describe '#create_replica_connection_pool' do
|
|
it 'creates a new connection pool with specific pool size and name' do
|
|
with_replica_pool(5, 'other_host') do |replica_pool|
|
|
expect(replica_pool)
|
|
.to be_kind_of(ActiveRecord::ConnectionAdapters::ConnectionPool)
|
|
|
|
expect(replica_pool.db_config.host).to eq('other_host')
|
|
expect(replica_pool.db_config.pool).to eq(5)
|
|
expect(replica_pool.db_config.name).to end_with("_replica")
|
|
end
|
|
end
|
|
|
|
it 'allows setting of a custom hostname and port' do
|
|
with_replica_pool(5, 'other_host', 5432) do |replica_pool|
|
|
expect(replica_pool.db_config.host).to eq('other_host')
|
|
expect(replica_pool.db_config.configuration_hash[:port]).to eq(5432)
|
|
end
|
|
end
|
|
|
|
it 'does not modify connection class pool' do
|
|
expect { with_replica_pool(5) { } }.not_to change { ActiveRecord::Base.connection_pool }
|
|
end
|
|
|
|
def with_replica_pool(*args)
|
|
pool = lb.create_replica_connection_pool(*args)
|
|
yield pool
|
|
ensure
|
|
pool&.disconnect!
|
|
end
|
|
end
|
|
|
|
describe '#disconnect!' do
|
|
it 'calls disconnect on all hosts with a timeout', :skip_disconnect do
|
|
expect_next_instances_of(Gitlab::Database::LoadBalancing::Host, 2) do |host|
|
|
expect(host).to receive(:disconnect!).with(timeout: 30)
|
|
end
|
|
|
|
lb.disconnect!(timeout: 30)
|
|
end
|
|
end
|
|
end
|