gitlab-org--gitlab-foss/spec/initializers/load_balancing_spec.rb

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# frozen_string_literal: true
require 'spec_helper'
RSpec.describe 'load_balancing', :delete, :reestablished_active_record_base do
subject(:initialize_load_balancer) do
load Rails.root.join('config/initializers/load_balancing.rb')
end
before do
# Stub out middleware call, as not idempotent
allow(Gitlab::Application.instance.middleware).to receive(:use)
end
context 'with replica hosts configured' do
before do
# Setup host-based load balancing
# Patch in our load balancer config, simply pointing at the test database twice
allow(Gitlab::Database::LoadBalancing::Configuration).to receive(:for_model) do |base_model|
db_host = base_model.connection_pool.db_config.host
Gitlab::Database::LoadBalancing::Configuration.new(base_model, [db_host, db_host])
end
end
after do
# reset load balancing to original state
allow(Gitlab::Database::LoadBalancing::Configuration).to receive(:for_model).and_call_original
allow(Gitlab::Cluster::LifecycleEvents).to receive(:in_clustered_puma?).and_call_original
load Rails.root.join('config/initializers/load_balancing.rb')
end
it 'configures load balancer with two replica hosts' do
expect(ApplicationRecord.connection.load_balancer.configuration.hosts.size).to eq(0)
expect(Ci::ApplicationRecord.connection.load_balancer.configuration.hosts.size).to eq(0)
initialize_load_balancer
expect(ApplicationRecord.connection.load_balancer.configuration.hosts.size).to eq(2)
expect(Ci::ApplicationRecord.connection.load_balancer.configuration.hosts.size).to eq(2)
end
context 'for a clustered puma worker' do
let!(:group) { create(:group, name: 'my group') }
before do
# Pretend we are in clustered environment
allow(Gitlab::Cluster::LifecycleEvents).to receive(:in_clustered_puma?).and_return(true)
end
it 'configures load balancer to have two replica hosts' do
initialize_load_balancer
simulate_puma_worker do
expect(ApplicationRecord.connection.load_balancer.configuration.hosts.size).to eq(2)
expect(Ci::ApplicationRecord.connection.load_balancer.configuration.hosts.size).to eq(2)
end
end
# We tried using Process.fork for a more realistic simulation
# but run into bugs where GPRC cannot be used before forking processes.
# See https://gitlab.com/gitlab-org/gitlab/-/issues/333184#note_1081658113
def simulate_puma_worker
# Called in https://github.com/rails/rails/blob/6-1-stable/activerecord/lib/active_record/connection_adapters/pool_config.rb#L73
ActiveRecord::ConnectionAdapters::PoolConfig.discard_pools!
# Called in config/puma.rb
Gitlab::Cluster::LifecycleEvents.do_worker_start
yield
end
it 'makes a read query successfully' do
# Clear any previous sticky writes
::Gitlab::Database::LoadBalancing::Session.clear_session
initialize_load_balancer
group_name = simulate_puma_worker do
Group.find_by_name('my group').name
end
expect(group_name).to eq(group.name)
end
it 'makes a write query successfully' do
initialize_load_balancer
expect do
simulate_puma_worker do
Group.touch_all
end
group.reload
end.to change(group, :updated_at)
end
end
end
end