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|
# frozen_string_literal: true
require 'spec_helper'
RSpec.describe Gitlab::Database::LoadBalancing::HostList do
def expect_metrics(hosts)
expect(Gitlab::Metrics.registry.get(:db_load_balancing_hosts).get({})).to eq(hosts)
end
before do
allow(Gitlab::Database)
.to receive(:create_connection_pool)
.and_return(ActiveRecord::Base.connection_pool)
end
let(:load_balancer) { double(:load_balancer) }
let(:host_count) { 2 }
let(:host_list) do
hosts = Array.new(host_count) do
Gitlab::Database::LoadBalancing::Host.new('localhost', load_balancer, port: 5432)
end
described_class.new(hosts)
end
describe '#initialize' do
it 'sets metrics for current number of hosts and current index' do
host_list
expect_metrics(2)
end
end
describe '#length' do
it 'returns the number of hosts in the list' do
expect(host_list.length).to eq(2)
end
end
describe '#host_names_and_ports' do
context 'with ports' do
it 'returns the host names of all hosts' do
hosts = [
['localhost', 5432],
['localhost', 5432]
]
expect(host_list.host_names_and_ports).to eq(hosts)
end
end
context 'without ports' do
let(:host_list) do
hosts = Array.new(2) do
Gitlab::Database::LoadBalancing::Host.new('localhost', load_balancer)
end
described_class.new(hosts)
end
it 'returns the host names of all hosts' do
hosts = [
['localhost', nil],
['localhost', nil]
]
expect(host_list.host_names_and_ports).to eq(hosts)
end
end
end
describe '#manage_pool?' do
before do
allow(Gitlab::Database).to receive(:create_connection_pool) { double(:connection) }
end
context 'when the testing pool belongs to one host of the host list' do
it 'returns true' do
pool = host_list.hosts.first.pool
expect(host_list.manage_pool?(pool)).to be(true)
end
end
context 'when the testing pool belongs to a former host of the host list' do
it 'returns false' do
pool = host_list.hosts.first.pool
host_list.hosts = [
Gitlab::Database::LoadBalancing::Host.new('foo', load_balancer)
]
expect(host_list.manage_pool?(pool)).to be(false)
end
end
context 'when the testing pool belongs to a new host of the host list' do
it 'returns true' do
host = Gitlab::Database::LoadBalancing::Host.new('foo', load_balancer)
host_list.hosts = [host]
expect(host_list.manage_pool?(host.pool)).to be(true)
end
end
context 'when the testing pool does not have any relation with the host list' do
it 'returns false' do
host = Gitlab::Database::LoadBalancing::Host.new('foo', load_balancer)
expect(host_list.manage_pool?(host.pool)).to be(false)
end
end
end
describe '#hosts' do
it 'returns a copy of the host' do
first = host_list.hosts
expect(host_list.hosts).to eq(first)
expect(host_list.hosts.object_id).not_to eq(first.object_id)
end
end
describe '#hosts=' do
it 'updates the list of hosts to use' do
host_list.hosts = [
Gitlab::Database::LoadBalancing::Host.new('foo', load_balancer)
]
expect(host_list.length).to eq(1)
expect(host_list.hosts[0].host).to eq('foo')
expect_metrics(1)
end
end
describe '#next' do
it 'returns a host' do
expect(host_list.next)
.to be_an_instance_of(Gitlab::Database::LoadBalancing::Host)
end
it 'cycles through all available hosts' do
expect(host_list.next).to eq(host_list.hosts[0])
expect_metrics(2)
expect(host_list.next).to eq(host_list.hosts[1])
expect_metrics(2)
expect(host_list.next).to eq(host_list.hosts[0])
expect_metrics(2)
end
it 'skips hosts that are offline' do
allow(host_list.hosts[0]).to receive(:online?).and_return(false)
expect(host_list.next).to eq(host_list.hosts[1])
expect_metrics(2)
end
it 'returns nil if no hosts are online' do
host_list.hosts.each do |host|
allow(host).to receive(:online?).and_return(false)
end
expect(host_list.next).to be_nil
expect_metrics(2)
end
it 'returns nil if no hosts are available' do
expect(described_class.new.next).to be_nil
end
end
describe '#shuffle' do
let(:host_count) { 3 }
it 'randomizes the list' do
2.times do
all_hosts = host_list.hosts
host_list.shuffle
expect(host_list.length).to eq(host_count)
expect(host_list.hosts).to contain_exactly(*all_hosts)
end
end
end
end
|
