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# frozen_string_literal: true
require 'spec_helper'
RSpec.describe Gitlab::Database::LoadBalancing::ServiceDiscovery do
let(:service) do
described_class.new(nameserver: 'localhost', port: 8600, record: 'foo')
end
before do
resource = double(:resource, address: IPAddr.new('127.0.0.1'))
packet = double(:packet, answer: [resource])
allow(Net::DNS::Resolver).to receive(:start)
.with('localhost', Net::DNS::A)
.and_return(packet)
end
describe '#initialize' do
describe ':record_type' do
subject { described_class.new(nameserver: 'localhost', port: 8600, record: 'foo', record_type: record_type) }
context 'with a supported type' do
let(:record_type) { 'SRV' }
it { expect(subject.record_type).to eq Net::DNS::SRV }
end
context 'with an unsupported type' do
let(:record_type) { 'AAAA' }
it 'raises an argument error' do
expect { subject }.to raise_error(ArgumentError, 'Unsupported record type: AAAA')
end
end
end
end
describe '#start' do
before do
allow(service)
.to receive(:loop)
.and_yield
end
it 'starts service discovery in a new thread' do
expect(service)
.to receive(:refresh_if_necessary)
.and_return(5)
expect(service)
.to receive(:rand)
.and_return(2)
expect(service)
.to receive(:sleep)
.with(7)
service.start.join
end
it 'reports exceptions to Sentry' do
error = StandardError.new
expect(service)
.to receive(:refresh_if_necessary)
.and_raise(error)
expect(Gitlab::ErrorTracking)
.to receive(:track_exception)
.with(error)
expect(service)
.to receive(:rand)
.and_return(2)
expect(service)
.to receive(:sleep)
.with(62)
service.start.join
end
end
describe '#refresh_if_necessary' do
let(:address_foo) { described_class::Address.new('foo') }
let(:address_bar) { described_class::Address.new('bar') }
context 'when a refresh is necessary' do
before do
allow(service)
.to receive(:addresses_from_load_balancer)
.and_return(%w[localhost])
allow(service)
.to receive(:addresses_from_dns)
.and_return([10, [address_foo, address_bar]])
end
it 'refreshes the load balancer hosts' do
expect(service)
.to receive(:replace_hosts)
.with([address_foo, address_bar])
expect(service.refresh_if_necessary).to eq(10)
end
end
context 'when a refresh is not necessary' do
before do
allow(service)
.to receive(:addresses_from_load_balancer)
.and_return(%w[localhost])
allow(service)
.to receive(:addresses_from_dns)
.and_return([10, %w[localhost]])
end
it 'does not refresh the load balancer hosts' do
expect(service)
.not_to receive(:replace_hosts)
expect(service.refresh_if_necessary).to eq(10)
end
end
end
describe '#replace_hosts' do
let(:address_foo) { described_class::Address.new('foo') }
let(:address_bar) { described_class::Address.new('bar') }
let(:load_balancer) do
Gitlab::Database::LoadBalancing::LoadBalancer.new([address_foo])
end
before do
allow(service)
.to receive(:load_balancer)
.and_return(load_balancer)
end
it 'replaces the hosts of the load balancer' do
service.replace_hosts([address_bar])
expect(load_balancer.host_list.host_names_and_ports).to eq([['bar', nil]])
end
it 'disconnects the old connections' do
host = load_balancer.host_list.hosts.first
allow(service)
.to receive(:disconnect_timeout)
.and_return(2)
expect(host)
.to receive(:disconnect!)
.with(2)
service.replace_hosts([address_bar])
end
end
describe '#addresses_from_dns' do
let(:service) { described_class.new(nameserver: 'localhost', port: 8600, record: 'foo', record_type: record_type) }
let(:packet) { double(:packet, answer: [res1, res2]) }
before do
allow(service.resolver)
.to receive(:search)
.with('foo', described_class::RECORD_TYPES[record_type])
.and_return(packet)
end
context 'with an A record' do
let(:record_type) { 'A' }
let(:res1) { double(:resource, address: IPAddr.new('255.255.255.0'), ttl: 90) }
let(:res2) { double(:resource, address: IPAddr.new('127.0.0.1'), ttl: 90) }
it 'returns a TTL and ordered list of IP addresses' do
addresses = [
described_class::Address.new('127.0.0.1'),
described_class::Address.new('255.255.255.0')
]
expect(service.addresses_from_dns).to eq([90, addresses])
end
end
context 'with an SRV record' do
let(:record_type) { 'SRV' }
let(:res1) { double(:resource, host: 'foo1.service.consul.', port: 5432, weight: 1, priority: 1, ttl: 90) }
let(:res2) { double(:resource, host: 'foo2.service.consul.', port: 5433, weight: 1, priority: 1, ttl: 90) }
let(:res3) { double(:resource, host: 'foo3.service.consul.', port: 5434, weight: 1, priority: 1, ttl: 90) }
let(:packet) { double(:packet, answer: [res1, res2, res3], additional: []) }
before do
expect_next_instance_of(Gitlab::Database::LoadBalancing::SrvResolver) do |resolver|
allow(resolver).to receive(:address_for).with('foo1.service.consul.').and_return(IPAddr.new('255.255.255.0'))
allow(resolver).to receive(:address_for).with('foo2.service.consul.').and_return(IPAddr.new('127.0.0.1'))
allow(resolver).to receive(:address_for).with('foo3.service.consul.').and_return(nil)
end
end
it 'returns a TTL and ordered list of hosts' do
addresses = [
described_class::Address.new('127.0.0.1', 5433),
described_class::Address.new('255.255.255.0', 5432)
]
expect(service.addresses_from_dns).to eq([90, addresses])
end
end
end
describe '#new_wait_time_for' do
it 'returns the DNS TTL if greater than the default interval' do
res = double(:resource, ttl: 90)
expect(service.new_wait_time_for([res])).to eq(90)
end
it 'returns the default interval if greater than the DNS TTL' do
res = double(:resource, ttl: 10)
expect(service.new_wait_time_for([res])).to eq(60)
end
it 'returns the default interval if no resources are given' do
expect(service.new_wait_time_for([])).to eq(60)
end
end
describe '#addresses_from_load_balancer' do
it 'returns the ordered host names of the load balancer' do
load_balancer = Gitlab::Database::LoadBalancing::LoadBalancer.new(%w[b a])
allow(service)
.to receive(:load_balancer)
.and_return(load_balancer)
addresses = [
described_class::Address.new('a'),
described_class::Address.new('b')
]
expect(service.addresses_from_load_balancer).to eq(addresses)
end
end
end
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