Commit c184407e authored by Kamil Trzciński's avatar Kamil Trzciński

Merge branch 'an-opentracing-factory' into 'master'

Conditionally initialize the global opentracing tracer

See merge request gitlab-org/gitlab-ce!24186
parents af70d985 57a8859a
......@@ -304,6 +304,12 @@ group :metrics do
gem 'raindrops', '~> 0.18'
end
group :tracing do
# OpenTracing
gem 'opentracing', '~> 0.4.3'
gem 'jaeger-client', '~> 0.10.0'
end
group :development do
gem 'foreman', '~> 0.84.0'
gem 'brakeman', '~> 4.2', require: false
......
......@@ -392,6 +392,9 @@ GEM
cause
json
ipaddress (0.8.3)
jaeger-client (0.10.0)
opentracing (~> 0.3)
thrift
jira-ruby (1.4.1)
activesupport
multipart-post
......@@ -547,6 +550,7 @@ GEM
activesupport
nokogiri (>= 1.4.4)
omniauth (~> 1.0)
opentracing (0.4.3)
org-ruby (0.9.12)
rubypants (~> 0.2)
orm_adapter (0.5.0)
......@@ -870,6 +874,7 @@ GEM
rack (>= 1, < 3)
thor (0.19.4)
thread_safe (0.3.6)
thrift (0.11.0.0)
tilt (2.0.8)
timecop (0.8.1)
timfel-krb5-auth (0.8.3)
......@@ -1040,6 +1045,7 @@ DEPENDENCIES
httparty (~> 0.13.3)
icalendar
influxdb (~> 0.2)
jaeger-client (~> 0.10.0)
jira-ruby (~> 1.4)
jquery-atwho-rails (~> 1.3.2)
js_regex (~> 2.2.1)
......@@ -1080,6 +1086,7 @@ DEPENDENCIES
omniauth-shibboleth (~> 1.3.0)
omniauth-twitter (~> 1.4)
omniauth_crowd (~> 2.2.0)
opentracing (~> 0.4.3)
org-ruby (~> 0.9.12)
peek (~> 1.0.1)
peek-gc (~> 0.0.2)
......
---
title: Conditionally initialize the global opentracing tracer
merge_request: 24186
author:
type: other
# frozen_string_literal: true
if Gitlab::Tracing.enabled?
require 'opentracing'
# In multi-processed clustered architectures (puma, unicorn) don't
# start tracing until the worker processes are spawned. This works
# around issues when the opentracing implementation spawns threads
Gitlab::Cluster::LifecycleEvents.on_worker_start do
tracer = Gitlab::Tracing::Factory.create_tracer(Gitlab.process_name, Gitlab::Tracing.connection_string)
OpenTracing.global_tracer = tracer if tracer
end
end
# frozen_string_literal: true
module Gitlab
module Tracing
# Only enable tracing when the `GITLAB_TRACING` env var is configured. Note that we avoid using ApplicationSettings since
# the same environment variable needs to be configured for Workhorse, Gitaly and any other components which
# emit tracing. Since other components may start before Rails, and may not have access to ApplicationSettings,
# an env var makes more sense.
def self.enabled?
connection_string.present?
end
def self.connection_string
ENV['GITLAB_TRACING']
end
end
end
# frozen_string_literal: true
require "cgi"
module Gitlab
module Tracing
class Factory
OPENTRACING_SCHEME = "opentracing"
def self.create_tracer(service_name, connection_string)
return unless connection_string.present?
begin
opentracing_details = parse_connection_string(connection_string)
driver_name = opentracing_details[:driver_name]
case driver_name
when "jaeger"
JaegerFactory.create_tracer(service_name, opentracing_details[:options])
else
raise "Unknown driver: #{driver_name}"
end
rescue => e
# Can't create the tracer? Warn and continue sans tracer
warn "Unable to instantiate tracer: #{e}"
nil
end
end
def self.parse_connection_string(connection_string)
parsed = URI.parse(connection_string)
unless valid_uri?(parsed)
raise "Invalid tracing connection string"
end
{
driver_name: parsed.host,
options: parse_query(parsed.query)
}
end
private_class_method :parse_connection_string
def self.parse_query(query)
return {} unless query
CGI.parse(query).symbolize_keys.transform_values(&:first)
end
private_class_method :parse_query
def self.valid_uri?(uri)
return false unless uri
uri.scheme == OPENTRACING_SCHEME &&
uri.host.to_s =~ /^[a-z0-9_]+$/ &&
uri.path.empty?
end
private_class_method :valid_uri?
end
end
end
# frozen_string_literal: true
require 'jaeger/client'
module Gitlab
module Tracing
class JaegerFactory
# When the probabilistic sampler is used, by default 0.1% of requests will be traced
DEFAULT_PROBABILISTIC_RATE = 0.001
# The default port for the Jaeger agent UDP listener
DEFAULT_UDP_PORT = 6831
# Reduce this from default of 10 seconds as the Ruby jaeger
# client doesn't have overflow control, leading to very large
# messages which fail to send over UDP (max packet = 64k)
# Flush more often, with smaller packets
FLUSH_INTERVAL = 5
def self.create_tracer(service_name, options)
kwargs = {
service_name: service_name,
sampler: get_sampler(options[:sampler], options[:sampler_param]),
reporter: get_reporter(service_name, options[:http_endpoint], options[:udp_endpoint])
}
extra_params = options.except(:sampler, :sampler_param, :http_endpoint, :udp_endpoint, :strict_parsing, :debug) # rubocop: disable CodeReuse/ActiveRecord
if extra_params.present?
message = "jaeger tracer: invalid option: #{extra_params.keys.join(", ")}"
if options[:strict_parsing]
raise message
else
warn message
end
end
Jaeger::Client.build(kwargs)
end
def self.get_sampler(sampler_type, sampler_param)
case sampler_type
when "probabilistic"
sampler_rate = sampler_param ? sampler_param.to_f : DEFAULT_PROBABILISTIC_RATE
Jaeger::Samplers::Probabilistic.new(rate: sampler_rate)
when "const"
const_value = sampler_param == "1"
Jaeger::Samplers::Const.new(const_value)
else
nil
end
end
private_class_method :get_sampler
def self.get_reporter(service_name, http_endpoint, udp_endpoint)
encoder = Jaeger::Encoders::ThriftEncoder.new(service_name: service_name)
if http_endpoint.present?
sender = get_http_sender(encoder, http_endpoint)
elsif udp_endpoint.present?
sender = get_udp_sender(encoder, udp_endpoint)
else
return nil
end
Jaeger::Reporters::RemoteReporter.new(
sender: sender,
flush_interval: FLUSH_INTERVAL
)
end
private_class_method :get_reporter
def self.get_http_sender(encoder, address)
Jaeger::HttpSender.new(
url: address,
encoder: encoder,
logger: Logger.new(STDOUT)
)
end
private_class_method :get_http_sender
def self.get_udp_sender(encoder, address)
pair = address.split(":", 2)
host = pair[0]
port = pair[1] ? pair[1].to_i : DEFAULT_UDP_PORT
Jaeger::UdpSender.new(
host: host,
port: port,
encoder: encoder,
logger: Logger.new(STDOUT)
)
end
private_class_method :get_udp_sender
end
end
end
# frozen_string_literal: true
require 'fast_spec_helper'
describe Gitlab::Tracing::Factory do
describe '.create_tracer' do
let(:service_name) { 'rspec' }
context "when tracing is not configured" do
it 'ignores null connection strings' do
expect(described_class.create_tracer(service_name, nil)).to be_nil
end
it 'ignores empty connection strings' do
expect(described_class.create_tracer(service_name, '')).to be_nil
end
it 'ignores unknown implementations' do
expect(described_class.create_tracer(service_name, 'opentracing://invalid_driver')).to be_nil
end
it 'ignores invalid connection strings' do
expect(described_class.create_tracer(service_name, 'open?tracing')).to be_nil
end
end
context "when tracing is configured with jaeger" do
let(:mock_tracer) { double('tracer') }
it 'processes default connections' do
expect(Gitlab::Tracing::JaegerFactory).to receive(:create_tracer).with(service_name, {}).and_return(mock_tracer)
expect(described_class.create_tracer(service_name, 'opentracing://jaeger')).to be(mock_tracer)
end
it 'processes connections with parameters' do
expect(Gitlab::Tracing::JaegerFactory).to receive(:create_tracer).with(service_name, { a: '1', b: '2', c: '3' }).and_return(mock_tracer)
expect(described_class.create_tracer(service_name, 'opentracing://jaeger?a=1&b=2&c=3')).to be(mock_tracer)
end
end
end
end
# frozen_string_literal: true
require 'fast_spec_helper'
describe Gitlab::Tracing::JaegerFactory do
describe '.create_tracer' do
let(:service_name) { 'rspec' }
it 'processes default connections' do
expect(described_class.create_tracer(service_name, {})).to respond_to(:active_span)
end
it 'handles debug options' do
expect(described_class.create_tracer(service_name, { debug: "1" })).to respond_to(:active_span)
end
it 'handles const sampler' do
expect(described_class.create_tracer(service_name, { sampler: "const", sampler_param: "1" })).to respond_to(:active_span)
end
it 'handles probabilistic sampler' do
expect(described_class.create_tracer(service_name, { sampler: "probabilistic", sampler_param: "0.5" })).to respond_to(:active_span)
end
it 'handles http_endpoint configurations' do
expect(described_class.create_tracer(service_name, { http_endpoint: "http://localhost:1234" })).to respond_to(:active_span)
end
it 'handles udp_endpoint configurations' do
expect(described_class.create_tracer(service_name, { udp_endpoint: "localhost:4321" })).to respond_to(:active_span)
end
it 'ignores invalid parameters' do
expect(described_class.create_tracer(service_name, { invalid: "true" })).to respond_to(:active_span)
end
it 'accepts the debug parameter when strict_parser is set' do
expect(described_class.create_tracer(service_name, { debug: "1", strict_parsing: "1" })).to respond_to(:active_span)
end
it 'rejects invalid parameters when strict_parser is set' do
expect { described_class.create_tracer(service_name, { invalid: "true", strict_parsing: "1" }) }.to raise_error(StandardError)
end
end
end
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