2015 ZendCon - Do you queue?

Presentation given during ZendCon 2015 on queuing.

Transcript

1. DO YOU QUEUE? ZendCon 2015
2. I AM MIKE WILLBANKS • Father, Husband, Developer • VP of Development at Packet Power • Twitter: @mwillbanks
3. Task Producer Consumer Messages Messages Messages WHAT IS A QUEUE? • Pub/Sub • FIFO buffer • Push / Pull • A way to communicate between applications / systems. • A way to decouple components. • A way to offload work.
4. WHY QUEUE?
5. THE LONG RUNNING CASE Request Long-process Send Response Response
6. THE INTEROP CASE Request Conditioning Service Response Response Web Service Call Send Response
7. NOT YOUR DATABASE Request Process Response Send Response DB
8. SO WHY QUEUE • User experience • System Security • Load Distribution • System Reliability
9. IN PRACTICE You’ve seen this before…
13. WHAT YOU MIGHT QUEUE
14. COMMUNICATIONS • Emails • SMS • Push Notifications
15. IMAGES • Conversions • Resize • Thumbnail • Watermark
16. VIDEO • Conversion • Resampling • Audio overlay
17. IOT • Receive messages from devices and process responses
18. PATTERNS
19. POINT TO POINT Point to Point Channel Receiver Sender
20. PUBLISH / SUBSCRIBE Publiser Subscribe Channel Subscriber Subscriber Subscriber
21. MESSAGE BUS Application Application Application Message Bus
22. PIPELINE Sender Receiver Point to Point Channel Receiver Point to Point Channel
23. INVALID MESSAGE Channel Receiver Sender X Invalid Message Channel
24. PROTOCOLS Or implementations for that matter.
25. AMQP • AMQP Working Group (Community and Vendor) • Platform agnostic protocol. • Completely open, interoperable and broadly applicable. • Many severs available and many client libraries.
27. STOMP • Simple protocol • Behaviors follow very simple commands. • Most message queues can communicate over STOMP.
28. Connect Send Disconnect /queue/ msg P H P S T O M P S E R V E R Connect Subscribe Disconnect /queue/ msg Read Ack
29. SQS • Fairly simple protocol • Supports delays, timers, and multiple policies.
31. SPECIAL PURPOSE Many queue implementations exist that don’t necessarily sit under standards…
32. XMPP • Best for real-time data. • Leveraging pub/sub can turn it into more of a generic message system. • Multiple libraries available.
33. SOCKET.IO • New comer • Real-time bidirectional event-based communication • Largely leverages pub/sub
34. ZEROMQ • The ultimate in message queue flexibility. • Socket library that acts as a concurrency framework.
35. GEARMAN • Application framework for farming out work. • Job sever for asynchronous or synchronous messages.
36. BEANSTALKD • Asynchronous Job Queue • Supports delays • Many PHP clients exist
37. CONSIDERATIONS How do we evaluate our options…
38. PULL VS. PUSH • Always PULL, whenever possible. • Push eliminates several benefits.
39. DURABILITY • Memory residence • Persistence • Restart survival
40. SECURITY • Authentication • Queue permissions / restrictions
41. DELIVERY • Is the delivery guaranteed? • If a message cannot be delivered how it it handled?
42. ROUTING • Multiple routing scenarios • Fanout • Direct • Topic • Broadcast
43. BATCHING • Do it later but in bulk (credit card processing) • Can be done via scheduling (cron)
44. RECEIPT • Do you get an acknowledgement of receipt?
45. IMPLEMENTING QUEUES
46. STARTING POINTS
47. PUSHING MESSAGES <?php class UserService { public function save($user) { $this->db->save($user); $stomp = new Stomp('tcp://localhost:61613'); $stomp->send('/queue/email', [ 'to' => $user->getEmail(), 'subject' => 'Welcome', 'message' => 'Welcome', 'headers' => [], ]); } }
48. HANDLING MESSAGES <?php $stomp = new Stomp('tcp://localhost:61613'); $stomp->subscribe('/queue/email'); while (true) { if (!$stomp->hasFrame()) { sleep(2); continue ; } $stomp->readFrame(); $email = json_decode($frame->body); mail($email->to, $email->subject, $email->message, $email->headers); }
49. MESSAGES
50. MESSAGE CONSIDERATIONS • Message Format • Message Contents
51. SERIALIZE O:7:"Message":1:{s:7:"content";a:1:{s:3:"foo";a:1:{s:3:"bar";a:1:{i:0;s: 3:"baz";}}}}
52. WORKERS
53. WORKER CONSIDERATIONS • Should do ONE thing and ONE thing well. • Should attempt to be as quick as possible in handling that type. • Should be able to be scaled horizontally.
54. HANDLING WORKERS • Prevent Memory Leaks • memory_get_usage • Handle Signals! • pcntl_signal
55. ABSTRACTIONS We want to make this easy…
56. <?php interface QueueInterface { public function __construct(Stomp $stomp, $queue); public function dispatch(); public function publish(array $message); public function work(StompFrame $message); }
57. <?php class AbstractQueue implements QueueInterface { protected $stomp; protected $queue; protected $signal; public function __construct(Stomp $stomp, $queue) { $this->stomp = $stomp; $this->queue = $queue; } protected function prepare() { if (php_sapi_name() != 'cli') { throw new RuntimeException('You cannot dispatch outside of the CLI'); } if (function_exists('pcntl_signal')) { pcntl_signal(SIGTERM, array($this, 'signal')); pcntl_signal(SIGINT, array($this, 'signal')); pcntl_signal(SIGHUP, array($this, 'signal')); } } protected function signal($signal) { $this->signal = $signal; }
58. public function dispatch() { $this->prepare(); while (true) { if ($this->signal) { break ; } if (!$this->stomp->hasFrame()) { $this->wait(); continue ; } $frame = $this->stomp->readFrame(); if ($this->validate($frame)) { $this->work($frame); } $this->stomp->ack($frame); } } protected function wait() { sleep(1); } protected function validate(StompFrame $message) { return false; } public function publish(array $message) { return $this->stomp->send($this->queue, json_encode($message)); }
59. <?php class EmailQueue extends AbstractQueue { public function validate(StompFrame $message) { if (!array_key_exists('to', $message)) { return false; } return true; } public function work(StompFrame $message) { $mail = json_decode($message); mail($mail->to, $mail->subject, $mail->message); } }
60. BOOTSTRAPPING Leverage your existing infrastructure as much as possible!
61. <?php declare(ticks=1); include 'vendor/autoload.php'; $app = Zend\Mvc\Application::init(include 'config/application.config.php'); $sm = $app->getServiceManager(); if (!isset($argv[1])) { fprintf(STDERR, "Syntax: worker <name>\n\n"); exit(1); } $name = $argv[1]; try { echo "Starting worker: " . $name . ' as ' . get_current_user() . PHP_EOL; $consumer = $sm->get($name); $consumer->dispatch(); } catch (\Exception $e) { fprintf(STDERR, "%s\n", $msg); exit(1); } $consumer = null; echo 'Shutdown ' . $name . ' worker gracefully.' . PHP_EOL; exit(0);
62. EVENTS
63. SERVICES TRIGGER EVENTS <?php use Zend\EventManager\EventManagerAwareTrait; class UserService { use EventManagerAwareTrait; public function save($user) { $this->db->save($user); $this->getEventManager()->trigger('save', null, ['user' => $user]); } }
64. ATTACH EVENTS <?php use Zend\ServiceManager\ServiceManager; $sm = new ServiceManager(); $service = $sm->get('UserService'); $queue = $sm->get('EmailQueue'); $service->getEventManager()->attach('save', function($e) use ($queue) { $params = $e->getParams(); $queue->publish([ 'to' => $params['user']['email'], 'subject' => 'Welcome', 'message' => 'Welcome', 'headers' => [], ]); });
65. HANDLING PROGRESS • Keep track by using a generic handler • Or, keep track via your database.
66. TOOLING
67. SUPERVISOR • Daemon that runs on the server. • Monitors programs and keeps them running in case of failure. • Handles logging.
68. PAINLESS INSTALLATION sudo easy_install supervisor sudo echo_supervisord_conf > /etc/supervisord.conf sudo service supervisor start
69. EXAMPLE PROGRAM CONFIGURATION [program:emailworker] command=/usr/bin/php /var/www/worker "MyProject\Queue\Email" process_name=%(program_name)s_%(process_num)d numprocs=2 numprocs_start=2 user=www-data autostart=true ; start at supervisord start (default: true) autorestart=true ; retstart at unexpected quit (default: true) startsecs=10 ; number of secs prog must stay running (def. 10) startretries=5 ; max # of serial start failures (default 3) log_stdout=true ; if true, log program stdout (default true) log_stderr=true ; if true, log program stderr (def false) redirect_stderr=true ; if true, redirect stderr to stdout stdout_logfile=/var/www/logs/worker-panoramaqueuekrpano.log stdout_logfile_maxbytes=10MB stdout_logfile_backups=15
70. SUPERVISORD MULTI SERVER MONITORING TOOL https://github.com/mlazarov/supervisord-monitor
71. WHEN BAD THINGS HAPPEN
72. QUEUE BACKUP • Most of all issues with queues are that a queue has backed up.
73. WORKER EXCEPTIONS • Broken code causes hardships, but recoverable!
74. • https://pixabay.com/en/autobahn-accident-germany-car-road-837643/ • https://pixabay.com/en/traffic-rent-a-car-traffic-jam-637118/ • https://pixabay.com/en/airplanes-line-runway-military-713662/ • https://pixabay.com/en/leo-animal-savannah-lioness-safari-350690/ • https://pixabay.com/en/user-top-view-office-keyboard-154199/ • https://pixabay.com/en/mechanics-engine-springs-mechanic-424130/ • https://pixabay.com/en/laughter-fun-happiness-boy-child-449781/ • https://pixabay.com/en/umbrellas-red-blue-patterns-205386/ • https://pixabay.com/en/spot-runs-start-la-stadion-862274/ • https://pixabay.com/en/artistic-the-art-of-abstraction-948588/ • https://pixabay.com/en/boots-work-boots-shoes-647035/ • https://pixabay.com/en/meerkat-watch-guard-cute-676944/ • https://pixabay.com/en/broken-window-hole-glass-damage-960188/ • https://pixabay.com/en/police-security-safety-protection-869216/ • https://pixabay.com/en/parcel-package-packaging-box-575623/ • https://pixabay.com/en/directory-signposts-trail-direction-494457/ • https://pixabay.com/en/cookies-chocolate-chip-food-dessert-28423/ • https://pixabay.com/en/phone-communication-call-select-735060/ • https://pixabay.com/en/receipt-note-paper-bill-document-575750/ • https://pixabay.com/en/tools-construct-craft-repair-864983/ • https://pixabay.com/en/moore-oklahoma-tornado-disaster-112781/ • https://pixabay.com/en/network-iot-internet-of-things-782707/ • https://pixabay.com/en/mobile-phone-smartphone-app-426559/ • https://pixabay.com/en/mr-site-build-crane-baukran-462074/ • https://pixabay.com/en/film-projector-movie-projector-738806/ • https://pixabay.com/en/calves-legs-human-standing-on-540519/ • https://pixabay.com/en/notebook-pages-opened-paper-note-820078/ • https://pixabay.com/en/letters-penpal-cards-leave-stack-566810/ • https://pixabay.com/en/spray-household-surface-shine-315164/ • https://pixabay.com/en/industry-crafts-gears-mechanical-94448/ • https://pixabay.com/en/hornet-wasp-insect-sting-macro-11514/ • https://pixabay.com/en/honey-bees-bees-hive-bee-hive-401238/ • https://pixabay.com/en/temple-china-door-handle-840526/ • https://pixabay.com/en/no-button-push-sign-icon-symbol-685042/ Image Credits THANK YOU! http://joind.in/talk/view/15538