Scaling applications with RabbitMQ at SunshinePHP
14 likes5,509 views
This document discusses using RabbitMQ for scaling applications, highlighting its features as a multi-protocol messaging server that is open-source and polyglot. It includes examples of RabbitMQ use cases, code snippets for both publishing and consuming messages, and emphasizes its capability for handling requirements like message persistence and fault tolerance. The document serves as an exploratory talk rather than a step-by-step guide, encouraging innovative use of RabbitMQ in various scenarios.
![Consumer Code
$consumer = function($msg){
!
$meta = json_decode($msg->body, true);
resize_picture($meta['image_id'], $meta['image_path']);
$msg->delivery_info['channel']->
basic_ack($msg->delivery_info['delivery_tag']);
};](https://image.slidesharecdn.com/scalingapplicationswithrabbitmq-sunshinephp-140208133631-phpapp01/85/Scaling-applications-with-RabbitMQ-at-SunshinePHP-92-320.jpg)
![Consumer Code
$consumer = function($msg){
!
$meta = json_decode($msg->body, true);
resize_picture($meta['image_id'], $meta['image_path']);
$msg->delivery_info['channel']->
basic_ack($msg->delivery_info['delivery_tag']);
};](https://image.slidesharecdn.com/scalingapplicationswithrabbitmq-sunshinephp-140208133631-phpapp01/85/Scaling-applications-with-RabbitMQ-at-SunshinePHP-93-320.jpg)
![Consumer Code
$consumer = function($msg){
!
$meta = json_decode($msg->body, true);
resize_picture($meta['image_id'], $meta['image_path']);
$msg->delivery_info['channel']->
basic_ack($msg->delivery_info['delivery_tag']);
};](https://image.slidesharecdn.com/scalingapplicationswithrabbitmq-sunshinephp-140208133631-phpapp01/85/Scaling-applications-with-RabbitMQ-at-SunshinePHP-94-320.jpg)
![Consumer Code
$consumer = function($msg){
!
$meta = json_decode($msg->body, true);
resize_picture($meta['image_id'], $meta['image_path']);
$msg->delivery_info['channel']->
basic_ack($msg->delivery_info['delivery_tag']);
};](https://image.slidesharecdn.com/scalingapplicationswithrabbitmq-sunshinephp-140208133631-phpapp01/85/Scaling-applications-with-RabbitMQ-at-SunshinePHP-95-320.jpg)
![Consumer Code
$consumer = function($msg){
!
$meta = json_decode($msg->body, true);
resize_picture($meta['image_id'], $meta['image_path']);
$msg->delivery_info['channel']->
basic_ack($msg->delivery_info['delivery_tag']);
};](https://image.slidesharecdn.com/scalingapplicationswithrabbitmq-sunshinephp-140208133631-phpapp01/85/Scaling-applications-with-RabbitMQ-at-SunshinePHP-96-320.jpg)
Scaling applications with RabbitMQ at SunshinePHP
- 1. Scaling Applications with RabbitMQ Alvaro Videla - RabbitMQ
- 2. Alvaro Videla • • • • • Developer Advocate at Pivotal / RabbitMQ! Co-Author of RabbitMQ in Action! Creator of the RabbitMQ Simulator! Blogs about RabbitMQ Internals: http://videlalvaro.github.io/internals.html! @old_sound — alvaro@rabbitmq.com — github.com/videlalvaro
- 3. About Me Co-authored! ! RabbitMQ in Action! http://bit.ly/rabbitmq
- 4. About this Talk • Exploratory Talk • A ‘what could be done’ talk instead of ‘this is how you do it’
- 6. RabbitMQ
- 7. RabbitMQ
- 8. RabbitMQ • Multi Protocol Messaging Server
- 9. RabbitMQ • Multi Protocol Messaging Server! • Open Source (MPL)
- 10. RabbitMQ • Multi Protocol Messaging Server! • Open Source (MPL)! • Polyglot
- 11. RabbitMQ • Multi Protocol Messaging Server! • Open Source (MPL)! • Polyglot! • Written in Erlang/OTP
- 13. Polyglot
- 14. Polyglot
- 15. Polyglot • Java
- 17. Polyglot • Java! • node.js! • Erlang
- 18. Polyglot • Java! • node.js! • Erlang! • PHP
- 19. Polyglot • Java! • node.js! • Erlang! • PHP! • Ruby
- 20. Polyglot • Java! • node.js! • Erlang! • PHP! • Ruby! • .Net
- 21. Polyglot • Java! • node.js! • Erlang! • PHP! • Ruby! • .Net! • Haskell
- 23. Some users of RabbitMQ
- 24. Some users of RabbitMQ • Instagram
- 25. Some users of RabbitMQ • • Instagram! Indeed.com
- 26. Some users of RabbitMQ • • • Instagram! Indeed.com! Telefonica
- 27. Some users of RabbitMQ • • • • Instagram! Indeed.com! Telefonica! Mercado Libre
- 28. Some users of RabbitMQ • • • • • Instagram! Indeed.com! Telefonica! Mercado Libre! NHS
- 29. Some users of RabbitMQ • • • • • • Instagram! Indeed.com! Telefonica! Mercado Libre! NHS! Mozilla
- 31. Messaging with RabbitMQ A demo with the RabbitMQ Simulator https://github.com/RabbitMQSimulator/RabbitMQSimulator
- 34. What you get out of the box
- 36. Some RabbitMQ Features • No message loss
- 37. Some RabbitMQ Features • No message loss • Persistent Messages
- 38. Some RabbitMQ Features • No message loss • Persistent Messages • Publisher Confirms
- 39. Some RabbitMQ Features • No message loss • Persistent Messages • Publisher Confirms • Message Acknowledgment
- 40. Some RabbitMQ Features • No message loss • Persistent Messages • Publisher Confirms • Message Acknowledgment • Mirrored Queues
- 41. Some RabbitMQ Features • No message loss • Persistent Messages • Publisher Confirms • Message Acknowledgment • Mirrored Queues • Message Ordering
- 43. Some RabbitMQ Features • Dead Letter Exchanges
- 44. Some RabbitMQ Features • Dead Letter Exchanges • Alternate Exchanges
- 45. Some RabbitMQ Features • Dead Letter Exchanges • Alternate Exchanges • Message and Queues TTLs
- 46. Some RabbitMQ Features • Dead Letter Exchanges • Alternate Exchanges • Message and Queues TTLs • Consumer Priorities
- 47. Some RabbitMQ Features • Dead Letter Exchanges • Alternate Exchanges • Message and Queues TTLs • Consumer Priorities • Federation
- 48. Some RabbitMQ Features • Dead Letter Exchanges • Alternate Exchanges • Message and Queues TTLs • Consumer Priorities • Federation • Shovel
- 49. Preventing unbounded buffers with RabbitMQ http://bit.ly/1eCKYK8
- 52. Requirements
- 54. Requirements • Generate XML • Distribution Over a Cluster
- 55. Requirements • Generate XML • Distribution Over a Cluster • Elasticity - Add/Remove new workers
- 56. Requirements • Generate XML • Distribution Over a Cluster • Elasticity - Add/Remove new workers • No Code Changes
- 57. Design
- 58. Publisher Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); ! $msg = new AMQPMessage($video_info, array('content_type' => 'text/plain', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'video-desc-ex'); ! $channel->close(); $conn->close();
- 59. Publisher Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); ! $msg = new AMQPMessage($video_info, array('content_type' => 'text/plain', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'video-desc-ex'); ! $channel->close(); $conn->close();
- 60. Publisher Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); ! $msg = new AMQPMessage($video_info, array('content_type' => 'text/plain', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'video-desc-ex'); ! $channel->close(); $conn->close();
- 61. Publisher Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); ! $msg = new AMQPMessage($video_info, array('content_type' => 'text/plain', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'video-desc-ex'); ! $channel->close(); $conn->close();
- 62. Publisher Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); ! $msg = new AMQPMessage($video_info, array('content_type' => 'text/plain', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'video-desc-ex'); ! $channel->close(); $conn->close();
- 63. Publisher Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); ! $msg = new AMQPMessage($video_info, array('content_type' => 'text/plain', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'video-desc-ex'); ! $channel->close(); $conn->close();
- 64. Consumer Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); $channel->queue_declare('video-desc-queue', false, true, false, false); $channel->queue_bind('video-desc-queue', 'video-desc-ex'); ! $channel->basic_consume('video-desc-queue', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 65. Consumer Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); $channel->queue_declare('video-desc-queue', false, true, false, false); $channel->queue_bind('video-desc-queue', 'video-desc-ex'); ! $channel->basic_consume('video-desc-queue', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 66. Consumer Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); $channel->queue_declare('video-desc-queue', false, true, false, false); $channel->queue_bind('video-desc-queue', 'video-desc-ex'); ! $channel->basic_consume('video-desc-queue', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 67. Consumer Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); $channel->queue_declare('video-desc-queue', false, true, false, false); $channel->queue_bind('video-desc-queue', 'video-desc-ex'); ! $channel->basic_consume('video-desc-queue', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 68. Consumer Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); $channel->queue_declare('video-desc-queue', false, true, false, false); $channel->queue_bind('video-desc-queue', 'video-desc-ex'); ! $channel->basic_consume('video-desc-queue', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 69. Consumer Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); $channel->queue_declare('video-desc-queue', false, true, false, false); $channel->queue_bind('video-desc-queue', 'video-desc-ex'); ! $channel->basic_consume('video-desc-queue', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 70. Consumer Code $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST); $channel = $conn->channel(); ! $channel->exchange_declare('video-desc-ex', 'direct', false, true, false); $channel->queue_declare('video-desc-queue', false, true, false, false); $channel->queue_bind('video-desc-queue', 'video-desc-ex'); ! $channel->basic_consume('video-desc-queue', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 72. Requirements
- 75. Requirements • Upload Picture • Reward User • Notify User Friends
- 76. Requirements • Upload Picture • Reward User • Notify User Friends • Resize Picture
- 77. Requirements • Upload Picture • Reward User • Notify User Friends • Resize Picture • No Code Changes
- 78. Design
- 79. Design
- 80. Design
- 81. Publisher Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $metadata = json_encode(array( 'image_id' => $image_id, 'user_id' => $user_id, ‘image_path' => $image_path)); ! $msg = new AMQPMessage($metadata, array('content_type' => 'application/json', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'upload-pictures');
- 82. Publisher Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $metadata = json_encode(array( 'image_id' => $image_id, 'user_id' => $user_id, ‘image_path' => $image_path)); ! $msg = new AMQPMessage($metadata, array('content_type' => 'application/json', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'upload-pictures');
- 83. Publisher Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $metadata = json_encode(array( 'image_id' => $image_id, 'user_id' => $user_id, ‘image_path' => $image_path)); ! $msg = new AMQPMessage($metadata, array('content_type' => 'application/json', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'upload-pictures');
- 84. Publisher Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $metadata = json_encode(array( 'image_id' => $image_id, 'user_id' => $user_id, ‘image_path' => $image_path)); ! $msg = new AMQPMessage($metadata, array('content_type' => 'application/json', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'upload-pictures');
- 85. Publisher Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $metadata = json_encode(array( 'image_id' => $image_id, 'user_id' => $user_id, ‘image_path' => $image_path)); ! $msg = new AMQPMessage($metadata, array('content_type' => 'application/json', 'delivery_mode' => 2)); ! $channel->basic_publish($msg, 'upload-pictures');
- 86. Consumer Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $channel->queue_declare('resize-picture', false, true, false, false); ! $channel->queue_bind('resize-picture', 'upload-pictures'); ! $channel->basic_consume('resize-picture', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 87. Consumer Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $channel->queue_declare('resize-picture', false, true, false, false); ! $channel->queue_bind('resize-picture', 'upload-pictures'); ! $channel->basic_consume('resize-picture', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 88. Consumer Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $channel->queue_declare('resize-picture', false, true, false, false); ! $channel->queue_bind('resize-picture', 'upload-pictures'); ! $channel->basic_consume('resize-picture', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 89. Consumer Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $channel->queue_declare('resize-picture', false, true, false, false); ! $channel->queue_bind('resize-picture', 'upload-pictures'); ! $channel->basic_consume('resize-picture', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 90. Consumer Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $channel->queue_declare('resize-picture', false, true, false, false); ! $channel->queue_bind('resize-picture', 'upload-pictures'); ! $channel->basic_consume('resize-picture', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 91. Consumer Code $channel->exchange_declare('upload-pictures', 'fanout', false, true, false); ! $channel->queue_declare('resize-picture', false, true, false, false); ! $channel->queue_bind('resize-picture', 'upload-pictures'); ! $channel->basic_consume('resize-picture', $consumer_tag, false, false, false, false, $consumer); ! while(count($channel->callbacks)) { $channel->wait(); }
- 92. Consumer Code $consumer = function($msg){ ! $meta = json_decode($msg->body, true); resize_picture($meta['image_id'], $meta['image_path']); $msg->delivery_info['channel']-> basic_ack($msg->delivery_info['delivery_tag']); };
- 93. Consumer Code $consumer = function($msg){ ! $meta = json_decode($msg->body, true); resize_picture($meta['image_id'], $meta['image_path']); $msg->delivery_info['channel']-> basic_ack($msg->delivery_info['delivery_tag']); };
- 94. Consumer Code $consumer = function($msg){ ! $meta = json_decode($msg->body, true); resize_picture($meta['image_id'], $meta['image_path']); $msg->delivery_info['channel']-> basic_ack($msg->delivery_info['delivery_tag']); };
- 95. Consumer Code $consumer = function($msg){ ! $meta = json_decode($msg->body, true); resize_picture($meta['image_id'], $meta['image_path']); $msg->delivery_info['channel']-> basic_ack($msg->delivery_info['delivery_tag']); };
- 96. Consumer Code $consumer = function($msg){ ! $meta = json_decode($msg->body, true); resize_picture($meta['image_id'], $meta['image_path']); $msg->delivery_info['channel']-> basic_ack($msg->delivery_info['delivery_tag']); };
- 98. Requirements
- 100. Requirements • Several Web Servers • Logic Separated by Module/Action
- 101. Requirements • Several Web Servers • Logic Separated by Module/Action • Several Log Levels: info, warning and error
- 102. Requirements • Several Web Servers • Logic Separated by Module/Action • Several Log Levels: info, warning and error • Add Remove log listeners at will
- 103. Design
- 104. Design
- 105. Design
- 106. Design
- 107. Design
- 108. Publisher Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $msg = new AMQPMessage('some log message', array('content_type' => 'text/plain')); ! $channel->basic_publish($msg, 'logs', 'server1.user.profile.info');
- 109. Publisher Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $msg = new AMQPMessage('some log message', array('content_type' => 'text/plain')); ! $channel->basic_publish($msg, 'logs', 'server1.user.profile.info');
- 110. Publisher Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $msg = new AMQPMessage('some log message', array('content_type' => 'text/plain')); ! $channel->basic_publish($msg, 'logs', 'server1.user.profile.info');
- 111. Publisher Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $msg = new AMQPMessage('some log message', array('content_type' => 'text/plain')); ! $channel->basic_publish($msg, 'logs', 'server1.user.profile.info');
- 112. Consumer Code Get messages sent by host: ! server1
- 113. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('server1-logs', false, true, false, false); ! $channel->queue_bind('server1-logs', 'logs', 'server1.#');
- 114. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('server1-logs', false, true, false, false); ! $channel->queue_bind('server1-logs', 'logs', 'server1.#');
- 115. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('server1-logs', false, true, false, false); ! $channel->queue_bind('server1-logs', 'logs', 'server1.#');
- 116. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('server1-logs', false, true, false, false); ! $channel->queue_bind('server1-logs', 'logs', 'server1.#');
- 117. Consumer Code Get all error messages
- 118. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('error-logs', false, true, false, false); ! $channel->queue_bind('error-logs', 'logs', '#.error');
- 119. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('error-logs', false, true, false, false); ! $channel->queue_bind('error-logs', 'logs', '#.error');
- 120. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('error-logs', false, true, false, false); ! $channel->queue_bind('error-logs', 'logs', '#.error');
- 121. Consumer Code $channel->exchange_declare('logs', 'topic', false, true, false); ! $channel->queue_declare('error-logs', false, true, false, false); ! $channel->queue_bind('error-logs', 'logs', '#.error');
- 122. Distributed Apps
- 125. Ad-hoc solution
- 126. A process that replicates data to the remote server
- 127. Possible issues • Remote server is offline • • • Prevent unbounded local buffers Prevent message loss Prevent unnecessary message replication • No need for those messages on remote server • Messages that became stale
- 128. Can we do better?
- 129. RabbitMQ Federation
- 130. RabbitMQ Federation • Supports replication across different administrative domains • Supports mix of Erlang and RabbitMQ versions • Supports Network Partitions • Specificity - not everything has to be federated
- 131. RabbitMQ Federation
- 132. RabbitMQ Federation
- 133. RabbitMQ Federation
- 134. RabbitMQ Federation • It’s a RabbitMQ Plugin
- 135. RabbitMQ Federation • It’s a RabbitMQ Plugin • Internally uses Queues and Exchanges Decorators
- 136. RabbitMQ Federation • It’s a RabbitMQ Plugin • Internally uses Queues and Exchanges Decorators • Managed using Parameters and Policies
- 137. Enabling the Plugin rabbitmq-plugins enable rabbitmq_federation
- 138. Enabling the Plugin rabbitmq-plugins enable rabbitmq_federation rabbitmq-plugins enable rabbitmq_federation_management
- 139. Federating an Exchange rabbitmqctl set_parameter federation-upstream my-upstream ‘{“uri":"amqp://server-name","expires":3600000}'
- 140. Federating an Exchange rabbitmqctl set_parameter federation-upstream my-upstream ‘{“uri":"amqp://server-name","expires":3600000}' ! rabbitmqctl set_policy --apply-to exchanges federate-me "^amq." '{"federation-upstream-set":"all"}'
- 142. With RabbitMQ we can
- 143. With RabbitMQ we can • Ingest data using various protocols: AMQP, MQTT and STOMP
- 144. With RabbitMQ we can • Ingest data using various protocols: AMQP, MQTT and STOMP • Distribute that data globally using Federation
- 145. With RabbitMQ we can • Ingest data using various protocols: AMQP, MQTT and STOMP • Distribute that data globally using Federation • Scale up using with different consumer strategies
- 146. With RabbitMQ we can • Ingest data using various protocols: AMQP, MQTT and STOMP • Distribute that data globally using Federation • Scale up using with different consumer strategies • Integrate across many platforms and programming languages
- 147. Questions?
- 149. Thanks Alvaro Videla - @old_sound Credits world map: wikipedia.org federation diagrams: rabbitmq.com