Adding Real-time Features to PHP Applications
- 1. Adding Real-time Features to PHP Applications
- 2. About me @ronnylt Ronny López Technical Lead Opinions are my own
- 3. Agenda • Concepts and foundations • Real-time communication patterns • Implementations • Examples
- 4. Real-time A system is said to be real-time if the total correctness of an operation depends not only upon its logical correctness, but also upon the time in which it is performed
- 5. Real-time Applications must guarantee response within specified time constraints, often referred to as “deadlines”
- 6. Real-time Applications in which the computer must respond as rapidly as required by the user
- 7. Criteria for real-time • Hard – missing a deadline is a total system failure • Firm – infrequent deadline misses are tolerable, but may degrade the system's QoS. Results are NOT usefulness after its deadline • Soft – the usefulness of a result degrades after its deadline, thereby degrading the system’s QoS
- 9. Soft real-time Typically used to solve issues of concurrent access and the need to keep a number of connected systems up-to-date through changing situations
- 10. Soft real-time use cases • Live audio-video systems • Users collaboration • Messaging applications, etc… • Real-time analytics • Gaming • Etc…
- 11. The road to 500 million Symfony downloads https://symfony.com/500million
- 12. Why adding a soft real-time feature? • To improve end-user experience • Due to insufficient scaling capacity
- 14. A Bit of History • Flash • Ajax (XMLHttpRequest) • Comet (reverse Ajax) • WebSocket • Polyfills
- 15. The Modern Web • WebSockets • HTTP/2
- 16. WebSockets • Full-duplex communication channels over a single TCP connection • Currently supported in most major browsers • Can be used by any client or server application
- 17. HTTP/2 • Major revision of the HTTP • Replacement for how HTTP is expressed “on the wire” • Focus on performance, end-user perceived latency, network and server resource usage
- 18. The Mobile Internet • Inestable connections • HTTP & TCP slow-start are usually not a good match for constantly dropped connections • Network interface kills battery • Large responses + periodic polling = bad
- 19. What EveryWeb Developer Should Know About Networking and Browser Performance
- 21. The “actors” Client Server Peer Peer
- 22. Basic Patterns • Remote Procedure Call (RPC) • PUB/SUB
- 23. RPC • Allows to call a procedure (function) remotely • Involves peers of these three roles Caller CalleeDealer
- 24. RPC – Example 1 Something you usually do with Ajax Browser Server GetConference(123) {name:deSymfony,where: Madrid}
- 25. RPC – Example 2 Push data to the browser BrowserServer DisplayOffer(offer)
- 26. RPC – Example 3 Communication between micro-services Auth Server login(user) Analytics Payments track(user) process(order)
- 27. Publisher/Subscriber • A peer subscribe to a topic • Another peer publish a message about this topic • All publishers interested in the topic receives the message
- 28. PUB/SUB – Example 1 Notifications Browser Server updateStats(stats) Browser Browser Subscribed To: StatsUpdate
- 29. PUB/SUB – Example 2 Micro-services Synchronization Auth Admin Service updateSettings(freshSettings) Encoding Payments Subscribed To: SettingsChanges Analytics
- 30. Web Application Messaging Protocol http://wamp-proto.org/
- 31. Not to be confused with WAMP: ”Windows + Apache + MySQL + PHP"
- 32. WAMP • Open standard WebSocket subprotocol • Provides two application messaging patterns in one unified protocol • Remote Procedure Calls • Publish & Subscribe
- 33. WAMP Features • Enables different technologies, processes, machines, etc… to communicate with each other, in soft real-time
- 34. WAMP Features • Based on modern Web standards: WebSocket, JSON and URIs • Designed with first-class support for different languages in mind (Polyglot)
- 35. Unified Application Routing Routing of events (for PUB/SUB) and routing of calls (for RPC) in one unified protocol Caller CalleeDealer Publisher SubscriberBroker
- 36. Dealer • Routes calls from the caller to the callee and routes back results or errors • Callers and callee don’t know about each other • Applications using RPC benefit from these loose coupling Caller CalleeDealer
- 37. Broker • Keeps a book of subscriptions • Forward the events (messages) to all subscribers • Publisher are subscribers are loosely coupled Publisher SubscriberBroker
- 38. Unified Protocol • When you combine a Broker and a Dealer you get what WAMP calls a Router Router Broker Dealer= +
- 39. The Big Picture WAMP Router (Dealer + Broker) BrowserBrowserBrowserBrowser Mobile Clients Services
- 40. Do we really need another wheel? How does WAMMP compare to other technologies
- 41. Criteria • Pub/Sub • RPC • Routed RPC (not only point-to-point) • Web native: run natively on the Web (without tunneling or bridging) • Cross Language • Open Standard
- 42. Tech PubSub RPC Routed RPC Web native Cross Language Open Standard WAMP ✔ ✔ ✔ ✔ ✔ ✔ Ajax ✔ ✔ ✔ Comet ✔ ✔ JSON-RPC ✔ ✔ ✔ ✔ socket.io ✔ ✔ ZMQ ✔ ✔ XMPP ✔ ✔ ✔ ✔
- 43. Implementations • Client libraries for most popular languages • Full featured router implementations in several languages
- 44. WAMP Routers • crossbar.io – Advanced, open-source, full featured, supported by the creators of WAMP • Your own… It’s an open protocol
- 45. WAMP Ecosystem • Thruway – library built in PHP that provides both a client and a router • Turnpike – router implemented in Go • wamp.rt – router for NodeJS • Erwa – router implemented in Erlang
- 46. Choosing an implementation Let’s talk about trade-offs
- 47. Is PHP suitable for soft real-time applications?
- 48. Is PHP the right tool for the job?
- 49. No.
- 50. No?
- 51. Why not?
- 52. Let’s use Node.js ! It’s an opportunity to deploy Erlang or Golang, or …
- 53. Languages War
- 56. Trade-off • Situation that involves losing one quality or aspect of something in return for gaining another quality or aspect • It often implies a decision to be made with full comprehension of both the upside and downside of a particular choice
- 57. Is PHP the right tool for the job? There is not simple answer
- 58. The simpler answer I know is: “I don’t care”
- 59. PHP Codebase (Symfony, Silex, Laravel, Drupal, etc…) Clients Web, Mobile, etc… Request/Response
- 60. Request/Response Real-time API Pub/Sub, RPC, etc.. RPC
- 61. • A big ecosystem of thousands of useful libraries and components easily installable thanks to Composer • Very powerful template engines, ORMs, etc…
- 62. • We have implemented very powerful design patters in PHP coming from Java and other languages • We have several thousands of high quality code running on production • We have invested multiple hours testing, refactoring and improving the codebase
- 63. It’s here to stay
- 65. Remember Full comprehension of both the upsides and downsides of a particular choice
- 66. Downsides • We have to introduce a new stack to provide real-time features
- 67. Upsides • Possibility to introduce real-time features without deep modifications in the current codebase • No need to learn a whole new language/ stack, with the implications it has • Loosely coupled systems
- 68. Upsides cont… • Opens the door to write reactive, event- based, distributed architectures • Scalability is easier to achieve by distributing messages to multiple systems
- 69. Examples
- 70. The Stack • crossbar.io used as the router (dealer+broker) • PHP client gathers and publish events • Silex/Symfony backend serve the data and contains the biz logic
- 71. crossbar.io • Networking platform for distributed and micro-services applications • Full implementation of the WAMP protocol • Feature rich, scalable, robust and secure • It takes care of the hard parts of messaging so you can focus on your app's features
- 73. Tips and Tricks • WSS • Deadlines • Timeouts • Retries with back-off, etc… • Idempotency
- 74. Opinionated Conclusion • Understand core concepts and patterns, technology is volatile • Question everything: Why?, why not? • Decide based on several factors: user experience, scalability, feasibility, developer experience, maintenance costs/debt, etc…
- 75. Don’t Stop Here • gRPC – A high performance, open-source universal RPC framework from Google http://www.grpc.io/ • IoT, WoT, etc… – real world objects connected to the wider internet
- 76. References • WAMP Proto – http://wamp-proto.org/ • https://github.com/voryx/ThruwayBundle • https://www.infoq.com/articles/websocket- and-http2-coexist
- 77. Questions • What about React PHP? • Multi-Threading in PHP with pthreads? https://gist.github.com/krakjoe/6437782/ • Micro-services what?