Adding Real-time Features to PHP Applications

It's possible to introduce real-time features to PHP applications without deep modifications of the current codebase.

Using WAMP you can build distributed systems out of application components which are loosely coupled and communicate in (soft) real-time.

There is no need to learn a whole new language, with the implications it has.

It also opens the door to write reactive, event-based, distributed architectures and to achieve easier scalability by distributing messages to multiple systems.

Transcript

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
8. Real-time Soft real-time
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
13. Real-time Communication on the Web
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 Every Web Developer Should Know About Networking and Browser Performance
20. Real-time Communication Patterns
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 Callee Dealer
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 Browser Server 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 Callee Dealer Publisher Subscriber Broker
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 Callee Dealer
37. Broker • Keeps a book of subscriptions • Forward the events (messages) to all subscribers • Publisher are subscribers are loosely coupled Publisher Subscriber Broker
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) Browser Browser Browser Browser 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
54. Conflicts Everywhere
55. Conflicts everywhere Trade-offs everywhere
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?
78. Gracias! @ronnylt Work with us!