Real-time Services with Silex and Symfony – deSymfony 2016

En los micro-servicios modernos, los cuales se basan en eventos, comunicación bidireccional, stream multiplexing y otras formas de sincronización de los datos, la arquitectura clásica basada en HTTP/REST no siempre es la mejor opción.

Algunas veces las aplicaciones requieren servicios donde es necesario mantener una comunicación asíncrona de eventos fluyendo en ambas direcciones, por ejemplo, un cliente conectado por Websocket.

¿Qué hacer en estos casos si tenemos la gran mayoría de nuestros servicios implementados con Symfony o Silex y queremos tener comunicación en real time con un cliente? ¿Qué opciones tenemos, qué soluciones podemos aplicar y con qué trade-offs?

El objetivo de la charla es dar respuestas a estas preguntas, basándonos en casos de usos reales en producción, comparar las distintas alternativas existentes y ver ejemplos prácticos de integración Silex/Symfony.

Transcript

1. deSymfony 16-17 septiembre 2016
   Madrid
   MICROSERVICIOS EN
   TIEMPO REAL CON
   SYMFONY Y SILEX
   Ronny López
   

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2. deSymfony
   ¡Muchas gracias a nuestros
   patrocinadores!
   

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3. About me
   @ronnylt
   Ronny López
   Technical Lead
   Opinions are my own
   

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4. Agenda
   • Concepts and foundations
   • Real-time communication patterns
   • Implementations
   • Examples
   

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5. 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
   

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6. Real-time
   Applications must guarantee response within
   specified time constraints, often referred to as
   “deadlines”
   

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7. Real-time
   Applications in which the computer must
   respond as rapidly as required by the user
   

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8. 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
   

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9. Real-time
   Soft real-time
   

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10. 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
    

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11. Soft real-time use cases
    • Live audio-video systems
    • Users collaboration
    • Messaging applications, etc…
    • Real-time analytics
    • Gaming
    • Etc…
    

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12. The road to 500 million
    Symfony downloads
    https://symfony.com/500million
    

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13. Why adding a soft

    real-time feature?
    • To improve end-user experience
    • Due to insufficient scaling capacity
    

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14. Real-time
    Communication on the
    Web
    

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15. A Bit of History
    • Flash
    • Ajax (XMLHttpRequest)
    • Comet (reverse Ajax)
    • WebSocket
    • Polyfills
    

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16. The Modern Web
    • WebSockets
    • HTTP/2
    

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17. 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
    

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18. 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
    

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19. 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
    

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20. What Every Web
    Developer Should Know
    About Networking and
    Browser Performance
    

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21. Real-time
    Communication
    Patterns
    

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22. The “actors”
    Client Server
    Peer Peer
    

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23. Basic Patterns
    • Remote Procedure Call (RPC)
    • PUB/SUB
    

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24. RPC
    • Allows to call a procedure (function)
    remotely
    • Involves peers of these three roles
    Caller Callee
    Dealer
    

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25. RPC – Example 1
    Something you usually do with Ajax
    Browser Server
    GetConference(123)
    {name:deSymfony,where: Madrid}
    

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26. RPC – Example 2
    Push data to the browser
    Browser
    Server DisplayOffer(offer)
    

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27. RPC – Example 3
    Communication between micro-services
    Auth
    Server
    login(user)
    Analytics Payments
    track(user) process(order)
    

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28. 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
    

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29. PUB/SUB – Example 1
    Notifications
    Browser
    Server
    updateStats(stats)
    Browser Browser
    Subscribed To: StatsUpdate
    

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30. PUB/SUB – Example 2
    Micro-services Synchronization
    Auth
    Admin
    Service
    updateSettings(freshSettings)
    Encoding Payments
    Subscribed To: SettingsChanges
    Analytics
    

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31. Web Application Messaging Protocol

    http://wamp-proto.org/
    

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32. Not to be confused with WAMP:
    ”Windows + Apache + MySQL + PHP"
    

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33. WAMP
    • Open standard WebSocket subprotocol
    • Provides two application messaging
    patterns in one unified protocol
    • Remote Procedure Calls
    • Publish & Subscribe
    

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34. WAMP Features
    • Enables different technologies, processes,
    machines, etc… to communicate with each
    other, in soft real-time
    

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35. WAMP Features
    • Based on modern Web standards:
    WebSocket, JSON and URIs
    • Designed with first-class support for
    different languages in mind (Polyglot)
    

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36. 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
    

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37. 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
    

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38. Broker
    • Keeps a book of subscriptions
    • Forward the events (messages) to all
    subscribers
    • Publisher are subscribers are loosely
    coupled
    Publisher Subscriber
    Broker
    

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39. Unified Protocol
    • When you combine a Broker and a Dealer
    you get what WAMP calls a Router
    Router Broker Dealer
    = +
    

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40. The Big Picture
    WAMP Router
    (Dealer + Broker)
    Browser
    Browser
    Browser
    Browser
    Mobile
    Clients
    Services
    

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41. Do we really need
    another wheel?
    How does WAMMP compare to other technologies
    

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42. 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
    

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43. Tech PubSub RPC
    Routed
    RPC
    Web native
    Cross
    Language
    Open
    Standard
    WAMP ✔ ✔ ✔ ✔ ✔ ✔
    Ajax ✔ ✔ ✔
    Comet ✔ ✔
    JSON-RPC ✔ ✔ ✔ ✔
    socket.io ✔ ✔
    ZMQ ✔ ✔
    XMPP ✔ ✔ ✔ ✔
    

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44. Implementations
    • Client libraries for most popular languages
    • Full featured router implementations in
    several languages
    

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45. WAMP Routers
    • crossbar.io – Advanced, open-source, full
    featured, supported by the creators of
    WAMP

    • Your own… It’s an open protocol
    

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46. 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

    

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47. Choosing an
    implementation
    Let’s talk about trade-offs
    

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48. Is PHP suitable for soft
    real-time applications?
    

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49. Is PHP the right tool
    for the job?
    

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50. No.
    

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51. No?
    

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52. Why not?
    

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53. Let’s use
    Node.js ! It’s an opportunity to
    deploy Erlang or
    Golang, or …
    

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54. Languages War
    

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55. Conflicts Everywhere
    

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56. Conflicts everywhere
    Trade-offs everywhere
    

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57. 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
    

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58. Is PHP the right tool
    for the job?
    There is not simple answer
    

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59. The simpler answer I know is:
    “I don’t care”
    

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60. PHP Codebase

    (Symfony, Silex, Laravel, Drupal, etc…)
    Clients
    Web, Mobile, etc…
    Request/Response
    

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61. Request/Response
    Real-time API

    Pub/Sub, RPC, etc..
    RPC
    

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62. • A big ecosystem of thousands of useful
    libraries and components easily installable
    thanks to Composer
    • Very powerful template engines, ORMs,
    etc…
    

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63. • 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
    

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64. It’s here to stay
    

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66. Remember
    Full comprehension of both the upsides and downsides
    of a particular choice
    

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67. Downsides
    • We have to introduce a new stack to
    provide real-time features
    

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68. 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
    

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69. Upsides cont…
    • Opens the door to write reactive, event-
    based, distributed architectures
    • Scalability is easier to achieve by
    distributing messages to multiple systems
    

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70. Examples
    

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71. 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
    

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72. 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
    

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74. Tips and Tricks
    • WSS
    • Deadlines
    • Timeouts
    • Retries with back-off, etc…
    • Idempotency
    

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75. 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…
    

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76. 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
    

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77. References
    • WAMP Proto – http://wamp-proto.org/
    • https://github.com/voryx/ThruwayBundle
    • https://www.infoq.com/articles/websocket-
    and-http2-coexist
    

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78. Questions
    • What about React PHP?
    • Multi-Threading in PHP with pthreads?

    https://gist.github.com/krakjoe/6437782/
    • Micro-services what?
    

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79. Gracias!
    @ronnylt
    Work with us!
    

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