Caching with PSRs at PHP Tour

In this talk you will learn what PSR-6 and PSR-16 are, why they are designed like they are, what the differences are, and how to use them. From the provided interfaces, the virtual package on Packagist.org, to the implementations available. Everything will be explained for both beginners and more experienced developers. We will dive into implementations, cache stampede protection, all using libraries we can find on Packagist.org. We will also show how to start using it today in our current applications by using adapters. The entire talk will be accompanied with code samples and live demos, showing both working and failing caching systems.

Transcript

1. Caching with PSRs
   PHP Tour Montpellier
   #phptour @hannesvdvreken
   

   View Slide

2. Hi, my name is Hannes.
   

   View Slide

3. Caching PSRs
   Caching in PHP anno 2018
   

   View Slide

4. 1. Intro
   2. Caching in 2015
   3. Hello PSR-6
   4. Hello PSR-16
   

   View Slide

5. 1. Intro
   what is caching?
   

   View Slide

6. WHAT IS CACHING
   Speeding up your
   app
   

   View Slide

7. WHAT IS CACHING
   1. Query stored value
   2.Execute slow task
   3.Remember result
   

   View Slide

8. WHAT IS CACHING
   Should not cause
   app failure
   

   View Slide

9. WHAT IS CACHING - EXAMPLES
   • HTTP Request
   • Slow DB call
   • Process image/zip/…
   

   View Slide

10. WHAT IS CACHING
    Should not cause
    app failure
    

    View Slide

11. WHAT IS CACHING
    geocode IP
    check cache store result
    check cache
    

    View Slide

12. WHAT IS CACHING
    Should not cause
    app failure
    

    View Slide

13. WHAT IS CACHING
    At different layers:
    User-Agent
    Webserver (Varnish/Nginx)
    Application
    Opcache
    

    View Slide

14. WHAT IS CACHING
    Should not cause
    app failure
    

    View Slide

15. WHAT IS CACHING
    • cache busting
    • TTL
    • warming up
    

    View Slide

16. 2. Caching in 2015
    the state of caching (pre PSR-FIG)
    

    View Slide

17. APPLICATION CACHING IN 2015
    1. Libraries do it
    2.Frameworks do it
    3.Cache libs do it
    

    View Slide

18. APPLICATION CACHING IN 2015
    Frameworks & cache libs have their own:
    - set of supported caching back-
    ends
    - maybe an interface to allow
    custom implementations
    

    View Slide

19. APPLICATION CACHING IN 2015
    Adapters everywhere!
    

    View Slide

20. APPLICATION CACHING IN 2015
    Framework X cache Framework Y cache
    Package W cache Cache package Z
    Adapter W->X Adapter W->Y
    Adapter W->Z
    Adapter Y->Z
    

    View Slide

21. APPLICATION CACHING IN 2015
    If no adapter available
    - Write your own
    - Store in different cache stores

    (ops will not love you for that)
    

    View Slide

22. 3. Hello PSR-6
    

    View Slide

23. INTRODUCING PSR-6
    Finalized & accepted
    in December 2015
    

    View Slide

24. INTRODUCING PSR-6
    Repository - Entity
    

    View Slide

25. INTRODUCING PSR-6
    use Psr\Cache\CacheItemPoolInterface;
    use Psr\Cache\CacheItemInterface;
    $item = $pool->getItem($key);
    $item->getKey();
    $item->get();
    

    View Slide

26. INTRODUCING PSR-6
    Item is an entity,
    it’s not immutable,
    but the Key is
    

    View Slide

27. INTRODUCING PSR-6
    Don’t instantiate your own Items.
    $item = $pool->getItem(‘key’)
    ->set($value)
    ->expiresAfter(3600);
    $pool->save($item);
    

    View Slide

28. INTRODUCING PSR-6
    Pool has support for multi-actions
    $pool->getItems($keys);
    $pool->saveDeferred($item);
    $pool->commit();
    

    View Slide

29. INTRODUCING PSR-6
    Repository - Entity model
    allows extensions
    

    View Slide

30. INTRODUCING PSR-6
    Allows future specced features by
    reserving characters
    - {}()/\@:
    

    View Slide

31. INTRODUCING PSR-6
    Cache features:
    - Stampede protection:
    Parallel incoming requests
    executing long process to
    update cache value
    

    View Slide

32. STAMPEDE PROTECTION
    

    View Slide

33. STAMPEDE PROTECTION
    

    View Slide

34. STAMPEDE PROTECTION
    

    View Slide

35. STAMPEDE PROTECTION
    

    View Slide

36. STAMPEDE PROTECTION
    

    View Slide

37. STAMPEDE PROTECTION
    

    View Slide

38. STAMPEDE PROTECTION
    

    View Slide

39. STAMPEDE PROTECTION
    

    View Slide

40. STAMPEDE PROTECTION
    

    View Slide

41. INTRODUCING PSR-6
    Cache features:
    - Stampede protection
    - Taggable cache
    cache/taggable-cache
    

    View Slide

42. INTRODUCING PSR-6
    Cache features:
    - Stampede protection
    - Taggable cache
    $item->setTags([‘cat-1']);
    $pool->invalidateTags([‘cat-1’]);
    

    View Slide

43. INTRODUCING PSR-6
    Cache features:
    - Stampede protection
    - Taggable cache
    - Hierarchical cache
    cache/hierarchical-cache
    

    View Slide

44. INTRODUCING PSR-6
    Cache features:
    - Stampede protection
    - Taggable cache
    - Hierarchical cache
    $pool->hasItem('|users|4711|followers'); // true
    $pool->delete(‘|users|4711');
    $pool->hasItem('|users|4711|followers'); // false
    

    View Slide

45. Practical
    who uses it, and how can I use it?
    

    View Slide

46. View Slide

47. View Slide

48. View Slide

49. START USING IT
    Integration tests for
    implementations:
    cache/integration-tests
    

    View Slide

50. View Slide

51. START USING IT
    class PoolIntegrationTest extends CachePoolTest
    {
    public function createCachePool()
    {
    return new MyCustomCachePool();
    }
    }
    

    View Slide

52. START USING IT
    cache/taggable-cache
    cache/namespaced-cache
    cache/hierarchical-cache
    cache/chain-adapter
    cache/array-adapter
    cache/void-adapter
    cache/prefix-adapter
    

    View Slide

53. START USING IT - UPGRADE
    Upgrade paths
    

    View Slide

54. START USING IT - UPGRADE
    Libraries
    

    View Slide

55. START USING IT - UPGRADE
    Libraries (next major versions)
    have a PSR-6 caching decorator
    

    View Slide

56. START USING IT - UPGRADE
    Frameworks
    

    View Slide

57. START USING IT - UPGRADE
    Start using PSR-6 enabled libraries
    with adapters for current FW’s
    implementation.
    

    View Slide

58. START USING IT - UPGRADE
    Example:
    symfony/cache
    cache/illuminate-adapter
    

    View Slide

59. START USING IT
    Adoption?
    

    View Slide

60. View Slide

61. 4. Hello PSR-16
    

    View Slide

62. INTRODUCING PSR-16
    Finalised & accepted
    in December 2016
    

    View Slide

63. One simple interface
    INTRODUCING PSR-16
    

    View Slide

64. Psr\SimpleCache\CacheInterface
    INTRODUCING PSR-16
    

    View Slide

65. // Returns null when not available.
    // Returns null when you set it to null.
    $cache->set($key, null);
    $value = $cache->get($key); // null
    INTRODUCING PSR-16
    

    View Slide

66. $cache->set($key, new ValueObject());
    INTRODUCING PSR-16
    

    View Slide

67. CacheInterface::getMultiple
    CacheInterface::setMultiple
    CacheInterface::deleteMultiple
    INTRODUCING PSR-16
    

    View Slide

68. Differences from PSR-6
    - No `null` values
    - No deferring
    INTRODUCING PSR-16
    

    View Slide

69. Also allows future extension thanks to
    reservation of characters
    - {}()/\@:
    INTRODUCING PSR-16
    

    View Slide

70. Practical
    who uses it, and how can I use it?
    

    View Slide

71. View Slide

72. View Slide

73. START USING IT
    Upgrade path?
    Same as PSR-6
    

    View Slide

74. START USING IT
    Adoption?
    

    View Slide

75. View Slide

76. View Slide

77. View Slide

78. $laravelCache = App::make(‘cache’);
    $psr6Cache = new IlluminateCachePool($laravelCache);
    $psr16Cache = new SimpleCacheBridge($psr6Cache);
    INTRODUCING PSR-16
    

    View Slide

79. 1. Intro
    2. Caching in 2015
    3. Hello PSR-6
    4. Hello PSR-16
    RECAP
    

    View Slide

80. Thank you!
    #phptour @hannesvdvreken
    

    View Slide

81. Time for questions!
    #phptour @hannesvdvreken
    

    View Slide