Bumping our Stack to PHP 5.5

A bit of a dev story, followed by a bit more of an ops story.

Here's what happened when we decided it was about time to get around to upgrading our PHP 5.3 app to something a bit more current.

Transcript

2. Glen Mailer
3. A short
 audience survey
4. Set the Scene
 (as of September 2013)
5. The Codebase
6. First commit April 2010
 60k commits since According to git
7. 9300 PHP files
 690k lines of code According to cloc
8. 10 releases a week
 35 active committers
 10 concurrent streams
 1 deployable
9. The Platform
10. 8 Test Environments
 1 Staging Environment
 2 Live Environments
11. 74 Live PHP boxes
12. 1300 req/s peak
 500k uniques/week
13. Why Upgrade?
14. Using basically the same PHP version as the first commit with security patches
15. PHP 5.3 is dead
16. Bug fixes
 Performance
17. New Features! short array syntax traits $this in closures yield finally
19. Bug #64827
 GC causes segfaults
20. The Plan
21. Upgrade a dev box Support 5.3 and 5.5 Pass all tests Upgrade 1 Test env Upgrade CI Upgrade Test & Staging Incrementally Upgrade Live
22. Vagrant
 Chef
 Unit Tests
 Acceptance Tests
23. Hack hack hack...
24. 3 days later
25. What changed?
26. APC
 becomes
 OPcache and APCu
27. Check for new function, fall back to old one if (function_exists('opcache_reset')) { opcache_reset(); } else { apc_clear_cache(); }
28. “The PHP api will retain compatibility with APC, as will common configuration options, providing a drop in replacement.” APCu
29. Not a drop in replacement
30. APCu 4.0.1
 APCu 4.0.2
 master is closer still
31. No more
 mysql_
32. It will not be missed
33. preg_replace /e
 becomes
 preg_replace_callback
34. (string) array()
 Now raises a warning Still returns “Array”
35. "Type-checked" function function inc($int) { if (!is_int($int)) { throw new InvalidArgumentException( 'Expected int, got: ' . $int ); } return $int + 1; }
36. Unit test for type-checked function /** * @dataprovider provideIncInvalid */ function testIncRejectsInvalid($a) { try { inc($a); $this->fail('Expected exception'); } catch (InvalidArgumentException $ex) {} } function provideIncInvalid() { return array( null, true, "string", array() ); }
37. Simplest fix throw new InvalidArgumentException( 'Expected int, got: ' . json_encode($int) );
38. $a = "string”;
 $a['index'];
 Now raises a warning
39. // protected $a;
 ++$this->a
 Now raises a warning
40. Progress
41. Upgrade a dev box
 Support 5.3 and 5.5
 Pass all tests
 Upgrade 1 Test env
 Upgrade CI
 Upgrade Test & Staging
 Incrementally Upgrade Live
42. Upgrade a dev box
 Support 5.3 and 5.5
 Pass all tests
 Upgrade 1 Test env
 Upgrade CI
 Upgrade Test & Staging
 Incrementally Upgrade Live
43. PHPNW 2013
44. The Rollout
49. APCu Failures
 APCu #49: Segfaults
 APCu #19: deadlock
50. Forwards
 or
 Backwards
52. Segfaults - 100 point Moving Average 7.2/s 6.0/s 4.8/s 3.6/s 2.4/s 1.2/s Oct Nov Dec Jan
54. Shared Memory?
 I'm out.
55. Can we
 leverage OPCache?
56. The Barwell Cache
57. function barwell_store($key, $value) { $path = BARWELL_BASE . '/' . md5($key); file_put_contents( $path, '<?php return ' . var_export($value, 1) ); opcache_invalidate($path); } function barwell_fetch($key) { return include(BARWELL_BASE . '/' . md5($key)); }
58. function barwell_store_obj($key, $value) { $path = BARWELL_BASE . '/' . md5($key); file_put_contents( $path, '<?php return unserialize("' . serialize($value) . '")' ); opcache_invalidate($path); }
59. Are you mad?
62. Probably.
63. Take a moment.
 Stop.
 Think.
64. What is the problem we're trying to solve?
65. Fast k/v access
 for hot paths
66. How fast do we really need to be?
67. Move almost everything over to memcached
68. Autoload Map
 Environment Config
 Weird Zend Reflection
69. function simple_store($key, $value) { file_put_contents( path($key), serialize($value)); } function simple_fetch($key) { return unserialize( file_get_contents(path($key))); }
70. The
 Aftermath
71. Performance
72. Average Response Time in ms
73. Average Memory Use in MB
74. Average Response Time in ms
 on one API endpoint with minimal external calling
75. New Features
76. 17 Traits
 +
 4 in tests
77. 2 uses of
 finally
78. 37 uses of
 yield
79. New array syntax?
80. A few snowflake boxes are still on 5.3
81. Have bumped minor version a couple of times since
82. Began upgrading
 to 5.6 this week
83. Takeaways
84. Use configuration management tools
85. Frequently upgrade things in small increments
86. Shared memory is inherently complicated
87. Monitor absolutely everything
88. When you think you're doing something crazy
 
 You might be right
89. Understand why you're doing something
90. Fin.
91. @glenathan https://joind.in/11801