The document provides an overview of the modern architecture pattern known as the worker pattern. It discusses risks and uncertainties involved in developing and delivering new functionality for services. It emphasizes designing applications as small, independent services that rely on well-defined dependencies, environment variables, and shared services. The goals are to make creating new applications trivial, provide consistency across production environments, and focus on the application rather than the platform.

1. Modern Architecture

2. The Worker Pattern

3. Modern Architecture

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5. Ryan Smith

6. Ryan Smith
@ryandotsmith

7. ryandotsmith.heroku.com

9. The Vault

11. 1

12. Designed for the Cloud

13. Goals

14. Goals
{ engineering concepts }

15. Goals
{ engineering concepts }
concept => implementation

16. UNIX

17. “Write programs that do one thing and do it well.”
‐‐ Doug McIlroy

20. Background Apps

23. small > large

24. Informal agreement on pre/post conditions.

25. Dependencies

26. Common
HTTP
JSON
Queueing
Scheduling

27. Formal Declaration

28. Easy install for new developers.

29. Consistency in Production.

30. Java Maven
Ruby Bundler
Python Pip
Node.js NPM
Clojure Lein

32. Environment

33. Production
Staging
Development

34. Creating apps should be trivial.

35. Caveat

36. Caveat
Staging Credit Card gateway

37. Caveat
Staging Credit Card gateway
$VERBOSE=‘true’

38. Application Code
if ENV[‘VERBOSE’] == ‘true’
log(‘message’)
end

39. Application Code
if ENV[‘VERBOSE’] == ‘true’
log(‘message’)
end
Production Environment
$ export VERBOSE=‘false’

40. Application Code
if ENV[‘VERBOSE’] == ‘true’
log(‘message’)
end
Production Environment
$ export VERBOSE=‘false’
Development Environment
$ export VERBOSE=‘true’

42. cat .env | xargs env

43. Services

44. Database

45. Database
Cache

46. Database
Cache
Message Bus

47. Database
Cache
Message Bus
Log Drain

48. Database
Cache
Message Bus
Log Drain
Heartbeat Monitor

49. Everything is a service.

50. New Features :)
DBA :(

51. CREATE INDEX

52. PRO TIP
CREATE INDEX CONCURRENTLY

53. Provision a new DB in < 60s

54. Configured in environment.

55. database = DB.connect(
ENV[“DATABASE_URL”]
);

56. App App
DB

57. App App
DB

58. Deploy

59. Developer Deploys Code

60. I want for my deploy.

61. Incremental Rollout

62. SELECT ... WHERE MOD(id, 4) = 0;

63. Rollback

64. Continuous Deployment

65. Visibility

66. Science

67. Hypothesis

68. Hypothesis
Conclude Implications

69. Hypothesis
Conclude Implications
Observe Reality*

70. Logging

71. Think of your logs as streams of data.

72. App App App
Log Service
Log Drain API

74. papertrail Sinatra Heroku API
heroku restart -a app_name -ps worker.5

76. App App App
Log Service
Log Drain API

77. log = event stream

79. Administration

80. If you do it twice, automate it.

81. Conclusion

82. Small Apps

83. Small Apps
Dependencies

84. Small Apps
Dependencies
Environment Vars

85. Small Apps
Dependencies
Environment Vars
Services

86. Small Apps
Dependencies
Environment Vars
Services
Deployment

87. Small Apps
Dependencies
Environment Vars
Services
Deployment
Visibility

88. Focus on your application not your platform

89. finnish