Flasky Goodness

Use the best tool for the job.

https://github.com/kennethreitz
http://twitter.com/kennethreitz

Transcript

1. Flasky Goodness Kenneth Reitz (Or Why Django Sucks?)
2. Hi.
3. @kennethreitz
5. Open Source
6. Python-Guide.org • Documented best practices. • Guidebook for newcomers. • Reference for seasoned veterans. • Don’t panic & always carry a towel. The Hitchhiker’s Guide to Python
7. Requests HTTP for Humans
8. Httpbin.org $ curl http://httpbin.org/get?test=1 { "url": "http://httpbin.org/get", "headers": { "Content-Length": "", "Connection": "keep-alive", "Accept": "*/*", "User-Agent": "curl/7.21.4 ...", "Host": "httpbin.org", "Content-Type": "" }, "args": { “test”: “1” }, "origin": "67.163.102.42" }
9. Et Cetera • Legit: Git Work ow for Humans • Envoy: Subprocess for Humans • Tablib: Tabular Data for Humans • Clint: CLI App Toolkit • Autoenv: Magic Shell Environments • OSX-GCC-Installer: Provokes Lawyers 275+ More
10. Open Source All The Things!
11. Build for Open Source • Components become concise & decoupled. • Concerns separate themselves. • Best practices emerge (e.g. no creds in code). • Documentation and tests become crucial. • Code can be released at any time.
12. Abstraction
13. Let’s build something. We’ll use Django, of course.
14. Django Benefits • Makes modular decisions for you. • Makes security decisions for you. • Excellent documentation available. • Installable third-party Django apps. • Tremendous resources & community.
15. Django Handles Things • Admin & Management Interface • Database Schema & Migrations • User Pro les and Authentication • User Sessions and Cookies • Internationalization
16. Anything is possible*.
17. Django Application
18. Django Application Tools & Utilities Web Process Worker Process
19. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process
20. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks
21. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
22. Single Codebases are Great • All the bene ts of the Django stack. • Figure out architecture as you go. • Shared modules keep you DRY. • Make broad and sweeping changes quickly. • Only need to deploy once.
24. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
25. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
26. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
27. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
28. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
29. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
30. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
31. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
32. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
33. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
34. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
35. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
36. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
37. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
38. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
39. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
40. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
41. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
42. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
43. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
44. Django Application Management Tools Supporting Services Tools & Utilities Web Process Worker Process Scheduled Tasks Deferred Tasks API Service CRUD Admin Data Persistence User Interface Authentication
45. Single Codebases are Evil! • Components are tightly coupled. • Broad tribal knowledge is required. • Iterative change of components di cult. • Technical debt has a tendency to spread. • Forced to deploy everything at once.
46. Anything is possible*. * But it’ll often be a monolithic app.
47. CONSTRAINTS FOSTER CREATIVITY
48. Constraints are Good • Text Editors vs IDEs • Prime vs Zoom Lenses • Mac OS X vs Desktop Linux • Pen & Paper vs Digital Notes • Monolithic Apps vs Services
49. Keep ‘em Separated
50. Data Persistence Developers End Users API Service Frontend
51. Build for Open Source • Components become concise & decoupled. • Concerns separate themselves. • Best practices emerge (e.g. no creds in code). • Documentation and tests become crucial. • Code can be released at any time.
52. Build for Services • Components become concise & decoupled. • Concerns seperate themselves. • Best practices emerge (e.g. ideal tools). • Documentation and contracts become crucial. • Services can be scaled separately at any time • Dogfood is delicious.
53. Composability
55. End Users
56. End Users Developers
57. End Users API Service Developers
58. API Service End Users API Service Developers
59. API Service End Users API Service Developers
60. API Service End Users API Service API Service Developers
61. API Service End Users API Service API Service Developers ( )
62. API Service End Users API Service API Service Developers ( ) Data Persistence
63. API Service End Users API Service Internal API Service Developers ( ) Data Persistence
64. API Service End Users API Service Internal API Service Developers ( ) Data Persistence Message Queue Workers
65. Let’s try it out. We’ll use Django, of course.
66. Django: It Just Sits There™
67. Two Basic Components API Service & Frontend Client API Service Frontend Client Data Interface Business Logic Authentication User Interface State and Sessions Public Face
68. Django for API Services • Signi cant boilerplate code for simple views. • No need for templates, tags, etc. • API libraries are buggy; could use some love. • if request.method == 'POST' (and nothing else)
69. Django as API Consumer • Keep in mind, database is handled by API. • Makes modular decisions for you. • Deals with the database for you. • Installable third-party Django apps. (and nothing else)
70. Django as API Consumer • Everything is tied to the ORM. • Third-party Django apps do too. • User model requires sessions; isn’t exible. (and nothing else)
71. What’s Left? ?
72. Flask
73. Enter, Flask. • HTTP Web Framework based on Werkzeug. • Excellent for building web services.
74. Elegant & Simple from flask import Flask app = Flask(__name__) @app.route("/") def hello(): return "Hello World!" if __name__ == "__main__": app.run()
75. Flask Familiarities • WSGI Application Framework. • Built-in Templating System (Jinja2). • Active community, extensions for everything.
76. Flask Philosphies • Started as an April Fool’s joke. • Very minimal; 800 lines of code. • Heavily tested; 1500 lines of tests. • Exhaustively documented; 200 pages of docs. • Layered API; built on Werkzeug, WSGI.
77. Flask Differences • Explicit & passable app objects. • Simple, elegant API. No boiler plate. • BYOB: Bring Your Own Batteries. • No built-in ORM or form validation. • Context locals. Keeps things looking clean.
78. Flask Improvements • Fewer batteries == greater exibility. • Jinja2 is an incredible template system. • Everything harnesses actual references. • Con guration is a simple dictionary. • It’s hard to build monolithic applications. • Response objects are WSGI applications.
79. Flask Improvements • Werkzueug debugger. • No import-time side e ects. • Signals system outside of ORM. • Tests are simpler with real app objects. • return (content, status)
80. Popular Extensions • Flask-SQLAlchemy: Database Mapper. • Flask-Celery: Delayed Jobs. • Flask-Script: Management Commands. • Flask-WTF: Form Validation.
81. Shameless Plug • Flask-SSLify: App HSTS (SSL) Policies • Flask-GoogleFed: Google Federated Auth • Flask-Heroku: Env Variable Con gurations
82. Flask is a sharp tool for building sharp services. Use the right tool for the job.
83. Torn?
84. Flask vs.Django
85. Alcohol vs. Ponies
86. Why not both?
87. Services are agnostic. Just speak HTTP.
88. github.com/kennethreitz Questions?