Fast Flask Dev For Big Codebases

Transcript

1. Fast Flask dev
   
   for
   
   Big Codebases
   

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2. ssslides
   

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5. Python Mauritius UserGroup
   (pymug)
   More info: mscc.mu/python-mauritius-usergroup-pymug/
   Why Where
   codes github.com/pymug
   share events twitter.com/pymugdotcom
   ping professionals linkedin.com/company/pymug
   all info pymug.com
   tell friends by like facebook.com/pymug
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6. Abdur-Rahmaan Janhangeer
   Help people get into OpenSource
   People hire me to work on Python projects
   www.compileralchemy.com
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7. Fav foreign (https://metabob.com)
   
   
   
   World's most advanced code analysis tool?
   Fav local (https://oceandba.com)
   
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8. Fast Flask dev
   
   for
   
   Big Codebases
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9. The Flask Story
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10. Begin new project
    
    
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11. Code features
    
    
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12. Deploy
    
    
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13. Refine Deploy
    
    
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14. TEST AND PROD ENV DIFFERENT
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15. USE CONFIGURATION PROFILES
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16. ADD APP FACTORY
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17. APP BREAKING
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18. WRITE TESTS
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19. CODE DISORGANISED
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20. ORGANISE CODEBASE
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21. TESTS ARE BORING
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22. WRITE FIXTURES, WRITE SCHEMAS
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23. I HAVE TO START A NEW PROJECT
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24. HAVE A TEMPLATE
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25. NOW I HAVE TO USE APIS
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26. INTEGRATE API-FRAMEWORK
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27. pulls some more hair
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28. I WANT TO INTEGRATE CELERY
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29. INTEGRATE CELERY
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30. dev left ...
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31. THE NEW INTERN DOES NOT UNDERSTAND
    ANYTHING
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32. WRITE DOCS!!!
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33. You need something that flies in all
    weather
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34. The Application Factory
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35. def create_app(app_name):
    
    app = Flask(app_name)
    
    
    
    return app
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36. Configuration Profiles
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37. class Config:
    
    TESTING = False
    
    class ProductionConfig(Config):
    
    FAV_FLOWER = 'rose'
    
    class DevelopmentConfig(Config):
    
    FAV_FLOWER = 'sunflower'
    
    class TestingConfig(Config):
    
    FAV_FLOWER = 'moonlight petal'
    
    TESTING = True
    
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38. from config import ProductionConfig
    
    from config import DevelopmentConfig
    
    from config import TestingConfig
    
    profiles = {
    
    'development': DevelopmentConfig(),
    
    'production': ProductionConfig(),
    
    'testing': TestingConfig()
    
    }
    
    def create_app(profile):
    
    app = Flask(__name__)
    
    app.config.from_object(profiles[profile])
    
    return app
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39. Tests
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40. Use Pytest
    Use class-based testing
    Define fixtures for common actions e.g. logout/login
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41. Docs
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42. Use Sphinx from the start
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43. Separate Initialisations From The Factory
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44. Use a file for initialisations
    Reduces import errors to a max
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45. app.py
    
    init.py
    
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46. init.py
    db = SQLAlchemy()
    
    ma = Marshmallow()
    
    login_manager = LoginManager()
    
    migrate = Migrate()
    
    mail = Mail()
    
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47. from init import mail
    
    def create_app(...):
    
    app = ...
    
    mail.init_app(app)
    
    in other files: from init import db
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48. Use modules for everything!!!
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49. app.py
    
    module1/
    
    module2/
    
    module3/
    
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50. app.py
    
    modules/
    
    module1/
    
    module2/
    
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51. module1/
    
    templates/
    
    static/
    
    test/
    
    models.py
    
    forms.py
    
    view.py
    
    etc
    
    etc
    
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52. Use flask to simplify your life
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53. @app.cli.command("jump", short_help="skip something")
    
    def jump():
    
    # do something
    
    return 0
    
    # cli
    
    flask jump
    
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54. Automate blueprint registration
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55. 1. name each blueprint: foldername_blueprint
    2. In app.py
    # pseudocode
    
    for folder in modules:
    
    blueprint = import(f'modules.{folder}.view.{folder}_blueprint')
    
    app.register(blueprint)
    
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56. Automate module creation
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57. # pseudocode
    
    def createmodule(name):
    
    mkdir(folder)
    
    touch(folder/models.py)
    
    touch(folder/)
    
    ...
    
    # cli
    
    flask createmodule apple
    
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58. Form help yourself
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59. Use flask-wtf
    Use wtforms-alchemy
    class ConfForm(ModelForm):
    
    class Meta:
    
    model = Conf
    
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60. Contain static in module, implement
    collecstatic
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61. app.py
    
    static/ # served from here in production
    
    modules/
    
    m1/
    
    static/
    
    file.png
    m2/
    
    static/
    
    file.png
    collectstatic just collects all assets in all modules and add it
    under
    app.py
    
    static/
    
    modules/
    
    m1/
    
    file.png
    
    m2/
    
    file.png
    
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62. define function serve_asset(module, resource_path)
    
    e.g. serve_asset('m1', 'file.png')
    
    if mode is dev serve from /modules/m1/static/file.png
    
    i.e /modules/module_name/m1/static/path/to/file.png
    
    if mode is prod serve from /static/modules/m1/file.png (assumes collecstatic run before)
    
    i.e /static/modules/module_name/path/to/file.png
    
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63. What for celery?
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64. app.py
    
    init.py
    
    celery_app.py
    
    modules/
    
    m1/
    
    task.py
    
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65. init.py
    celery = Celery(
    
    __name__,
    
    broker=BaseConfig.CELERY_BROKER_URL,
    
    backend=BaseConfig.CELERY_RESULT_BACKEND,
    
    )
    
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66. app.py
    from init import celery
    
    def init_celery(app=None):
    
    app = create_app(os.getenv("FLASK_ENV", ""))
    
    app = app or create_app()
    
    celery.conf.update(app.config)
    
    class ContextTask(celery.Task):
    
    """Make celery tasks work with Flask app context"""
    
    def __call__(self, *args, **kwargs):
    
    with app.app_context():
    
    return self.run(*args, **kwargs)
    
    celery.Task = ContextTask
    
    return celery
    
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67. celery_app.py
    from app import init_celery
    
    celery = init_celery()
    
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68. modules/m1/task.py
    from init import celery
    
    @celery.task(name="do something", bind=True)
    
    def task_do_something(self):
    
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69. What for flask-restx?
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70. modules/
    
    app.py
    
    init.py
    
    api_util.py
    
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71. init.py
    api = Api(
    
    version="1.0",
    
    title="MVP Data",
    
    description="Backend Part",
    
    authorizations=authorizations,
    
    )
    
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72. api_util.py #
    from modules.some.api import some_ns
    
    from modules.some2.api import some2_ns
    
    # ns: namespace
    
    from init import api_v1
    
    api_v = api_v1 # /api/v1
    
    def add_api(api):
    
    api.add_namespace(some_ns, path=api_v + "/someapi")
    
    api.add_namespace(some2_ns, path=api_v + "/someapi2")
    
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73. app.py
    from init import api
    
    from api_util import add_api
    
    def create_app(...):
    
    app = ...
    
    api.init_app(app)
    
    add_api(api)
    
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74. Migrations to the next level
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75. # make flask-migrate auto detect models
    
    for folder in modules:
    
    import(f'modules.{folder}.models.py')
    
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76. Modular migration ideas:
    make flask_migrate or alembic load only specific classes
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77. Reuse base
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78. Use cookiecutter
    cookiecutter
    
    Keep modules and init.py empty
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79. The ongoing conclusion:
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80. https://github.com/shopyo/shopyo
    Star it to show support!
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81. Why not use Django?
    Because Flask
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88. And, that's what shopyo is!
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89. Like it? Appreciate a mail at: arj.python[@]gmail[.]com
    Means a lot to me!
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