如何在应用程序工厂模式下管理其他模块? [英] How can I manage extra modules in app factory pattern?

问题描述

我正在使用带有应用程序工厂模式的烧瓶. 我知道应用程序工厂模式仅在工厂功能中管理配置对象. (如以下代码所示)

I'm using flask with the app factory pattern. I do know that the app factory pattern manages configuration objects only in the factory function. (as in the following code)

def create_app(config):
    app.config.from_object(config)
    sentry.init(app)
    ...

    return app

但是我该如何管理需要该配置但无法在应用程序创建时初始化的额外模块?

But how do I manage the extra module that needs that configuration, but couldn't be initialized in app creating time?

所以我想做类似的事情

def create_app(config):
    some_module_obj = Module(host=config.host, port=config.port)

    app.config.from_object(config)
    sentry.init(app)

    return some_module_obj, app

而不是

# I don't want to use `config` outside of the `create_app` function!
some_module_obj = Module(host=config.host, port=config.port)

def create_app(config):
    app.config.from_object(config)
    sentry.init(app)

    return app

推荐答案

不确定是不是您需要的，但是您要求在注释中添加inject + Flask的小示例.据我了解，主要问题与Flask + configuration + initialization有关.这只是它如何工作的一个示例.

Not sure that is what you need, but you asked for a small example with inject + Flask in comments. As I understood the main problem is related with Flask + configuration + initialization. This is just an example how it works.

app.py:

from flask import Flask

from api import bp
from configurator import configure


def create_app():
    app = Flask(__name__)
    # configure Flask app config as you wish... (app.config.from_object(config))
    # just some settings for demonstration
    app.config.update(dict(
        MODULE1_TIMER=1,
        MODULE2_LIMIT=2,
    ))
    # configure inject using app context and Flask config
    with app.app_context():
        configure()
    # demo blueprint
    app.register_blueprint(bp)

    return app


if __name__ == '__main__':
    create_app().run(debug=True)

让我们想象一下，我们有一些模块:

Let's imagine that we have some modules:

# mod1.py
class Module1:
    def __init__(self, timer: int) -> None:
        self._timer = timer

# mod2.py
class Module2:
    def __init__(self, limit: int) -> None:
        self._limit = limit

    def get_limit(self):
        return self._limit

# mod3.py - works with mod1 and mod2
class Module3:
    def __init__(self, module1, module2) -> None:
        self._module1 = module1
        self._module2 = module2

    def get_limit(self):
        return self._module2.get_limit()

configurator.py :

import inject
from flask import current_app

from mod1 import Module1
from mod2 import Module2
from mod3 import Module3


@inject.params(
    module1=Module1,
    module2=Module2,
)
def _init_module3(module1, module2):
    # module1 and module2 are injected instances
    return Module3(module1, module2)


def _injector_config(binder):
    # initialization of Module1 and Module2 using Flask config
    binder.bind(Module1, Module1(current_app.config['MODULE1_TIMER']))
    binder.bind(Module2, Module2(current_app.config['MODULE2_LIMIT']))
    # initialization of Module3 using injected Module1 + Module2
    # you can use bind_to_constructor + any function
    binder.bind_to_constructor(Module3, _init_module3)


def configure():
    def config(binder):
        binder.install(_injector_config)
        # one more binder.install... etc...

    inject.clear_and_configure(config)

api.py :

import inject
from flask import Blueprint, jsonify

from mod1 import Module1
from mod2 import Module2
from mod3 import Module3

bp = Blueprint('api', __name__)


@bp.route('/test')
def test():
    # get instances which was created using inject
    return jsonify(dict(
        module1=str(type(inject.instance(Module1))),
        module2=str(type(inject.instance(Module2))),
        module3=str(type(inject.instance(Module3))),
    ))


# you can inject something as arg
@bp.route('/test2')
@inject.params(module3=Module3)
def test2(module3: Module3):
    return jsonify(dict(module3=str(type(module3))))


@bp.route('/test3')
def test3():
    # you can inject something into anything
    class Example:
        module3 = inject.attr(Module3)

        @inject.params(module2=Module2)
        def __init__(self, module2: Module2) -> None:
            self.module2 = module2

    return jsonify({
        'MODULE2_LIMIT': Example.module3.get_limit(),
        'example': dir(Example()),
    })

运行服务器，打开/test，test2，/test3.

Run server, open /test, test2, /test3.

关于好处的几句话:

• 初始化和配置要点
• 降低对current_app，flask配置/上下文等的依赖.
• 递归导入的问题较少
• 易于编写测试

希望这会有所帮助.

这篇关于如何在应用程序工厂模式下管理其他模块?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！