fastapi - 从 main.py 导入配置

Question

我是 fastapi 的新手，到目前为止真的很棒，但我很难找到一种干净的方法将我的应用程序配置导入另一个模块。

编辑：我需要能够在运行单元测试时更改配置

这是我的目录树：

/app
| __init__.py
| /router
| | __init__.py
| | my_router.py
| /test
| | test_api.py
| config.py
| main.py

这是我的main.py文件：

from functools import lru_cache

from fastapi import FastAPI

from .router import my_router
from . import config

app = FastAPI()

app.include_router(
    my_router.router,
    prefix="/r",
    tags=["my-router"],
)


@lru_cache()
def get_setting():
    return config.Settings(admin_email="admin@domain.com")


@app.get('/')
def hello():
    return 'Hello world'

这是router.py ：

from fastapi import APIRouter

from ..main import get_setting

router = APIRouter()

@router.get('/test')
def get_param_list(user_id: int):
    config = get_setting()
    return 'Import Ok'

这是配置文件

from pydantic import BaseSettings


class Settings(BaseSettings):
    param_folder: str = "param"
    result_folder: str = "output"

    class Config:
        env_prefix = "APP_"

然后运行uvicorn app.main:app --reload我得到： ERROR: Error loading ASGI app. Could not import module "app.main". ERROR: Error loading ASGI app. Could not import module "app.main". 我猜是因为一种循环导入。 但是我不知道如何将我的配置传递给我的路由器？

谢谢你的帮助：）

Answer 1

直接在config.py中设置 lru 缓存怎么样。

from functools import lru_cache
from pydantic import BaseSettings


class Settings(BaseSettings):
    admin_email: str = "admin@example.com"
    param_folder: str = "param"
    result_folder: str = "output"

    class Config:
        env_prefix = "APP_"

@lru_cache()
def get_setting():
    return Settings()

和my_router.py

from fastapi import APIRouter, Depends

from ..config import Settings, get_setting

router = APIRouter()

@router.get('/test')
def get_param_list(config: Settings = Depends(get_setting)):
    return config

和test.py

from fastapi.testclient import TestClient

from . import config, main

client = TestClient(main.app)


def get_settings_override():
    return config.Settings(admin_email="testing_admin@example.com")


main.app.dependency_overrides[config.get_settings] = get_settings_override

def test_app():
    response = client.get("/r/test")
    data = response.json()
    assert data == config.Settings(admin_email="testing_admin@example.com")

Answer 2

我使用 FastAPI Dependency 系统让它工作，并且按照@Kassym Dorsel 的建议，通过将 lru_cache 移动到config.py 。

唯一的缺点是我必须在每个需要设置的 function 调用中添加setting: config.Setting = Depends(config.get_setting) ，这非常“繁重”。

我是这样做的：

config.py文件：

from pydantic import BaseSettings


class Settings(BaseSettings):
    param_folder: str = "param"
    result_folder: str = "output"

    class Config:
        env_prefix = "APP_"

@lru_cache()
def get_setting():
    return config.Settings(admin_email="admin@domain.com")

main.py文件：

from functools import lru_cache

from fastapi import FastAPI

from .router import my_router

app = FastAPI()

app.include_router(
    my_router.router,
    prefix="/r",
    tags=["my-router"],
)

@app.get('/')
def hello():
    return 'Hello world'

router.py文件：

from fastapi import APIRouter, Depends

from .. import config

router = APIRouter()

@router.get('/test')
def get_param_list(user_id: int, setting: config.Setting = Depends(config.get_setting)):
    return setting

这样我就可以使用test_api.py中的dependency_overrides来更改测试的配置：

from fastapi.testclient import TestClient

from .. import config, server

client = TestClient(server.app)

TEST_PARAM_FOLDER = 'server/test/param'
TEST_RESULT_FOLDER = 'server/test/result'

def get_setting_override():
    return config.Setting(param_folder=TEST_PARAM_FOLDER, result_folder=TEST_RESULT_FOLDER)


server.app.dependency_overrides[config.get_setting] = get_setting_override

def test_1():
    ...

Answer 3

唯一的缺点是我必须在每个需要设置的 function 调用中添加设置：config.Setting = Depends(config.get_setting)，这非常“繁重”。

您可以使用来自 fastapi_utils package 的基于Class 的视图：

from fastapi import APIRouter, Depends
from fastapi_utils.cbv import cbv
from starlette import requests
from logging import Logger
from .. import config

router = APIRouter()

@cbv(router)
class MyQueryCBV:
    settings: config.Setting = Depends(config.get_setting)  # you can introduce settings dependency here

    def __init__(self, r: requests.Request):  # called for each query
        self.logger: Logger = self.settings.logger
        self.logger.warning(str(r.headers))

    @router.get('/test')
    def get_param_list(self, user_id: int)
        self.logger.warning(f"get_param_list: {user_id}")
        return self.settings

    @router.get("/test2")
    def get_param_list2(self):
        self.logger.warning(f"get_param_list2")
        return self.settings