路径错误 ImportError：尝试在没有已知父 package 的情况下进行相对导入

Question

像下面这样的项目

server
├── celery.py
├── tasks.py

任务.py

from __future__ import absolute_import, unicode_literals
from sys import path 
from .celery import app_celery
from time import sleep


@app_celery.task
def my_func():
    sleep(5)
    print("Process finished")

celery.py

from __future__ import absolute_import, unicode_literals
from celery import Celery

app_celery = Celery('server',
             broker='redis://',
             backend='redis://',
             include=['server.tasks'])

app_celery.conf.update(
    result_expires=3600,
)

if __name__ == '__main__':
    app_celery.start()

celery -A server worker -l info启动良好，进行如下测试，结果完美

$ ipython
Python 3.7.4 (default, Aug 13 2019, 20:35:49) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.8.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from server.tasks import my_func                                                                                                                     

In [2]: my_func.delay()                                                                                                                                      
Out[2]: <AsyncResult: 39a21329-0e80-4f6e-ac08-536832414756>

我想在server下添加一个脚本test.py

测试.py

from tasks import my_func

my_func.delay()

当我在server下运行python test.py时，它报告

Traceback (most recent call last):
  File "test.py", line 2, in <module>
    from tasks import my_func
  File "/xxx/server/tasks.py", line 3, in <module>
    from .celery import app_celery
ImportError: attempted relative import with no known parent package

Answer 1

在您的服务器目录中添加一个__init__.py文件。 该文件可以为空。

Python 只允许在常规包中进行相对导入。 常规 package 定义为包含__init__.py文件的目录。

https://docs.python.org/3/reference/import.html