我找到了问题的原因。

它非常非常 非常。

问题有两个：

1. 没有 USER cron作业中的环境变量；仅 LOGNAME ;


2. 在下运行 manage.py 时一个指定的管理命令，如果在导入设置模块期间引发异常，则Django 安静地会故障转移为空白设置。

1. There is no USER environment variable in a cron job; only LOGNAME;
2. When manage.py is run with a management command specified, Django quietly fails over to blank settings if an exception is raised during the import of the settings module.

我的设置模块正在尝试引用 os.environ ['USER'] ，在cron的环境中不存在。因此，导入设置模块会引发异常，而Django会悄悄地故障转移为空白设置，这意味着空白 INSTALLED_APPS 且没有 celery 命令！

My settings module was trying to reference os.environ['USER'], which doesn't exist in cron's environment. So importing the settings module causes an exception to be raised, and Django quietly fails over to blank settings, which means blank INSTALLED_APPS and no celery command!