通过 docker-compose 运行时，Flask CLI 抛出“OSError: [Errno 8] Exec format error”

我正在运行一个 Flask 应用程序自定义脚本。无论如何，或者尝试这样做。

我使用的是 Windows 10，应用程序应该使用以下命令在 Linux Docker 容器中运行：

docker-compose up api

Docker-compose 是version 1.23.2。在 dockerfile 中，api服务通过以下命令运行：

command: python manage.py run --host "0.0.0.0" --with-threads

当它尝试启动时，我看到了异常

OSError: [Errno 8] Exec format error: '/api/manage.py'

我最初以为这将是可怕的 Windows 行结尾，再次为我而来，但正在运行dos2unix我的所有源文件都没有解决问题。

我怎样才能避免这个错误？

管理.py

    import click
    from flask.cli import FlaskGroup

    from my_app_api import create_app


    def create_my_app(info):
        return create_app()


    @click.group(cls=FlaskGroup, create_app=create_my_app)
    def cli():
        pass


    if __name__ == "__main__":
        cli()

全程追溯

api_1          | Traceback (most recent call last):
api_1          |   File "manage.py", line 22, in <module>
api_1          |     cli()
api_1          |   File "/usr/local/lib/python3.6/site-packages/click/core.py", line 764, in __call__
api_1          |     return self.main(*args, **kwargs)
api_1          |   File "/usr/local/lib/python3.6/site-packages/flask/cli.py", line 380, in main
api_1          |     return AppGroup.main(self, *args, **kwargs)
api_1          |   File "/usr/local/lib/python3.6/site-packages/click/core.py", line 717, in main
api_1          |     rv = self.invoke(ctx)
api_1          |   File "/usr/local/lib/python3.6/site-packages/click/core.py", line 1137, in invoke
api_1          |     return _process_result(sub_ctx.command.invoke(sub_ctx))
api_1          |   File "/usr/local/lib/python3.6/site-packages/click/core.py", line 956, in invoke
api_1          |     return ctx.invoke(self.callback, **ctx.params)
api_1          |   File "/usr/local/lib/python3.6/site-packages/click/core.py", line 555, in invoke
api_1          |     return callback(*args, **kwargs)
api_1          |   File "/usr/local/lib/python3.6/site-packages/click/decorators.py", line 64, in new_func
api_1          |     return ctx.invoke(f, obj, *args, **kwargs)
api_1          |   File "/usr/local/lib/python3.6/site-packages/click/core.py", line 555, in invoke
api_1          |     return callback(*args, **kwargs)
api_1          |   File "/usr/local/lib/python3.6/site-packages/flask/cli.py", line 438, in run_command
api_1          |     use_debugger=debugger, threaded=with_threads)
api_1          |   File "/usr/local/lib/python3.6/site-packages/werkzeug/serving.py", line 988, in run_simple
api_1          |     run_with_reloader(inner, extra_files, reloader_interval, reloader_type)
api_1          |   File "/usr/local/lib/python3.6/site-packages/werkzeug/_reloader.py", line 332, in run_with_reloader
api_1          |     sys.exit(reloader.restart_with_reloader())
api_1          |   File "/usr/local/lib/python3.6/site-packages/werkzeug/_reloader.py", line 176, in restart_with_reloader
api_1          |     exit_code = subprocess.call(args, env=new_environ, close_fds=False)
api_1          |   File "/usr/local/lib/python3.6/subprocess.py", line 287, in call
api_1          |     with Popen(*popenargs, **kwargs) as p:
api_1          |   File "/usr/local/lib/python3.6/subprocess.py", line 729, in __init__
api_1          |     restore_signals, start_new_session)
api_1          |   File "/usr/local/lib/python3.6/subprocess.py", line 1364, in _execute_child
api_1          |     raise child_exception_type(errno_num, err_msg, err_filename)
api_1          | OSError: [Errno 8] Exec format error: '/api/manage.py'

看起来像你的api/manage.py没有shebang ([维基百科]：Shebang (Unix)），所以默认（当前）命令处理器（ashell- 通常bash）正在尝试运行它，但（显然）失败了。

要纠正该问题，请添加shebang（在文件的开头，确保您的编辑器添加了Nix样式行尾 (\n, 0x0A, LF)):

• Default Python安装：

  #!/usr/bin/env python
  

  • 变体（指定Python 3明确）：

    #!/usr/bin/env python3
    

• Custom Python安装：

  #!/full/path/to/your/custom/python/executable
  

请注意，您还需要exec文件的权限（chmod +x api/manage.py).

Example:

[cfati@cfati-5510-0:/cygdrive/e/Work/Dev/StackOverflow/q055271912]> ~/sopr.sh
### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###

[064bit prompt]> ls
code00.py  code01.py
[064bit prompt]>
[064bit prompt]> cat code00.py
print("This is:", __file__)

[064bit prompt]> python3 -c "import os, subprocess;subprocess.Popen(os.path.join(os.getcwd(), \"code00.py\")).communicate()"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3.6/subprocess.py", line 709, in __init__
    restore_signals, start_new_session)
  File "/usr/lib/python3.6/subprocess.py", line 1344, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
OSError: [Errno 8] Exec format error: '/cygdrive/e/Work/Dev/StackOverflow/q055271912/code00.py'
[064bit prompt]>
[064bit prompt]> cat code01.py
#!/usr/bin/env python3

print("This is:", __file__)

[064bit prompt]> python3 -c "import os, subprocess;subprocess.Popen(os.path.join(os.getcwd(), \"code01.py\")).communicate()"
This is: /cygdrive/e/Work/Dev/StackOverflow/q055271912/code01.py

另一种方法是运行解释器，后跟文件名，但我不知道如何从Flask- 实际上这需要修补Werkzeug (_reloader.py: _get_args_for_reloading），但这只是一个蹩脚的解决方法（gainarie） - 见下文。

Update #0

看看@AxelGrytt的回答，发现这是一个已知问题：[GitHub]：pallets/werkzeug - 0.15.0 导致 OSError：[Errno 8] Exec 格式错误：在 Docker for Windows 中（嗯，在这个问题的同一天提交（发布后2天）:)）。

所以，我上面所说的是正确的，但值得一提的是，还有另一种修复方法：删除exec文件的权限：

chmod -x api/manage.py

根据Werkzeug作者们，从现在开始，这是期望的行为（也适用于v0.15.2):

• A file with exec权限集，should还有一个shebang
• A file without a shebang, 不应该有exec权限集