python - 部署 Django/Heroku 时 PySFTP 失败并显示 "No hostkey for host X found"

Question

我正在尝试部署一个 Django Web 应用程序，该应用程序使用 pysftp 通过某些 View 访问 SFTP 服务器。

这件事在本地开发中运行得很好，但是当尝试在 Heroku 上进行第一次部署时，下面的回溯似乎以错误结束。似乎我需要配置主机 key ，并且我相信我还需要在 Heroku 的known_hosts 中设置它们，但我不知道如何做到这一点。在本地开发中，我使用用户/密码访问没有问题，但从 Heroku 出现此错误:

remote: paramiko.ssh_exception.SSHException: No hostkey for host somehost.myftp.org found

您可以在此处查看整个输出:

remote: -----> Compressing...
remote:        Done: 68.8M
remote: -----> Launching...
remote:  !     Release command declared: this new release will not be available until the command succeeds.
remote:        Released v16
remote:        https://somehostonlineproject.herokuapp.com/ deployed to Heroku
remote: 
remote: Verifying deploy... done.
remote: Running release command...
remote: 
remote: ===============> ParseResult(scheme='', netloc='', path='somehost.sytes.net', params='', query='', fragment='')
remote: /app/.heroku/python/lib/python3.7/site-packages/pysftp/__init__.py:61: UserWarning: Failed to load HostKeys from /app/.ssh/known_hosts.  You will need to explicitly load HostKeys (cnopts.hostkeys.load(filename)) or disableHostKey checking (cnopts.hostkeys = None).
remote:   warnings.warn(wmsg, UserWarning)
remote: Traceback (most recent call last):
remote:   File "manage.py", line 31, in <module>
remote:     execute_from_command_line(sys.argv)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
remote:     utility.execute()
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/__init__.py", line 375, in execute
remote:     self.fetch_command(subcommand).run_from_argv(self.argv)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/base.py", line 323, in run_from_argv
remote:     self.execute(*args, **cmd_options)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/base.py", line 361, in execute
remote:     self.check()
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/base.py", line 390, in check
remote:     include_deployment_checks=include_deployment_checks,
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/commands/migrate.py", line 65, in _run_checks
remote:     issues.extend(super()._run_checks(**kwargs))
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/base.py", line 377, in _run_checks
remote:     return checks.run_checks(**kwargs)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/checks/registry.py", line 72, in run_checks
remote:     new_errors = check(app_configs=app_configs)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/checks/urls.py", line 40, in check_url_namespaces_unique
remote:     all_namespaces = _load_all_namespaces(resolver)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/core/checks/urls.py", line 57, in _load_all_namespaces
remote:     url_patterns = getattr(resolver, 'url_patterns', [])
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
remote:     res = instance.__dict__[self.name] = self.func(instance)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/urls/resolvers.py", line 584, in url_patterns
remote:     patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
remote:     res = instance.__dict__[self.name] = self.func(instance)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/urls/resolvers.py", line 577, in urlconf_module
remote:     return import_module(self.urlconf_name)
remote:   File "/app/.heroku/python/lib/python3.7/importlib/__init__.py", line 127, in import_module
remote:     return _bootstrap._gcd_import(name[level:], package, level)
remote:   File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
remote:   File "<frozen importlib._bootstrap>", line 983, in _find_and_load
remote:   File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
remote:   File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
remote:   File "<frozen importlib._bootstrap_external>", line 728, in exec_module
remote:   File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
remote:   File "/app/config/urls.py", line 27, in <module>
remote:     path("browse/", include("django_sftpbrowser.urls", namespace="sftpbrowser-root"), name='browse_option'),
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/django/urls/conf.py", line 34, in include
remote:     urlconf_module = import_module(urlconf_module)
remote:   File "/app/.heroku/python/lib/python3.7/importlib/__init__.py", line 127, in import_module
remote:     return _bootstrap._gcd_import(name[level:], package, level)
remote:   File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
remote:   File "<frozen importlib._bootstrap>", line 983, in _find_and_load
remote:   File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
remote:   File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
remote:   File "<frozen importlib._bootstrap_external>", line 728, in exec_module
remote:   File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
remote:   File "/app/django_sftpbrowser/urls.py", line 2, in <module>
remote:     from .views import browse_page
remote:   File "/app/django_sftpbrowser/views.py", line 9, in <module>
remote:     srv = pysftp.Connection(settings.SOMEHOST_SFTP_SERVER_URL, username='madtyn', password=settings.SFTP_PASSWORD)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/pysftp/__init__.py", line 132, in __init__
remote:     self._tconnect['hostkey'] = self._cnopts.get_hostkey(host)
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/pysftp/__init__.py", line 71, in get_hostkey
remote:     raise SSHException("No hostkey for host %s found." % host)
remote: paramiko.ssh_exception.SSHException: No hostkey for host somehost.myftp.org found.
remote: Exception ignored in: <function Connection.__del__ at 0x7fd94274b950>
remote: Traceback (most recent call last):
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/pysftp/__init__.py", line 1013, in __del__
remote:     self.close()
remote:   File "/app/.heroku/python/lib/python3.7/site-packages/pysftp/__init__.py", line 784, in close
remote:     if self._sftp_live:
remote: AttributeError: 'Connection' object has no attribute '_sftp_live'
remote: Waiting for release... failed.
To https://git.heroku.com/somehostonlineproject.git
 * [new branch]      deployment -> master

Answer 1

有关“找不到主机的主机 key ...”的一般讨论，请参阅:
Verify host key with pysftp

<小时/>

关于 Heroku 上的实现:我不熟悉它，但是据我所知，正如您所评论的那样，它没有持久文件存储。

因此，使用硬编码主机 key 的实现是合适的。我对上述问题的回答中有两个解决方案适合需要:

1. If you do not want to use an external file, you can also use

   from base64 import decodebytes
   # ...
   
   keydata = b"""AAAAB3NzaC1yc2EAAAADAQAB..."""
   key = paramiko.RSAKey(data=decodebytes(keydata))
   cnopts = pysftp.CnOpts()
   cnopts.hostkeys.add('example.com', 'ssh-rsa', key)
    
   with pysftp.Connection(host, username, password, cnopts=cnopts) as sftp:
   

2. If you need to verify the host key using its fingerprint only, see Python - pysftp / paramiko - Verify host key using its fingerprint.

<小时/>

这也是相关的(直接与 Paramiko 相关，而不是与 pysftp 包装器相关):
Paramiko SSH failing with "Server '...' not found in known_hosts" when run on web server