部署 Django/Heroku 時，PySFTP 失敗並顯示“找不到主機 X 的主機密鑰”

Question

我正在嘗試部署一個 Django Web 應用程序，該應用程序使用 pysftp 通過某些視圖訪問 SFTP 服務器。

這東西在本地開發中完美運行，但是在 Heroku 上嘗試第一次部署時，下面的回溯似乎以錯誤結尾。 似乎我需要配置主機密鑰，我相信我還需要在 Heroku 的 known_hosts 中設置它們，但我不知道如何做到這一點。 在本地開發中，我使用用戶/密碼訪問沒有問題，但從 Heroku 中出現此錯誤：

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

你可以在這里看到整個輸出：

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

有關“No hostkey for host ... found”的一般性討論，請參閱：
使用 pysftp 驗證主機密鑰

---

關於 Heroku 上的實現：我不熟悉它，但是 afaik，正如你所評論的，它沒有持久的文件存儲。

因此，使用具有硬編碼主機密鑰的實現是合適的。 我對上述問題的回答中的兩個解決方案適合需要：

1. 如果不想使用外部文件，也可以使用

   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. 如果您只需要使用其指紋驗證主機密鑰，請參閱Python - pysftp / paramiko - 使用其指紋驗證主機密鑰。

---

這也是相關的（雖然直接關於 Paramiko，而不是關於 pysftp 包裝器）：
在 Web 服務器上運行時，Paramiko SSH 失敗並顯示“Server '...' not found in known_hosts”