Add default session class if backend couldn't be imported.

broker/session.py

@@ -9,7 +9,6 @@
       not these classes directly.
 """
 from contextlib import contextmanager
-import os
 from pathlib import Path
 import tempfile
 
@@ -23,6 +22,7 @@
 SSH_BACKEND = settings.SSH_BACKEND
 
 logger.info(f"{SSH_BACKEND=}")
+
 try:
     if SSH_BACKEND == "ansible-pylibssh":
         from broker.ssh_session_pylibssh import InteractiveShell, Session
@@ -31,12 +31,16 @@
     elif SSH_BACKEND in ("ssh2-python", "ssh2-python312"):
         from broker.ssh_session_ssh2 import InteractiveShell, Session  # noqa: F401
     else:
+        from broker.ssh_session import BaseSession as Session
+
         logger.warning(
             f"SSH backend {SSH_BACKEND!r} not supported.\n"
             "Supported ssh backends:\n"
             f"{SSH_BACKENDS}"
         )
 except ImportError:
+    from broker.ssh_session import BaseSession as Session  # noqa: F401
+
     logger.warning(
         f"{SSH_BACKEND} is not installed.\n"
         "ssh actions will not work.\n"

broker/ssh_session.py

@@ -53,3 +53,7 @@ def _create_connect_socket(host, port, timeout, ipv6=False, ipv4_fallback=True,
     else:
         sock.connect((host, port))
     return sock, ipv6
+
+
+class BaseSession:
+    """Default wrapper around ssh backend's auth/connection system."""