sync errors

sftp.py

@@ -1,12 +1,15 @@
 import io
 import logging
 import posixpath
+import socket
 import stat
 from dataclasses import dataclass
 from pathlib import Path
 
 import paramiko
 
+CONNECT_TIMEOUT = 30  # seconds for TCP + SSH handshake
+
 import db
 from config import SFTPConfig
 
@@ -46,12 +49,18 @@ def get_key_fingerprint(pem: str) -> str | None:
 
 
 def _make_transport(cfg: SFTPConfig) -> paramiko.Transport:
-    transport = paramiko.Transport((cfg.host, cfg.port))
+    log.debug("Opening TCP connection to %s:%s", cfg.host, cfg.port)
+    sock = socket.create_connection((cfg.host, cfg.port), timeout=CONNECT_TIMEOUT)
+    transport = paramiko.Transport(sock)
+    transport.banner_timeout = CONNECT_TIMEOUT
+    transport.handshake_timeout = CONNECT_TIMEOUT
+    log.debug("Starting SSH handshake")
     if cfg.auth_method == "key" and cfg.key:
         key = _load_private_key(cfg.key)
         transport.connect(username=cfg.user, pkey=key)
     else:
         transport.connect(username=cfg.user, password=cfg.password)
+    log.debug("SSH authenticated")
     return transport