LFTP timeout locks thread, requires restart

[nitrobass24]

When LFTP times out, the thread doesn't recover properly. Download speeds drop significantly and stay low until the container is restarted.

pexpect.exceptions.TIMEOUT: Timeout exceeded.

The LFTP process appears to get stuck and subsequent commands don't work correctly.

Potential fix: Better timeout recovery, possibly killing and restarting the LFTP process after repeated timeouts.

Ref: ipsingh06/seedsync#119

[Boss-man]

Dont know, but maybe have something to do with the low timeout value here:

seedsync/src/python/lftp/lftp.py

Line 58 in 7260932

self.__timeout = 3 # in seconds

3 seconds seems to be a low value ?

[stephenmoore33]

I would love for this to be resolved. SeedSync is unfortunately not useable for me. SSH with key authentication works without issues, but when attempting starting to copy from my Seedbox -> local I receive a timeout error.

`2026/02/15 09:40:29 - DEBUG - RemoteScanner.RemoteScanner.Sshcp - Return code: 0

2026/02/15 09:40:29 - DEBUG - RemoteScanner.RemoteScanner.Sshcp - Command took 5.110s

2026/02/15 09:40:29 - DEBUG - RemoteScanner.RemoteScanner.Sshcp - Command: ssh -p 22 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=error -o PasswordAuthentication=no REDACTED@REDACTED "'/home/REDACTED/seedsync/scanfs' '/home/REDACTED/data/torrents/completed'"

2026/02/15 09:40:29 - DEBUG - LocalScanner - Running a scan

2026/02/15 09:40:30 - DEBUG - LocalScanner - Scan took 0.613s

2026/02/15 09:40:31 - DEBUG - seedsync.Controller.Model - LftpModel: Adding a listener

2026/02/15 09:40:39 - DEBUG - LocalScanner - Running a scan

2026/02/15 09:40:40 - DEBUG - LocalScanner - Scan took 0.629s

2026/02/15 09:40:49 - DEBUG - seedsync - Persisting states to file`

Then:
`026/02/15 09:43:29 - ERROR - RemoteScanner.RemoteScanner.Sshcp - Timed out Traceback (most recent call last): File "/app/python/ssh/sshcp.py", line 296, in __run_command i = sp.expect( ^^^^^^^^^^ File "/usr/local/lib/python3.12/site-packages/pexpect/spawnbase.py", line 354, in expect return self.expect_list(compiled_pattern_list, ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.12/site-packages/pexpect/spawnbase.py", line 383, in expect_list return exp.expect_loop(timeout) ^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.12/site-packages/pexpect/expect.py", line 181, in expect_loop return self.timeout(e) ^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.12/site-packages/pexpect/expect.py", line 144, in timeout raise exc pexpect.exceptions.TIMEOUT: Timeout exceeded. <pexpect.pty_spawn.spawn object at 0x14d3f129d370> command: /usr/bin/ssh args: ['/usr/bin/ssh', '-p', '22', '-o', 'StrictHostKeyChecking=no', '-o', 'UserKnownHostsFile=/dev/null', '-o', 'LogLevel=error', '-o', 'PasswordAuthentication=no', 'REDACTED@REDACTED', "'/home/REDACTED/seedsync/scanfs' '/home/REDACTED/data/torrents/completed'"] buffer (last 100 chars): b'' before (last 100 chars): '' after: <class 'pexpect.exceptions.TIMEOUT'> match: None match_index: None exitstatus: None flag_eof: False pid: 144 child_fd: 69 closed: False timeout: 30 delimiter: <class 'pexpect.exceptions.EOF'> logfile: None logfile_read: None logfile_send: None maxread: 2000 ignorecase: False searchwindowsize: None delaybeforesend: 0.05 delayafterclose: 0.1 delayafterterminate: 0.1 searcher: searcher_re: 0: EOF 1: re.compile(b'password: ') 2: re.compile(b'lost connection') 3: re.compile(b'Could not resolve hostname') 4: re.compile(b'Connection refused')

2026/02/15 09:43:29 - ERROR - RemoteScanner.RemoteScanner.Sshcp - Command output before: b''

2026/02/15 09:43:29 - WARNING - RemoteScanner.RemoteScanner - Caught an SshcpError: Timed out

2026/02/15 09:43:29 - DEBUG - RemoteScanner - Process caught an exception

2026/02/15 09:43:29 - ERROR - seedsync.ControllerJob - Caught exception in job ControllerJob
Traceback (most recent call last):
File "/app/python/common/job.py", line 44, in run
self.execute()
File "/app/python/controller/controller_job.py", line 29, in execute
self.__controller.process()
File "/app/python/controller/controller.py", line 201, in process
self.__propagate_exceptions()
File "/app/python/controller/controller.py", line 528, in __propagate_exceptions
self.__remote_scan_process.propagate_exception()
File "/app/python/common/app_process.py", line 124, in propagate_exception
raise exc.re_raise()
^^^^^^^^^^^^^^
File "/app/python/common/app_process.py", line 30, in re_raise
raise self.ee.with_traceback(self.tb)
File "/app/python/common/app_process.py", line 87, in run
self.run_loop()
File "/app/python/controller/scan/scanner_process.py", line 90, in run_loop
files = self.__scanner.scan()
^^^^^^^^^^^^^^^^^
File "/app/python/controller/scan/remote_scanner.py", line 78, in scan
raise ScannerError(
^^^^^^^^^^^^^^^^^
controller.scan.scanner_process.ScannerError: An error occurred while scanning the remote server: 'Timed out'.

2026/02/15 09:43:29 - DEBUG - seedsync.ControllerJob - Calling cleanup for ControllerJob

2026/02/15 09:43:29 - DEBUG - seedsync.Controller - Exiting controller

2026/02/15 09:43:30 - ERROR - seedsync - Caught exception
Traceback (most recent call last):
File "/app/python/seedsync.py", line 164, in run
controller_job.propagate_exception()
File "/app/python/common/job.py", line 77, in propagate_exception
raise exc_info[1].with_traceback(exc_info[2])
File "/app/python/common/job.py", line 44, in run
self.execute()
File "/app/python/controller/controller_job.py", line 29, in execute
self.__controller.process()
File "/app/python/controller/controller.py", line 201, in process
self.__propagate_exceptions()
File "/app/python/controller/controller.py", line 528, in __propagate_exceptions
self.__remote_scan_process.propagate_exception()
File "/app/python/common/app_process.py", line 124, in propagate_exception
raise exc.re_raise()
^^^^^^^^^^^^^^
File "/app/python/common/app_process.py", line 30, in re_raise
raise self.ee.with_traceback(self.tb)
File "/app/python/common/app_process.py", line 87, in run
self.run_loop()
File "/app/python/controller/scan/scanner_process.py", line 90, in run_loop
files = self.__scanner.scan()
^^^^^^^^^^^^^^^^^
File "/app/python/controller/scan/remote_scanner.py", line 78, in scan
raise ScannerError(
^^^^^^^^^^^^^^^^^
controller.scan.scanner_process.ScannerError: An error occurred while scanning the remote server: 'Timed out'.`

I am currently on the :develop branch.

[nitrobass24]

This is a completely different issue related to scanfs getting hung up. I've opened a new issue #61

[nitrobass24]

@stephenmoore33 Thanks for the detailed logs — they were really helpful in tracking this down. We've identified the root cause and submitted a fix in #62.

What was happening:

1. Pexpect process leak — When an SSH command timed out, the child process was never cleaned up (sp.close() was skipped). This leaked orphaned SSH connections, which likely caused subsequent scanfs invocations to hang.
2. No retry on timeout — A single timeout on the first scan was treated as a fatal, non-recoverable error that killed the entire app. Timeouts are inherently transient and shouldn't crash SeedSync.
3. No SSH keepalive — Without keepalive packets, a stalled connection would sit silently for the full 180s timeout before being detected.

What the fix does:

• Ensures SSH child processes are always cleaned up (even on timeout)
• Retries transient errors (timeouts, lost connections) up to 3 times before giving up
• Makes timeouts recoverable so the scanner loop continues instead of crashing the app
• Adds SSH ServerAliveInterval=15 and ConnectTimeout=30 to detect dead connections faster

The fix is on the develop branch in PR #62. Would appreciate if you could test it when it's merged and let us know if it resolves the issue for you.