Fabric 3.0.0 locks main thread until timeout finish

[puerkito66]

Fabric 3.0.0 prevents the interpreter to exit if a timeout was specified when running a remote command

For example this small script:

import fabric
import sys

conn = fabric.Connection("localhost", user="ubuntu", connect_kwargs={"key_filename":"key"})
sys.exit(conn.run("whoami", hide=True, warn=True, timeout=30)

will generate the following output:

Command exited with status 0.
=== stdout ===
ubuntu

(no stderr)

but the interpreter will hang until the the timeout.
Hitting ctrl-C while hanging generates the following traceback:

Exception ignored in: <module 'threading' from '/usr/lib/python3.9/threading.py'>
Traceback (most recent call last):
  File "/usr/lib/python3.9/threading.py", line 1428, in _shutdown
    lock.acquire()
KeyboardInterrupt:

This happens no matter the server we connect.

This is a special problem since there are some commands that needs a huge timeout windows, and if the commands executes relatively fast, the program won't finish until the timeout is acomplished.

Expected behaviour
Program finish inmediatly

Environment
Python 3.9
Ubuntu Linux 5.4.0-126-generic #142-Ubuntu
Fabric 3.0.0
Paramiko 3.0.0
Invoke 2.0.0

[DamonHolland]

I am observing this issue as well. A timer thread is being held until the timeout expires, even when the command has finished within the allotted window.

A threading.enumerate() call at the end of main function results with [<_MainThread(MainThread, started 10828)>, <Timer(Thread-3, started 10292)>].

The Timer thread is generated from within fabric when using timeout parameter.

PR #2242 has resolved the issue on my end.

[davidjmemmett]

Fabric3 is an unmaintained, unofficial fork. Please retry using fabric v2.

[puerkito66]

@davidjmemmett I'm aware of the fork of Fabric3 and since 2018 is not longer maintenaed.

But nobody is talking about that fork.
The issue described above is in this repo, which latest release of this very project is tagged as 3.0.0

https://github.com/fabric/fabric/releases/tag/3.0.0

[bitprophet]

Will be fixed in next bugfix release.