Hangs with Python 3.7

[cjltsod]

I'm using SSHTunnelForwarder with Python 3.7. After finishing my work, I run server.stop() and hangs.

I believe it caused by socketserver.ThreadingMixIn
https://docs.python.org/3.7/library/socketserver.html#socketserver.ThreadingMixIn

Changed in version 3.7: socketserver.ForkingMixIn.server_close() and socketserver.ThreadingMixIn.server_close() now waits until all child processes and non-daemonic threads complete. Add a new socketserver.ForkingMixIn.block_on_close class attribute to opt-in for the pre-3.7 behaviour.

Here's my work around. I changed the attribute server._server_list[0].block_on_close = False, and it behave like usual. It closed normally and not being hang.

I'm not sure if setting block_on_close = False is a good way or not.

Issue #135 may have the same cause.

[cjltsod]

Here's what I work around. cjltsod@2e56a5b
Still not sure if it's a good way or not.

[fernandezcuesta]

Hi, thanks for the valuable information.
If I understand properly, when daemon_threads is True and server_close() is executed it will not wait for the threads created by ThreadingMixIn to be closed, which is the same as block_on_close = False.
My guess is that this parameter is more focused on unifying both ForkingMixIn and ThreadingMixIn behaviour rather than changing how things worked until now.
Did you try setting DAEMON = True or just daemon_threads = True? Do you obtain the same results?

[cjltsod]

Yes, setting DAEMON = True solved my problem in Python 3.7 too.
What situation should I set DAEMON = True manually?

[fernandezcuesta]

Well maybe it's much easier just setting tunnel.daemon_forward_servers = True before starting the tunnel rather than patching the constant.

[cjltsod]

Thanks a lot for helping. It solved the issues. cjltsod@13c0f2e

[alejoar]

So are we getting a release with this fix or not? sshtunnel currently doesn't work properly in Python 3.7+

[rkkautsar]

Still hangs in 3.7+.
I tried setting daemon_forward_servers = True before starting the forwarder but it still doesn't work..

[cjltsod]

It has been patched with v0.1.5 at fa85471 (#149) which is not on pypi yet.
It has been merged into master branch, so you can simply install through GitHub by using
pip install git+https://github.com/pahaz/sshtunnel.git

[fernandezcuesta]

updated PYPI

[rkkautsar]

Any plan to also update the conda-forge package?
Related: conda-forge/sshtunnel-feedstock#10

[eannam]

Hi, I am still getting this issue with python 3.7 using v0.1.5.

[pyMan]

Hi, I am still getting this issue with python 3.8 using v0.1.5.

EDIT: specifically it happens to me only if I execute any kind of query through the ssh tunnel (I'm using django 2.2.9)

[PozziSan]

Hi, I am still getting this issue with python 3.8 using v0.1.5.

EDIT: specifically it happens to me only if I execute any kind of query through the ssh tunnel (I'm using django 2.2.9)

Hi! I'm getting the same here, after executing queries with pandas, on a flask application using sqlAlchemy.
The application is running with Python 3.8 using v0.1.5.

[dem82]

I've solved the hanging problem with #72
Python 3.7 using v0.1.5

[pahaz]

I reopened this issue as I found a lot of new comments!

1. sshtunnel is always waiting until closing all connections during the stop() called.
2. If you don't want to wait, you can use .stop(force=True)
3. You can have a problem with hangs if you don't call .stop. For example, you have some unhandled exception in MainThread and you don't call .stop in this case. As a dirty workaround, you can use this hack at the beginning:

# I don't recommend to use this hack!
# Hack threadings https://docs.python.org/3/library/threading.html#threading.Thread.daemon ...
sshtunnel.SSHTunnelForwarder.daemon_forward_servers = True
sshtunnel.SSHTunnelForwarder.daemon_transport = True

4. It's better to use with open_tunnel(...) which always stops the tunnel.

Do anyone have an issue related to hangs with sshtunnel==0.3.1 and .stop(force=True) ?

[pahaz]

@tdstarkisoc thanks you for feedback and tests.

I'll close the issue. And if anyone have an issue related to hangs with sshtunnel==0.3.1 and .stop(force=True) please open a new issue. And read this first: #138 (comment)

And also we have a plan to change the default threading daemon option for sshtunnel threads.
But we needed more tests for those cases.

UPD (2021): we released 0.4.0 and changed the default threading daemon option for sshtunnel threads with functional tests.