[BUG]: Server and CvSource constructors hang; cannot use CTRL-C

[seasew]

Problem description

When I run the code snippet to addServer to the CameraServer instance, the program sporadically hangs on that line. Then I have to terminate the Python script with CTRL-\ because CTRL-C doesn't work. Then when I try it again, it usually makes it past that hang, but then hangs at the next line, where I set the CvSource for the server. Then I have to terminate again, run the script again, and usually on this third try the program will make it through.

I haven't been able to discern a particular reason as to why it hangs, it just does sometimes but once I restart the script twice it's usually back to normal.

Operating System

Linux

Installed Python Packages

No response

Reproducible example code

from cscore import CameraServer, CvSource, VideoMode

# Initialize a camera server
cam_server = CameraServer.getInstance()

# Add a camera server
print('Attempting add a MjpegServer')
server = cam_server.addServer(name='0')
print('Completed attempt to add server')
stream = CvSource('0', VideoMode.PixelFormat.kMJPEG, 160, 120, 10)
server.setSource(stream)
print('CvSource has been set for server at port ' + str(server.getPort()))

[virtuald]

Which version of cscore, which version of Python, and on what platform (x86, rpi, etc... )

[auscompgeek]

Also: what Linux distro?

[seasew]

Running python3 --version gives Python 3.6.9
Running python --version gives Python 2.7.17

I always run the Python code in question using python3 in the terminal.

Running pip3 list shows robotpy-cscore version 2021.0.0. pip list also shows the 2021 version.

Running uname -m gives aarch64. uname -r gives 4.9.140-tegra.

NAME="Ubuntu"
VERSION="18.04.6 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.6 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

Also it's probably helpful to note that I'm running this code on a Nvidia Jetson Nano.
Thanks.

[auscompgeek]

Ah, this is probably #105. I'm guessing you're using my distro packages from build.opensuse.org? Looks like I forgot to update the robotpy-cscore package there with that bugfix. I'll push up 2021.0.2 in a bit.

[seasew]

Yep, I downloaded the debian file from opensuse here (https://software.opensuse.org/download.html?project=home%3Aauscompgeek%3Arobotpy&package=python3-cscore) for Ubuntu.

[auscompgeek]

Updated the OBS repo. Your 2021.0.2 bionic aarch64 package should be available for download now. Let us know how it goes.

[seasew]

The CameraServer code is no longer hanging, but I've also got an issue with the pynetworktables code hanging. It's on version 2021.0.0, and it doesn't look like any updates are available through pip3 install --upgrade pynetworktables. Any idea why this could be happening?

Code snippet:

# Start thread to connect to NetworkTables
cond = threading.Condition()
notified = [False]

def connection_listener(connected, info):
    print(info, '; Connected=%s' % connected)
    with cond:
        notified[0] = True
        cond.notify()

# Use RoboRIO static IP address
NetworkTables.initialize(server='10.1.92.2')
NetworkTables.addConnectionListener(connection_listener, immediateNotify=True)

with cond:
    print('Waiting')
    if not notified[0]:
        cond.wait()

print('Connected to NetworkTables!')

I've been running this code without issues for the past couple of weeks, but it suddenly stopped working. The cscore update hasn't changed the status of this error.

[virtuald]

Sorry we didn't get back to you last year! But it sounds like your cscore issue has been resolved. In 2023 everything will be switching over to ntcore, so I expect this will disappear.