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wpilibsuite / WPILibPi

WPILib Raspberry Pi images designed for FRC (formerly FRCVision)
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Uploaded python files not printing to web dashboard console #46

Closed mjansen4857 closed 5 years ago

mjansen4857 commented 5 years ago

When I upload a python file to run on the pi, it is run as a bash script instead of through python. This causes a few problems for me. After doing some research, I found that I must add #!/usr/bin/env python3 to the top of the file. But after doing so I get this error:

/usr/bin/env: 'python3\r': No such file or directory

So I made another script to remove all \r characters from the file before I upload it. I either have to do this or edit the runCamera script by replacing exec ./uploaded.py with python3 ./uploaded.py every time I upload a python file to get it to run. Once I get the file to run, it is shown as running in the Vision Status tab but I receive no output to the console. If I run the python file or the runCamera script manually on the pi I can see the console output, so it is not a problem with the file.

mjansen4857 commented 5 years ago

I should also mention that I get console output for included examples and uploaded Java jars. So I have only experienced this problem with uploaded python files.

PeterJohnson commented 5 years ago

I'll fix the line-endings upload issue, but I'm not planning on changing the need for the #!/usr/bin/env python3 first line, as the use of "exec" is important for the service control buttons on the webdash to work properly. I can't reproduce the no console output issue you are seeing; is that the case even after you fix the line endings and reboot?

mjansen4857 commented 5 years ago

Before I fix the line endings I keep getting the error I mentioned before every five seconds. After fixing the line endings I get one Waiting 5 seconds... print then nothing else. The python file I've been trying only prints a string every few seconds as a test. I've tried a couple different files, and I have experienced this same issue in beta 2 as well as the kickoff release, both on a fresh install.

PeterJohnson commented 5 years ago

Figured it out. Python output is buffered by default. I'll set an environment variable in the runCamera script to force Python to unbuffered mode.

mjansen4857 commented 5 years ago

Awesome. This will help a lot. Thank you!