Make mjpeg_streamer customizeable

[mloit]

It would be helpful having the systemd service script invoke a shell script, instead of streamer directly, and have the shell script somewhere accessible for OctoPrint to update through the UI, so that people can customize easily based on their webcam.

[goeland86]

Agreed, but at this point I've got too little time to take a crack at it for 2.1.2

[eliasbakken]

mjpeg.service fails on Refactor Recore, so we should find a solution to this.

[goeland86]

@eliasbakken it only fails if no webcam is plugged in. Just so we're clear. We could modify the systemd script to depend on /dev/video0?

[eliasbakken]

The OP is requesting a way to customize certain things, I imagine that is resolution etc. There are ways to fix this in OctoPrint using a combinatition of plugins etc. but it is not a very elegant solution. I think a better way would be to make a plugin for OctoPrint. That could be a solution for the future, but I think for now we should be satisfied with changing the settings by editing the service file directly.

There is a PR waiting to be merged that causes the service to not fail if there is no webcam present on Recore, I think that will be enough for now.