[RSDK-9261] Initial clean up of webcam.go

[hexbabe]

Summary

Let's put the numerous private helpers above their caller and arrange this file to be more readable. Additionally we remove some vestigial logic that doesn't belong anymore.

95% of changes are syntax, var renaming, function rearranging, comment additions and updates.
The only three semantic changes made:

1. [RSDK-9261] Initial clean up of webcam.go #4555 (comment)
2. [RSDK-9261] Initial clean up of webcam.go #4555 (comment)
3. [RSDK-9261] Initial clean up of webcam.go #4555 (comment)

Manual testing

Tested using go run with two webcams. Made sure hot swap and discovery and stream look good.

Tip for reviewing

Diff best viewed in split mode

Reminder for myself to merge in the Go interface PR before this one to avoid conflicts with the more high priority one

[randhid]

Looks good, definitley merge in after the camera interface pr, and one request about the two loggers that maybe would be bets left to a follow up pr, feel free to comment exactly that.

[randhid]

Can we try to just have one?

[seanavery]

I guess the separation is used for log search when path/label changes during reconnects.

c.logger = c.originalLogger.WithFields("camera_label", c.targetPath)

I think we can preserve the log structure for queryablity with multiple fields. something like:

logger: logger.WithFields(logrus.Fields{
    "camera_name":  conf.ResourceName().ShortName(),
    "camera_label": c.targetPath,
}),

[randhid]

I don't see the "camera_label" logger anywhere in NewWebCam, where are you looking?

[seanavery]

It happens in reconnectCamera here.

[hexbabe]

Talked to @dgottlieb and we now have the adapter support between the zap logger and our rdk logger i.e. we can assign the return value of WithFields to logger instead of having to use originalLogger to do so.

[seanavery]

I guess the separation is used for log search when path/label changes during reconnects.

c.logger = c.originalLogger.WithFields("camera_label", c.targetPath)

I think we can preserve the log structure for queryablity with multiple fields. something like:

logger: logger.WithFields(logrus.Fields{
    "camera_name":  conf.ResourceName().ShortName(),
    "camera_label": c.targetPath,
}),

[seanavery]

It happens in reconnectCamera here.