Build snapraid config files through container variables

[mgutt]

For Unraid it would be much easier for the user if it would be possible to manipulate the snapraid config through container variables.

Is it possible to parse all passed container variables dynamically? By that it would be possible to do this:

-e RUNNER_SNAPRAID_TOUCH=true
...
-e RUNNER_NOTIFICATION_SHORT=true
-e RUNNER_NOTIFICATION_URL=[true](discord://ID/Token)
...
-e CONFIG_PARITY=/mnt/HDD4/snapraid.parity
-e CONFIG_PARITY2=/mnt/HDD5/snapraid.2-parity
-e CONFIG_CONTENT=/config/snapraid.content
-e CONFIG_CONTENT2=/mnt/HDD1/snapraid.content
-e CONFIG_EXCLUDE=/tmp/
-e CONFIG_EXCLUDE2=/lost+found/

And then parse similar to this:

for key, value in args:
  key = key.lower()
  parts= key.split('_'):
  if parts[0] is "runner":
   # fill dict with config data of snapraid-runner.conf
  else if parts[0] is "config":
    # fill dict with config data of snapraid.conf  

# now create the two config files based on the variables...

All CONFIG variables ending to a number create additional lines. For example "CONFIG_CONTENT2" does not become "content2 /mnt/HDD1/snapraid.content". Instead it becomes "content /mnt/HDD1/snapraid.content" in a new line.

And as long no "CONFIG_..." or "RUNNER_..." variable is passed, the already existing config files are left untouched. By that this change would not break anything for already existing setups.