tool: Add ability to configure the tool via environent-variables instead of arguments
In some cases ( k8s and others) it is more handy to configure a tool via environment variables than it is to script out the command-line with more and more options.
For that, we should be able to configure the command-line tool via environment variables.
To avoid conflicts or "stealing" common words, all environment-variables should be prefixed with fex.CARAMEL_
.
For documentations sake, at Verbose-level debug
or info
we should also print out current configuration.
Environment-variables should match the command-line flags in spelling, syntax and meaning, fex.
CARAMEL_VERBOSE=3
Would match -vvv
or --verbose=3
or
CARAMEL_LOGLEVEL=info
would match --loglevel=info
Note that the examples are only examples, and the implementer is supposed to exercise good judgement