Error Handling Utility

[ryanlong1004]

Scope

The error handling utility will be used by every other UW Tool in the tool kit. It will standardize the way errors are handled and reported, and will allow users to treat errors and warnings at the level of severity required by the task at hand.

This utility will be the primary method of handling errors within the UW Framework. It will be a utility used by all other workflow tools, and will be closed to modification, but open to extension.

Our number 1 goal with this feature is to ensure that it works toward a standardized output.

Design

Error messages should provide, at minimum, the following output:

1. Time stamp
2. Caller
3. Data structure(s) involved
4. Environment info

Questions

• Can we use a 3rd party library for this?
• Where does the tool live?

[aerorahul]

logging.exception is a standard way of "logging" with an exception handling that I have seen/used in the past. There might be better other ways.
logging.exception will put a time-stamp and a Traceback so that should likely satisfy requirements 1 and 2.
I am not sure what 3. means. I think I understand what 4 is, but a dump of for e.g. printenv is a bit too much to have.

[christinaholtNOAA]

The uwtools package now uses standard logging, defined by the logging module, and handles uw-specific exceptions defined in the exceptions module.