Clean logging

[tnixon]

Resolving issue #25

[lgtm-com]

This pull request introduces 1 alert and fixes 1 when merging 5291710 into bcdb401 - view on LGTM.com

new alerts:

• 1 for Unused import

fixed alerts:

• 1 for 'import *' may pollute namespace

[rportilla-databricks]

This looks great. Just a couple suggestions (shouldn't be a blocker):

1. It would be great to validate log levels in a unit test (for example set logging.basicConfig(level=logging.WARNING)
   and validate that the info doesn't appear).

2. Is it simple enough to add for Scala also?

[CTCC1]

Hi there, just chiming-in as an end-user:
After this change, we can see the warnings log as follow in databricks:

WARNING:root:Column _c had no values within the lookback window. Consider using a larger window to avoid missing values. If this is the first record in the data frame, this warning can be ignored.

Note the "root" here.

https://docs.python.org/3.9/howto/logging.html#advanced-logging-tutorial
Based on my own experience, instead of log every line directly using logging.info, using a module level logger is preferred, such as:

logger = logging.getLogger(__name__)

Then the log lines will be more clear, and say sth like WARNING:tempo.tsdf, and user can also set logging level in their code, e.g.

import logging
logging.basicConfig(level=logging.INFO)
logging.getLogger("py4j").setLevel(logging.WARNING)
logging.getLogger("tempo").setLevel(logging.WARNING)

[tnixon]

Good suggestions, @CTCC1 - I agree, we should update the logging accordingly!