Add logger

[Jesus89]

Closes #422.

• Replace prints by log.x
• Add log_debug() and log_info() functions to set the log level

NOTE: this is the output of the logger, we can customize the message:

2019-12-10 09:49:27,922 - INFO - Success! Data uploaded correctly

@cmongut do you think we need to change this (remove time, log level, etc)?

[alrocar]

LGTM.

Just one question, how would a user of CARTOframes change the log level? Maybe we could document that in some place.

[Jesus89]

Using the log_debug() and log_info() methods. I thought this is for internal use. Do you think we should expose and document it for all the users?

[alrocar]

Sorry I meant a different thing.

Loggers allow to set the log level, so at runtime you decide if you want more verbose logs or not.

For example, now is set to INFO so I assume debug logs are not shown by default. As a user of CARTOframes how can I see the debug logs or only warnings and errors or in other words how can I set the log level?

[Jesus89]

Yes, that's the goal of those functions :). We might improve the naming: set_log_level('debug'), set_log_level('info'), etc.

UPDATE: 4156780

[alrocar]

sorry I misread them 🤦‍♂ the name change would help, thanks!

[simon-contreras-deel]

A detail. As a user, I would expect to have access to the log (since it is the Python logger) and set the level by myself, or even customizing how the log looks like.

For example, I could see all the CARTOframes logs doing:

from cartoframes.whatever.the.log.is import log
import logging

log.setLevel(logging.DEBUG)

[alrocar]

Acceptance 🍏

@Jesus89 not sure if you want to include the requested changes by @oleurud in this PR or in a different one.

[simon-contreras-deel]

Forget it. You could access to it by:

from cartoframes.core.logger import log 

I confused myself due to the function init_logger(), but it is called in the same module

[alrocar]

Cool, let's use this as much as possible :)