How can I disable logs from airflow?

[Praveenkumar Venkatesan]

I have too many INFO logs being printed by airflow modules. I am not an expert with the use of "logging" framework. But basing off of examples online, I've tried doing the following

```
airflow_log = logging.getLogger("airflow")
airflow_log.setLevel(logging.WARNING)
```

I've also tried playing with the `propagate` flag. Is airflow the logger name? I've tried changing the logger name to `airflow.hooks` but that doesn't work either.

[Praveenkumar Venkatesan]

@Max - any thoughts on this?

[Maxime Beauchemin]

I just landed a PR that might help with some of this. There's also the LOGGIN_LEVEL constant in `settings.py` that you can overwrite in your local config.

[Dmitriy Lee]

I think it would be great to have an option for loading logging configuration from an external file (either cfg or yaml, preferably yaml). It provides an easy way to control behavior of individual loggers. For example you can have airflow logger outputting at INFO level while suppressing output of boto logger (which is way too verbose) to WARNINGS.

Example config file 

version: 1
disable_existing_loggers: false

root:
    level: NOTSET
    handlers: [console, info_file_handler, error_file_handler]

formatters:

    standard:
        format: "%(asctime)s [%(levelname)s] %(name)s: %(message)s"
        datefmt: '%Y-%m-%d %H:%M:%S%z'

handlers:

    default:
        level: INFO
        class: logging.StreamHandler

    console:
        class: logging.StreamHandler
        level: DEBUG
        formatter: standard
        stream: ext://sys.stdout

    info_file_handler:
        class: logging.handlers.RotatingFileHandler
        level: INFO
        formatter: standard
        filename: ../log/mongodb_cdc_agent.log
        maxBytes: 10485760 # 10MB
        backupCount: 20
        encoding: utf8

loggers:
    paramiko.transport:
        level: WARNING

    boto3:
        level: WARNING

    botocore:
        level: WARNING