base_python.py.template

# Template for lambda and base python scripts
# Has logging and some built in features.

from __future__ import print_function
import os
import sys
import logging
import traceback
import boto3

LOG_LEVELS = {'CRITICAL': 50, 'ERROR': 40, 'WARNING': 30, 'INFO': 20, 'DEBUG': 10}

AWS_REGION = ''

def init_logging():
    # Setup loggin because debugging with print can get ugly.
    logger = logging.getLogger()
    logger.setLevel(logging.DEBUG)
    logging.getLogger("boto3").setLevel(logging.WARNING)
    logging.getLogger('botocore').setLevel(logging.WARNING)
    logging.getLogger('nose').setLevel(logging.WARNING)

    return logger


def setup_local_logging(logger, log_level = 'INFO'):
    # Set the Logger so if running locally, it will print out to the main screen.
    handler = logging.StreamHandler()
    formatter = logging.Formatter(
        '%(asctime)s %(name)-12s %(levelname)-8s %(message)s'
    )
    handler.setFormatter(formatter)
    logger.addHandler(handler)
    if log_level in LOG_LEVELS:
        logger.setLevel(LOG_LEVELS[log_level])
    else:
        logger.setLevel(LOG_LEVELS['INFO'])

    return logger


def set_log_level(logger, log_level = 'INFO'):
    # There is some stuff that needs to go here.
    if log_level in LOG_LEVELS:
        logger.setLevel(LOG_LEVELS[log_level])
    else:
        logger.setLevel(LOG_LEVELS['INFO'])

    return logger


def process_global_vars():
    logger.info("Processing variables from environment.")
    try:
        global AWS_REGION
        AWS_REGION = os.environ.get('AWS_REGION', AWS_REGION)
    except SystemExit:
        sys.exit(1)
    except:
        logger.error("Unexpected error!\n Stack Trace:", traceback.format_exc())


def lambda_handler(event, context):
    try:
        global logger
        logger = init_logging()
        logger = set_log_level(logger, os.environ.get('log_level', 'INFO'))

        logger.debug("Running function lambda_handler")
        process_global_vars()

    except SystemExit:
        logger.error("Exiting")
        sys.exit(1)
    except ValueError:
        exit(1)
    except:
        print ("Unexpected error!\n Stack Trace:", traceback.format_exc())
    exit(0)


if __name__ == "__main__":
    logger = init_logging()
    os.environ['log_level'] = os.environ.get('log_level', "INFO")

    logger = setup_local_logging(logger, os.environ['log_level'])

    event = {'log_level': 'INFO'}
    os.environ['AWS_REGION'] = os.environ.get('AWS_REGION', "us-east-2")


    # Add default level of debug for local execution
    lambda_handler(event, 0)