powertools_issue_409

README_no_swap.md

With Pytest and Lambda Powertools installed, run the following command to have human readable and highlighted log statements including stack traces:

POWERTOOLS_LOG_DEDUPLICATION_DISABLED="1" pytest -o log_cli=1 prod_no_swap.py

Output should look like this:

log.txt

2021-05-13 19:05:25,506+0200 — INFO — main:32 — Hello - {'context': {'device_id': '11e9034354f', 'device_location': 'London'}} -  - 
2021-05-13 19:05:25,507+0200 — ERROR — main:36 — Log stacktrace... - {} - ZeroDivisionError - Traceback (most recent call last):
  File "prod.py", line 34, in main
    1 / 0
ZeroDivisionError: division by zero

prod.py

from typing import Dict
import logging
import os

from aws_lambda_powertools import Logger
from aws_lambda_powertools.logging.formatter import LambdaPowertoolsFormatter


class LocalPlainFormatter(LambdaPowertoolsFormatter):
    def serialize(self, log: Dict) -> str:
        timestamp = log.pop("timestamp", "")
        level = log.pop("level", "")
        funcNameLoc = log.pop("location", "")
        message = log.pop("message", "")
        exception = log.pop("exception", "")
        exception_name = log.pop("exception_name", "")
        extras = log

        return f"{timestamp} — {level} — {funcNameLoc} — {message} - {extras} - {exception_name} - {exception}"


# use local formatter and local file only when PT_409 flag is set
has_flag = os.getenv("PT_409")
file_handler = logging.FileHandler("log.txt") if has_flag else None
formatter = LocalPlainFormatter() if has_flag else None

LOGGER = Logger(datefmt="%Y-%m-%dT%H:%M:%SZ", logger_formatter=formatter, logger_handler=file_handler)


def main():
    LOGGER.info("Hello")
    try:
        1 / 0
    except ZeroDivisionError:
        LOGGER.exception("Log stacktrace...")


if __name__ == "__main__":
    main()

prod_no_swap.py

from aws_lambda_powertools import Logger

LOGGER = Logger(datefmt="%Y-%m-%dT%H:%M:%SZ")

def main():
    LOGGER.info("Hello")
    try:
        1 / 0
    except ZeroDivisionError:
        LOGGER.exception("Log stacktrace...")

READE.md

Export custom flag PT_409 when running locally to log in plain text and write output into log.txt file

PT_409="1" python prod.py 

Output should look like this:

2021-05-13 19:05:25,506+0200 — INFO — main:32 — Hello - {'context': {'device_id': '11e9034354f', 'device_location': 'London'}} -  - 
2021-05-13 19:05:25,507+0200 — ERROR — main:36 — Log stacktrace... - {} - ZeroDivisionError - Traceback (most recent call last):
  File "prod.py", line 34, in main
    1 / 0
ZeroDivisionError: division by zero

test_prod.py

import prod



def test_main_logger():
    prod.main()