Logging as jsonl using vanilla Python logging

logging_jsonl.py

# https://stackoverflow.com/questions/71944328/how-to-implement-json-format-logs-in-python

import json
import logging

# https://docs.python.org/3/library/logging.html#logrecord-attributes
formatter = type('JsonFormatter', (logging.Formatter, ), dict(format = lambda self, record: json.dumps(dict(time = self.formatTime(record), level = record.levelname, message = record.getMessage(), module = record.module, lineno = record.lineno)) ))()

# simpler version below does not escape quotes in message and does not delete newlines in message
# formatter = logging.Formatter('{\"time\": \"%(asctime)-s\", \"level\": \"%(levelname)-s\", \"message\": \"%(message)s\", \"module\": \"%(module)s\", \"lineno\": %(lineno)d}')

handler_stderr = logging.StreamHandler()
handler_stderr.setFormatter(formatter)
handler_stderr.setLevel(logging.INFO)

logger = logging.getLogger(__name__)
logger.addHandler(handler_stderr)
logger.debug("This is a debug message (will not be shown by console handler).")
logger.info("This is an informational message.")
logger.error("This is an error message.")