AWS Lambda handler to avoid splitting log lines in cloudwatch

aws_lambda_logging.py

import sys
import logging
import traceback
import json

logger = logging.getLogger()
logger.setLevel(logging.INFO)


def process(record):
    logger.info(record["x"])
    # TODO


def log_exception(mssg):
    ex_type, ex_value, ex_tb = sys.exc_info()
    tb_str = traceback.format_exception(ex_type, ex_value, ex_tb)
    err_details = json.dumps(
        {
            "level": "ERROR",
            "message": mssg,
            "exception_type": ex_type.__name__,
            "exception_message": str(ex_value),
            "stack_trace": tb_str,
        }
    )

    logger.error(err_details)


def lambda_handler(event, context):
    """handles SQS message batch"""

    if event:
        logger.info(f"event: {event}")

        batch_item_failures = []
        sqs_batch_response = {}

        for record in event["Records"]:
            try:
                process(record)
            except Exception:
                batch_item_failures.append({"itemIdentifier": record["messageId"]})
                log_exception(f"Failed processing {record}")

        sqs_batch_response["batchItemFailures"] = batch_item_failures
        return sqs_batch_response


lambda_handler(
    {
        "Records": [
            {"messageId": 1, "x": 1},
            {"messageId": 2, "y": 1},
            {"messageId": 3, "z": 1},
        ]
    },
    None,
)