Cannot pass lambda context(JSON) to custom_fomat

[chikinchoi]

Hi,

I am developing the fluent-logger-python in AWS Lambda and I would like to pass the lambda context to fluent by using the custom_fomat. However, it seems the fluent-logger-python doesn't allow me to do it.
For the workaround, I pass the function_name only to the custom_format as a string first. But I would like to advise how to pass the entire context JSON to the custom_format.

Below is my lambda code:

import logging
from fluent import handler
def lambda_handler(event, context):
    function_name = context.function_name
    print(function_name)
    custom_format = {
        'host': '%(hostname)s',
        'where': '%(module)s.%(funcName)s',
        'type': '%(levelname)s',
        'stack_trace': '%(exc_text)s',
        'context': context,
        'function_name': function_name
    }
    logging.basicConfig(level=logging.INFO)
    log = logging.getLogger('fluent.test')
    log.setLevel(logging.DEBUG)
    h = handler.FluentHandler('lambdaPython.0434', host='********************', port=24224)
    formatter = handler.FluentRecordFormatter(custom_format)
    h.setFormatter(formatter)
    log.addHandler(h)
    log.info("This log entry will be logged2.")

Error Response:

Response:
{
  "errorMessage": "'LambdaContext' object has no attribute 'find'",
  "errorType": "AttributeError",
  "stackTrace": [
    "  File \"/var/task/lambda_function.py\", line 28, in lambda_handler\n    log.info(\"This log entry will be logged2.\")\n",
    "  File \"/var/lang/lib/python3.8/logging/__init__.py\", line 1434, in info\n    self._log(INFO, msg, args, **kwargs)\n",
    "  File \"/var/lang/lib/python3.8/logging/__init__.py\", line 1577, in _log\n    self.handle(record)\n",
    "  File \"/var/lang/lib/python3.8/logging/__init__.py\", line 1587, in handle\n    self.callHandlers(record)\n",
    "  File \"/var/lang/lib/python3.8/logging/__init__.py\", line 1649, in callHandlers\n    hdlr.handle(record)\n",
    "  File \"/var/lang/lib/python3.8/logging/__init__.py\", line 950, in handle\n    self.emit(record)\n",
    "  File \"/opt/python/lib/python3.8/site-packages/fluent/handler.py\", line 237, in emit\n    data = self.format(record)\n",
    "  File \"/var/lang/lib/python3.8/logging/__init__.py\", line 925, in format\n    return fmt.format(record)\n",
    "  File \"/opt/python/lib/python3.8/site-packages/fluent/handler.py\", line 97, in format\n    super(FluentRecordFormatter, self).format(record)\n",
    "  File \"/var/lang/lib/python3.8/logging/__init__.py\", line 665, in format\n    if self.usesTime():\n",
    "  File \"/opt/python/lib/python3.8/site-packages/fluent/handler.py\", line 169, in _format_by_dict_uses_time\n    return any([value.find(search) >= 0 for value in self._fmt_dict.values()])\n",
    "  File \"/opt/python/lib/python3.8/site-packages/fluent/handler.py\", line 169, in <listcomp>\n    return any([value.find(search) >= 0 for value in self._fmt_dict.values()])\n"
  ]
}

Please advise. Thank you very much!

[arcivanov]

This is not a bug.

You can't pass arbitrary objects to format. If you're logging JSON you're logging JSON as logger.log({'a': 1, 'b': 2}) but the object also needs to be formattable to begin with, which I doubt Lambda context is. Same with function name. https://docs.python.org/3/library/logging.html#formatter-objects

You are misusing a Formatter object where LoggerAdapter or Filter should be used: https://docs.python.org/3/howto/logging-cookbook.html#adding-contextual-information-to-your-logging-output