Question: How to include default / reserved attributes in the log message?

[meitham]

Thank you for making this library available. I have been looking at the tests and docs but could not find out how I can include some of the keys you defined as "RESERVED" in my message, such as asctime. I would like to say::

>>> logger.info("hello")
"asctime=2022-04-20 msg='hello'"

without having to pass asctime in as an extra. I have tried the below in my dictconfig but did not work::

        'logfmt': {
            'format': 'on=%(asctime)s level=%(levelname)s module=%(name)s msg=%(message)s',
            'class': 'logfmter.Logfmter',
        },

Is this possible?

[jteppinette]

This functionality has been added by the latest 0.0.5 release.

Thank you for using the library and providing this support!

Please consider starring or sponsoring this project to help continue development!

---

Default Keys

You can request that the formatter always include certain attributes on the
log record by using the keys parameter. If the key you want to include in
your output is represented by a different attribute on the log record, then
you can use the mapping parameter to provide that key/attribute mapping.

Notice, the keys parameter defaults to ["at"] and will be overridden
by any provided keys.

import logging
from logfmter import Logfmter

formatter = Logfmter(keys=["at", "processName"])

handler = logging.StreamHandler()
handler.setFormatter(formatter)

logging.basicConfig(handlers=[handler])

logging.error("hello") # at=ERROR processName=MainProceess msg=hello

Utilizing a mapping to convert the processName attribute to process.

Notice, the mapping parameter defaults to {"at": "levelname"} and will be overridden
by any provided mapping.

import logging
from logfmter import Logfmter

formatter = Logfmter(
    keys=["at", "process"],
    mapping={"at": "levelname", "process": "processName"}
)

handler = logging.StreamHandler()
handler.setFormatter(formatter)

logging.basicConfig(handlers=[handler])

logging.error("hello") # at=ERROR process=MainProceess msg=hello

Date Formatting

If you request the asctime attribute (directly or through a mapping), then the date format
can be overridden through the datefmt parameter.

import logging
from logfmter import Logfmter

formatter = Logfmter(
    keys=["at", "when"],
    mapping={"at": "levelname", "when": "asctime"},
    datefmt="%Y-%m-%d"
)

handler = logging.StreamHandler()
handler.setFormatter(formatter)

logging.basicConfig(handlers=[handler])

logging.error("hello") # at=ERROR when=2022-04-20 msg=hello

[jteppinette]

@meitham Let me know if this resolves your question, then I will close this issue.

[meitham]

@jteppinette Very kind of you to have this feature added at such a short notice, much appreciated.

It does indeed solve my issue, thank you very much.