I want to print out root logs in logfmt format. structlog also should print logs in the same format. I tried this example for JSON format and looks like it doesn’t work with logfmt.

Here is a first try:

import logging
import sys

import logfmter
import structlog

handler = logging.StreamHandler(sys.stdout)
handler.setFormatter(logfmter.Logfmter())
root_logger = logging.getLogger()
root_logger.addHandler(handler)

structlog.get_logger("test").warning("hello")
logging.getLogger("test").warning("hello")

It prints:

2024-06-04 22:11:01 [warning  ] hello                         
at=WARNING msg=hello

Here is structlog is definitely not a logfmt formatted.

I tried to add logfmt render then:

import logging
import sys

import logfmter
import structlog

handler = logging.StreamHandler(sys.stdout)
handler.setFormatter(logfmter.Logfmter())
root_logger = logging.getLogger()
root_logger.addHandler(handler)

structlog.configure(
    processors=[
        structlog.stdlib.filter_by_level,
        structlog.stdlib.add_logger_name,
        structlog.stdlib.add_log_level,
        structlog.stdlib.PositionalArgumentsFormatter(),
        structlog.processors.TimeStamper(fmt='iso'),
        structlog.processors.StackInfoRenderer(),
        structlog.processors.format_exc_info,
        # ADD LOGFMT RENDER
        structlog.processors.LogfmtRenderer(),
    ],
    logger_factory=structlog.stdlib.LoggerFactory(),
    wrapper_class=structlog.stdlib.BoundLogger,
    cache_logger_on_first_use=True,
)

structlog.get_logger("test").warning("hello")
logging.getLogger("test").warning("hello")

And fail again:

at=WARNING msg="event=hello logger=test level=warning timestamp=2024-06-04T13:12:54.637931Z"
at=WARNING msg=hello

Obviously correct log line should be like:

at=WARNING msg=hello logger=test level=warning timestamp=2024-06-04T13:12:54.637931Z

Is it possible to format both structlog and logging as logfmt?