Structlog

Logfire has a built-in structlog processor that can be used to emit Logfire logs for every structlog event.

main.py

from dataclasses import dataclass

import structlog
import logfire

logfire.configure()

structlog.configure(
    processors=[
        structlog.contextvars.merge_contextvars,
        structlog.processors.add_log_level,
        structlog.processors.StackInfoRenderer(),
        structlog.dev.set_exc_info,
        structlog.processors.TimeStamper(fmt='%Y-%m-%d %H:%M:%S', utc=False),
        logfire.StructlogProcessor(),
        structlog.dev.ConsoleRenderer(),
    ],
)
logger = structlog.get_logger()


@dataclass
class User:
    id: int
    name: str


logger.info('Login', user=User(id=42, name='Fred'))
#> 2024-03-22 12:57:33 [info     ] Login                          user=User(id=42, name='Fred')

The Logfire processor MUST come before the last processor that renders the logs in the structlog configuration.

By default, LogfireProcessor shown above disables console logging by logfire so you can use the existing logger you have configured for structlog, if you want to log with logfire, use LogfireProcessor(console_log=True).

Note

Positional arguments aren't collected as attributes by the processor, since they are already part of the event message when the processor is called.

If you have the following:

logger.error('Hello %s!', 'Fred')
#> 2024-03-22 13:39:26 [error    ] Hello Fred!

The string 'Fred' will not be collected by the processor as an attribute, just formatted with the message.