Logging

Application and request level loggers can be configured using the LoggingConfig:

import logging

from litestar import Litestar, Request, get
from litestar.logging import LoggingConfig


@get("/")
def my_router_handler(request: Request) -> None:
    request.logger.info("inside a request")
    return None


logging_config = LoggingConfig(
    root={"level": logging.getLevelName(logging.INFO), "handlers": ["console"]},
    formatters={
        "standard": {"format": "%(asctime)s - %(name)s - %(levelname)s - %(message)s"}
    },
)

app = Litestar(route_handlers=[my_router_handler], logging_config=logging_config)

Attention

Litestar configures a non-blocking QueueListenerHandler which is keyed as queue_listener in the logging configuration. The above example is using this handler, which is optimal for async applications. Make sure to use it in your own loggers as in the above example.

Standard Library Logging (Manual Configuration)

logging is Python’s builtin standard logging library and can be integrated with LoggingConfig as the root logging. By using logging_config()() you can build a logger to be used around your project.

import logging

from litestar import Litestar, Request, get
from litestar.logging import LoggingConfig

logging_config = LoggingConfig(
    root={"level": logging.getLevelName(logging.INFO), "handlers": ["console"]},
    formatters={
        "standard": {"format": "%(asctime)s - %(name)s - %(levelname)s - %(message)s"}
    },
)

logger = logging_config.configure()()


@get("/")
def my_router_handler(request: Request) -> None:
    request.logger.info("inside a request")
    logger.info("here too")


app = Litestar(
    route_handlers=[my_router_handler],
    logging_config=logging_config,
)

The above example is the same as using logging without the litestar LoggingConfig.

import logging

from litestar import Litestar, Request, get


def get_logger(mod_name: str) -> logging.Logger:
    """Return logger object."""
    format = "%(asctime)s: %(name)s: %(levelname)s: %(message)s"
    logger = logging.getLogger(mod_name)
    # Writes to stdout
    ch = logging.StreamHandler()
    ch.setLevel(logging.INFO)
    ch.setFormatter(logging.Formatter(format))
    logger.addHandler(ch)
    return logger


logger = get_logger(__name__)


@get("/")
def my_router_handler(request: Request) -> None:
    logger.info("logger inside a request")


app = Litestar(
    route_handlers=[my_router_handler],
)

Using Picologging

Picologging is a high performance logging library that is developed by Microsoft. Litestar will default to using this library automatically if its installed - requiring zero configuration on the part of the user. That is, if picologging is present the previous example will work with it automatically.

Using StructLog

StructLog is a powerful structured-logging library. Litestar ships with a dedicated logging config for using it:

from litestar import Litestar, Request, get
from litestar.logging import StructLoggingConfig


@get("/")
def my_router_handler(request: Request) -> None:
    request.logger.info("inside a request")
    return None


logging_config = StructLoggingConfig()

app = Litestar(route_handlers=[my_router_handler], logging_config=logging_config)

Subclass Logging Configs

You can easily create you own LoggingConfig class by subclassing BaseLoggingConfig and implementing the configure method.