Often when debugging web applications, it is required to display response/request fields in logs. This module allows you to switch from regular uvicorn logging to advanced FasApi logging using Middleware. You can either use logging or loguru. An extra-logger has also been added to the module, when called in any module, fields are added containing the name of the file and function, as well as parameters included in the function.

Additional fields
- Adding fields to logging
- Translation of logging to loguru
Extra-Logger
- logging extra-logger
- loguru extra-logger

Additional fields

You can use the following additional fields when formatting logs:

duration - Duration time
exceptions - Traceback
request_uri - Request URL
request_referrer - Referrer
request_protocol - Protocol (HTTP, HTTPS)
request_method - Method (GET, POST, PUT, DELETE)
request_path - Request path
request_host - Request host
request_size - Request size
request_content_type - Request content type
remote_ip - Remote ip
remote_port - Remote port
response_size - Response size
response_headers - Response header
request_headers - Request header
request_body - Request body
response_status_code - Response status code
response_body - Response body

Adding fields to logging

If you are using the logging module, then just call the following command:

from fastapi import FastAPI
from fastapi_logging import init_logging
app = FastAPI()
init_logging(app)

Let's look at an example call. Let's create an endpoint with an error and call it

@app.get("/err")
def err_get():
    1 / 0

When initiating init_logging you can use the following options:

logger_name - Logger name for logging module. This name will be used to get logger later. So all configurations for console logging logger should by applied to this name. By default it take name of main application
format - String format for message, by default LOGGING_DEFAULT_FORMAT
datefmt - Date format, by default DATE_DEFAULT_FORMAT
level - Logging level, by default "INFO"
traceback_to_console - Set True if you want to see traceback in your console, False if you don't, by default False

init_logging(
    app,
    logger_name=__name__,
    format="%(levelprefix)s %(asctime)s path: %(request_path)s %(response_status_code)-4s %(message)s request body: %(request_body)s",
    traceback_to_console=True,
    level="INFO",
)

The format can be set according to logging standards. If the traceback_to_console argument is set to True, then when you call the same endpoint, you will see the traceback directly in the console.

Note

To add traceback when logging, for example to a file, use the exceptions attribute

Translation of logging to loguru

To transfer all dogging to loguru, just run the following commands:

from fastapi import FastAPI
from fastapi_logging import init_loguru
app = FastAPI()
init_loguru(app)

Let's look at an example call

When initiating init_logging you can use the following options:

format - String format for message, by default LOGURU_DEFAULT_FORMAT
level - Logging level, by default "INFO"
traceback_to_console - Set True if you want to see traceback in your console, False if you don't, by default False

init_loguru(
    app, 
    traceback_to_console=True, 
    format="<green>{time:YYYY-MM-DD HH:mm:ss}</green> <level>{level: <8}</level> {extra[request_path]} <level>{extra[response_status_code]: <3} {message}</level>",
    level="DEBUG"
)

When the traceback_to_console argument is set to True, you will see the traceback directly in the console.

Extra-Logger

You can use extra-logger anywhere in your code. With using it you'll get logger with additional 'request_path' and 'request_body' fields. 'request_path' will contain filename and module name, from which it was called. 'request_body' will contain function args. Also you can add fields using addintional_fields attribute.

logging extra-logger

from fastapi_logging.extra_logger import LoggingExtraLogger

extra_logger = LoggingExtraLogger(logger_name=__name__)

Let's work on the following example

from pydantic import BaseModel


class Body(BaseModel):
    field_str: str
    field_int: int

@app.post("/extra_logger_example")
def extra_logger_example(body: Body):
    extra_logger.info("here is your info")
    extra_logger.warn("here is your warning")
    extra_logger.critical("here is your critical")
    extra_logger.debug("here is your debug")
    extra_logger.fatal("here is your fatal")
    extra_logger.error("here is your error")

The logs will show the following:

loguru extra-logger

from fastapi_logging.extra_logger import LoguruExtraLogger

extra_logger = LoguruExtraLogger()