stvnksslr/dataslate-parser

import logging
import sys
from pprint import pformat
from typing import TYPE_CHECKING, Optional

from loguru import logger
from loguru._defaults import LOGURU_FORMAT

if TYPE_CHECKING:
    from types import FrameType


class InterceptHandler(logging.Handler):
    def emit(self, record: logging.LogRecord):
        # Get corresponding Loguru level if it exists
        try:
            level = logger.level(record.levelname).name
        except ValueError:
            level = logging.getLevelName(record.levelno)  # Convert int to level name string

        # Find caller from where originated the logged message
        frame: Optional[FrameType] = logging.currentframe()
        depth = 2
        while frame and frame.f_code.co_filename == logging.__file__:
            frame = frame.f_back
            depth += 1

        logger.opt(depth=depth, exception=record.exc_info).log(level, record.getMessage())


def format_record(record: dict) -> str:
    """Custom format for loguru loggers.
    Uses pformat for log any data like request/response body during debug.
    Works with logging if loguru handler it.

    Example:
    -------
    >>> payload = [{"users":[{"name": "Nick", "age": 87, "is_active": True},
    >>> {"name": "Alex", "age": 27, "is_active": True}], "count": 2}]
    >>> logger.bind(payload=).debug("users payload")
    >>> [   {   'count': 2,
    >>>         'users': [   {'age': 87, 'is_active': True, 'name': 'Nick'},
    >>>                      {'age': 27, 'is_active': True, 'name': 'Alex'}]}].
    """
    format_string = LOGURU_FORMAT
    if record["extra"].get("payload") is not None:
        record["extra"]["payload"] = pformat(record["extra"]["payload"], indent=4, compact=True, width=88)
        format_string += "\n<level>{extra[payload]}</level>"

    format_string += "{exception}\n"
    return format_string


def init_logging():
    """Replaces logging handlers with a handler for using the custom handler.

    WARNING!
    if you call the init_logging in startup event function,
    then the first logs before the application start will be in the old format
    >>> app.add_event_handler("startup", init_logging)
    stdout:
    INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
    INFO:     Started reloader process [11528] using statreload
    INFO:     Started server process [6036]
    INFO:     Waiting for application startup.
    2020-07-25 02:19:21.357 | INFO     | uvicorn.lifespan.on:startup:34 - Application startup complete.

    """
    # disable handlers for specific uvicorn loggers
    # to redirect their output to the default uvicorn logger
    # works with uvicorn==0.11.6
    loggers = (logging.getLogger(name) for name in logging.root.manager.loggerDict if name.startswith("uvicorn."))
    for uvicorn_logger in loggers:
        uvicorn_logger.handlers = []

    # change handler for default uvicorn logger
    intercept_handler = InterceptHandler()
    logging.getLogger("uvicorn").handlers = [intercept_handler]

    # set logs output, level and format
    logger.configure(handlers=[{"sink": sys.stdout, "level": logging.DEBUG, "format": format_record}])