Source code for scrapy.utils.log

from __future__ import annotations

import logging
import sys
from logging.config import dictConfig
from types import TracebackType
from typing import (
    TYPE_CHECKING,
    Any,
    Dict,
    List,
    MutableMapping,
    Optional,
    Tuple,
    Type,
    Union,
    cast,
)

from twisted.python import log as twisted_log
from twisted.python.failure import Failure

import scrapy
from scrapy.logformatter import LogFormatterResult
from scrapy.settings import Settings, _SettingsKeyT
from scrapy.utils.versions import scrapy_components_versions

if TYPE_CHECKING:
    from scrapy.crawler import Crawler

logger = logging.getLogger(__name__)


def failure_to_exc_info(
    failure: Failure,
) -> Optional[Tuple[Type[BaseException], BaseException, Optional[TracebackType]]]:
    """Extract exc_info from Failure instances"""
    if isinstance(failure, Failure):
        assert failure.type
        assert failure.value
        return (
            failure.type,
            failure.value,
            cast(Optional[TracebackType], failure.getTracebackObject()),
        )
    return None


class TopLevelFormatter(logging.Filter):
    """Keep only top level loggers's name (direct children from root) from
    records.

    This filter will replace Scrapy loggers' names with 'scrapy'. This mimics
    the old Scrapy log behaviour and helps shortening long names.

    Since it can't be set for just one logger (it won't propagate for its
    children), it's going to be set in the root handler, with a parametrized
    ``loggers`` list where it should act.
    """

    def __init__(self, loggers: Optional[List[str]] = None):
        self.loggers: List[str] = loggers or []

    def filter(self, record: logging.LogRecord) -> bool:
        if any(record.name.startswith(logger + ".") for logger in self.loggers):
            record.name = record.name.split(".", 1)[0]
        return True


DEFAULT_LOGGING = {
    "version": 1,
    "disable_existing_loggers": False,
    "loggers": {
        "filelock": {
            "level": "ERROR",
        },
        "hpack": {
            "level": "ERROR",
        },
        "scrapy": {
            "level": "DEBUG",
        },
        "twisted": {
            "level": "ERROR",
        },
    },
}


[docs]def configure_logging( settings: Union[Settings, Dict[_SettingsKeyT, Any], None] = None, install_root_handler: bool = True, ) -> None: """ Initialize logging defaults for Scrapy. :param settings: settings used to create and configure a handler for the root logger (default: None). :type settings: dict, :class:`~scrapy.settings.Settings` object or ``None`` :param install_root_handler: whether to install root logging handler (default: True) :type install_root_handler: bool This function does: - Route warnings and twisted logging through Python standard logging - Assign DEBUG and ERROR level to Scrapy and Twisted loggers respectively - Route stdout to log if LOG_STDOUT setting is True When ``install_root_handler`` is True (default), this function also creates a handler for the root logger according to given settings (see :ref:`topics-logging-settings`). You can override default options using ``settings`` argument. When ``settings`` is empty or None, defaults are used. """ if not sys.warnoptions: # Route warnings through python logging logging.captureWarnings(True) observer = twisted_log.PythonLoggingObserver("twisted") observer.start() dictConfig(DEFAULT_LOGGING) if isinstance(settings, dict) or settings is None: settings = Settings(settings) if settings.getbool("LOG_STDOUT"): sys.stdout = StreamLogger(logging.getLogger("stdout")) # type: ignore[assignment] if install_root_handler: install_scrapy_root_handler(settings)
_scrapy_root_handler: Optional[logging.Handler] = None def install_scrapy_root_handler(settings: Settings) -> None: global _scrapy_root_handler if ( _scrapy_root_handler is not None and _scrapy_root_handler in logging.root.handlers ): logging.root.removeHandler(_scrapy_root_handler) logging.root.setLevel(logging.NOTSET) _scrapy_root_handler = _get_handler(settings) logging.root.addHandler(_scrapy_root_handler) def get_scrapy_root_handler() -> Optional[logging.Handler]: return _scrapy_root_handler def _get_handler(settings: Settings) -> logging.Handler: """Return a log handler object according to settings""" filename = settings.get("LOG_FILE") handler: logging.Handler if filename: mode = "a" if settings.getbool("LOG_FILE_APPEND") else "w" encoding = settings.get("LOG_ENCODING") handler = logging.FileHandler(filename, mode=mode, encoding=encoding) elif settings.getbool("LOG_ENABLED"): handler = logging.StreamHandler() else: handler = logging.NullHandler() formatter = logging.Formatter( fmt=settings.get("LOG_FORMAT"), datefmt=settings.get("LOG_DATEFORMAT") ) handler.setFormatter(formatter) handler.setLevel(settings.get("LOG_LEVEL")) if settings.getbool("LOG_SHORT_NAMES"): handler.addFilter(TopLevelFormatter(["scrapy"])) return handler def log_scrapy_info(settings: Settings) -> None: logger.info( "Scrapy %(version)s started (bot: %(bot)s)", {"version": scrapy.__version__, "bot": settings["BOT_NAME"]}, ) versions = [ f"{name} {version}" for name, version in scrapy_components_versions() if name != "Scrapy" ] logger.info("Versions: %(versions)s", {"versions": ", ".join(versions)}) def log_reactor_info() -> None: from twisted.internet import reactor logger.debug("Using reactor: %s.%s", reactor.__module__, reactor.__class__.__name__) from twisted.internet import asyncioreactor if isinstance(reactor, asyncioreactor.AsyncioSelectorReactor): logger.debug( "Using asyncio event loop: %s.%s", reactor._asyncioEventloop.__module__, reactor._asyncioEventloop.__class__.__name__, ) class StreamLogger: """Fake file-like stream object that redirects writes to a logger instance Taken from: https://www.electricmonk.nl/log/2011/08/14/redirect-stdout-and-stderr-to-a-logger-in-python/ """ def __init__(self, logger: logging.Logger, log_level: int = logging.INFO): self.logger: logging.Logger = logger self.log_level: int = log_level self.linebuf: str = "" def write(self, buf: str) -> None: for line in buf.rstrip().splitlines(): self.logger.log(self.log_level, line.rstrip()) def flush(self) -> None: for h in self.logger.handlers: h.flush() class LogCounterHandler(logging.Handler): """Record log levels count into a crawler stats""" def __init__(self, crawler: Crawler, *args: Any, **kwargs: Any): super().__init__(*args, **kwargs) self.crawler: Crawler = crawler def emit(self, record: logging.LogRecord) -> None: sname = f"log_count/{record.levelname}" assert self.crawler.stats self.crawler.stats.inc_value(sname) def logformatter_adapter( logkws: LogFormatterResult, ) -> Tuple[int, str, Union[Dict[str, Any], Tuple[Any, ...]]]: """ Helper that takes the dictionary output from the methods in LogFormatter and adapts it into a tuple of positional arguments for logger.log calls, handling backward compatibility as well. """ level = logkws.get("level", logging.INFO) message = logkws.get("msg") or "" # NOTE: This also handles 'args' being an empty dict, that case doesn't # play well in logger.log calls args = cast(Dict[str, Any], logkws) if not logkws.get("args") else logkws["args"] return (level, message, args) class SpiderLoggerAdapter(logging.LoggerAdapter): def process( self, msg: str, kwargs: MutableMapping[str, Any] ) -> Tuple[str, MutableMapping[str, Any]]: """Method that augments logging with additional 'extra' data""" if isinstance(kwargs.get("extra"), MutableMapping): kwargs["extra"].update(self.extra) else: kwargs["extra"] = self.extra return msg, kwargs