text: # sqlalchemy/log.py
  # Copyright (C) 2006-2021 the SQLAlchemy authors and contributors
  # <see AUTHORS file>
  # Includes alterations by Vinay Sajip vinay_sajip@yahoo.co.uk
  #
  # This module is part of SQLAlchemy and is released under
  # the MIT License: https://www.opensource.org/licenses/mit-license.php
  
  """Logging control and utilities.
  
  Control of logging for SA can be performed from the regular python logging
  module.  The regular dotted module namespace is used, starting at
  'sqlalchemy'.  For class-level logging, the class name is appended.
  
  The "echo" keyword parameter, available on SQLA :class:`_engine.Engine`
  and :class:`_pool.Pool` objects, corresponds to a logger specific to that
  instance only.
  
  """
  
  import logging
  import sys
  
  
  # set initial level to WARN.  This so that
  # log statements don't occur in the absence of explicit
  # logging being enabled for 'sqlalchemy'.
  rootlogger = logging.getLogger("sqlalchemy")
  if rootlogger.level == logging.NOTSET:
      rootlogger.setLevel(logging.WARN)
  
  
  def _add_default_handler(logger):
      handler = logging.StreamHandler(sys.stdout)
      handler.setFormatter(
          logging.Formatter("%(asctime)s %(levelname)s %(name)s %(message)s")
      )
      logger.addHandler(handler)
  
  
  _logged_classes = set()
  
  
  def _qual_logger_name_for_cls(cls):
      return (
          getattr(cls, "_sqla_logger_namespace", None)
          or cls.__module__ + "." + cls.__name__
      )
  
  
  def class_logger(cls):
      logger = logging.getLogger(_qual_logger_name_for_cls(cls))
      cls._should_log_debug = lambda self: logger.isEnabledFor(logging.DEBUG)
      cls._should_log_info = lambda self: logger.isEnabledFor(logging.INFO)
      cls.logger = logger
      _logged_classes.add(cls)
      return cls
  
  
  class Identified:
      logging_name = None
  
      def _should_log_debug(self):
          return self.logger.isEnabledFor(logging.DEBUG)
  
      def _should_log_info(self):
          return self.logger.isEnabledFor(logging.INFO)
  
  
  class InstanceLogger:
      """A logger adapter (wrapper) for :class:`.Identified` subclasses.
  
      This allows multiple instances (e.g. Engine or Pool instances)
      to share a logger, but have its verbosity controlled on a
      per-instance basis.
  
      The basic functionality is to return a logging level
      which is based on an instance's echo setting.
  
      Default implementation is:
  
      'debug' -> logging.DEBUG
      True    -> logging.INFO
      False   -> Effective level of underlying logger (
      logging.WARNING by default)
      None    -> same as False
      """
  
      # Map echo settings to logger levels
      _echo_map = {
          None: logging.NOTSET,
          False: logging.NOTSET,
          True: logging.INFO,
          "debug": logging.DEBUG,
      }
  
      def __init__(self, echo, name):
          self.echo = echo
          self.logger = logging.getLogger(name)
  
          # if echo flag is enabled and no handlers,
          # add a handler to the list
          if self._echo_map[echo] <= logging.INFO and not self.logger.handlers:
              _add_default_handler(self.logger)
  
      #
      # Boilerplate convenience methods
      #
      def debug(self, msg, *args, **kwargs):
          """Delegate a debug call to the underlying logger."""
  
          self.log(logging.DEBUG, msg, *args, **kwargs)
  
      def info(self, msg, *args, **kwargs):
          """Delegate an info call to the underlying logger."""
  
          self.log(logging.INFO, msg, *args, **kwargs)
  
      def warning(self, msg, *args, **kwargs):
          """Delegate a warning call to the underlying logger."""
  
          self.log(logging.WARNING, msg, *args, **kwargs)
  
      warn = warning
  
      def error(self, msg, *args, **kwargs):
          """
          Delegate an error call to the underlying logger.
          """
          self.log(logging.ERROR, msg, *args, **kwargs)
  
      def exception(self, msg, *args, **kwargs):
          """Delegate an exception call to the underlying logger."""
  
          kwargs["exc_info"] = 1
          self.log(logging.ERROR, msg, *args, **kwargs)
  
      def critical(self, msg, *args, **kwargs):
          """Delegate a critical call to the underlying logger."""
  
          self.log(logging.CRITICAL, msg, *args, **kwargs)
  
      def log(self, level, msg, *args, **kwargs):
          """Delegate a log call to the underlying logger.
  
          The level here is determined by the echo
          flag as well as that of the underlying logger, and
          logger._log() is called directly.
  
          """
  
          # inline the logic from isEnabledFor(),
          # getEffectiveLevel(), to avoid overhead.
  
          if self.logger.manager.disable >= level:
              return
  
          selected_level = self._echo_map[self.echo]
          if selected_level == logging.NOTSET:
              selected_level = self.logger.getEffectiveLevel()
  
          if level >= selected_level:
              self.logger._log(level, msg, args, **kwargs)
  
      def isEnabledFor(self, level):
          """Is this logger enabled for level 'level'?"""
  
          if self.logger.manager.disable >= level:
              return False
          return level >= self.getEffectiveLevel()
  
      def getEffectiveLevel(self):
          """What's the effective level for this logger?"""
  
          level = self._echo_map[self.echo]
          if level == logging.NOTSET:
              level = self.logger.getEffectiveLevel()
          return level
  
  
  def instance_logger(instance, echoflag=None):
      """create a logger for an instance that implements :class:`.Identified`."""
  
      if instance.logging_name:
          name = "%s.%s" % (
              _qual_logger_name_for_cls(instance.__class__),
              instance.logging_name,
          )
      else:
          name = _qual_logger_name_for_cls(instance.__class__)
  
      instance._echo = echoflag
  
      if echoflag in (False, None):
          # if no echo setting or False, return a Logger directly,
          # avoiding overhead of filtering
          logger = logging.getLogger(name)
      else:
          # if a specified echo flag, return an EchoLogger,
          # which checks the flag, overrides normal log
          # levels by calling logger._log()
          logger = InstanceLogger(echoflag, name)
  
      instance.logger = logger
  
  
  class echo_property:
      __doc__ = """\
      When ``True``, enable log output for this element.
  
      This has the effect of setting the Python logging level for the namespace
      of this element's class and object reference.  A value of boolean ``True``
      indicates that the loglevel ``logging.INFO`` will be set for the logger,
      whereas the string value ``debug`` will set the loglevel to
      ``logging.DEBUG``.
      """
  
      def __get__(self, instance, owner):
          if instance is None:
              return self
          else:
              return instance._echo
  
      def __set__(self, instance, value):
          instance_logger(instance, echoflag=value)
  