pycharm duplicated log for SQLALCHEMY_ECHO = True

Question

When I want to log sqlalchemy queries by setting SQLALCHEMY_ECHO = True in my flask app I am getting duplicated log in console. Once with red color then once with white. How can I get single color?

Answer 1

This most probably happens because SQLAlchemy adds their own handlers to their loggers in sqlalchemy.log.InstanceLogger.__init__:

    def __init__(self, echo: _EchoFlagType, name: str):
        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)  # <=== Handler is added here

But the logger still propagates log record to the higher level loggers and their attached handlers. So if you have a handler attached to your root logger then the log record will be printed from both the handler attached by SQLAlchemy and the root logger's handler(s).

SQLAlchemy developers should have instead attached their handler to root logger and only in case if there are no other handlers attached already. Similar to standard library logging.basicConfig() behavior.

This is how I work around it:

from sqlalchemy import log as sqlalchemy_log
sqlalchemy_log._add_default_handler = lambda x: None  # Patch to avoid duplicate logging