TimingLogger context manager

timinglogger.py

import datetime
import logging


class TimingLogger(object):
    """
    Simple timer context manager to log the time spent in the context
    to given logger (logging api).

    Usage example:

        with TimingLogger(title="Compile"):
            # Do compile stuff here

        # Result: start, end and elapsed time will be logged (to root logger in this case)
    """

    def __init__(self, logger=None, title="Timer"):
        self._logger = logger or logging.getLogger()
        self._title = title

    def __enter__(self):
        self.start_time = datetime.datetime.utcnow()
        self._logger.info('{title} start time: {time}'.format(title=self._title, time=self.start_time))
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.end_time = datetime.datetime.utcnow()
        self.elapsed = self.end_time - self.start_time
        self._logger.info('{title} end time: {time}, elapsed: {elapsed}'.format(title=self._title, time=self.end_time, elapsed=self.elapsed))