watcher.py

"""
Filename: watcher.py
Authors: Pablo Winant
Time long computation and send a message when finished.
"""

import contextlib

@contextlib.contextmanager
def watcher(task_name=None, email=None):

    import time
    import datetime
    t = time.time()
    starting_date = datetime.datetime.now()
    try:
        yield
    finally:
        finishing_date = datetime.datetime.now()
        delta = finishing_date - starting_date
        if delta.days == 0:
            print(delta)
            dd = delta.seconds + delta.microseconds/1e6
            elapsed = "{} seconds".format(dd)
        else:
            elapsed = "{} days and {} seconds".format(delta.days, delta.seconds)

        short_msg = "Task {} finished after {} seconds.".format(task_name, elapsed)

        long_msg = '''
        Task {} completed.
        Started:  {}
        Finished: {}
        Elapsed: {}'''.format(task_name, starting_date.isoformat(), finishing_date.isoformat(), str(delta))

        print(short_msg)

        if email:

            try:
                import smtplib
                from email.mime.text import MIMEText

                msg = MIMEText(long_msg)
                msg['Subject'] = short_msg
                msg['From'] = email
                msg['To'] = email

                s = smtplib.SMTP('localhost')
                s.sendmail(email, msg.as_string())
                s.quit()

            except Exception as e:
                import warnings
                warnings.warn("Impossible to send email using 'smtplib'")

def test_watcher():

    from time import sleep

    def fun(n):
        sleep(n)

    with watcher("Sleep"):
        sleep(1)

    with watcher(task_name="Sleep", email='pablo.winant@gmail.com'):
        sleep(1)

if __name__ == '__main__':
    test_watcher()