Print timestamp for logging in Python

I want to print the current timestamp, when an event succeeded or not in my python script. By only adding…

datetime.datetime.now().strftime("%d.%b %Y %H:%M:%S")

…. at the beginning of each line, te same date appears in every line

[INFO] 04.Feb 2015 20:49:41: cl1
[ OK ] 04.Feb 2015 20:49:41: 8.8.8.8 ONLINE!
[INFO] 04.Feb 2015 20:49:41: cl2
[ OK ] 04.Feb 2015 20:49:41: 8.8.8.8 ONLINE!
[INFO] 04.Feb 2015 20:49:41: cl3
[ OK ] 04.Feb 2015 20:49:41: 8.8.8.8 ONLINE!

(I added time.sleep(5)in between)

My next idea was to create a function, calling the current time, but i’m failing at embedding this function to the printcommand.

File rs.py

OK =   "[" + bc.OKGREEN + " OK "  + bc.ENDC + "] " + datetime.datetime.now().strftime("%d.%b %Y %H:%M:%S")
INFO = "[" + bc.OKBLUE  + "INFO"  + bc.ENDC + "] " + datetime.datetime.now().strftime("%d.%b %Y %H:%M:%S")
WARN = "[" + bc.WARN    + "WARN"  + bc.ENDC + "] " + datetime.datetime.now().strftime("%d.%b %Y %H:%M:%S")
ERR =  "[" + bc.ERR     + "FAIL"  + bc.ENDC + "] " + datetime.datetime.now().strftime("%d.%b %Y %H:%M:%S")
DEB =  "[" + bc.HEADER  + "DEBUG" + bc.ENDC + "] " + datetime.datetime.now().strftime("%d.%b %Y %H:%M:%S")

File myapp.py

import rs # importing rs.py

print rs.OK + hostname + "is up!"
time.sleep(3)
print rs.ERR+ hostname + "is down!"

Is printing:

>>> [INFO] 04.Feb 2015 20:49:41: xxx is up!
>>> [ERR ] 04.Feb 2015 20:49:41: xxx is down!

Answer

Before the first time you log anything do this:

logging.basicConfig(
    format='%(asctime)s %(levelname)-8s %(message)s',
    level=logging.INFO,
    datefmt='%Y-%m-%d %H:%M:%S')

Example on the REPL:

>>> import logging
>>> logging.basicConfig(
...         format='%(asctime)s %(levelname)-8s %(message)s',
...         level=logging.INFO,
...         datefmt='%Y-%m-%d %H:%M:%S')
>>> 
>>> logging.info('an info messge')
2017-05-25 00:58:28 INFO     an info messge
>>> logging.debug('a debug messag is not shown')
>>>