# Logging cookbook¶

The Atomica logger is named 'atomica'. At any point, from anywhere, you can retrieve it using

import logging
logger = getLogger('atomica')


## Changing the amount of output¶

Once you have the logger object (e.g. in your own script) you can change the logging level to control the amount of output displayed. The most common levels are

Level Command
Show warnings or worse only logger.setLevel('WARNING')
Default - Show normal output logger.setLevel('INFO')
Show extra detailed output logger.setLevel('DEBUG')

When writing code for Atomica, set the level of the message accordingly e.g. in the code you are writing, use

logger.warning('This should be displayed as a warning')
logger.info('This is information that the user will normally see')
logger.debug('This is extra-verbose output')


Note that the use of logger.debug means that you do not need to set verbose flags and if statements - instead, just set the logging level to debug.

Note also that the default logging level is set in atomica/__init__.py so normally you should set the logging level in your script after importing Atomica e.g.

import atomica.ui as au
logger.setLevel('DEBUG')


logger.setLevel('DEBUG')
import atomica.ui as au


then the logging level will be reset to INFO so you won’t see debug messages.

## Dumping output to a log file¶

A common task is storing the log messages for a simulation run. This can be accomplished easily through the logging module, by adding a file handler to the root logger. At the top of your script, add the following snippet:

import logging
logger = logging.getLogger()
h = logging.FileHandler('output.log',mode='w')

Then any messages logged by Atomica will be written to the specified file, in addition to being printed in the console. If you run the commands above before importing Atomica, then the version information printed when Atomica is imported will be recorded as well (so it is recommended to initialize the FileHandler at the start of your scripts).