Search code examples
pythongoogle-app-engineloggingpython-logging

How do I write to the console in Google App Engine?

Often when I am coding I just like to print little things (mostly the current value of variables) out to console. I don't see anything like this for Google App Engine, although I note that the Google App Engine Launcher does have a Log terminal. Is there any way to write to said Terminal, or to some other terminal, using Google App Engine?

Solution

  • You'll want to use the Python's standard logging module.

    import logging

logging.info("hello")
logging.debug("hi") # this won't show up by default

    To see calls to logging.debug() in the GoogleAppEngineLauncher Logs console, you have to first add the flag --dev_appserver_log_level=debug to your app. However, beware that you're going to see a lot of debug noise from the App Engine SDK itself. The full set of levels are:

    • debug
    • info
    • warning
    • error
    • critical

    You can add the flag by double clicking the app and then dropping it into the Extra Flags field.

    Adding the --dev_appserver_log_level flag to your app in the GoogleAppEngineLauncher