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?
11 Answers
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:
debuginfowarningerrorcritical
You can add the flag by double clicking the app and then dropping it into the Extra Flags field.
See https://cloud.google.com/appengine/docs/python/requests#Python_Logging
and http://docs.python.org/library/logging.html
You probably want to use something like:
logging.debug("value of my var is %s", str(var))
You should also give FirePython a look. It allows you to get server log messages in firebug.
http://appengine-cookbook.appspot.com/recipe/firepython-logger-console-inside-firebug/
Hello I'm using the version 1.8.6 of GoogleAppEngineLauncher, you can use a flag to set the messages log level you want to see, for example for debug messages:
--dev_appserver_log_level debug
Use it instead of --debug (see @Christopher answer).
Using the logging module is good practice, but it's not required.
You can just do plain-old print()s to write to the Google App Engine Log Console.
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