Getting logging.debug() to work on Google App Engine/Python

Question

I\'m just getting started on building a Python app for Google App Engine. In the localhost environment (on a Mac)

I\'m trying to send debug info to the GoogleAppEng

Answer 1

In case someone is using the Windows Google Application Launcher. The argument for debug can be set under Edit > Application Settings

In the Extra Command Line Flags, add --log_level=debug

Answer 2

On a Mac:

1) click Edit > Application Settings

2) then copy and paste the following line into the "Extra Flags:" field

--log_level=debug

3) click Update

your debug logs will now show up in the Log Console

Answer 3

another alternative to setting the log_level flag:

logging.getLogger().handlers[0].setLevel(logging.DEBUG)

Answer 4

The flag is --log_level debug.

Concretely, start your dev server with this command line:

dev_appserver.py --log_level debug .

You can find this information by running dev_appserver.py --help. Here's the relevant quote from the command output:

--log_level {debug,info,warning,critical,error} the log level below which logging messages generated by application code will not be displayed on the console (default: info)

Using an equal sign (i.e., --log_level=debug) will also work, because the python script google-cloud-sdk/platform/google_appengine/google/appengine/tools/devappserver2/devappserver2.py relies on the argparse module, and the latter handles both spaces and the equal sign the same way, as stated in the official doc.