Debugging the installed version of Horizon

Most instructions for debugging Horizon assume that you are running in Devstack, or in some other manual install, where you have a checkout of the source code available. When Horizon has been installed system-wide (e.g. with Fuel or Foreman), you don't have this.

So, the idea is to fake it, using a lot of symlinks.

mkdir HORIZON_TEST
cd HORIZON_TEST
ln -s /usr/share/openstack-dashboard/static
ln -s /usr/share/openstack-dashboard/manage.py
mkdir openstack_dashboard
cd openstack_dashboard
ln -s /usr/share/openstack-dashboard/openstack_dashboard/*
rm static
ln -s /usr/share/openstack-dashboard/static
cd ..
mkdir horizon
cd horizon
ln -s /usr/lib/python2.7/site-packages/horizon/*
rm static
ln -s /usr/share/openstack-dashboard/static
cd ..

Then, in that HORIZON_TEST folder, you can run

python -m pdb manage.py runserver

This launches the Horizon dashboard on port 8080. None of the CSS, images, or javascript will work correctly, but the site is still (somewhat) usable.

Then by inserting pdb traces in the right locations, you can debug Horizon with pdb.