Took me awhile, although it was really simple in the end. Unfortunately I've lost my bash history so if you find a mistake, please leave a comment or edit in the correction.
Note that I had already got mod_wsgi working, so I had to remove it:
$ a2dismod wsgi
$ sudo apt-get remove libapache2-mod-wsgi
EDIT: Due to apt-get installing an outdated package (which results in a minor error creeping into Apache's error log) I don't at time of writing recommend this:
$ sudo apt-get install libapache2-mod-wsgi-py3
$ a2enmod wsgi
Instead, first set up your py3 virtual environment, (and might as well in install Flask into it while you're at it)
$ pip install virtualenv
$ cd ~/web/flaskapp
$ virtualenv -p python3 ./venv3
$ source ./venv3/bin/activate # enter virtual environment
$ pip install Flask
Now follow Installing mod_wsgi for Python3 on Ubuntu to install mod_wsgi into this venv, and ...
$ deactivate # ... & exit
This was from the original apt-get approach, now it is not relevant:
Now I have to make mod_wsgi
use this new Py3:
$ sudo nano /etc/apache2/mods-enabled/wsgi.conf
And do:
#WSGIPythonPath directory|directory-1:directory-2:...
WSGIPythonPath /home/pi/web/flaskapp/venv3/lib/python3.4/site-packages
Finally I need to modify my ~/web/flaskapp/flaskapp.wsgi so that it now supports Python3:
$ cat web/piFlask/piFlask.wsgi
# http://flask.pocoo.org/docs/0.10/deploying/mod_wsgi/#creating-a-wsgi-file
# http://www.enigmeta.com/2012/08/16/starting-flask/
# for Py3:
# http://askubuntu.com/questions/488529/pyvenv-3-4-error-returned-non-zero-exit-status-1
import os, sys
PROJECT_DIR = '/home/pi/web/flaskapp'
sys.path.insert(0, PROJECT_DIR)
def execfile(filename):
globals = dict( __file__ = filename )
exec( open(filename).read(), globals )
activate_this = os.path.join( PROJECT_DIR, 'venv3/bin', 'activate_this.py' )
execfile( activate_this )
from piFlask import app as application
application.debug = True
Just a reminder of how Apache uses mod_wsgi to execute this file when the user points their browser to http://myfoo.org/flask:
$ cat /etc/apache2/sites-available/000-default.conf
:
WSGIDaemonProcess flaskProcess user=pi group=pi threads=5
WSGIScriptAlias /flask /home/pi/web/flaskapp/flaskapp.wsgi
<Location /flask>
WSGIProcessGroup flaskProcess
WSGIApplicationGroup %{GLOBAL}
Require all granted
</Location>
:
Discussion: It seems a bit messy that I am installing mod_wsgi module into Apache, but it resides in a venv3 which is inside my flaskapp folder. But this is at least ensuring Apache -> mod_wsgi -> (uses the correct i.e. venv3 Python) -> {to launch my FlaskApp}.
The alternative would be to update the system Python, and use that instead of venv.