I have two python (3.6) Flask apps running on Ubuntu 18.04 and I am trying to use Apache2 (v2.4.29) to serve these two apps to two different domains – app1domain.com and app2domain.com. I have two .conf files that I have been trying to modify to get this to work. They currently look like this (replace app1 with app2 for the second one):

WSGIDaemonProcess app1 python-home=/var/www/app1/venv user=brett group=sudo home=/ threads=5
WSGIScriptAlias / /var/www/app1/app.wsgi
WSGIProcessGroup app1
WSGIApplicationGroup %{GLOBAL}

<VirtualHost *:80>

    ServerAdmin myemail@outlook.com
    ServerName app1domain.com
    ServerAlias www.app1domain.com

    <Directory /var/www/app1>
        Require all granted
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined

    RewriteEngine on
    RewriteCond %{SERVER_NAME} =app1domain.com [OR]
    RewriteCond %{SERVER_NAME} =www.app1domain.com
    RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]

</VirtualHost>

<VirtualHost *:443>

        ServerName app1domain.com
        ServerAlias www.app1domain.com
        ServerAdmin myemail@outlook.com

        LogLevel debug
        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined

        Include /etc/letsencrypt/options-ssl-apache.conf

        SSLCertificateFile /etc/letsencrypt/live/app1domain.com/fullchain.pem
        SSLCertificateKeyFile /etc/letsencrypt/live/app1domain.com/privkey.pem
</VirtualHost>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

Here is where I get stuck, and here is what I have tried:

1. If both conf files are in the format shown above, app1 will be served to both https://app1domain.com and https://app2domain.com, and app2 will not be shown.
2. If I disable the conf for app1, app2 is served to both https://app1domain.com and https://app2domain.com which suggests that, at a minimum, both conf files 'work' and the apps are working correctly.
3. From my investigations, I see a lot of conf files have the WSGI instructions inside the <VirtualHost> tags. If I do this for both confs, the default Apache2 page is displayed on both domains.
4. I have tried just about every combination of the WSGI instructions inside and outside the <VirtualHost> tag and also the nested <Directory> tag. Most of the just resulting in the default apache2 page.

Am I missing some other option that I need to change? What am I doing wrong here?

I have also been looking for some good documentation on how to interpret these conf files, what the options actually do, so would love if someone could point me to something, particularly if it covers WSGI.