Where do I place environment variables so that they can be picked up by Apache?

Question

I'm using Ubuntu 18.04. I have defined a series of environment variables in my /etc/profile file. When I login as my user, I can see them using

$ echo $DB_NAME
directory_data

I have Apache 2.4 also running on my machine under a www-data user (who has no home directory). I have set up my Apache configuration with "PassEnv" (https://httpd.apache.org/docs/2.4/mod/mod_env.html), hoping it would pick up my environment variables ...

$ cat /etc/apache2/sites-available/000-default.conf 
<VirtualHost *:80>
    # The ServerName directive sets the request scheme, hostname and port that
    # the server uses to identify itself. This is used when creating
    # redirection URLs. In the context of virtual hosts, the ServerName
    # specifies what hostname must appear in the request's Host: header to
    # match this virtual host. For the default virtual host (this file) this
    # value is not decisive as it is used as a last resort host regardless.
    # However, you must set it for any further virtual host explicitly.
    ServerName my.server.com

    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html/web

        PassEnv DB_NAME
        PassEnv DB_USER
        PassEnv DB_PASS
        PassEnv DB_SERVICE
        PassEnv DB_PORT

    # Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
    # error, crit, alert, emerg.
    # It is also possible to configure the loglevel for particular
    # modules, e.g.
    LogLevel info

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

        AliasMatch ^/(?!phpmyadmin)(?!states/)(?!countries/)(?!coops/)(?!data).* /var/www/html/client/build/$0
    # For most configuration files from conf-available/, which are
    # enabled or disabled at a global level, it is possible to
    # include a line for only one particular virtual host. For example the
    # following line enables the CGI configuration for this host only
    # after it has been globally disabled with "a2disconf".
    Include conf-available/phpmyadmin.conf

        WSGIDaemonProcess maps \
            home=/var/www/html/web python-home=/var/www/html/web/venv
        WSGIProcessGroup maps 
        WSGIScriptAlias /coops /var/www/html/web/directory/wsgi.py/coops process-group=maps
        WSGIScriptAlias /data /var/www/html/web/directory/wsgi.py/data process-group=maps
        WSGIScriptAlias /countries /var/www/html/web/directory/wsgi.py/countries process-group=maps
        WSGIScriptAlias /states /var/www/html/web/directory/wsgi.py/states process-group=maps
        WSGIPassAuthorization On

        <Directory /var/www/html/web/maps>
            <Files wsgi.py>
                Require all granted
            </Files>
        </Directory>
</VirtualHost>

Apache uses WSGI to connect to Python, where I ultimately want to reference the env vars. Here is my Python file, settings.py

DATABASES = {
    'default': {,
        'ENGINE': 'django.db.backends.mysql',
        'NAME': os.environ['DB_NAME'],
        'USER': os.environ['DB_USER'],
        'PASSWORD': os.environ['DB_PASS'],
        'HOST': os.environ['DB_SERVICE'],
        'PORT': os.environ['DB_PORT']
    }
}

but the env var isn't getting picked up.

[Thu Jun 25 17:29:28.870247 2020] [wsgi:error] [pid 11363]   File "/var/www/html/web/directory/settings.py", line 93, in <module>
[Thu Jun 25 17:29:28.870319 2020] [wsgi:error] [pid 11363]     'NAME': os.environ['DB_NAME'],
[Thu Jun 25 17:29:28.870408 2020] [wsgi:error] [pid 11363]   File "/usr/lib/python3.6/os.py", line 669, in __getitem__
[Thu Jun 25 17:29:28.870474 2020] [wsgi:error] [pid 11363]     raise KeyError(key) from None
[Thu Jun 25 17:29:28.870564 2020] [wsgi:error] [pid 11363] KeyError: 'DB_NAME'

Where are environment variables generally placed so that they can be recognized by the Apache process?

Answer 1

I assume you run a fresh install of 18.04 with systemd? If you've updated the OS over time then some components like systemd may be a bit different from stock 18.04.

In /lib/systemd/system/apache2.service, add Environment= statements for your desired variables to the [Service] section. Do not use quotes. Example:

[Service]
Type=forking
Environment=APACHE_STARTED_BY_SYSTEMD=true
Environment=DB_SERVICE=localhost
ExecStart=/usr/sbin/apachectl start
...

Together with the PassEnv stanzas in your description that should do it.

Restart apache with

$ sudo systemctl restart apache2

to pick up any changed settings