Apache setHandler only only works on index - php

Question

I am using docker for local development on a PHP powered craft website. My shared host requires a SetHandler php70-cgi directive, but the version of apache in the official PHP container does not have php-cgi and does not interpret PHP scripts. Because the container is development only, and not an attempt to 1:1 replicate production, I'm attempting to work around this with a custom apache config that sets an InDocker request variable:
<VirtualHost *:80>
ServerAdmin me#mydomain.com
DocumentRoot /var/www/craft/public
SetEnv InDocker true
<!-- ... more config -->
</VirtualHost>
And an .htaccess in my public folder that conditionally checks for the request env and only runs the:
Header set InDocker "%{InDocker}e"
<FilesMatch \.php$>
<If "!reqenv('InDocker') =~ /true/">
Header set IfMatch "We are not in docker"
SetHandler php70-cgi
</If>
Header set FilesMatch "yo"
</FilesMatch>
When I make a request to the root of my application, things render correctly and I see the following headers:
http -h :4020/
InDocker: true
FilesMatch: yo
However, if I make a request to another path, things do not render correctly and I can see the following headers are set:
http -h :4020/
InDocker: true
FilesMatch: yo
IfMatch: We are not in a container
Is there a way I can get this to work using my If or a better way to accomplish conditionally using SetHandler?

Answer 1

I could not get this to work using SetEnv and if reqenv so I had to fall back to using Define and IfDefine.
I added Define InDocker to my container's apache config:
<VirtualHost *:80>
ServerAdmin me#mydomain.com
DocumentRoot /var/www/public
Define InDocker
<Directory /var/www/public>
Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order deny,allow
Allow from all
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
And then used IfDefine in my .htaccess file:
<IfDefine !InDocker>
<FilesMatch \.php$>
SetHandler php70-cgi
</FilesMatch>
</IfDefine>
This allows me to keep things as-is on my shared host and use the same .htacess for development.