I’ve only used Caddy as a reverse proxy in production, but on my development machine I use Caddy with php-fpm. That makes me a bit unsure if I understand your questions correctly.
It looks like your Docker (?) image is exposing the php-fmp socket? I did not even know that was possible, but I don’t doubt it is.
Caddy has no issues serving multiple hosts from the same server, it can even be with different php-fpm sockets. Caddy will just nod at you, maybe silently question your choice of still running PHP 7.4, but it accepts it and runs. Just make another block with a different host in the same Caddyfile, and it will work just fine.
I’ve only used Caddy as a reverse proxy in production, but on my development machine I use Caddy with php-fpm. That makes me a bit unsure if I understand your questions correctly.
For me that would look something like this:
test.example.com { root * var/www/html php_fastcgi unix//run/php/php7.4-fpm.sock file_server }(Yeah, PHP 7.4, I know)
It looks like your Docker (?) image is exposing the php-fmp socket? I did not even know that was possible, but I don’t doubt it is.
Caddy has no issues serving multiple hosts from the same server, it can even be with different php-fpm sockets. Caddy will just nod at you, maybe silently question your choice of still running PHP 7.4, but it accepts it and runs. Just make another block with a different host in the same Caddyfile, and it will work just fine.