Combining a PHP app and Caddy with two distinct Docker containers and FastCGI

Question

I am currently trying to understand the functionality of Caddy and FastCGI. I have a setup that was working perfectly fine with NGINX and where I want to switch to Caddy to use the built-in SSL functionality. I am setting up 2 services in my Docker Compose configuration:

A PHP service (based on php:8.2-fpm-alpine) containing my PHP Symfony application
A Caddy service that is supposed to pass requests to my PHP container

First of all, the following was my NGINX configuration file:

server {
    listen 80;
    index index.php index.html;

    root /srv/app/public;

    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }

    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass php:9000;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_path_info;
        fastcgi_hide_header X-Powered-By;
    }
}

With this setup, the NGINX server passed requests to my PHP service named "php" without mounting or copying my source code into the NGINX image. I have to admit, I do not quite understand why I need the "root" directive when it is just an empty folder in my NGINX container.

Now with Caddy, I switched to the following configuration:

localhost {
    root * /srv/app/public
    php_fastcgi ${PHP_SERVICE_NAME}:9000
    file_server
}

This Caddy configuration is working as well, but only when mounting my source code into the server container. Once removing the bind mount, all I get is a "404 Not Found".

So I hope someone can help me with my understanding of FastCGI and Caddy and tell me what I need to change in my configuration so that access to the source code from within the Caddy container is not needed.

score 0 · Answer 1 · answered May 07 '23 at 17:30

Encountering the same 404 problem, after reading this post that share code source between dockers could solve this problem, i realize it's because php is running inside php docker, and the php file location it could recognize is also the path inside docker. when caddy redirect php file to php process, the file location is host path which could not be recognized by docker php, thus raising "404 not found".

The solution is to make caddy take care of the php location

        php_fastcgi  127.0.0.1:9000 {
          root /var/www/html
        }

note: wordpress + caddy in seperate docker in my case.

Combining a PHP app and Caddy with two distinct Docker containers and FastCGI

1 Answers1