NGINX config for multiple Symfony installations using subfolders

Question

I have a shopware installation (version 6.5.5.1) running on my domain. I want to add more independent Shopware installations, using the same domain (for different languages/countries).

For example, mydomain.com and mydomain.com/de, mydomain.com/en, etc..

I have two independent installations:

1. /var/www/html/developer/dev-test (gerwin-gesundheitsprodukte.com)

2. /var/www/html/developer/dev-app1 (gerwin-gesundheitsprodukte.com/app1)

The first installation (gerwin-gesundheitsprodukte.com) is running fine, including backend.

For the second installation of Shopware, I tried to extend my NGINX config, using a reverse proxy (proxy_pass 127.0.0.1:81).

The storefront of the second installation (gerwin-gesundheitsprodukte.com/app1) opens as well, but once I want to access the backend (gerwin-gesundheitsprodukte.com/app1/admin), I get an error:

Shopware\Administration\Controller\AdministrationController::index(): Argument #2 ($context) must be of type Shopware\Core\Framework\Context, null given, called in /var/www/html/developer/dev-app1/vendor/symfony/http-kernel/HttpKernel.php on line 182

It seems that some information ($context) doesn't pass the proxy?

What's wrong in my conf file and is the approach generally correct to use proxy_pass for this?

Related part of my config:

server {

    index index.php index.html;
    server_name gerwin-gesundheitsprodukte.com;

    client_max_body_size 128M;

    location ^~ /app1 {
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto https;
        proxy_pass http://127.0.0.1:81;
        proxy_redirect off;
    }
#rest is Shopware standard config for first installation
}

server {
#the server block for the second installation
    listen 81;
    server_name 127.0.0.1;

    set $subdir_root /var/www/html/developer/dev-app1/public;
    root $subdir_root;

    rewrite ^/app1(.*)$ /$1 break;
    sub_filter "https://gerwin-gesundheitsprodukte.com/" "https://gerwin-gesundheitsprodukte.com/app1/";
    sub_filter_once off;

#rest of the config
}

Here is the complete conf:

server {

    index index.php index.html;
    server_name gerwin-gesundheitsprodukte.com;

    client_max_body_size 128M;

    location ^~ /app1 {
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto https;
        proxy_pass http://127.0.0.1:81;
        proxy_redirect off;
    }

    root /var/www/html/developer/dev-test/public;

    # Shopware update
    location /recovery/update/ {
        location /recovery/update/assets {
        }
        if (!-e $request_filename){
            rewrite . /recovery/update/index.php last;
        }
    }

    # new for Shopware 6.5
    location /shopware-installer.phar.php {
        try_files $uri /shopware-installer.phar.php$is_args$args;
    }

    location ~* ^.+\.(?:css|cur|js|jpe?g|gif|ico|png|svg|webp|html|woff|woff2|xml)$ {
        expires 1y;
        add_header Cache-Control "public, must-revalidate, proxy-revalidate";

        access_log off;

        # The directive enables or disables messages in error_log about files not found on disk.
        log_not_found off;

        tcp_nodelay off;

        ## Set the OS file cache.
        open_file_cache max=3000 inactive=120s;
        open_file_cache_valid 45s;
        open_file_cache_min_uses 2;
        open_file_cache_errors off;

        try_files $uri /index.php$is_args$args;
    }

    location ~* ^.+\.svg$ {
        add_header Content-Security-Policy "script-src 'none'";
    }

    location / {
        try_files $uri /index.php$is_args$args;
    }

    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        include fastcgi.conf;
        fastcgi_param HTTP_PROXY "";
        fastcgi_buffers 8 16k;
        fastcgi_buffer_size 32k;
        proxy_connect_timeout 300s;
        proxy_send_timeout 300s;
        proxy_read_timeout 300s;
        send_timeout 300s; 
        client_body_buffer_size 128k;
        fastcgi_pass unix:/run/php/php8.2-fpm.sock;
        http2_push_preload on;
    }

}


server {
    # Virtual host for web application 1:
    # - Only local (127.0.0.1), cannot be addressed directly (without gateway host).
    # - Listens on port 81 (HTTP) - IPv4 and IPv6.
    # - Is capable of serving requests for local IP address 127.0.0.1.

    listen 81;
    server_name 127.0.0.1;

    set $subdir_root /var/www/html/developer/dev-app1/public;
    root $subdir_root;

    rewrite ^/app1(.*)$ /$1 break;
    sub_filter "https://gerwin-gesundheitsprodukte.com/" "https://gerwin-gesundheitsprodukte.com/app1/";
    sub_filter_once off;


    # Shopware update
    location /recovery/update/ {
        location /recovery/update/assets {
        }
        if (!-e $request_filename){
            rewrite . /recovery/update/index.php last;
        }
    }

    # new for Shopware 6.5
    location /shopware-installer.phar.php {
        try_files $uri /shopware-installer.phar.php$is_args$args;
    }

    location ~* ^.+\.(?:css|cur|js|jpe?g|gif|ico|png|svg|webp|html|woff|woff2|xml)$ {
        expires 1y;
        add_header Cache-Control "public, must-revalidate, proxy-revalidate";

        access_log off;

        # The directive enables or disables messages in error_log about files not found on disk.
        log_not_found off;

        tcp_nodelay off;

        ## Set the OS file cache.
        open_file_cache max=3000 inactive=120s;
        open_file_cache_valid 45s;
        open_file_cache_min_uses 2;
        open_file_cache_errors off;

        try_files $uri /index.php$is_args$args;
    }

    location ~* ^.+\.svg$ {
        add_header Content-Security-Policy "script-src 'none'";
    }

    location / {
        try_files $uri /index.php$is_args$args;
    }

    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        include fastcgi.conf;
        fastcgi_param SCRIPT_FILENAME $request_filename;
        fastcgi_param DOCUMENT_ROOT $subdir_root;
        fastcgi_param HTTPS on;
        fastcgi_param HTTP_PROXY "";
        fastcgi_buffers 8 16k;
        fastcgi_buffer_size 32k;
        proxy_connect_timeout 300s;
        proxy_send_timeout 300s;
        proxy_read_timeout 300s;
        send_timeout 300s;
        client_body_buffer_size 128k;
        fastcgi_pass unix:/run/php/php8.2-fpm.sock;
        http2_push_preload on;
    }

}