Can't access parent directory through reverse proxy on subdomain - nginx

Question

This is my current Nginx server block:
server {
listen 80;
server_name ~^(?<tenant>.+)\.mysalon\.test$;
gzip on;
gzip_types text/plain application/xml text/css application/javascript;
gzip_min_length 1000;
location / {
expires $expires;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header x-Tenant $tenant;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_read_timeout 1m;
proxy_connect_timeout 1m;
proxy_pass http://127.0.0.1:3000/subdomain/;
}
}
It's a reverse proxy for {tenant}.mysalon.test to http://127.0.0.1:3000/subdomain/.
The issue:
It works correctly, but it returns 404's for everything within {tenant}.mysalon.test/_nuxt/, that's because /_nuxt does not live in the /subdomain/ directory, but in the parent http://127.0.0.1:3000/.
So I added the following:
location ^~ /_nuxt/ {
proxy_pass http://127.0.0.1:3000/_nuxt/;
}
So that even on the subdomains, it can access /_nuxt.
However, this new location block makes the first location block inactive for some reason.
When visiting {tenant}.mysalon.test it returns http://127.0.0.1:3000 instead of http://127.0.0.1:3000/subdomain/.

Answer 1

I can't tell you why your second location block breaks the workflow, I didn't see any problems with this config, but you can try to use single location block and append the /subdomain prefix to the requested URI inside this block if the requested URI doesn't start with /_nuxt/:
location / {
expires $expires;
rewrite ^(?!/_nuxt)(/.*) /subdomain$1 break;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header x-Tenant $tenant;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_read_timeout 1m;
proxy_connect_timeout 1m;
proxy_pass http://127.0.0.1:3000;
}