nginx subdomain configuration example.com/blog - node.js

Question

I've spent all day yesterday and today learning how nginx works and I got two different domains working, one with Ghost blogging platform and a static page (future NodeJS app), now I'm trying to setup the subdomain, but I'm kind of frustrated because I feel like I'm almost there but it's not working... This is my current setup:
#Main Domain
server {
listen 80;
listen [::]:80;
server_name example.com;
root /var/www/portfolio;
index index.html;
location / {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $http_host;
# proxy_pass http://127.0.0.1:2222;
}
location ~ /.well-known {
allow all;
}
client_max_body_size 50m;
}
#Sub domain
server {
listen 80;
listen [::]:80;
server_name example.com/blog;
root /var/www/ghost/system/nginx-root;
location / {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://127.0.0.1:2368;
}
location ~ /.well-known {
allow all;
}
client_max_body_size 50m;
}
The idea is to create mysite.com/blog where eventually mysite would be a nodejs app, prob linking the route later will be another problem but... one at a time lol, how can I establish that subdomain?
If I separate the config file into a separate file, I would get the other domain working :/
Thanks
EDIT: I've found that with bucket in S3 on AWS I could acomplish that, but now I don't need it for what I'm doing jeje, but it's good to know.

Answer 1

First: it's not a subdomain, but a subfolder called blog.
If you want to run two apps where one appears in a subfolder, you could do the following
Define two upstreams / proxy pass them to different ports the
Have them in the same config file then
Have two location blocks (location / and location /blog)
Does that make sense? Otherwise one will probably shadow the other.

Answer 2

Note: This is not a complete answer, you probably will need to tinker a bit
As #Jonathan mentioned, from nginx's point of view this is the same site, but you need nginx to handle both locations differently.
Here's how it would look like
server {
listen 80;
listen [::]:80;
server_name example.com;
root /var/www/portfolio;
index index.html;
client_max_body_size 50m;
location / {
# your normal location settings
}
# your blog is defined here
location /blog {
root /var/www/ghost/system/nginx-root;
# You'll probably need to do a rewrite here, because a
# /blog/article needs to be passed as `/article` to the
# app server
# rewrite ^/blog/(.*) $1;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://127.0.0.1:2368;
}
}
}