proxy pass configuration in nginx - nginx

Question

I am a front end developer and tried my hands in nginx configuration last time which is working fine. The below is the configuration:
server {
listen 80;
server_name localhost;
access_log /var/log/nginx/localhost.access.log;
location / {
#By default route to node.js running on localhost:9000 port
proxy_pass http://localhost:9000;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
}
#currently only one server but will have to redirect to n hosts based on a parameter
location /hosts.json {
proxy_pass http://app-host.net:3000;
}
#currently only one server but will have to redirect to n hosts based on a parameter
location /hosts/ {
proxy_pass http://app-host.net:3000;
}
}
Now, I need to redirect to 4 different servers based on a parameter. ie if the city is Bangalore, I need to redirect to bangalore.corp.net:3000 and if the city is NewYork, then I need to redirect to newyork.corp.net:3000 and so on.
Here is somewhat I am expecting:
location /app1/hosts/ {
proxy_pass http://app1-host.net:3000;
}
#But the proxy pass should point to http://app1-host.net:3000/hosts and not http://app1-host.net:3000/app1/hosts
How can we handle such proxy pass in the nginx configuration file. Please let me know.

Answer 1

You have a URL of the form /app1/hosts/foo which should map to http://app1-host.net:3000/hosts/foo. The can be achieved by appending a URI in the proxy_pass directive, which will act like an alias.
location /app1/hosts/ {
proxy_pass http://app1-host.net:3000/hosts/;
}
See this document for details.