Multiple websites with one IP: settings with proxy server and proxy cache (flask, uwsgi, nginx) - caching

Question

I want to allow my nginx server to server multiple subdomains.
Each site is served by a flask + uwsgi, listening to own ports.
All sites have many endpoints with same name, and responses are cached in different zones: I want to serve the correct cache (or correct site) from the proxy server.
I read https://askubuntu.com/questions/766352/multiple-websites-on-nginx-one-ip : in my configuration I keep having domain2 redirected to domain1.
I cannot find proper configuration for listening to uwsgi and have the proxy server serve the correct site.
How to properly set the ports and proxy_cache on the proxy_server to allow nginx serve two flask sites from a single server?
Below is my set current setup:
configuration domain_1
server {
server_name www.domain1.com;
return 301 $scheme://domain1.com$request_uri;
}
server {
listen 8000 default_server;
server_name domain1.com;
root /var/www/example_site_1;
# common locations for all sites
location / {
include uwsgi_params;
uwsgi_pass unix:/var/www/example_site_1/domain1.sock;
}
# API
location /api {
include uwsgi_params;
uwsgi_param UWSGI_SCRIPT wsgi;
uwsgi_pass unix:/var/www/example_site_1/domain1.sock;
}
}
# Set cache directory for site
proxy_cache_path /tmp/nginx/domain1 levels=1:2 keys_zone=my_zone_domain_1:10m max_size=50m inactive=60m;
proxy_cache_key "$scheme$request_method$host$request_uri";
# Virtualhost/server configuration
server {
listen 80 default_server;
server_name domain1;
root /var/www/domain1;
## how to serve proxy_cache if locations of domain_1 and domain_2 are the same ?
location / {
proxy_cache my_zone_domain_1;
add_header X-Proxy-Cache $upstream_cache_status;
include proxy_params;
proxy_pass http://domain1.com:8000;
}
location /api {
add_header X-Proxy-Cache $upstream_cache_status;
proxy_cache my_zone_domain_1;
proxy_pass http://domain1.com:8000/api;
}
}
configuration domain_2
server {
server_name www.domain2.com;
return 301 $scheme://domain2.com$request_uri;
}
server {
listen 3000;
server_name domain2.com;
root /var/www/example_site_2;
# common locations for all sites
location / {
include uwsgi_params;
uwsgi_pass unix:/var/www/example_site_2/domain2.sock;
}
# API
location /api {
include uwsgi_params;
uwsgi_param UWSGI_SCRIPT wsgi;
uwsgi_pass unix:/var/www/example_site_2/domain2.sock;
}
}
# Set cache directory for site
proxy_cache_path /tmp/nginx/domain2 levels=1:2 keys_zone=my_zone_domain_2:10m max_size=50m inactive=60m;
proxy_cache_key "$scheme$request_method$host$request_uri";
# Virtualhost/server configuration
server {
# I tried listening on other ports than 80, but kept having redirects on domain_1
listen 80;
server_name domain2;
root /var/www/domain2;
## how to serve proxy_cache if locations of domain_1 and domain_2 are the same ?
location / {
proxy_cache my_zone_domain_2;
add_header X-Proxy-Cache $upstream_cache_status;
include proxy_params;
proxy_pass http://domain2.com:3000;
}
location /api {
add_header X-Proxy-Cache $upstream_cache_status;
proxy_cache my_zone_domain_2;
proxy_pass http://domain2.com:3000/api;
}
}

Answer 1

Your domain_2 configuration uses proxy_pass http://domain2.com:8000 but there is only domain_1 server listens on the port 8000 so it gets to serve requests directed to domain_2.
I also recommend you to rethink usage of proxy_pass in your configuration, it isn't really necessary.

Answer 2

I found the culprit was Uwsgi : it was loaded from usr/bin folder, and not from virtual environment folder of my app.
Maybe virtualenv folder was corrupted: when I tried to re-install uwsgi (pip install uwsgi), it kept saying requirements satisfied until I noticed that which uwsgi was not loaded from virtualenv.
I had to remove and reinstall virtualenv folder with uwsgi and python modules.
Now applications were running (answer to the question), but proxy_server configuration has to be further adjusted in my case.
The following may be useful for people making use of url_for() directives in flask: url_for() directive routes to an absolute path, which may conflict with the nginx proxy.
Example: nginx proxy server listens on domains2.com on port 80, proxy_pass /path location to http://domain2.com:3000; if flask is redirecting a route to /path (with url_for()), the resulting url will be http://domain2.com:3000/path (because it follows the port specified in absolute path) instead of http://domain2.com/path (the url of the proxy).
Add proxy_set_header Host $http_host; to /path location to allow nginx proxy follow the correct redirect of your flask application.