nginx proxy to Tomcat with SSL

I posted this on stackoverflow by mistake (https://stackoverflow.com/questions/65942820/nginx-proxy-to-tomcat) and I'm putting it here as well in hope of finding some solution.

I went through dozens of tutorials and I can't figure out following (althougt it should be pretty basic):

I have my compiled vue application in /var/www/mydomain.com and I want it to be shared as static content.

My backend running on 8080 by tomcat with public APIs on /api/something... URLs. The URLs are hardcoded including the "api" part.

I'd like to configure nginx to proxy mydomain.com/api/something... requests to tomcat and rest be served statically from /var/www/mydomain.com. Everything served through SSL.

I litterally don't need anything else.

Can you help me configure the nginx and tomcat to achieve that? Thank you!

nginx config /etc/nginx/sites-available/mydomain.com

upstream tomcat {
    server 127.0.0.1:8080 fail_timeout=0;
}

server {
        listen 443 ssl default_server;
        #listen [::]:443 ssl default_server;

        root /var/www/mydomain.com;
        index index.html index.htm index.nginx-debian.html;

       server_name _ mydomain.com www.mydomain.com;

        location /api/ {
                include proxy_params;
                proxy_set_header Host $server_name;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header X-Forwarded-Proto $scheme;
                proxy_pass http://tomcat;
        }

        location / {
                try_files $uri $uri/ /index.html;
        }

        ssl_certificate /etc/letsencrypt/live/www.mydomain.com/fullchain.pem; # managed by Certbot
        ssl_certificate_key /etc/letsencrypt/live/www.mydomain.com/privkey.pem; # managed by Certbot
}
server {
    if ($host = www.mydomain.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = mydomain.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


       listen 80 default_server;
        listen [::]:80 default_server;

       server_name _ mydomain.com www.mydomain.com;
   return 404; # managed by Certbot
}

(1) Alternative location block I'm experimenting with

        location /api/ {
                proxy_set_header Host $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-Proto https;
                proxy_pass http://localhost:8080/api/;
        }

(2) Alternative block suggested by Praveen Premaratne.

This way I get "GET /api/docs HTTP/1.0" 302 - and static files work as well. Going to /api/docs makes redirect to domain:8443/api/docs where I get ERR_CONNECTION_REFUSED.

        location /api/ {
                include proxy_params;
                proxy_pass http://tomcat;
        }

        location / {
                try_files $uri $uri/ /index.html;
        }

(3) Alternative using subdomain.

I was able to create subdomain api.mydomain.com and configure nginx to go to index page from there (adding following block). No idea how to do the proxing afterwards.

server {
        listen 443 ssl;

        root /var/www/www.mydomain.com; <- redundand I guess?
        index index.html index.htm index.nginx-debian.html; <- redundand I guess?

        server_name api.mydomain.com

        ssl_certificate /etc/letsencrypt/live/www.mydomain.com/fullchain.pem; # managed by Certbot
        ssl_certificate_key /etc/letsencrypt/live/www.mydomain.com/privkey.pem; # managed by Certbot
}

Tomcat config server.xml

<Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               address="127.0.0.1"
               redirectPort="8443" />
<Engine name="Catalina" defaultHost="localhost">
   ...
   <Host name="localhost"  appBase="webapps"
         unpackWARs="true" autoDeploy="true">
      
      <Valve className="org.apache.catalina.valves.AccessLogValve" 
         directory="logs"
         prefix="localhost_access_log" suffix=".txt"
         requestAttributesEnabled="true"
         pattern="%h %l %u %t &quot;%r&quot; %s %b" />
        
      <Valve className="org.apache.catalina.valves.RemoteIpValve"
         protocolHeader="X-Forwarded-Proto" /> 
   ...    

Current situation is that when I go to mydomain.com/api/docs where swagger should be running, I get redirected back to mydomain.com or get 500 or 502 error.

Solution 1:

Ok, so with help of @Praveen Premaratne and @Piotr P. Karwasz and this article I came up with following configuration:

don't put in lines with "# managed by Certbot", those are created by certbot, check https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-18-04

etc/nginx/sites-available/mydomain.com

server {
    server_name    mydomain.com www.mydomain.com;

    root /var/www/mydomain.com;
    index index.html;

    access_log /var/log/nginx/mydomain-access.log;
    error_log /var/log/nginx/mydomain-error.log;

    location / {
        try_files $uri $uri/ /index.html;
    }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/www.mydomain.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/www.mydomain.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}

server {
    if ($host = www.mydomain.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = mydomain.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    server_name    mydomain.com www.mydomain.com;
    listen 80;
    return 404; # managed by Certbot
}

/etc/nginx/sites-available/api.mydomain.com

server {
    server_name    api.mydomain.com;

    access_log /var/log/nginx/api-mydomain-access.log;
    error_log /var/log/nginx/api-mydomain-error.log;

    location / {
        proxy_set_header Host $http_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-Host $http_host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_pass http://127.0.0.1:8080;
    }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/www.mydomain.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/www.mydomain.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}

server {
    if ($host = api.mydomain.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

    server_name    api.mydomain.com;
    listen 80;
    return 404; # managed by Certbot
}

Tomcat server.xml

<Service name="Catalina">
<Connector port="8080" protocol="HTTP/1.1"
    connectionTimeout="20000"
    address="127.0.0.1"
    proxyName="api.mydomain.com"
    proxyPort="80"/>

<Engine name="Catalina" defaultHost="localhost">

    <Realm className="org.apache.catalina.realm.LockOutRealm">
    ...
    </Realm>

    <Host name="localhost"  appBase="webapps"
        unpackWARs="true" autoDeploy="true">

        <Valve className="org.apache.catalina.valves.RemoteIpValve"
            remoteIpHeader="x-forwarded-for"
            proxiesHeader="x-forwarded-by"
            protocolHeader="x-forwarded-proto" />

        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
            prefix="localhost_access_log" suffix=".txt"
            pattern="%h %l %u %t %r %s %b" />

  </Host>
</Engine>