Simple https nginx config to route to docker containers by subdomain

gistfile1.txt

upstream foo {
    server foo-container:80;
}

upstream bar {
    server bar-container:3000;
}

map $subdomain $container {
  foo foo;
  foo_alias foo;
  bar bar;
}

# Routes to the docker container given in the subdomain map or 404s.
server {
    listen              443 ssl;
    server_name         ~^(?<subdomain>\w+)\.example\.com$;

    ssl_certificate     /etc/ssl/certs/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/ssl/certs/live/example.com/privkey.pem;

    location / {
        if ($container = "") {
            return 404;
        }

        proxy_redirect off;
        proxy_pass http://$container;

        proxy_set_header  Host $host;
        proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header  X-Forwarded-Proto $scheme;
        proxy_set_header  X-Forwarded-Port $server_port;
        proxy_set_header  X-Forwarded-Host $host;
    }
}

# Universal HTTPs redirect and challenge serving.
server {
    listen              80;
    listen              [::]:80;
    server_name         ~^(?<subdomain>\w+)\.example\.com$;

    location ^~ /.well-known/acme-challenge/ {
        root /var/www/letsencrypt;
    }

    location / {
        return 301 https://$subdomain.example.com$request_uri;
    }
}