nginx + consul

gistfile1.nginxconf

server {
 server_name titans.local;
 location / {
            set $target '';
            set $upstream_name 'titans_staging_web';

            rewrite_by_lua '
                local resolver = require "resty.dns.resolver"
                local r, err = resolver:new {
                    nameservers = {{"127.0.0.1", 8600}},
                    retrans = 5,  -- 5 retransmissions on receive timeout
                    timeout = 2000,  -- 2 sec
                }

                if not r then
                    ngx.say("resolver error: ", err)
                    return ngx.exit(503)
                end

                local srvs, err = r:query(ngx.var.upstream_name .. ".service.consul", { qtype = r.TYPE_SRV })
                if not srvs then
                    ngx.say("failed to query the DNS server: ", err)
                    return ngx.exit(503)
                end

                if srvs.errcode then
                    ngx.say("server returned error code: ", srvs.errcode,
                            ": ", srvs.errstr)
                    return ngx.exit(503)
                end

                -- pick a server, but we still need to lookup the final address
                local srv_target = table.remove(srvs, 1)

                local answers, err = r:query(srv_target.target)
                if not answers then
                  ngx.say("failed to query DNS server: ", err)
                  return ngx.exit(503)
                end

                if answers.errcode then
                  ngx.say("failed to query DNS server: ", answers.errcode, ": ", answers.errstr)
                  return ngx.exit(503)
                end

                local server_target = table.remove(answers, 1)

                ngx.var.target = server_target.address .. ":" .. srv_target.port
            ';

          proxy_http_version 1.1;
          proxy_set_header Upgrade $http_upgrade;
          proxy_set_header Connection "Upgrade";
          proxy_set_header Host $host;
          proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
          proxy_redirect off;
          proxy_connect_timeout 10;
          proxy_pass http://$target;
        }
}