[nginx] Pass request port to real server

[danielqsj]

If nginx ingress controller is behind some loadbalancer like haproxy, which redirect other port (not 80 or 443) to nginx ingress controller.
So request may looks like http://host:port. But nginx set Host and X-Forwarded-Host as $host, which without port like host. Therefore when real server send redirects to client requests, the url looks like http://host/redirect_url instead of correct url http://host:port/redirect_url.
If using $http_host instead of $host, the correct port will be passed to real server.

[aledbf]

@danielqsj we already pass this information with the header X-Forwarded-Port

[danielqsj]

@aledbf Thanks for your reply.
But in my environment, the http_x_forwarded_port always be null. So X-Forwarded-Port will be the $server_port which is 443 (listened by nginx) not the real port (listened by haproxy).
Here is my environment:

client <-> kube-proxy <-> haproxy (used to redirect port, in tcp mode) <-> nginx ingress controller <-> real server

Will there be some misconfigurations?

[danielqsj]

@aledbf The problem seems that nginx behind tcp mode proxy of haproxy can only see haproxy's IP. And haproxy can not rewrite http head if using tcp mode.
In this scenario, I find only $http_host contain the correct port. Is there better solution ?

[aledbf]

@danielqsj the problem with $http_host is that could be blank but $host always contains a value. I think instead of choosing one of the variables we can use map directive like:

    map $http_host $best_http_host {
        default          $http_host;
        ''               $host;
    }

[danielqsj]

@aledbf Great idea. I will fix it. Thank you a lot.

[danielqsj]

@aledbf I have fixed this PR #454 .