How to maintain X-Forwarded-Proto header to Pod through HTTP Route

Issue

• The external loadbalancer offloads SSL, so that connection between loadbalancer and OpenShift HAProxy Router is all HTTP
• How to maintain the X-Forwarded-Proto header as defined by the client application?

Client -(https)-> Load balancer (SSL termination) -(http)-> Haproxy (Openshift Router) -> Container

• The client application will send either http or https request. F5 loadbalancer offloads this to http.
• The client application will send X-Forwarded-Proto. F5 loadbalancer does NOT overwrite this and will maintain it even if it offloads https to http.
• We need HAProxy router to maintain the X-Forwarded-Proto as sent forward from F5 loadbalancer.
• The built-in configuration will not work:

http-request set-header X-Forwarded-Proto http if !{ ssl_fc }
http-request set-header X-Forwarded-Proto https if { ssl_fc }

• Because this is set based on the connection between F5 and HAProxy, which will always be http