MEDIUM: revise SSL redirection if redirecting to default HTTPS port

* The default for the controller is to generate redirects to port
  8443, as this port can be bound to in a rootless container.
* Running the container in a Kubernetes setting having a service
  port mapping to port 443 introduces the need to change this
  default configuration.
* Having the default HTTPS port 443 appended to the redirect
  breaks certain caching behaviors and is thus not ideal.
* This commit aims to purely switch the scheme from HTTP to
  HTTPS without changing anything else about the request, the
  only user visible change being that the :443 in the redirect
  URL is no longer visible.
* fixes #642

Author: BuJo

pkg/haproxy/rules/reqRequestRedirect.go

@@ -18,6 +18,8 @@ type RequestRedirect struct {
 	SSLRedirect  bool
 }
 
+const DefaultHTTPSPort = 443
+
 func (r RequestRedirect) GetType() Type {
 	return REQ_REDIRECT
 }
@@ -37,14 +39,18 @@ func (r RequestRedirect) Create(client api.HAProxyClient, frontend *models.Front
 }
 
 func (r RequestRedirect) sslRedirect() models.HTTPRequestRule {
-	rule := fmt.Sprintf("https://%%[hdr(host),field(1,:)]:%d%%[capture.req.uri]", r.RedirectPort)
 	httpRule := models.HTTPRequestRule{
-		Type:       "redirect",
-		RedirCode:  utils.PtrInt64(r.RedirectCode),
-		RedirValue: rule,
-		RedirType:  "location",
+		Type:      "redirect",
+		RedirCode: utils.PtrInt64(r.RedirectCode),
+	}
+	if r.RedirectPort == DefaultHTTPSPort {
+		httpRule.RedirType = "scheme"
+		httpRule.RedirValue = "https"
+	} else {
+		rule := fmt.Sprintf("https://%%[hdr(host),field(1,:)]:%d%%[capture.req.uri]", r.RedirectPort)
+		httpRule.RedirType = "location"
+		httpRule.RedirValue = rule
 	}
-
 	return httpRule
 }