From d42e380e97f694a8c85833f0d995d9503e963fa6 Mon Sep 17 00:00:00 2001
From: Alex Rowley <rowleyaj@gmail.com>
Date: Fri, 14 Jul 2017 20:59:02 +0100
Subject: [PATCH] Modify how locations are built

The HTTPIngressPath defines the path as an extended POSIX regex.
https://github.com/kubernetes/kubernetes/blob/master/pkg/apis/extensions/types.go#L704

This treats any path passed from the ingress as a regex based location block.
The only exception to this is the / path, which is set as a prefix location
block, this should work as a catchall without affecting other locations defined
using regex location blocks.

It should be noted that there may be some incompatibilities between the spec
and the regex implementation within nginx.
---
 controllers/nginx/pkg/template/template.go    | 23 ++++++++++++++-----
 .../nginx/pkg/template/template_test.go       |  4 ++--
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/controllers/nginx/pkg/template/template.go b/controllers/nginx/pkg/template/template.go
index 71dc52665..56fa9d2f3 100644
--- a/controllers/nginx/pkg/template/template.go
+++ b/controllers/nginx/pkg/template/template.go
@@ -185,8 +185,7 @@ func buildResolvers(a interface{}) string {
 	return strings.Join(r, " ")
 }
 
-// buildLocation produces the location string, if the ingress has redirects
-// (specified through the ingress.kubernetes.io/rewrite-to annotation)
+// Helper to create the correct path for location blocks
 func buildLocation(input interface{}) string {
 	location, ok := input.(*ingress.Location)
 	if !ok {
@@ -194,10 +193,19 @@ func buildLocation(input interface{}) string {
 	}
 
 	path := location.Path
+
+	// Although per spec all paths should be treated as regex
+	// returning slash directly will result in a fall through catchall
+	// prefix style location block instead which will match any path
+	// for which a regex is not defined
+	if path == slash {
+		return slash
+	}
+
+	// When rewrite is enabled via the rewrite target annotation
+	// (ingress.kubernetes.io/rewrite-target) this allows the baseuri to be
+	// appended to the path
 	if len(location.Redirect.Target) > 0 && location.Redirect.Target != path {
-		if path == slash {
-			return fmt.Sprintf("~* %s", path)
-		}
 		// baseuri regex will parse basename from the given location
 		baseuri := `(?<baseuri>.*)`
 		if !strings.HasSuffix(path, slash) {
@@ -207,7 +215,10 @@ func buildLocation(input interface{}) string {
 		return fmt.Sprintf(`~* ^%s%s`, path, baseuri)
 	}
 
-	return path
+	// Return an anchored regex location block, although not identical to the
+	// spec due to the type of regex used this is the closest nginx equivalent
+	// to the intended regex based path as defined in HTTPIngressPath
+	return fmt.Sprintf(`~* ^%s`, path)
 }
 
 func buildAuthLocation(input interface{}) string {
diff --git a/controllers/nginx/pkg/template/template_test.go b/controllers/nginx/pkg/template/template_test.go
index ac8a1b5c7..df9953556 100644
--- a/controllers/nginx/pkg/template/template_test.go
+++ b/controllers/nginx/pkg/template/template_test.go
@@ -42,7 +42,7 @@ var (
 		AddBaseURL bool
 	}{
 		"invalid redirect / to /": {"/", "/", "/", "proxy_pass http://upstream-name;", false},
-		"redirect / to /jenkins": {"/", "/jenkins", "~* /",
+		"redirect / to /jenkins": {"/", "/jenkins", "/",
 			`
 	rewrite /(.*) /jenkins/$1 break;
 	proxy_pass http://upstream-name;
@@ -60,7 +60,7 @@ var (
 	rewrite /something-complex/(.*) /not-root/$1 break;
 	proxy_pass http://upstream-name;
 	`, false},
-		"redirect / to /jenkins and rewrite": {"/", "/jenkins", "~* /", `
+		"redirect / to /jenkins and rewrite": {"/", "/jenkins", "/", `
 	rewrite /(.*) /jenkins/$1 break;
 	proxy_pass http://upstream-name;
 	subs_filter '<head(.*)>' '<head$1><base href="$scheme://$http_host/$baseuri">' r;