Add X-Forwarded-Prefix on rewrites

internal/ingress/annotations/annotations.go

@@ -47,6 +47,7 @@ import (
 	"k8s.io/ingress-nginx/internal/ingress/annotations/upstreamhashby"
 	"k8s.io/ingress-nginx/internal/ingress/annotations/upstreamvhost"
 	"k8s.io/ingress-nginx/internal/ingress/annotations/vtsfilterkey"
+	"k8s.io/ingress-nginx/internal/ingress/annotations/xforwardedprefix"
 	"k8s.io/ingress-nginx/internal/ingress/errors"
 	"k8s.io/ingress-nginx/internal/ingress/resolver"
 )
@@ -81,6 +82,7 @@ type Ingress struct {
 	UpstreamVhost        string
 	VtsFilterKey         string
 	Whitelist            ipwhitelist.SourceRange
+	XForwardedPrefix     bool
 }
 
 // Extractor defines the annotation parsers to be used in the extraction of annotations
@@ -115,6 +117,7 @@ func NewAnnotationExtractor(cfg resolver.Resolver) Extractor {
 			"UpstreamVhost":        upstreamvhost.NewParser(cfg),
 			"VtsFilterKey":         vtsfilterkey.NewParser(cfg),
 			"Whitelist":            ipwhitelist.NewParser(cfg),
+			"XForwardedPrefix":     xforwardedprefix.NewParser(cfg),
 		},
 	}
 }

internal/ingress/annotations/xforwardedprefix/main.go

@@ -0,0 +1,23 @@
+package xforwardedprefix
+
+import (
+	extensions "k8s.io/api/extensions/v1beta1"
+
+	"k8s.io/ingress-nginx/internal/ingress/annotations/parser"
+	"k8s.io/ingress-nginx/internal/ingress/resolver"
+)
+
+type xforwardedprefix struct {
+	r resolver.Resolver
+}
+
+// NewParser creates a new xforwardedprefix annotation parser
+func NewParser(r resolver.Resolver) parser.IngressAnnotation {
+	return xforwardedprefix{r}
+}
+
+// Parse parses the annotations contained in the ingress rule
+// used to add an x-forwarded-prefix header to the request
+func (cbbs xforwardedprefix) Parse(ing *extensions.Ingress) (interface{}, error) {
+	return parser.GetBoolAnnotation("x-forwarded-prefix", ing)
+}

internal/ingress/annotations/xforwardedprefix/main_test.go

@@ -0,0 +1,46 @@
+package xforwardedprefix
+
+import (
+	"testing"
+
+	api "k8s.io/api/core/v1"
+	extensions "k8s.io/api/extensions/v1beta1"
+	meta_v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/ingress-nginx/internal/ingress/annotations/parser"
+	"k8s.io/ingress-nginx/internal/ingress/resolver"
+)
+
+func TestParse(t *testing.T) {
+	annotation := parser.GetAnnotationWithPrefix("x-forwarded-prefix")
+	ap := NewParser(&resolver.Mock{})
+	if ap == nil {
+		t.Fatalf("expected a parser.IngressAnnotation but returned nil")
+	}
+
+	testCases := []struct {
+		annotations map[string]string
+		expected    bool
+	}{
+		{map[string]string{annotation: "true"}, true},
+		{map[string]string{annotation: "1"}, true},
+		{map[string]string{annotation: ""}, false},
+		{map[string]string{}, false},
+		{nil, false},
+	}
+
+	ing := &extensions.Ingress{
+		ObjectMeta: meta_v1.ObjectMeta{
+			Name:      "foo",
+			Namespace: api.NamespaceDefault,
+		},
+		Spec: extensions.IngressSpec{},
+	}
+
+	for _, testCase := range testCases {
+		ing.SetAnnotations(testCase.annotations)
+		result, _ := ap.Parse(ing)
+		if result != testCase.expected {
+			t.Errorf("expected %v but returned %v, annotations: %s", testCase.expected, result, testCase.annotations)
+		}
+	}
+}