[k8s] Remove rule type path list.

Instead of doing sanity checks in the Kubernetes provider, we just
accept any non-empty value from the annotation and rely on the server
part to filter out unknown rules.

This allows us to automatically stay in sync with the currently
supported Path matchers/modifiers.

provider/kubernetes/kubernetes.go

@@ -27,9 +27,6 @@ var _ provider.Provider = (*Provider)(nil)
 
 const (
 	annotationFrontendRuleType = "traefik.frontend.rule.type"
-	ruleTypePathPrefixStrip    = "PathPrefixStrip"
-	ruleTypePathStrip          = "PathStrip"
-	ruleTypePath               = "Path"
 	ruleTypePathPrefix         = "PathPrefix"
 )
 
@@ -199,12 +196,8 @@ func (p *Provider) loadIngresses(k8sClient Client) (*types.Configuration, error)
 				}
 
 				if len(pa.Path) > 0 {
-					ruleType, unknown := getRuleTypeFromAnnotation(i.Annotations)
+					ruleType := i.Annotations[annotationFrontendRuleType]
-					switch {
+					if ruleType == "" {
-					case unknown:
-						log.Warnf("Unknown RuleType '%s' for Ingress %s/%s, falling back to PathPrefix", ruleType, i.ObjectMeta.Namespace, i.ObjectMeta.Name)
-						fallthrough
-					case ruleType == "":
 						ruleType = ruleTypePathPrefix
 					}
 
@@ -392,24 +385,3 @@ func (p *Provider) loadConfig(templateObjects types.Configuration) *types.Config
 	}
 	return configuration
 }
-
-func getRuleTypeFromAnnotation(annotations map[string]string) (ruleType string, unknown bool) {
-	ruleType = annotations[annotationFrontendRuleType]
-	for _, knownRuleType := range []string{
-		ruleTypePathPrefixStrip,
-		ruleTypePathStrip,
-		ruleTypePath,
-		ruleTypePathPrefix,
-	} {
-		if strings.ToLower(ruleType) == strings.ToLower(knownRuleType) {
-			return knownRuleType, false
-		}
-	}
-
-	if ruleType != "" {
-		// Annotation is set but does not match anything we know.
-		unknown = true
-	}
-
-	return ruleType, unknown
-}

provider/kubernetes/kubernetes_test.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
-	"strings"
 	"testing"
 
 	"github.com/containous/traefik/types"
@@ -333,19 +332,14 @@ func TestRuleType(t *testing.T) {
 		frontendRuleType string
 	}{
 		{
-			desc:             "implicit default",
+			desc:             "rule type annotation missing",
 			ingressRuleType:  "",
 			frontendRuleType: ruleTypePathPrefix,
 		},
 		{
-			desc:             "unknown ingress / explicit default",
+			desc:             "rule type annotation set",
-			ingressRuleType:  "unknown",
+			ingressRuleType:  "Path",
-			frontendRuleType: ruleTypePathPrefix,
+			frontendRuleType: "Path",
-		},
-		{
-			desc:             "explicit ingress",
-			ingressRuleType:  ruleTypePath,
-			frontendRuleType: ruleTypePath,
 		},
 	}
 
@@ -1773,65 +1767,6 @@ func TestInvalidPassHostHeaderValue(t *testing.T) {
 	}
 }
 
-func TestGetRuleTypeFromAnnotation(t *testing.T) {
-	tests := []struct {
-		in            string
-		wantedUnknown bool
-	}{
-		{
-			in:            ruleTypePathPrefixStrip,
-			wantedUnknown: false,
-		},
-		{
-			in:            ruleTypePathStrip,
-			wantedUnknown: false,
-		},
-		{
-			in:            ruleTypePath,
-			wantedUnknown: false,
-		},
-		{
-			in:            ruleTypePathPrefix,
-			wantedUnknown: false,
-		},
-		{
-			wantedUnknown: false,
-		},
-		{
-			in:            "Unknown",
-			wantedUnknown: true,
-		},
-	}
-
-	for _, test := range tests {
-		test := test
-		inputs := []string{test.in, strings.ToLower(test.in)}
-		if inputs[0] == inputs[1] {
-			// Lower-casing makes no difference -- truncating to single case.
-			inputs = inputs[:1]
-		}
-		for _, input := range inputs {
-			t.Run(fmt.Sprintf("in='%s'", input), func(t *testing.T) {
-				t.Parallel()
-				annotations := map[string]string{}
-				if test.in != "" {
-					annotations[annotationFrontendRuleType] = test.in
-				}
-
-				gotRuleType, gotUnknown := getRuleTypeFromAnnotation(annotations)
-
-				if gotUnknown != test.wantedUnknown {
-					t.Errorf("got unknown '%t', wanted '%t'", gotUnknown, test.wantedUnknown)
-				}
-
-				if gotRuleType != test.in {
-					t.Errorf("got rule type '%s', wanted '%s'", gotRuleType, test.in)
-				}
-			})
-		}
-	}
-}
-
 func TestKubeAPIErrors(t *testing.T) {
 	ingresses := []*v1beta1.Ingress{{
 		ObjectMeta: v1.ObjectMeta{