Refactor handling of path Prefix and Exact

internal/ingress/controller/location.go

@@ -0,0 +1,112 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controller
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/mitchellh/copystructure"
+	networking "k8s.io/api/networking/v1beta1"
+	"k8s.io/ingress-nginx/internal/ingress"
+	"k8s.io/klog/v2"
+)
+
+var (
+	pathTypeExact  = networking.PathTypeExact
+	pathTypePrefix = networking.PathTypePrefix
+)
+
+// updateServerLocations inspects the generated locations configuration for a server
+// normalizing the path and adding an additional exact location when is possible
+func updateServerLocations(locations []*ingress.Location) []*ingress.Location {
+	newLocations := []*ingress.Location{}
+
+	// get Exact locations to check if one already exists
+	exactLocations := map[string]*ingress.Location{}
+	for _, location := range locations {
+		if *location.PathType == pathTypeExact {
+			exactLocations[location.Path] = location
+		}
+	}
+
+	for _, location := range locations {
+		// location / does not require any update
+		if location.Path == rootLocation {
+			newLocations = append(newLocations, location)
+			continue
+		}
+
+		// only Prefix locations could require an additional location block
+		if *location.PathType != pathTypePrefix {
+			newLocations = append(newLocations, location)
+			continue
+		}
+
+		// locations with rewrite or using regular expressions are not modified
+		if needsRewrite(location) || location.Rewrite.UseRegex {
+			newLocations = append(newLocations, location)
+			continue
+		}
+
+		// If exists an Exact location is not possible to create a new one.
+		if _, alreadyExists := exactLocations[location.Path]; alreadyExists {
+			// normalize path. Must end in /
+			location.Path = normalizePrefixPath(location.Path)
+			newLocations = append(newLocations, location)
+			continue
+		}
+
+		// copy location before any change
+		el, err := copystructure.Copy(location)
+		if err != nil {
+			klog.ErrorS(err, "copying location")
+		}
+
+		// normalize path. Must end in /
+		location.Path = normalizePrefixPath(location.Path)
+		newLocations = append(newLocations, location)
+
+		// add exact location
+		exactLocation := el.(*ingress.Location)
+		exactLocation.PathType = &pathTypeExact
+
+		newLocations = append(newLocations, exactLocation)
+	}
+
+	return newLocations
+}
+
+func normalizePrefixPath(path string) string {
+	if path == rootLocation {
+		return rootLocation
+	}
+
+	if !strings.HasSuffix(path, "/") {
+		return fmt.Sprintf("%v/", path)
+	}
+
+	return path
+}
+
+func needsRewrite(location *ingress.Location) bool {
+	if len(location.Rewrite.Target) > 0 && location.Rewrite.Target != location.Path {
+		return true
+	}
+
+	return false
+}