Move codes to pkg (#46)

pkg/ingress/kube/annotations/rewrite.go

@@ -0,0 +1,106 @@
+// Copyright (c) 2022 Alibaba Group Holding Ltd.
+//
+// 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 annotations
+
+import (
+	"regexp"
+	"strings"
+
+	networking "istio.io/api/networking/v1alpha3"
+)
+
+const (
+	rewriteTarget = "rewrite-target"
+	useRegex      = "use-regex"
+	upstreamVhost = "upstream-vhost"
+
+	re2Regex = "\\$[0-9]"
+)
+
+var (
+	_ Parser       = &rewrite{}
+	_ RouteHandler = &rewrite{}
+)
+
+type RewriteConfig struct {
+	RewriteTarget string
+	UseRegex      bool
+	RewriteHost   string
+}
+
+type rewrite struct{}
+
+func (r rewrite) Parse(annotations Annotations, config *Ingress, _ *GlobalContext) error {
+	if !needRewriteConfig(annotations) {
+		return nil
+	}
+
+	rewriteConfig := &RewriteConfig{}
+	rewriteConfig.RewriteTarget, _ = annotations.ParseStringASAP(rewriteTarget)
+	rewriteConfig.UseRegex, _ = annotations.ParseBoolASAP(useRegex)
+	rewriteConfig.RewriteHost, _ = annotations.ParseStringASAP(upstreamVhost)
+
+	if rewriteConfig.RewriteTarget != "" {
+		// When rewrite target is present and not empty,
+		// we will enforce regex match on all rules in this ingress.
+		rewriteConfig.UseRegex = true
+
+		// We should convert nginx regex rule to envoy regex rule.
+		rewriteConfig.RewriteTarget = convertToRE2(rewriteConfig.RewriteTarget)
+	}
+
+	config.Rewrite = rewriteConfig
+	return nil
+}
+
+func (r rewrite) ApplyRoute(route *networking.HTTPRoute, config *Ingress) {
+	rewriteConfig := config.Rewrite
+	if rewriteConfig == nil || (rewriteConfig.RewriteTarget == "" &&
+		rewriteConfig.RewriteHost == "") {
+		return
+	}
+
+	route.Rewrite = &networking.HTTPRewrite{}
+	if rewriteConfig.RewriteTarget != "" {
+		route.Rewrite.UriRegex = &networking.RegexMatchAndSubstitute{
+			Pattern:      route.Match[0].Uri.GetRegex(),
+			Substitution: rewriteConfig.RewriteTarget,
+		}
+	}
+
+	if rewriteConfig.RewriteHost != "" {
+		route.Rewrite.Authority = rewriteConfig.RewriteHost
+	}
+}
+
+func convertToRE2(target string) string {
+	if match, err := regexp.MatchString(re2Regex, target); err != nil || !match {
+		return target
+	}
+
+	return strings.ReplaceAll(target, "$", "\\")
+}
+
+func NeedRegexMatch(annotations map[string]string) bool {
+	target, _ := Annotations(annotations).ParseStringASAP(rewriteTarget)
+	regex, _ := Annotations(annotations).ParseBoolASAP(useRegex)
+
+	return regex || target != ""
+}
+
+func needRewriteConfig(annotations Annotations) bool {
+	return annotations.HasASAP(rewriteTarget) || annotations.HasASAP(useRegex) ||
+		annotations.HasASAP(upstreamVhost)
+}