refactor rewrite rule generation / add integration test

.vscode/settings.json

@@ -1,5 +1,6 @@
 {
     "go.testEnvVars": {
-      "KUBEBUILDER_ASSETS": "${workspaceFolder}/bin/k8s/current"
+      "KUBEBUILDER_ASSETS": "${workspaceFolder}/bin/k8s/current",
+      "TEST_ASSET_COREDNS": "${workspaceFolder}/bin/coredns"
     }
 }

Dockerfile

@@ -18,10 +18,11 @@ COPY pkg/ pkg/
 COPY internal/ internal/
 COPY crds/ crds/
 COPY Makefile Makefile
+COPY hack/ hack/
 
 # Run tests and build
-RUN make envtest \
- && CGO_ENABLED=0 KUBEBUILDER_ASSETS="/workspace/bin/k8s/current" go test ./... \
+RUN make envtest coredns \
+ && CGO_ENABLED=0 KUBEBUILDER_ASSETS="/workspace/bin/k8s/current" TEST_ASSET_COREDNS=/workspace/bin/coredns go test ./... \
  && CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build -a -o manager main.go
 
 # Use distroless as minimal base image to package the manager binary

Makefile

@@ -3,6 +3,7 @@
 IMG ?= controller:latest
 # ENVTEST_K8S_VERSION refers to the version of kubebuilder assets to be downloaded by envtest binary.
 ENVTEST_K8S_VERSION = 1.25.0
+COREDNS_VERSION= 1.10.1
 
 # Get the currently used golang install path (in GOPATH/bin, unless GOBIN is set)
 ifeq (,$(shell go env GOBIN))
@@ -57,8 +58,8 @@ vet: ## Run go vet against code.
 	go vet ./...
 
 .PHONY: test
-test: manifests generate fmt vet envtest ## Run tests.
-	KUBEBUILDER_ASSETS="$(LOCALBIN)/k8s/current" go test ./... -coverprofile cover.out
+test: manifests generate fmt vet envtest coredns ## Run tests.
+	KUBEBUILDER_ASSETS="$(LOCALBIN)/k8s/current" TEST_ASSET_COREDNS="$(LOCALBIN)/coredns" go test ./... -coverprofile cover.out
 
 ##@ Build
 
@@ -132,6 +133,7 @@ $(LOCALBIN):
 KUSTOMIZE ?= $(LOCALBIN)/kustomize
 CONTROLLER_GEN ?= $(LOCALBIN)/controller-gen
 ENVTEST ?= $(LOCALBIN)/setup-envtest
+COREDNS ?= $(LOCALBIN)/coredns
 CLIENT_GEN ?= $(shell pwd)/bin/client-gen
 INFORMER_GEN ?= $(shell pwd)/bin/informer-gen
 LISTER_GEN ?= $(shell pwd)/bin/lister-gen
@@ -160,6 +162,11 @@ $(ENVTEST): $(LOCALBIN)
 	rm -f $(LOCALBIN)/k8s/current ;\
 	ln -s $$ENVTESTDIR $(LOCALBIN)/k8s/current
 
+.PHONY: coredns
+coredns: $(COREDNS) ## Download coredns
+$(COREDNS): $(LOCALBIN)
+	test -s $(LOCALBIN)/coredns || ./hack/download-coredns $(COREDNS_VERSION) $(LOCALBIN)/coredns
+
 .PHONY: client-gen
 client-gen: $(CLIENT_GEN) ## Download client-gen
 $(CLIENT_GEN): $(LOCALBIN)

api/v1alpha1/masqueradingrule_webhook.go

@@ -8,7 +8,7 @@ package v1alpha1
 import (
 	"fmt"
 
-	"github.com/sap/dns-masquerading-operator/internal/netutil"
+	"github.com/sap/dns-masquerading-operator/internal/coredns"
 	"k8s.io/apimachinery/pkg/runtime"
 	ctrl "sigs.k8s.io/controller-runtime"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
@@ -59,17 +59,9 @@ func (r *MasqueradingRule) ValidateDelete() error {
 }
 
 func (r *MasqueradingRule) validate() error {
-	if err := netutil.CheckDnsName(r.Spec.From, true); err != nil {
-		return fmt.Errorf("invalid .spec.from: %s (%s)", r.Spec.From, err)
-	}
-	if netutil.IsIpAddress(r.Spec.To) {
-		if netutil.IsWildcardDnsName(r.Spec.From) {
-			return fmt.Errorf("invalid .spec.to: %s (.spec.from must not be a wildcard DNS name if .spec.to is an IP address)", r.Spec.To)
-		}
-	} else {
-		if err := netutil.CheckDnsName(r.Spec.To, false); err != nil {
-			return fmt.Errorf("invalid .spec.to: %s (%s)", r.Spec.To, err)
-		}
+	_, err := coredns.NewRewriteRule("", r.Spec.From, r.Spec.To)
+	if err != nil {
+		return fmt.Errorf("invalid rule specification: %s", err)
 	}
 	return nil
 }

go.mod

@@ -4,6 +4,8 @@ go 1.19
 
 require (
 	github.com/hashicorp/go-multierror v1.1.1
+	github.com/onsi/ginkgo/v2 v2.11.0
+	github.com/onsi/gomega v1.27.9
 	github.com/pkg/errors v0.9.1
 	github.com/sap/go-generics v0.1.1
 	istio.io/client-go v1.17.3
@@ -26,51 +28,53 @@ require (
 	github.com/go-openapi/jsonpointer v0.19.5 // indirect
 	github.com/go-openapi/jsonreference v0.20.0 // indirect
 	github.com/go-openapi/swag v0.19.14 // indirect
+	github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/google/gnostic v0.5.7-v3refs // indirect
 	github.com/google/go-cmp v0.5.9 // indirect
-	github.com/google/gofuzz v1.1.0 // indirect
+	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 // indirect
 	github.com/google/uuid v1.3.0 // indirect
-	github.com/hashicorp/errwrap v1.0.0 // indirect
+	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/imdario/mergo v0.3.12 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/mailru/easyjson v0.7.6 // indirect
-	github.com/matttproud/golang_protobuf_extensions v1.0.2 // indirect
+	github.com/kr/pretty v0.2.1 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/moby/spdystream v0.2.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/onsi/ginkgo/v2 v2.11.0 // indirect
-	github.com/onsi/gomega v1.27.9 // indirect
 	github.com/prometheus/client_golang v1.14.0 // indirect
 	github.com/prometheus/client_model v0.3.0 // indirect
-	github.com/prometheus/common v0.37.0 // indirect
+	github.com/prometheus/common v0.39.0 // indirect
 	github.com/prometheus/procfs v0.8.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	go.uber.org/atomic v1.7.0 // indirect
+	github.com/stretchr/testify v1.8.1 // indirect
+	go.uber.org/atomic v1.9.0 // indirect
 	go.uber.org/multierr v1.6.0 // indirect
 	go.uber.org/zap v1.24.0 // indirect
 	golang.org/x/net v0.12.0 // indirect
-	golang.org/x/oauth2 v0.0.0-20220223155221-ee480838109b // indirect
+	golang.org/x/oauth2 v0.3.0 // indirect
 	golang.org/x/sys v0.10.0 // indirect
 	golang.org/x/term v0.10.0 // indirect
 	golang.org/x/text v0.11.0 // indirect
 	golang.org/x/time v0.3.0 // indirect
+	golang.org/x/tools v0.9.3 // indirect
 	gomodules.xyz/jsonpatch/v2 v2.2.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
-	google.golang.org/genproto v0.0.0-20221018160656-63c7b68cfc55 // indirect
+	google.golang.org/genproto v0.0.0-20221227171554-f9683d7f8bef // indirect
 	google.golang.org/protobuf v1.28.1 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	istio.io/api v0.0.0-20230523222408-21e7bb4b66a2 // indirect
 	k8s.io/apiextensions-apiserver v0.26.1 // indirect
 	k8s.io/component-base v0.26.1 // indirect
-	k8s.io/klog/v2 v2.80.1 // indirect
+	k8s.io/klog/v2 v2.90.0 // indirect
 	k8s.io/kube-openapi v0.0.0-20221012153701-172d655c2280 // indirect
 	k8s.io/utils v0.0.0-20221128185143-99ec85e7a448 // indirect
 	sigs.k8s.io/json v0.0.0-20220713155537-f223a00ba0e2 // indirect