Repository: helm/helm (go)

Issue:
gateway api template
Now that the gateway api has hit v1.0, it would be nice if:
```
helm create foo
```

Included generating support for a gateway api HTTPRoute (https://gateway-api.sigs.k8s.io/api-types/httproute/) out of the box.

Pull request description:
feat: add httproute from gateway-api to create chart template
This closes #12603

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**What this PR does / why we need it**:

This PR adds the HTTPRoute from [gateway-api](https://gateway-api.sigs.k8s.io/reference/spec/) to the example getting started chart. 
It is disabled by default, just like ingress.  
Adding the resource will make helm charts future-proof for the gateway-api and may also increase its adoption rate.

**Special notes for your reviewer**:

If enabled, the via `httpRoute.enabled: true`, it will produce a valid `HTTPRoute` but it will not route real traffic since a `Gateway` must be installed and configured which is in the responsibility of the cluster admin, just like ingress-controller.

The gateway api is still quite young and the gateway-api CRDs are not yet part of a default k8s installation. They currently have to be installed separably with `kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.0.0/standard-install.yaml`.  
~~The template checks if the `v1` or the `v1alpha2` version is installed and sets the api version accordingly.  
If the CRDs are missing the installation fails.~~

**If applicable**:
- [ ] this PR contains documentation
- [ ] this PR contains unit tests
- [x] this PR has been tested for backwards compatibility


Patch:
diff --git a/pkg/chart/v2/util/create.go b/pkg/chart/v2/util/create.go
index 7eb3398f5..35a8c64a0 100644
--- a/pkg/chart/v2/util/create.go
+++ b/pkg/chart/v2/util/create.go
@@ -54,6 +54,8 @@ const (
 	IgnorefileName = ".helmignore"
 	// IngressFileName is the name of the example ingress file.
 	IngressFileName = TemplatesDir + sep + "ingress.yaml"
+	// HTTPRouteFileName is the name of the example HTTPRoute file.
+	HTTPRouteFileName = TemplatesDir + sep + "httproute.yaml"
 	// DeploymentName is the name of the example deployment file.
 	DeploymentName = TemplatesDir + sep + "deployment.yaml"
 	// ServiceName is the name of the example service file.
@@ -177,6 +179,44 @@ ingress:
   #    hosts:
   #      - chart-example.local
 
+# -- Expose the service via gateway-api HTTPRoute
+# Requires Gateway API resources and suitable controller installed within the cluster
+# (see: https://gateway-api.sigs.k8s.io/guides/)
+httpRoute:
+  # HTTPRoute enabled.
+  enabled: false
+  # HTTPRoute annotations.
+  annotations: {}
+  # Which Gateways this Route is attached to.
+  parentRefs:
+  - name: gateway
+    sectionName: http
+    # namespace: default
+  # Hostnames matching HTTP header.
+  hostnames:
+  - chart-example.local
+  # List of rules and filters applied.
+  rules:
+  - matches:
+    - path:
+        type: PathPrefix
+        value: /headers
+  #   filters:
+  #   - type: RequestHeaderModifier
+  #     requestHeaderModifier:
+  #       set:
+  #       - name: My-Overwrite-Header
+  #         value: this-is-the-only-value
+  #       remove:
+  #       - User-Agent
+  # - matches:
+  #   - path:
+  #       type: PathPrefix
+  #       value: /echo
+  #     headers:
+  #     - name: version
+  #       value: v2
+
 resources: {}
   # We usually recommend not to specify default resources and to leave this as a conscious
   # choice for the user. This also increases chances charts run on environments with little
@@ -297,6 +337,46 @@ spec:
 {{- end }}
 `
 
+const defaultHTTPRoute = `{{- if .Values.httpRoute.enabled -}}
+{{- $fullName := include "<CHARTNAME>.fullname" . -}}
+{{- $svcPort := .Values.service.port -}}
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: {{ $fullName }}
+  labels:
+    {{- include "<CHARTNAME>.labels" . | nindent 4 }}
+  {{- with .Values.httpRoute.annotations }}
+  annotations:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+spec:
+  parentRefs:
+    {{- with .Values.httpRoute.parentRefs }}
+      {{- toYaml . | nindent 4 }}
+    {{- end }}
+  {{- with .Values.httpRoute.hostnames }}
+  hostnames:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+  rules:
+    {{- range .Values.httpRoute.rules }}
+    {{- with .matches }}
+    - matches:
+      {{- toYaml . | nindent 8 }}
+    {{- end }}
+    {{- with .filters }}
+      filters:
+      {{- toYaml . | nindent 8 }}
+    {{- end }}
+      backendRefs:
+        - name: {{ $fullName }}
+          port: {{ $svcPort }}
+          weight: 1
+    {{- end }}
+{{- end }}
+`
+
 const defaultDeployment = `apiVersion: apps/v1
 kind: Deployment
 metadata:
@@ -444,7 +524,20 @@ spec:
 `
 
 const defaultNotes = `1. Get the application URL by running these commands:
-{{- if .Values.ingress.enabled }}
+{{- if .Values.httpRoute.enabled }}
+{{- if .Values.httpRoute.hostnames }}
+    export APP_HOSTNAME={{ .Values.httpRoute.hostnames | first }}
+{{- else }}
+    export APP_HOSTNAME=$(kubectl get --namespace {{(first .Values.httpRoute.parentRefs).namespace | default .Release.Namespace }} gateway/{{ (first .Values.httpRoute.parentRefs).name }} -o jsonpath="{.spec.listeners[0].hostname}")
+  {{- end }}
+{{- if and .Values.httpRoute.rules (first .Values.httpRoute.rules).matches (first (first .Values.httpRoute.rules).matches).path.value }}
+    echo "Visit http://$APP_HOSTNAME{{ (first (first .Values.httpRoute.rules).matches).path.value }} to use your application"
+
+    NOTE: Your HTTPRoute depends on the listener configuration of your gateway and your HTTPRoute rules.
+    The rules can be set for path, method, header and query parameters.
+    You can check the gateway configuration with 'kubectl get --namespace {{(first .Values.httpRoute.parentRefs).namespace | default .Release.Namespace }} gateway/{{ (first .Values.httpRoute.parentRefs).name }} -o yaml'
+{{- end }}
+{{- else if .Values.ingress.enabled }}
 {{- range $host := .Values.ingress.hosts }}
   {{- range .paths }}
   http{{ if $.Values.ingress.tls }}s{{ end }}://{{ $host.host }}{{ .path }}
@@ -658,6 +751,11 @@ func Create(name, dir string) (string, error) {
 			path:    filepath.Join(cdir, IngressFileName),
 			content: transform(defaultIngress, name),
 		},
+		{
+			// httproute.yaml
+			path:    filepath.Join(cdir, HTTPRouteFileName),
+			content: transform(defaultHTTPRoute, name),
+		},
 		{
 			// deployment.yaml
 			path:    filepath.Join(cdir, DeploymentName),


Test patch:
diff --git a/pkg/cmd/create_test.go b/pkg/cmd/create_test.go
index bfdf3db5a..26eabbfc3 100644
--- a/pkg/cmd/create_test.go
+++ b/pkg/cmd/create_test.go
@@ -105,7 +105,7 @@ func TestCreateStarterCmd(t *testing.T) {
 		t.Errorf("Wrong API version: %q", c.Metadata.APIVersion)
 	}
 
-	expectedNumberOfTemplates := 9
+	expectedNumberOfTemplates := 10
 	if l := len(c.Templates); l != expectedNumberOfTemplates {
 		t.Errorf("Expected %d templates, got %d", expectedNumberOfTemplates, l)
 	}
@@ -173,7 +173,7 @@ func TestCreateStarterAbsoluteCmd(t *testing.T) {
 		t.Errorf("Wrong API version: %q", c.Metadata.APIVersion)
 	}
 
-	expectedNumberOfTemplates := 9
+	expectedNumberOfTemplates := 10
 	if l := len(c.Templates); l != expectedNumberOfTemplates {
 		t.Errorf("Expected %d templates, got %d", expectedNumberOfTemplates, l)
 	}