interval: 15s
    relabelings:
    - action: keep
      sourceLabels: [__meta_kubernetes_pod_container_name]
      regex: "istio-proxy"
    - action: keep
      sourceLabels: [__meta_kubernetes_pod_annotationpresent_prometheus_io_scrape]
    - action: replace
      regex: (\d+);(([A-Fa-f0-9]{1,4}::?){1,7}[A-Fa-f0-9]{1,4})
      replacement: '[$2]:$1'
      sourceLabels:
      - __meta_kubernetes_pod_annotation_prometheus_io_port

kind: VirtualService
metadata:
  name: fault
  namespace: testns
spec:
  hosts:
    - fault.test.istio.io
  http:
    - match:
      - headers:
          version:
            exact: v2
        sourceLabels:
          version: v1
      route:
      - destination:
          host: c
          subset: v2
        weight: 100
      fault:
        delay:
          percentage:
            value: 100.0

	// queryparams
	out.QueryParams = maps.MergeCopy(root.QueryParams, delegate.QueryParams)

	if out.Port == 0 {
		out.Port = root.Port
	}

	// SourceLabels
	out.SourceLabels = maps.MergeCopy(root.SourceLabels, delegate.SourceLabels)

	if out.SourceNamespace == "" {
		out.SourceNamespace = root.SourceNamespace
	}

	if len(out.Gateways) == 0 {
		out.Gateways = root.Gateways
	}

kind: VirtualService
metadata:
  name: headers-route
  namespace: testns
spec:
  hosts:
    - headers.test.istio.io
  http:
    - match:
      - headers:
          version:
            exact: v2
        sourceLabels:
          version: v1
      route:
      - destination:
          host: c-weighted.extsvc.com
          subset: v2
        weight: 100
    - route:
      - destination:

kind: VirtualService
metadata:
  name: regex-route
  namespace: testns
spec:
  hosts:
    - regex.extsvc.com
  http:
    - match:
      - headers:
          foo:
            regex: "b.*"
        sourceLabels:
          version: v1
      route:
      - destination:
          host: regex.extsvc.com
          subset: v2
        weight: 100
    - route:
      - destination:
          host: regex.extsvc.com

"timeout"
"retries"
"fault"
"mirror"
"mirrorPercentage"
"corsPolicy"
"headers"
"mirrorPercent"
"namespace"
"request"
"response"
"route"
"uri"
"method"
"authority"
"sourceLabels"
"queryParams"
"ignoreUriCase"
"withoutHeaders"
"sourceNamespace"
"destination"
"destinationSubnets"
"sniHosts"
"redirectCode"
"retryRemoteLocalities"
"retryOn"
"perTryTimeout"

	//
	// A list of matches may contain duplicate runtime matches, but different static matches. For example:
	//
	// {sni_hosts: A, sourceLabels: X} => destination M
	// {sni_hosts: A, sourceLabels: *} => destination N
	//
	// For a proxy with labels X, we can evaluate the static predicates to get:
	// {sni_hosts: A} => destination M
	// {sni_hosts: A} => destination N
	//

			root: []*networking.HTTPMatchRequest{
				{
					SourceLabels: map[string]string{"app": "test"},
				},
			},
			delegate: []*networking.HTTPMatchRequest{
				{
					SourceLabels: map[string]string{"version": "v1"},
				},
			},
			expected: []*networking.HTTPMatchRequest{
				{
					SourceLabels: map[string]string{"app": "test", "version": "v1"},
				},
			},
		},

		vs := config.Spec.(*networking.VirtualService)
		for _, httpRoute := range vs.Http {
			for _, match := range httpRoute.Match {
				// if vs has source match, not cacheable
				if len(match.SourceLabels) > 0 || match.SourceNamespace != "" {
					return false
				}
			}
		}
	}

	return true
}

func extractNamespaceForKubernetesService(hostname string) (string, error) {

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: mysvc-vs
spec:
  hosts:
  - {{.host}}
  http:
{{- range .dst }}
  - name: "{{ .Config.Cluster.Name }}-local"
    match:
    - sourceLabels:
        topology.istio.io/cluster: {{ .Config.Cluster.Name }}
    route:
    - destination:
        host: {{$.host}}
        subset: {{ .Config.Cluster.Name }}
{{- end }}