configure istio to collect custom metrics

metrics.yaml

---
apiVersion: config.istio.io/v1alpha2
kind: metric
metadata:
  labels:
    app: canary
    owner: canary-hack
  name: requestcountbypath
  namespace: sandbox-main
spec:
  dimensions:
    connection_security_policy: conditional((context.reporter.kind | "inbound") ==
      "outbound", "unknown", conditional(connection.mtls | false, "mutual_tls", "none"))
    destination_app: destination.labels["app"] | "unknown"
    destination_principal: destination.principal | "unknown"
    destination_version: destination.labels["version"] | "unknown"
    destination_workload: destination.workload.name | "unknown"
    destination_workload_namespace: destination.workload.namespace | "unknown"
    permissive_response_code: rbac.permissive.response_code | "none"
    permissive_response_policyid: rbac.permissive.effective_policy_id | "none"
    reporter: conditional((context.reporter.kind | "inbound") == "outbound", "source",
      "destination")
    request_path: request.path | "unknown"
    request_protocol: api.protocol | context.protocol | "unknown"
    response_code: response.code | 200
    response_flags: context.proxy_error_code | "-"
    source_app: source.labels["app"] | "unknown"
    source_principal: source.principal | "unknown"
    source_version: source.labels["version"] | "unknown"
    source_workload: source.workload.name | "unknown"
    source_workload_namespace: source.workload.namespace | "unknown"
  value: "1"
---
apiVersion: config.istio.io/v1alpha2
kind: rule
metadata:
  labels:
    app: canary
    owner: canary-hack
  name: promhttpbypath
  namespace: sandbox-main
spec:
  actions:
  - handler: prometheusbypath
    instances:
    - requestcountbypath.metric
  match: (context.protocol == "http") && (destination.workload.namespace == "sandbox-main") && (match((request.useragent
    | "-"), "kube-probe*") == false)
---
apiVersion: config.istio.io/v1alpha2
kind: handler
metadata:
  labels:
    app: canary
    owner: canary-hack
  name: prometheusbypath
  namespace: sandbox-main
spec:
  compiledAdapter: prometheus
  params:
    metrics:
    - instance_name: requestcountbypath.metric.sandbox-main
      kind: COUNTER
      label_names:
      - reporter
      - source_app
      - source_principal
      - source_workload
      - source_workload_namespace
      - source_version
      - destination_app
      - destination_principal
      - destination_workload
      - destination_workload_namespace
      - destination_version
      - request_path
      - request_protocol
      - response_code
      - response_flags
      - permissive_response_code
      - permissive_response_policyid
      - connection_security_policy
      name: requests_by_path_total
    metricsExpirationPolicy:
      metricsExpiryDuration: 10m