LocalRate limit path + http method regex support

Networking
1

one can install a rate limit that varies across paths.
in the simplified version (without using the cluster keyword):

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: route-ratelimit-test
  namespace: istio-system
...more code here...
      patch:
        operation: MERGE
        value:
          route:
            rate_limits:
              - actions:
                  - request_headers:
                      header_name: ":path"
                      descriptor_key: path
                  - request_headers:
                      header_name: ":method"
                      descriptor_key: method
          typed_per_filter_config:
            envoy.filters.http.local_ratelimit:
              "@type": type.googleapis.com/udpa.type.v1.TypedStruct
              type_url: type.googleapis.com/envoy.extensions.filters.http.local_ratelimit.v3.LocalRateLimit
              value:
                stat_prefix: http_local_rate_limiter
                descriptors:
                  - entries:
                      - key: path
                        value: "/v1/a/b/get/*"
                      - key: method
                        value: GET
                    token_bucket:
                      max_tokens: 1
                      tokens_per_fill: 1
                      fill_interval: 60s
...more code here...

using * for all path deeper than /v1/a/b/get/... doesn’t work. only exact string match works here.
if the descriptor entry value will be

   - key: path
     value: "/v1/a/b/get/1"

The rate limiter will be triggered only if you fire

curl http://localhost/v1/a/b/get/1

if the curl command will be changed even by one bit: rate limiter will ignore it.
How can I make it work with regex like for path ?

2

well I saw I can enhance the envoyfilter by using different actions:

      patch:
        operation: MERGE
        value:
          route:
            rate_limits:
              - actions:
                - header_value_match:
                    descriptor_value: path
                    headers:
                      - name: :path
                        prefix_match: "/v1"
                - request_headers:
                    header_name: ":method"
                    descriptor_key: method

or as full file :

# https://www.aboutwayfair.com/tech-innovation/understanding-envoy-rate-limits
apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: get-ratelimit
  namespace: istio-system
spec:
  workloadSelector:
    # bare in mind , rate limiter workloadSelector can select pods based on labels in the init phase. not later in the lifecycle.
    # so , the recommended way, is to look at labels from the relevant deployment/statefulset .
    labels:
      app: "myapp2"
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        context: SIDECAR_INBOUND
        listener:
          filterChain:
            filter:
              name: "envoy.filters.network.http_connection_manager"
      patch:
        operation: INSERT_BEFORE
        value:
          name: envoy.filters.http.local_ratelimit
          typed_config:
            "@type": type.googleapis.com/udpa.type.v1.TypedStruct
            type_url: type.googleapis.com/envoy.extensions.filters.http.local_ratelimit.v3.LocalRateLimit
            value:
              stat_prefix: http_local_rate_limiter
    - applyTo: HTTP_ROUTE
      match:
        context: SIDECAR_INBOUND
        routeConfiguration:
          vhost:
            name: "inbound|http|8080"
            route:
              action: ANY
      patch:
        operation: MERGE
        value:
          route:
            domain: get-methods
            rate_limits:
              - actions:
                - header_value_match:
                    descriptor_value: path
                    headers:
                      - name: :path
                        prefix_match: "/v1"
                - request_headers:
                    header_name: ":method"
                    descriptor_key: method
          typed_per_filter_config:
            envoy.filters.http.local_ratelimit:
              "@type": type.googleapis.com/udpa.type.v1.TypedStruct
              type_url: type.googleapis.com/envoy.extensions.filters.http.local_ratelimit.v3.LocalRateLimit
              value:
                stat_prefix: http_local_rate_limiter
                descriptors:
                  - entries: 
                      - key: path
                        value: "/v1/very/heavy/action1"
                      - key: method
                        value: GET
                    token_bucket:
                      max_tokens: 1
                      tokens_per_fill: 1
                      fill_interval: 60s
                  - entries:
                      - key: path
                        value: "/v1/healthz"
                      - key: method
                        value: GET
                    token_bucket:
                      max_tokens: 60 
                      tokens_per_fill: 60
                      fill_interval: 60s
                  - entries:
                      - key: path
                        value: "/v1/very/light/action"
                      - key: method
                        value: POST
                    token_bucket:
                      max_tokens: 100 
                      tokens_per_fill: 100
                      fill_interval: 60s
                enable_x_ratelimit_headers: "DRAFT_VERSION_03"
                # next line will give the default rate for anything not caught by previous lines.
                token_bucket:
                  max_tokens: 20 
                  tokens_per_fill: 20
                  fill_interval: 20s
                filter_enabled:
                  runtime_key: local_rate_limit_enabled
                  default_value:
                    numerator: 100
                    denominator: HUNDRED
                filter_enforced:
                  runtime_key: local_rate_limit_enforced
                  default_value:
                    numerator: 100
                    denominator: HUNDRED