Envoy-dynamic-forward proxy

dfw.yaml

admin:
  address:
    socket_address:
      protocol: TCP
      address: 127.0.0.1
      port_value: 9901
static_resources:
  listeners:
  - name: listener_0
    address:
      socket_address:
        protocol: TCP
        address: 0.0.0.0
        port_value: 10000
    filter_chains:
    - filters:
      - name: envoy.filters.network.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
          stat_prefix: ingress_http
          route_config:
            name: local_route
            virtual_hosts:
            - name: local_service
              domains: ["*"]
              routes:
              - match:
                  prefix: "/evax/"
                route:
                  cluster: dynamic_forward_proxy_cluster
                typed_per_filter_config:
                  envoy.filters.http.dynamic_forward_proxy:
                    "@type": type.googleapis.com/envoy.extensions.filters.http.dynamic_forward_proxy.v3.PerRouteConfig
                    host_rewrite_header: "x-pod-host-header"
                    #host_rewrite_path_regex: can be used once supported.
                    #  pattern:
                    #    google_re2: {}
                    #    regex: "^/metrics/(.+)/.+$"
                    #  substitution: \1
              - match:
                  prefix: "/"
                route:
                  cluster: dynamic_forward_proxy_cluster
          http_filters:
          - name: envoy.filters.http.lua
            typed_config:
              "@type": type.googleapis.com/envoy.extensions.filters.http.lua.v3.Lua
              inline_code: |
                -- /evax/{uuid}/live/{uuid} --> uuid.$ns.svc.cluster.local
                ns = "stability-asm-managed"
                port = "8080"
                function map_path(path)
                  local c=string.gmatch(path, "/evax/([^/]*)/.*")
                  return c() .. "." .. ns .. ".svc.cluster.local:" .. port
                end
                -- This part can be done in Wasm instead of lua
                function envoy_on_request(req)
                  local path = req:headers():get(":path")
                  local host_header = map_path(path)
                  req:logInfo("host=" .. host_header)
                  -- example host = "svc-0-8-77d9b59c96-5rkfw.stability-asm-managed.svc.cluster.local:8080"
                  req:headers():replace("x-pod-host-header", host_header)
                end
          - name: envoy.filters.http.dynamic_forward_proxy
            typed_config:
              "@type": type.googleapis.com/envoy.extensions.filters.http.dynamic_forward_proxy.v3.FilterConfig
              dns_cache_config:
                name: dynamic_forward_proxy_cache_config
                dns_lookup_family: V4_ONLY
          - name: envoy.filters.http.router
            typed_config:
              "@type": type.googleapis.com/envoy.extensions.filters.http.router.v3.Router
  clusters:
  - name: dynamic_forward_proxy_cluster
    lb_policy: CLUSTER_PROVIDED
    connect_timeout: 2s
    cluster_type:
      name: envoy.clusters.dynamic_forward_proxy
      typed_config:
        "@type": type.googleapis.com/envoy.extensions.clusters.dynamic_forward_proxy.v3.ClusterConfig
        dns_cache_config:
          name: dynamic_forward_proxy_cache_config
          dns_lookup_family: V4_ONLY