EnvoyFilterUsesRelativeOperation

当EnvoyFilter没有优先级并且使用相对补丁操作（INVALID、MERGE、REMOVE、INSERT_BEFORE、INSERT_AFTER、REPLACE）时，会出现此消息。使用相对补丁操作意味着该操作依赖于在评估当前EnvoyFilter过滤器时另一个过滤器是否存在。为了确保EnvoyFilters按用户期望的顺序应用，应指定优先级或使用非相对操作（ADD或INSERT_FIRST）。

一个例子

考虑一个补丁操作为INSERT_BEFORE的EnvoyFilter

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: test-relative
  namespace: bookinfo
spec:
  workloadSelector:
    labels:
      app: reviews2
  configPatches:
    # The first patch adds the Lua filter to the listener/http connection manager
  - applyTo: HTTP_FILTER
    match:
      context: SIDECAR_INBOUND
      listener:
        portNumber: 8080
        filterChain:
          filter:
            name: "envoy.filters.network.http_connection_manager"
            subFilter:
              name: "envoy.filters.http.router"
    patch:
      operation: INSERT_BEFORE
      value: # Lua filter specification
       name: envoy.lua
       typed_config:
          "@type": "type.googleapis.com/envoy.extensions.filters.http.lua.v3.Lua"
          inlineCode: |
            function envoy_on_request(request_handle)
              -- Make an HTTP call to an upstream host with the following headers, body, and timeout.
              local headers, body = request_handle:httpCall(
               "lua_cluster",
               {
                [":method"] = "POST",
                [":path"] = "/acl",
                [":authority"] = "internal.org.net"
               },
              "authorize call",
              5000)
            end

如何解决

由于使用了INSERT_BEFORE的相对操作，将其更改为INSERT_FIRST的绝对操作可以解决此问题。

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: test-relative
  namespace: bookinfo
spec:
  workloadSelector:
    labels:
      app: reviews2
  configPatches:
    # The first patch adds the Lua filter to the listener/http connection manager
  - applyTo: HTTP_FILTER
    match:
      context: SIDECAR_INBOUND
      listener:
        portNumber: 8080
        filterChain:
          filter:
            name: "envoy.filters.network.http_connection_manager"
            subFilter:
              name: "envoy.filters.http.router"
    patch:
      operation: INSERT_FIRST
      value: # Lua filter specification
       name: envoy.lua
       typed_config:
          "@type": "type.googleapis.com/envoy.extensions.filters.http.lua.v3.Lua"
          inlineCode: |
            function envoy_on_request(request_handle)
              -- Make an HTTP call to an upstream host with the following headers, body, and timeout.
              local headers, body = request_handle:httpCall(
               "lua_cluster",
               {
                [":method"] = "POST",
                [":path"] = "/acl",
                [":authority"] = "internal.org.net"
               },
              "authorize call",
              5000)
            end