响应 x-request-id

背景

有时希望在响应头中返回请求头中的 x-request-id，以便于跟踪请求，这时我们可以利用 EnvoyFilter 来实现。

EnvoyFilter

response-request-id.yaml

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: response-request-id
  namespace: istio-system # istio-system 表示针对所有命名空间生效
spec:
  workloadSelector: # 选中所有 ingressgateway
    labels:
      istio: ingressgateway # 所有 ingressgateway 都带此 label
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        context: GATEWAY
        listener:
          filterChain:
            filter:
              name: "envoy.filters.network.http_connection_manager"
              subFilter:
                name: "envoy.filters.http.router"
      patch:
        operation: INSERT_BEFORE
        value:
          name: envoy.lua
          typed_config:
            "@type": "type.googleapis.com/envoy.extensions.filters.http.lua.v3.Lua"
            inlineCode: |
              function envoy_on_request(handle)
                 local metadata = handle:streamInfo():dynamicMetadata()
                 local headers = handle:headers()
                 local rid = headers:get("x-request-id")
                 if rid ~= nil then
                   metadata:set("envoy.filters.http.lua", "req.x-request-id", rid)
                 end
              end
              function envoy_on_response(handle)
                 local metadata = handle:streamInfo():dynamicMetadata():get("envoy.filters.http.lua")
                 local rid = metadata["req.x-request-id"]
                 if rid ~= nil then
                   handle:headers():add("x-request-id", rid)
                 end
              end

效果

$ curl -I https://imroc.cc/istio
HTTP/2 200 
server: istio-envoy
date: Wed, 15 Nov 2023 03:39:31 GMT
content-type: text/html
content-length: 37698
last-modified: Sat, 14 Oct 2023 01:02:42 GMT
etag: "6529e8b2-9342"
accept-ranges: bytes
x-envoy-upstream-service-time: 5
x-request-id: 712fd33d-5dd8-441b-aac7-0280de975a85
vary: Accept-Encoding