什么是route filter

route filter是http connection manager的最后一个http filter，它必须出现在最后不然会报错。起到路由的作用。在所有的http连接场景中都会用到。它的工作原理是利用路由表进行路由，路由表包括静态路由和动态路由。它同时处理重试和stats逻辑。

配置

{
  "dynamic_stats": "{...}",是否产生动态统计信息，默认true，高性能场景可关闭
  "start_child_span": "...",是否启用子span 出口路由
  "upstream_log": [],配置上游日志
  "suppress_envoy_headers": "...",不添加额外的x-envoy- headers 到request和response
  "strict_check_headers": [],设置一个列表，严格检查头信息
  "respect_expected_rq_timeout": "...",是否忽略x-envoy-expected-rq-timeout-ms头
  "suppress_grpc_request_failure_code_stats": "..."是否避免产生grpc请求失败状态码stats
}

upstream_log：

{
  "name": "...",名称
  "filter": "{...}",过滤
  "typed_config": "{...}" 根据日志扩展设置自定义配置
}

name：

envoy.access_loggers.file  文件日志
envoy.access_loggers.http_grpc http_grpc日志
envoy.access_loggers.open_telemetry telemetry日志
envoy.access_loggers.stream 流日志
envoy.access_loggers.tcp_grpc tcp grpc日志
envoy.access_loggers.wasm  wasm日志

filter:

{
  "status_code_filter": "{...}", 状态码过滤
  "duration_filter": "{...}",  时间过滤
  "not_health_check_filter": "{...}", 没有健康检查过滤
  "traceable_filter": "{...}", 可跟踪过滤
  "runtime_filter": "{...}", 运行时过滤
  "and_filter": "{...}", 与过滤
  "or_filter": "{...}", 或过滤
  "header_filter": "{...}", 头过滤
  "response_flag_filter": "{...}",响应标识过滤
  "grpc_status_filter": "{...}",grpc状态过滤
  "extension_filter": "{...}",扩展过滤
  "metadata_filter": "{...}"元数据过滤
}

实战

没有crd配置方法

关闭动态统计信息

cat << EOF > ef-route-dynamic_stats.yaml
apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  namespace: istio-system
  name: route
spec:
  workloadSelector:
    labels:
      istio: ingressgateway
  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: REPLACE
        value:
          name: envoy.filters.http.router
          typed_config:
            "@type": type.googleapis.com/envoy.extensions.filters.http.router.v3.Router
            dynamic_stats: false
EOF
kubectl apply -f ef-route-dynamic_stats.yaml -n istio-system --context context-cluster1