CORS Configuration with Envoy

Envoy is a popular open-source service mesh. One of the features of Envoy is its support for Cross-Origin Resource Sharing (CORS), which is an essential security feature for web applications that need to access resources from different domains (origins).

Configuration

admin:
  address:
    socket_address:
      protocol: TCP
      address: 0.0.0.0
      port_value: 9901
static_resources:
  listeners:
  - name: listener_0
    address:
      socket_address:
        protocol: TCP
        address: 0.0.0.0
        port_value: 8081
    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
          generate_request_id: true
          stat_prefix: ingress_http
          route_config:
            name: local_route
            virtual_hosts:
            - name: local_service
              domains: ["*"]
              typed_per_filter_config:
                envoy.filters.http.cors:
                  "@type": type.googleapis.com/envoy.extensions.filters.http.cors.v3.CorsPolicy
                  allow_origin_string_match:
                  - safe_regex:
                      regex: \*
                  allow_methods: "GET,POST,PUT,PATCH,DELETE,OPTIONS"
                  allow_headers: "DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization,Access-Control-Allow-Origin"
                  allow_credentials: true
                  max_age: "1728000"
              routes:
              - match:
                  prefix: "/"
                route:
                  host_rewrite_literal: www.envoyproxy.io
                  cluster: service_envoyproxy_io
          http_filters:
          - name: envoy.filters.http.cors
            typed_config:
              "@type": type.googleapis.com/envoy.extensions.filters.http.cors.v3.Cors
          - name: envoy.filters.http.router
            typed_config:
              "@type": type.googleapis.com/envoy.extensions.filters.http.router.v3.Router
  clusters:
  - name: service_envoyproxy_io
    connect_timeout: 30s
    type: LOGICAL_DNS
    dns_lookup_family: V4_ONLY
    lb_policy: ROUND_ROBIN
    load_assignment:
      cluster_name: service_envoyproxy_io
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: www.envoyproxy.io
                port_value: 443
    transport_socket:
      name: envoy.transport_sockets.tls
      typed_config:
        "@type": type.googleapis.com/envoy.extensions.transport_sockets.tls.v3.UpstreamTlsContext
        sni: www.envoyproxy.io

Some other Envoy configurations examples are available in the Envoy Github repository.