External Authorization¶
External authorization architecture overview
This filter should be configured with the name envoy.filters.http.ext_authz.
The external authorization filter calls an external gRPC or HTTP service to check whether an incoming HTTP request is authorized or not. If the request is deemed unauthorized, then the request will be denied normally with 403 (Forbidden) response. Note that sending additional custom metadata from the authorization service to the upstream, to the downstream or to the authorization service is also possible. This is explained in more details at HTTP filter.
The content of the requests that are passed to an authorization service is specified by CheckRequest.
The HTTP filter, using a gRPC/HTTP service, can be configured as follows. You can see all the configuration options at HTTP filter.
Configuration Examples¶
A sample filter configuration for a gRPC authorization server:
http_filters:
- name: envoy.filters.http.ext_authz
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.http.ext_authz.v3.ExtAuthz
grpc_service:
envoy_grpc:
cluster_name: ext-authz
# Default is 200ms; override if your server needs e.g. warmup time.
timeout: 0.5s
include_peer_certificate: true
clusters:
- name: ext-authz
type: static
http2_protocol_options: {}
load_assignment:
cluster_name: ext-authz
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: 127.0.0.1
port_value: 10003
# This timeout controls the initial TCP handshake timeout - not the timeout for the
# entire request.
connect_timeout: 0.25s
Note
One of the features of this filter is to send HTTP request body to the configured gRPC authorization server as part of the check request.
A sample configuration is as follows:
http_filters:
- name: envoy.filters.http.ext_authz
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.http.ext_authz.v3.ExtAuthz
grpc_service:
envoy_grpc:
cluster_name: ext-authz
with_request_body:
max_request_bytes: 1024
allow_partial_message: true
pack_as_bytes: true
Please note that by default check request carries the HTTP request body as UTF-8 string and it fills the body field. To pack the request body as raw bytes, it is needed to set pack_as_bytes field to true. In effect to that, the raw_body field will be set and body field will be empty.
A sample filter configuration for a raw HTTP authorization server:
http_filters:
- name: envoy.filters.http.ext_authz
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.http.ext_authz.v3.ExtAuthz
http_service:
server_uri:
uri: 127.0.0.1:10003
cluster: ext-authz
timeout: 0.25s
failure_mode_allow: false
include_peer_certificate: true
clusters:
- name: ext-authz
connect_timeout: 0.25s
type: logical_dns
lb_policy: round_robin
load_assignment:
cluster_name: ext-authz
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: 127.0.0.1
port_value: 10003
Per-Route Configuration¶
A sample virtual host and route filter configuration. In this example we add additional context on the virtual host, and disabled the filter for /static prefixed routes.
route_config:
name: local_route
virtual_hosts:
- name: local_service
domains: ["*"]
typed_per_filter_config:
envoy.filters.http.ext_authz:
"@type": type.googleapis.com/envoy.extensions.filters.http.ext_authz.v3.ExtAuthzPerRoute
check_settings:
context_extensions:
virtual_host: local_service
routes:
- match: { prefix: "/static" }
route: { cluster: some_service }
typed_per_filter_config:
envoy.filters.http.ext_authz:
"@type": type.googleapis.com/envoy.extensions.filters.http.ext_authz.v3.ExtAuthzPerRoute
disabled: true
- match: { prefix: "/" }
route: { cluster: some_service }
Statistics¶
The HTTP filter outputs statistics in the cluster.<route target cluster>.ext_authz. namespace.
Name |
Type |
Description |
---|---|---|
ok |
Counter |
Total responses from the filter. |
error |
Counter |
Total errors (including timeouts) contacting the external service. |
timeout |
Counter |
Total timeouts contacting the external service (only counted when timeout is measured when check request is created). |
denied |
Counter |
Total responses from the authorizations service that were to deny the traffic. |
disabled |
Counter |
Total requests that are allowed without calling external services due to the filter is disabled. |
failure_mode_allowed |
Counter |
Total requests that were error(s) but were allowed through because of failure_mode_allow set to true. |
Dynamic Metadata¶
Note
The External Authorization filter emits dynamic metadata only when it is configured to use gRPC service as the authorization server.
The External Authorization filter emits dynamic metadata as an opaque google.protobuf.Struct
only when the gRPC authorization server returns a CheckResponse with a filled dynamic_metadata field.
Runtime¶
The fraction of requests for which the filter is enabled can be configured via the runtime_key value of the filter_enabled field.