Set-Filter-State Listener Filter

  • This filter should be configured with the type URL type.googleapis.com/envoy.extensions.filters.listener.set_filter_state.v3.Config.

  • v3 API reference

This filter is configured with a sequence of values to update the connection filter state using the connection metadata prior to network filter chains. The filter state value can then be used for routing, load balancing decisions, telemetry, etc. See the well-known filter state keys for the controls used by Envoy extensions.

The filter applies values at the following point in the connection lifecycle:

  • on_accept: applied when a new downstream socket is accepted.

Warning

This filter allows overriding the behavior of other extensions and significantly and indirectly altering the connection processing logic.

Examples

A sample filter configuration using a custom key with the generic string factory. Use this pattern when you want to store arbitrary connection data under a custom name:

on_accept:
- object_key: my.custom.client_address
  factory_key: envoy.string
  format_string:
    text_format_source:
      inline_string: "%DOWNSTREAM_REMOTE_ADDRESS%"

The stored value can then be accessed in access logs using %FILTER_STATE(my.custom.client_address)%.

Statistics

Currently, this filter generates no statistics.