Envoy Header-To-Metadata Filter

This filter is configured with rules that will be matched against requests. Each rule has either a header and can be triggered either when the header is present or missing.

The metadata can then be used for load balancing decisions, consumed from logs, etc.

A typical use case for this filter is to dynamically match requests with load balancer subsets. For this, a given header’s value would be extracted and attached to the request as dynamic metadata which would then be used to match a subset of endpoints.

A corresponding upstream cluster configuration could be:

This would then allow requests with the header set to be matched against endpoints with the corresponding version. Whereas requests with that header missing would be matched with the default endpoints.

Statistics

Currently, this filter generates no statistics.