Envoy: health check filter: cache response body

[snowp]

Currently the health check filter only caches the status code of health checks. It would be nice to be able to cache the entire response body to allow other clients that might care about the body go through envoy and the health checking filter.

[zyfjeff]

@mattklein123 Someone to do it?If not I'd be glad to

[mattklein123]

Sure @zyfjeff feel free to work on it.

[jmarantz]

FYI I am working on a design for a general caching infrastructure for Envoy. Health-check caching could be an interest application beyond general http response caching.

Color me subscribed to this; maybe we can collaborate if we you are still interested.

[jmarantz]

Also see https://github.com/envoyproxy/envoy/issues/868
and https://github.com/envoyproxy/envoy/issues/3023

[qiang-nutanix]

@jmarantz I am interested the "a general caching infrastructure for Envoy". I am looking for (or need to create) an AuthZ filter, which either accepts or denies the incoming request based on a set of policies; the AuthZ policy data is cached locally and updated periodically from external source. But based on envoy thread model: "Once a connection is accepted by a listener, the connection spends the rest of its lifetime bound to a single worker thread", how can this AuthZ filter running at different worker threads share same policy data? So, I guess your caching feature is what is needed. Can you share your thought or design if it is okay?