Proposal: Add dynamic metadata to rate limit actions

[clarakosi]

Description: Currently to pass information from the dynamic metadata to the rate limit actions one would need to use the Lua filter to append a header with the relevant information. Instead, it would be more useful to be able to use the dynamic metadata directly as one of the actions of the rate limiter.

The action can follow the current MetaData schema[1] to get the value:

actions:
  - { dynamic_metadata: { key: “…”, path: [] } }

key: The key name of metadata to retrieve the Struct from the metadata.
path: The path to retrieve the value from the Struct

Links:

1. https://www.envoyproxy.io/docs/envoy/latest/api-v3/type/metadata/v3/metadata.proto.html

[htuch]

Seems reasonable functionality; how will a value in the action be interpreted?

[clarakosi]

I think we can interpret it the same way we interpret the values from the other actions.

[htuch]

SGTM, should I assign this to you?

[clarakosi]

Yes, thanks!