grpc-caching-interceptors

gRPC caching interceptors

Interceptors used to make gRPC caching-aware. Used in "Towards soft circuit breaking in service meshes via application-agnostic caching".

The client/ directory contains the interceptor you want to use to get a simple TTL-abiding Cache component. See the Value Service Caching Component repo for how to use the code. You may want to use the reverse proxy that our modified Protobuf compiler gives you, but should not have to.

The server/ directory contains the interceptor that lets you estimate how long a response is valid. You can affect how this estimate is produced by setting the following environment variables for your program that includes the interceptor:

• PROXY_CACHE_BLACKLIST should be a regular expression that blacklists operations in your gRPC service from caching (they will not be assigned a caching header, and thus, not cached).
• PROXY_MAX_AGE should be set to one of the following values (if not possible to parse, the Estimator will act in pass-through mode and just not assign a TTL to responses):
  • static-N, where N is the number of seconds to statically always respond with, e.g., static-10 for 10 second TTL for every response object.
  • dynamic-adaptive-N, where N is the parameter to the Adaptive TTL algorithm (read the paper).
  • dynamic-updaterisk-N, where N is the parameter to the Update-risk based algorithm (read the paper).

See the Value Service Estimator Component repo for how to use the code. As with the Caching interceptor, you may want to use the reverse proxy that our modified Protobuf compiler gives you, but (again!) should not have to.