Extension SDK for Direct Policies

[philbrookes]

Summary

The Extension SDK enables extensions to dynamically register any gRPC service and orchestrate multi-phase calls during request processing. The SDK will be leveraging gRPC Server Reflection to discover schemas automatically, so extensions don't need to provide proto files, and wasm-shim converts CEL expressions to protobuf messages dynamically. Extensions become self-service - call RegisterService(), define OnRequest and OnResponse logic with metadata passing between phases, and it works without touching wasm-shim.

Once the extension sdk will have this capabilities, the existing TokenRateLimitPolicy will benefit from the multi-phase orchestration in order to comply with the functional requirements. Hence, a "migration" of the policy with the new extension will also be part of the epic's goal.

Sub-issues

Register Upstream

Document tracking proposal and work found here

• Extend RegisteredDataStore with upstream storage - Extend RegisteredDataStore with upstream storage kuadrant-operator#1790
• Implement server-side RegisterUpstreamMethod handler - Implement server-side RegisterUpstreamMethod handler kuadrant-operator#1791
• Add RegisterUpstreamMethod RPC to gRPC proto - Add RegisterUpstreamMethod RPC to gRPC proto kuadrant-operator#1792
• Implement client-side RegisterUpstreamMethod on ExtensionController - Implement client-side RegisterUpstreamMethod on ExtensionController kuadrant-operator#1795
• Add RegisterUpstreamMethod to KuadranctCtx interface and UpstreamConfig type - Add RegisterUpstreamMethod to KuadrantCtx interface and UpstreamConfig type kuadrant-operator#1796
• Create RegisterUpstreamMethod demo walkthrough and interactive script - Create RegisterUpstreamMethod demo walkthrough and interactive script kuadrant-operator#1797

gRPC Reflection and Dynamic Message Building

Document tracking proposal and work found here

• Operator reflection and caching - Operator Reflection and Caching kuadrant-operator#1841
• Operator reflection and caching - Operator Descriptor Service kuadrant-operator#1842
• Dynamic Service Type - Dynamic Service Type wasm-shim#319
• Descriptor fetching - Descriptor Fetching wasm-shim#320

Action Pipeline

Document tracking proposal and work found here

• Rename RegisterUpstreamMethod to RegisterActionMethod - Rename RegisterUpstreamMethod to RegisterActionMethod kuadrant-operator#1899
• Add ActionMethodConfig with Name and MessageTemplate fields - Add ActionMethodConfig with Name and MessageTemplate fields kuadrant-operator#1900
• Define action types and Pipeline interface - Define action types and Pipeline interface kuadrant-operator#1901
• Add PipelineOnRequest and PipelineOnResponse RPCs to gRPC proto - Add PipelineOnRequest and PipelineOnResponse RPCs to gRPC proto kuadrant-operator#1902
• Implement PipelineActionStore - Implement PipelineActionStore kuadrant-operator#1903
• Implement server-side pipeline handlers with CEL intention validation - Implement server-side pipeline handlers with CEL intention validation kuadrant-operator#1904
• Implement client-side NewPipeline and PipelineImpl - Implement client-side NewPipeline and PipelineImpl kuadrant-operator#1905
• Add ActionType discriminator to wasm Action struct - Add ActionType discriminator to wasm Action struct kuadrant-operator#1906
• Extend extension reconcilers for pipeline action to wasm Action translation - Extend extension reconcilers for pipeline action to wasm Action translation kuadrant-operator#1907
• Update wasm-shim to dispatch on ActionType - Update wasm-shim to dispatch on ActionType kuadrant-operator#1908