External provider adapter protocol

External provider adapter protocol

protocol/provider/v1/provider.proto is executable, not an interface sketch. Run the included adapter and a second local InferQoS instance:

INFERQOS_ADAPTER_LISTEN=127.0.0.1:50051 \
  cargo run -p inferqos-provider-protocol --bin example-adapter
cargo run --bin inferqos -- serve --config examples/external-provider/demo.yaml

Version 1 defines unary Estimate and Health RPCs plus server-streaming Dispatch. Response headers/status are sent with the first chunk; body chunks remain bounded by HTTP/gRPC backpressure; final usage can arrive on any chunk for post-stream reconciliation. Authorization, cookies, and provider API keys are never forwarded to an external adapter as ordinary metadata.

Unix-domain sockets are preferred on one host. Plain TCP is rejected unless it resolves to loopback. Remote TCP configuration requires TLS with an explicit CA and domain; client certificate and key enable mTLS and must be configured together. Both encoding and decoding are capped at 16 MiB. Treat an adapter as privileged provider-facing code and isolate its filesystem and egress.

The protobuf package is inferqos.provider.v1. During InferQoS 0.x, additive fields preserve wire compatibility; breaking RPC or semantic changes require another protobuf package version.