[tonyalaribe]

Every integration in this SDK is an HTTP middleware, so a gRPC service gets no request or response payloads at all — and in Go, gRPC is frequently a service's only protocol.

server := grpc.NewServer(grpc.UnaryInterceptor(
    monoscopegrpc.UnaryServerInterceptor(monoscopegrpc.Config{
        ServiceName:        "payment",
        CaptureRequestBody: true,
        RedactRequestBody:  []string{"$.creditCard.creditCardNumber"},
    }),
))

google.golang.org/grpc was already an indirect dependency, so promoting it to direct costs nothing new.

protojson, not encoding/json

For anything that is a proto.Message, marshalling goes through protojson: it applies the field names declared in the .proto and renders 64-bit fields as strings. encoding/json on a generated struct leaks the generator's internal state and produces field names that would not match a redaction path the user wrote against their schema. Same class of problem the JS SDK hit, where protobuf int64 arrived as {low, high, unsigned}.

Attributes

rpc.system / rpc.method / rpc.grpc.status_code are set alongside the HTTP-shaped fields, not instead of them. The server lifts bodies based on the HTTP shape, but a gRPC status says more than ok-or-not — NOT_FOUND and PERMISSION_DENIED both flatten to 500 — so the real code is kept for the UI to filter on natively later.

Scope

Unary only. Streaming has no single message to capture, so a stream interceptor would record nothing while appearing to work — better to say so than to ship a silent no-op.

Tests

Cover the parts that matter, not just the happy path: response and error reach the caller untouched, a sensitive field in a decoded message is redacted, the gRPC code survives unflattened, capture-off records nothing, and an unmarshalable message degrades to no body. That last one caught a real wart — RedactJSON turns nil into the literal null, which would have been captured as a body reading "null".

Cross-language plan: docs/grpc-sdk-support.md in the monoscope repo. The Node equivalent shipped as @monoscopetech/common@1.3.1 and is deployed in the demo's payment service.