DcsvIo.D2.Result.Grpc 0.1.1

DcsvIo.D2.Result.Grpc

Faithful in-memory → wire → in-memory D2Result round-trip over a gRPC D2ResultProto response envelope. Every service handler returns a D2Result as-is; the framework wraps it; the consumer re-materializes an equal D2Result on the other side — zero caller try-catch for business failures.

Install

dotnet add package DcsvIo.D2.Result.Grpc

Core API

// Server side: wrap
var response = new FindThingsResponse
{
    Result = result.ToProto(),
};
response.Data.AddRange(things);
return response;

// Consumer side: re-materialize
var res = await client.FindThings(req).HandleAsync(r => r.Result, r => r.Data);
if (res.Category == ErrorCategory.NotFound) { /* typed, no registry lookup */ }
res.StatusCode == HttpStatusCode.Conflict; // exact HTTP status, not a lossy gRPC bucket

Key properties

• Full fidelity: every field — Success, StatusCode (exact integer), ErrorCode, Category, Messages (key + params), InputErrors, TraceId, Data — round-trips equal.
• Typed ErrorCategory: populated by factories at generation time. ErrorCategory.NotFound is available directly on the rebuilt result; no runtime registry lookup on the hot path.
• TKMessageProto: structured message carrier (key + map<string,string> params). Full parameter fidelity — a TKMessage with substitution bindings survives the round-trip unchanged.
• Transport fault fail-open: RpcException → ServiceUnavailable; Cancelled → Canceled; any other Exception → UnhandledException. User-facing messages stay the factory TK constants — never raw transport strings.
• PII-safe logging: [LoggerMessage] signatures do NOT accept Exception. Transport detail is logged via SanitizedExceptionRender.TypeName + FirstFrame + StatusCode — never ex.Message (which can embed AMQP URIs, JWT contents, configured secrets).
• IsTransientGrpcException: classifies DeadlineExceeded, ResourceExhausted, Aborted, Internal, Unavailable as transient for retry callers.

Wire mechanism boundary

Two mechanisms coexist on every gRPC call — each has a distinct role and must not be conflated:

Boundary rule: a 401 from the JWT interceptor is RpcException(Unauthenticated) — never a D2ResultProto{ success=false, status_code=401 }. A 404 from a handler is D2ResultProto{ success=false, status_code=404 } — never an RpcException. The two paths are structurally separate and must stay that way.

Proto contract

The shared d2_result.proto contract is the single source of truth. Generated D2ResultProto / TKMessageProto / InputErrorProto types live in namespace D2.Services.Protos.Common.V1.

Dependencies

• DcsvIo.D2.Result — result-core (D2Result, InputError, TKMessage surface)
• DcsvIo.D2.ErrorCodes.Category — ErrorCategory, ErrorCategoryWire
• DcsvIo.D2.Utilities — Falsey() null-guard
• DcsvIo.D2.I18n.Abstractions — TKMessage ctor (InternalsVisibleTo)
• Google.Protobuf — proto runtime
• Grpc.Net.Client — AsyncUnaryCall<T>, RpcException