common/prpc, tools/cmd/cproto: prpc client

common/prpc/codes.go

Index: common/prpc/codes.go
diff --git a/common/prpc/codes.go b/common/prpc/codes.go
new file mode 100644
index 0000000000000000000000000000000000000000..98100e4800863a40fb9c42574b532c540e8d11a6
--- /dev/null
+++ b/common/prpc/codes.go
@@ -0,0 +1,84 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package prpc
+
+import (
+	"net/http"
+
+	"google.golang.org/grpc/codes"
+)
+
+// This file maps gRPC codes to HTTP statuses and vice-versa.
+
+// codeToStatus maps gRPC codes to HTTP statuses.
+// This map may need to be corrected when
+// https://github.com/grpc/grpc-common/issues/210
+// is closed.
+var codeToStatus = map[codes.Code]int{

[dnj, 2016/01/21 07:44:28]

Why do we need a full mapping? We have the status code in the header unless the
pRPC server couldn't be reached. We should only have to map things sent outside
of pRPC Server (handful of 400s, 500s).

[nodir, 2016/01/22 00:47:24]

the {code->status} map is used in server/prpc. I've moved it from there to keep
the mapping in one file

+	codes.OK:                 http.StatusOK,
+	codes.Canceled:           http.StatusNoContent,
+	codes.Unknown:            http.StatusInternalServerError,
+	codes.InvalidArgument:    http.StatusBadRequest,
+	codes.DeadlineExceeded:   http.StatusServiceUnavailable,
+	codes.NotFound:           http.StatusNotFound,
+	codes.AlreadyExists:      http.StatusConflict,
+	codes.PermissionDenied:   http.StatusForbidden,
+	codes.Unauthenticated:    http.StatusUnauthorized,
+	codes.ResourceExhausted:  http.StatusServiceUnavailable,
+	codes.FailedPrecondition: http.StatusPreconditionFailed,
+	codes.Aborted:            http.StatusInternalServerError,
+	codes.OutOfRange:         http.StatusBadRequest,
+	codes.Unimplemented:      http.StatusNotImplemented,
+	codes.Internal:           http.StatusInternalServerError,
+	codes.Unavailable:        http.StatusServiceUnavailable,
+	codes.DataLoss:           http.StatusInternalServerError,
+}
+
+// CodeStatus maps gRPC codes to HTTP statuses.
+//
+// The behavior of this function may change when
+// https://github.com/grpc/grpc-common/issues/210
+// is closed.
+func CodeStatus(code codes.Code) (status int, ok bool) {
+	status, ok = codeToStatus[code]
+	return
+}
+
+// StatusCode maps HTTP statuses to gRPC codes.
+// Falls back to codes.Unknown.
+//
+// The behavior of this function may change when
+// https://github.com/grpc/grpc-common/issues/210
+// is closed.
+func StatusCode(status int) codes.Code {
+	switch {
+
+	case status >= 200 && status < 300:
+		return codes.OK
+
+	case status == http.StatusUnauthorized:
+		return codes.Unauthenticated
+	case status == http.StatusForbidden:
+		return codes.PermissionDenied
+	case status == http.StatusNotFound:
+		return codes.NotFound
+	case status == http.StatusGone:
+		return codes.NotFound
+	case status == http.StatusPreconditionFailed:
+		return codes.FailedPrecondition
+	case status >= 400 && status < 500:
+		return codes.InvalidArgument
+
+	case status == http.StatusNotImplemented:
+		return codes.Unimplemented
+	case status == http.StatusServiceUnavailable:
+		return codes.Unavailable
+	case status >= 500 && status < 600:
+		return codes.Internal
+
+	default:
+		return codes.Unknown
+	}
+}