Changed to use more appropriate http status code for ResourceExhausted (

grpc-ecosystem#580)

* Adjust status codes to match googleapis code.proto

examples/integration_test.go

@@ -719,7 +719,7 @@ func TestTimeout(t *testing.T) {
 	}
 	defer resp.Body.Close()
 
-	if got, want := resp.StatusCode, http.StatusRequestTimeout; got != want {
+	if got, want := resp.StatusCode, http.StatusGatewayTimeout; got != want {
 		t.Errorf("resp.StatusCode = %d; want %d", got, want)
 	}
 }

runtime/errors.go

@@ -14,6 +14,7 @@ import (
 )
 
 // HTTPStatusFromCode converts a gRPC error code into the corresponding HTTP response status.
+// See: https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto
 func HTTPStatusFromCode(code codes.Code) int {
 	switch code {
 	case codes.OK:
@@ -25,7 +26,7 @@ func HTTPStatusFromCode(code codes.Code) int {
 	case codes.InvalidArgument:
 		return http.StatusBadRequest
 	case codes.DeadlineExceeded:
-		return http.StatusRequestTimeout
+		return http.StatusGatewayTimeout
 	case codes.NotFound:
 		return http.StatusNotFound
 	case codes.AlreadyExists:
@@ -35,9 +36,9 @@ func HTTPStatusFromCode(code codes.Code) int {
 	case codes.Unauthenticated:
 		return http.StatusUnauthorized
 	case codes.ResourceExhausted:
-		return http.StatusServiceUnavailable
+		return http.StatusTooManyRequests
 	case codes.FailedPrecondition:
-		return http.StatusPreconditionFailed
+		return http.StatusBadRequest
 	case codes.Aborted:
 		return http.StatusConflict
 	case codes.OutOfRange: