1/* 2 * 3 * Copyright 2016 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19// Package tap defines the function handles which are executed on the transport 20// layer of gRPC-Go and related information. 21// 22// Experimental 23// 24// Notice: This API is EXPERIMENTAL and may be changed or removed in a 25// later release. 26package tap 27 28import ( 29 "context" 30) 31 32// Info defines the relevant information needed by the handles. 33type Info struct { 34 // FullMethodName is the string of grpc method (in the format of 35 // /package.service/method). 36 FullMethodName string 37 // TODO: More to be added. 38} 39 40// ServerInHandle defines the function which runs before a new stream is 41// created on the server side. If it returns a non-nil error, the stream will 42// not be created and an error will be returned to the client. If the error 43// returned is a status error, that status code and message will be used, 44// otherwise PermissionDenied will be the code and err.Error() will be the 45// message. 46// 47// It's intended to be used in situations where you don't want to waste the 48// resources to accept the new stream (e.g. rate-limiting). For other general 49// usages, please use interceptors. 50// 51// Note that it is executed in the per-connection I/O goroutine(s) instead of 52// per-RPC goroutine. Therefore, users should NOT have any 53// blocking/time-consuming work in this handle. Otherwise all the RPCs would 54// slow down. Also, for the same reason, this handle won't be called 55// concurrently by gRPC. 56type ServerInHandle func(ctx context.Context, info *Info) (context.Context, error) 57