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. Everything here is EXPERIMENTAL. 21package tap 22 23import ( 24 "golang.org/x/net/context" 25) 26 27// Info defines the relevant information needed by the handles. 28type Info struct { 29 // FullMethodName is the string of grpc method (in the format of 30 // /package.service/method). 31 FullMethodName string 32 // TODO: More to be added. 33} 34 35// ServerInHandle defines the function which runs before a new stream is created 36// on the server side. If it returns a non-nil error, the stream will not be 37// created and a RST_STREAM will be sent back to the client with REFUSED_STREAM. 38// The client will receive an RPC error "code = Unavailable, desc = stream 39// terminated by RST_STREAM with error code: REFUSED_STREAM". 40// 41// It's intended to be used in situations where you don't want to waste the 42// resources to accept the new stream (e.g. rate-limiting). And the content of 43// the error will be ignored and won't be sent back to the client. For other 44// general usages, please use interceptors. 45// 46// Note that it is executed in the per-connection I/O goroutine(s) instead of 47// per-RPC goroutine. Therefore, users should NOT have any 48// blocking/time-consuming work in this handle. Otherwise all the RPCs would 49// slow down. Also, for the same reason, this handle won't be called 50// concurrently by gRPC. 51type ServerInHandle func(ctx context.Context, info *Info) (context.Context, error) 52