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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