1/*
 2 *
 3 * Copyright 2014 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 peer defines various peer information associated with RPCs and
20// corresponding utils.
21package peer
22
23import (
24	"context"
25	"fmt"
26	"net"
27	"strings"
28
29	"google.golang.org/grpc/credentials"
30)
31
32// Peer contains the information of the peer for an RPC, such as the address
33// and authentication information.
34type Peer struct {
35	// Addr is the peer address.
36	Addr net.Addr
37	// LocalAddr is the local address.
38	LocalAddr net.Addr
39	// AuthInfo is the authentication information of the transport.
40	// It is nil if there is no transport security being used.
41	AuthInfo credentials.AuthInfo
42}
43
44// String ensures the Peer types implements the Stringer interface in order to
45// allow to print a context with a peerKey value effectively.
46func (p *Peer) String() string {
47	if p == nil {
48		return "Peer<nil>"
49	}
50	sb := &strings.Builder{}
51	sb.WriteString("Peer{")
52	if p.Addr != nil {
53		fmt.Fprintf(sb, "Addr: '%s', ", p.Addr.String())
54	} else {
55		fmt.Fprintf(sb, "Addr: <nil>, ")
56	}
57	if p.LocalAddr != nil {
58		fmt.Fprintf(sb, "LocalAddr: '%s', ", p.LocalAddr.String())
59	} else {
60		fmt.Fprintf(sb, "LocalAddr: <nil>, ")
61	}
62	if p.AuthInfo != nil {
63		fmt.Fprintf(sb, "AuthInfo: '%s'", p.AuthInfo.AuthType())
64	} else {
65		fmt.Fprintf(sb, "AuthInfo: <nil>")
66	}
67	sb.WriteString("}")
68
69	return sb.String()
70}
71
72type peerKey struct{}
73
74// NewContext creates a new context with peer information attached.
75func NewContext(ctx context.Context, p *Peer) context.Context {
76	return context.WithValue(ctx, peerKey{}, p)
77}
78
79// FromContext returns the peer information in ctx if it exists.
80func FromContext(ctx context.Context) (p *Peer, ok bool) {
81	p, ok = ctx.Value(peerKey{}).(*Peer)
82	return
83}