1/*
2 *
3 * Copyright 2017 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 manual defines a resolver that can be used to manually send resolved
20// addresses to ClientConn.
21package manual
22
23import (
24	"google.golang.org/grpc/resolver"
25)
26
27// NewBuilderWithScheme creates a new test resolver builder with the given scheme.
28func NewBuilderWithScheme(scheme string) *Resolver {
29	return &Resolver{
30		ResolveNowCallback: func(resolver.ResolveNowOptions) {},
31		scheme:             scheme,
32	}
33}
34
35// Resolver is also a resolver builder.
36// It's build() function always returns itself.
37type Resolver struct {
38	// ResolveNowCallback is called when the ResolveNow method is called on the
39	// resolver.  Must not be nil.  Must not be changed after the resolver may
40	// be built.
41	ResolveNowCallback func(resolver.ResolveNowOptions)
42	scheme             string
43
44	// Fields actually belong to the resolver.
45	CC             resolver.ClientConn
46	bootstrapState *resolver.State
47}
48
49// InitialState adds initial state to the resolver so that UpdateState doesn't
50// need to be explicitly called after Dial.
51func (r *Resolver) InitialState(s resolver.State) {
52	r.bootstrapState = &s
53}
54
55// Build returns itself for Resolver, because it's both a builder and a resolver.
56func (r *Resolver) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
57	r.CC = cc
58	if r.bootstrapState != nil {
59		r.UpdateState(*r.bootstrapState)
60	}
61	return r, nil
62}
63
64// Scheme returns the test scheme.
65func (r *Resolver) Scheme() string {
66	return r.scheme
67}
68
69// ResolveNow is a noop for Resolver.
70func (r *Resolver) ResolveNow(o resolver.ResolveNowOptions) {
71	r.ResolveNowCallback(o)
72}
73
74// Close is a noop for Resolver.
75func (*Resolver) Close() {}
76
77// UpdateState calls CC.UpdateState.
78func (r *Resolver) UpdateState(s resolver.State) {
79	r.CC.UpdateState(s)
80}
81