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		BuildCallback:      func(resolver.Target, resolver.ClientConn, resolver.BuildOptions) {},
31		ResolveNowCallback: func(resolver.ResolveNowOptions) {},
32		CloseCallback:      func() {},
33		scheme:             scheme,
34	}
35}
36
37// Resolver is also a resolver builder.
38// It's build() function always returns itself.
39type Resolver struct {
40	// BuildCallback is called when the Build method is called.  Must not be
41	// nil.  Must not be changed after the resolver may be built.
42	BuildCallback func(resolver.Target, resolver.ClientConn, resolver.BuildOptions)
43	// ResolveNowCallback is called when the ResolveNow method is called on the
44	// resolver.  Must not be nil.  Must not be changed after the resolver may
45	// be built.
46	ResolveNowCallback func(resolver.ResolveNowOptions)
47	// CloseCallback is called when the Close method is called.  Must not be
48	// nil.  Must not be changed after the resolver may be built.
49	CloseCallback func()
50	scheme        string
51
52	// Fields actually belong to the resolver.
53	CC             resolver.ClientConn
54	bootstrapState *resolver.State
55}
56
57// InitialState adds initial state to the resolver so that UpdateState doesn't
58// need to be explicitly called after Dial.
59func (r *Resolver) InitialState(s resolver.State) {
60	r.bootstrapState = &s
61}
62
63// Build returns itself for Resolver, because it's both a builder and a resolver.
64func (r *Resolver) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
65	r.BuildCallback(target, cc, opts)
66	r.CC = cc
67	if r.bootstrapState != nil {
68		r.UpdateState(*r.bootstrapState)
69	}
70	return r, nil
71}
72
73// Scheme returns the test scheme.
74func (r *Resolver) Scheme() string {
75	return r.scheme
76}
77
78// ResolveNow is a noop for Resolver.
79func (r *Resolver) ResolveNow(o resolver.ResolveNowOptions) {
80	r.ResolveNowCallback(o)
81}
82
83// Close is a noop for Resolver.
84func (r *Resolver) Close() {
85	r.CloseCallback()
86}
87
88// UpdateState calls CC.UpdateState.
89func (r *Resolver) UpdateState(s resolver.State) {
90	r.CC.UpdateState(s)
91}
92
93// ReportError calls CC.ReportError.
94func (r *Resolver) ReportError(err error) {
95	r.CC.ReportError(err)
96}
97