diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer/base/balancer.go')
-rw-r--r-- | vendor/google.golang.org/grpc/balancer/base/balancer.go | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/balancer/base/balancer.go b/vendor/google.golang.org/grpc/balancer/base/balancer.go new file mode 100644 index 0000000..245785e --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer/base/balancer.go | |||
@@ -0,0 +1,171 @@ | |||
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 base | ||
20 | |||
21 | import ( | ||
22 | "context" | ||
23 | |||
24 | "google.golang.org/grpc/balancer" | ||
25 | "google.golang.org/grpc/connectivity" | ||
26 | "google.golang.org/grpc/grpclog" | ||
27 | "google.golang.org/grpc/resolver" | ||
28 | ) | ||
29 | |||
30 | type baseBuilder struct { | ||
31 | name string | ||
32 | pickerBuilder PickerBuilder | ||
33 | config Config | ||
34 | } | ||
35 | |||
36 | func (bb *baseBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer { | ||
37 | return &baseBalancer{ | ||
38 | cc: cc, | ||
39 | pickerBuilder: bb.pickerBuilder, | ||
40 | |||
41 | subConns: make(map[resolver.Address]balancer.SubConn), | ||
42 | scStates: make(map[balancer.SubConn]connectivity.State), | ||
43 | csEvltr: &balancer.ConnectivityStateEvaluator{}, | ||
44 | // Initialize picker to a picker that always return | ||
45 | // ErrNoSubConnAvailable, because when state of a SubConn changes, we | ||
46 | // may call UpdateBalancerState with this picker. | ||
47 | picker: NewErrPicker(balancer.ErrNoSubConnAvailable), | ||
48 | config: bb.config, | ||
49 | } | ||
50 | } | ||
51 | |||
52 | func (bb *baseBuilder) Name() string { | ||
53 | return bb.name | ||
54 | } | ||
55 | |||
56 | type baseBalancer struct { | ||
57 | cc balancer.ClientConn | ||
58 | pickerBuilder PickerBuilder | ||
59 | |||
60 | csEvltr *balancer.ConnectivityStateEvaluator | ||
61 | state connectivity.State | ||
62 | |||
63 | subConns map[resolver.Address]balancer.SubConn | ||
64 | scStates map[balancer.SubConn]connectivity.State | ||
65 | picker balancer.Picker | ||
66 | config Config | ||
67 | } | ||
68 | |||
69 | func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) { | ||
70 | if err != nil { | ||
71 | grpclog.Infof("base.baseBalancer: HandleResolvedAddrs called with error %v", err) | ||
72 | return | ||
73 | } | ||
74 | grpclog.Infoln("base.baseBalancer: got new resolved addresses: ", addrs) | ||
75 | // addrsSet is the set converted from addrs, it's used for quick lookup of an address. | ||
76 | addrsSet := make(map[resolver.Address]struct{}) | ||
77 | for _, a := range addrs { | ||
78 | addrsSet[a] = struct{}{} | ||
79 | if _, ok := b.subConns[a]; !ok { | ||
80 | // a is a new address (not existing in b.subConns). | ||
81 | sc, err := b.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{HealthCheckEnabled: b.config.HealthCheck}) | ||
82 | if err != nil { | ||
83 | grpclog.Warningf("base.baseBalancer: failed to create new SubConn: %v", err) | ||
84 | continue | ||
85 | } | ||
86 | b.subConns[a] = sc | ||
87 | b.scStates[sc] = connectivity.Idle | ||
88 | sc.Connect() | ||
89 | } | ||
90 | } | ||
91 | for a, sc := range b.subConns { | ||
92 | // a was removed by resolver. | ||
93 | if _, ok := addrsSet[a]; !ok { | ||
94 | b.cc.RemoveSubConn(sc) | ||
95 | delete(b.subConns, a) | ||
96 | // Keep the state of this sc in b.scStates until sc's state becomes Shutdown. | ||
97 | // The entry will be deleted in HandleSubConnStateChange. | ||
98 | } | ||
99 | } | ||
100 | } | ||
101 | |||
102 | // regeneratePicker takes a snapshot of the balancer, and generates a picker | ||
103 | // from it. The picker is | ||
104 | // - errPicker with ErrTransientFailure if the balancer is in TransientFailure, | ||
105 | // - built by the pickerBuilder with all READY SubConns otherwise. | ||
106 | func (b *baseBalancer) regeneratePicker() { | ||
107 | if b.state == connectivity.TransientFailure { | ||
108 | b.picker = NewErrPicker(balancer.ErrTransientFailure) | ||
109 | return | ||
110 | } | ||
111 | readySCs := make(map[resolver.Address]balancer.SubConn) | ||
112 | |||
113 | // Filter out all ready SCs from full subConn map. | ||
114 | for addr, sc := range b.subConns { | ||
115 | if st, ok := b.scStates[sc]; ok && st == connectivity.Ready { | ||
116 | readySCs[addr] = sc | ||
117 | } | ||
118 | } | ||
119 | b.picker = b.pickerBuilder.Build(readySCs) | ||
120 | } | ||
121 | |||
122 | func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) { | ||
123 | grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s) | ||
124 | oldS, ok := b.scStates[sc] | ||
125 | if !ok { | ||
126 | grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s) | ||
127 | return | ||
128 | } | ||
129 | b.scStates[sc] = s | ||
130 | switch s { | ||
131 | case connectivity.Idle: | ||
132 | sc.Connect() | ||
133 | case connectivity.Shutdown: | ||
134 | // When an address was removed by resolver, b called RemoveSubConn but | ||
135 | // kept the sc's state in scStates. Remove state for this sc here. | ||
136 | delete(b.scStates, sc) | ||
137 | } | ||
138 | |||
139 | oldAggrState := b.state | ||
140 | b.state = b.csEvltr.RecordTransition(oldS, s) | ||
141 | |||
142 | // Regenerate picker when one of the following happens: | ||
143 | // - this sc became ready from not-ready | ||
144 | // - this sc became not-ready from ready | ||
145 | // - the aggregated state of balancer became TransientFailure from non-TransientFailure | ||
146 | // - the aggregated state of balancer became non-TransientFailure from TransientFailure | ||
147 | if (s == connectivity.Ready) != (oldS == connectivity.Ready) || | ||
148 | (b.state == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) { | ||
149 | b.regeneratePicker() | ||
150 | } | ||
151 | |||
152 | b.cc.UpdateBalancerState(b.state, b.picker) | ||
153 | } | ||
154 | |||
155 | // Close is a nop because base balancer doesn't have internal state to clean up, | ||
156 | // and it doesn't need to call RemoveSubConn for the SubConns. | ||
157 | func (b *baseBalancer) Close() { | ||
158 | } | ||
159 | |||
160 | // NewErrPicker returns a picker that always returns err on Pick(). | ||
161 | func NewErrPicker(err error) balancer.Picker { | ||
162 | return &errPicker{err: err} | ||
163 | } | ||
164 | |||
165 | type errPicker struct { | ||
166 | err error // Pick() always returns this err. | ||
167 | } | ||
168 | |||
169 | func (p *errPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { | ||
170 | return nil, nil, p.err | ||
171 | } | ||