diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer/roundrobin')
-rw-r--r-- | vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go b/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go new file mode 100644 index 0000000..57aea9f --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go | |||
@@ -0,0 +1,79 @@ | |||
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 roundrobin defines a roundrobin balancer. Roundrobin balancer is | ||
20 | // installed as one of the default balancers in gRPC, users don't need to | ||
21 | // explicitly install this balancer. | ||
22 | package roundrobin | ||
23 | |||
24 | import ( | ||
25 | "context" | ||
26 | "sync" | ||
27 | |||
28 | "google.golang.org/grpc/balancer" | ||
29 | "google.golang.org/grpc/balancer/base" | ||
30 | "google.golang.org/grpc/grpclog" | ||
31 | "google.golang.org/grpc/resolver" | ||
32 | ) | ||
33 | |||
34 | // Name is the name of round_robin balancer. | ||
35 | const Name = "round_robin" | ||
36 | |||
37 | // newBuilder creates a new roundrobin balancer builder. | ||
38 | func newBuilder() balancer.Builder { | ||
39 | return base.NewBalancerBuilderWithConfig(Name, &rrPickerBuilder{}, base.Config{HealthCheck: true}) | ||
40 | } | ||
41 | |||
42 | func init() { | ||
43 | balancer.Register(newBuilder()) | ||
44 | } | ||
45 | |||
46 | type rrPickerBuilder struct{} | ||
47 | |||
48 | func (*rrPickerBuilder) Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker { | ||
49 | grpclog.Infof("roundrobinPicker: newPicker called with readySCs: %v", readySCs) | ||
50 | var scs []balancer.SubConn | ||
51 | for _, sc := range readySCs { | ||
52 | scs = append(scs, sc) | ||
53 | } | ||
54 | return &rrPicker{ | ||
55 | subConns: scs, | ||
56 | } | ||
57 | } | ||
58 | |||
59 | type rrPicker struct { | ||
60 | // subConns is the snapshot of the roundrobin balancer when this picker was | ||
61 | // created. The slice is immutable. Each Get() will do a round robin | ||
62 | // selection from it and return the selected SubConn. | ||
63 | subConns []balancer.SubConn | ||
64 | |||
65 | mu sync.Mutex | ||
66 | next int | ||
67 | } | ||
68 | |||
69 | func (p *rrPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { | ||
70 | if len(p.subConns) <= 0 { | ||
71 | return nil, nil, balancer.ErrNoSubConnAvailable | ||
72 | } | ||
73 | |||
74 | p.mu.Lock() | ||
75 | sc := p.subConns[p.next] | ||
76 | p.next = (p.next + 1) % len(p.subConns) | ||
77 | p.mu.Unlock() | ||
78 | return sc, nil, nil | ||
79 | } | ||