1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
/*
*
* Copyright 2024 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package gracefulswitch
import (
"encoding/json"
"fmt"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/serviceconfig"
)
type lbConfig struct {
serviceconfig.LoadBalancingConfig
childBuilder balancer.Builder
childConfig serviceconfig.LoadBalancingConfig
}
// ChildName returns the name of the child balancer of the gracefulswitch
// Balancer.
func ChildName(l serviceconfig.LoadBalancingConfig) string {
return l.(*lbConfig).childBuilder.Name()
}
// ParseConfig parses a child config list and returns a LB config for the
// gracefulswitch Balancer.
//
// cfg is expected to be a json.RawMessage containing a JSON array of LB policy
// names + configs as the format of the "loadBalancingConfig" field in
// ServiceConfig. It returns a type that should be passed to
// UpdateClientConnState in the BalancerConfig field.
func ParseConfig(cfg json.RawMessage) (serviceconfig.LoadBalancingConfig, error) {
var lbCfg []map[string]json.RawMessage
if err := json.Unmarshal(cfg, &lbCfg); err != nil {
return nil, err
}
for i, e := range lbCfg {
if len(e) != 1 {
return nil, fmt.Errorf("expected a JSON struct with one entry; received entry %v at index %d", e, i)
}
var name string
var jsonCfg json.RawMessage
for name, jsonCfg = range e {
}
builder := balancer.Get(name)
if builder == nil {
// Skip unregistered balancer names.
continue
}
parser, ok := builder.(balancer.ConfigParser)
if !ok {
// This is a valid child with no config.
return &lbConfig{childBuilder: builder}, nil
}
cfg, err := parser.ParseConfig(jsonCfg)
if err != nil {
return nil, fmt.Errorf("error parsing config for policy %q: %v", name, err)
}
return &lbConfig{childBuilder: builder, childConfig: cfg}, nil
}
return nil, fmt.Errorf("no supported policies found in config: %v", string(cfg))
}
|
