1/*
2 *
3 * Copyright 2019 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 weightedroundrobin defines a weighted roundrobin balancer.
20package weightedroundrobin
21
22import (
23	"google.golang.org/grpc/resolver"
24)
25
26// Name is the name of weighted_round_robin balancer.
27const Name = "weighted_round_robin"
28
29// attributeKey is the type used as the key to store AddrInfo in the Attributes
30// field of resolver.Address.
31type attributeKey struct{}
32
33// AddrInfo will be stored inside Address metadata in order to use weighted
34// roundrobin balancer.
35type AddrInfo struct {
36	Weight uint32
37}
38
39// Equal allows the values to be compared by Attributes.Equal.
40func (a AddrInfo) Equal(o interface{}) bool {
41	oa, ok := o.(AddrInfo)
42	return ok && oa.Weight == a.Weight
43}
44
45// SetAddrInfo returns a copy of addr in which the Attributes field is updated
46// with addrInfo.
47//
48// Experimental
49//
50// Notice: This API is EXPERIMENTAL and may be changed or removed in a
51// later release.
52func SetAddrInfo(addr resolver.Address, addrInfo AddrInfo) resolver.Address {
53	addr.BalancerAttributes = addr.BalancerAttributes.WithValue(attributeKey{}, addrInfo)
54	return addr
55}
56
57// GetAddrInfo returns the AddrInfo stored in the Attributes fields of addr.
58//
59// Experimental
60//
61// Notice: This API is EXPERIMENTAL and may be changed or removed in a
62// later release.
63func GetAddrInfo(addr resolver.Address) AddrInfo {
64	v := addr.BalancerAttributes.Value(attributeKey{})
65	ai, _ := v.(AddrInfo)
66	return ai
67}
68