1 /*
2 *
3 * Copyright 2020 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 state declares grpclb types to be set by resolvers wishing to pass
20 // information to grpclb via resolver.State Attributes.
21 package state
22 23 import (
24 "google.golang.org/grpc/resolver"
25 )
26 27 // keyType is the key to use for storing State in Attributes.
28 type keyType string
29 30 const key = keyType("grpc.grpclb.state")
31 32 // State contains gRPCLB-relevant data passed from the name resolver.
33 type State struct {
34 // BalancerAddresses contains the remote load balancer address(es). If
35 // set, overrides any resolver-provided addresses with Type of GRPCLB.
36 BalancerAddresses []resolver.Address
37 }
38 39 // Set returns a copy of the provided state with attributes containing s. s's
40 // data should not be mutated after calling Set.
41 func Set(state resolver.State, s *State) resolver.State {
42 state.Attributes = state.Attributes.WithValue(key, s)
43 return state
44 }
45 46 // Get returns the grpclb State in the resolver.State, or nil if not present.
47 // The returned data should not be mutated.
48 func Get(state resolver.State) *State {
49 s, _ := state.Attributes.Value(key).(*State)
50 return s
51 }
52