blob: 34b1f2994a7d69a85c9285fa1ed074915abfd134 [file] [log] [blame]
Holger Hildebrandtfa074992020-03-27 15:42:06 +00001/*
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 defines a balancer base that can be used to build balancers with
20// different picking algorithms.
21//
22// The base balancer creates a new SubConn for each resolved address. The
23// provided picker will only be notified about READY SubConns.
24//
25// This package is the base of round_robin balancer, its purpose is to be used
26// to build round_robin like balancers with complex picking algorithms.
27// Balancers with more complicated logic should try to implement a balancer
28// builder from scratch.
29//
30// All APIs in this package are experimental.
31package base
32
33import (
34 "google.golang.org/grpc/balancer"
35 "google.golang.org/grpc/resolver"
36)
37
38// PickerBuilder creates balancer.Picker.
39type PickerBuilder interface {
40 // Build takes a slice of ready SubConns, and returns a picker that will be
41 // used by gRPC to pick a SubConn.
42 Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker
43}
44
45// NewBalancerBuilder returns a balancer builder. The balancers
46// built by this builder will use the picker builder to build pickers.
47func NewBalancerBuilder(name string, pb PickerBuilder) balancer.Builder {
48 return NewBalancerBuilderWithConfig(name, pb, Config{})
49}
50
51// Config contains the config info about the base balancer builder.
52type Config struct {
53 // HealthCheck indicates whether health checking should be enabled for this specific balancer.
54 HealthCheck bool
55}
56
57// NewBalancerBuilderWithConfig returns a base balancer builder configured by the provided config.
58func NewBalancerBuilderWithConfig(name string, pb PickerBuilder, config Config) balancer.Builder {
59 return &baseBuilder{
60 name: name,
61 pickerBuilder: pb,
62 config: config,
63 }
64}