blob: 908579fffc74e91753910fa8269aef8b02a9a299 [file] [log] [blame]
// Copyright 2016 Google LLC.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package internal
import (
// TODO: move to transport/grpc package
// PoolResolver provides a fixed list of addresses to load balance between
// and does not provide further updates.
type PoolResolver struct {
poolSize int
dialOpt *DialSettings
ch chan []*naming.Update
// NewPoolResolver returns a PoolResolver
// This is an EXPERIMENTAL API and may be changed or removed in the future.
func NewPoolResolver(size int, o *DialSettings) *PoolResolver {
return &PoolResolver{poolSize: size, dialOpt: o}
// Resolve returns a Watcher for the endpoint defined by the DialSettings
// provided to NewPoolResolver.
func (r *PoolResolver) Resolve(target string) (naming.Watcher, error) {
if r.dialOpt.Endpoint == "" {
return nil, errors.New("no endpoint configured")
addrs := make([]*naming.Update, 0, r.poolSize)
for i := 0; i < r.poolSize; i++ {
addrs = append(addrs, &naming.Update{Op: naming.Add, Addr: r.dialOpt.Endpoint, Metadata: i})
} = make(chan []*naming.Update, 1) <- addrs
return r, nil
// Next returns a static list of updates on the first call,
// and blocks indefinitely until Close is called on subsequent calls.
func (r *PoolResolver) Next() ([]*naming.Update, error) {
return <, nil
// Close releases resources associated with the pool and causes Next to unblock.
func (r *PoolResolver) Close() {