refactor naming package
This commit is contained in:
iamqizhao
@ -34,115 +34,49 @@
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package etcd
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import (
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"sync"
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etcdcl "github.com/coreos/etcd/client"
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"golang.org/x/net/context"
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"google.golang.org/grpc/naming"
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)
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// update defines an etcd key-value update.
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type update struct {
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key, val string
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}
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// getNode reports the set of changes starting from node recursively.
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func getNode(node *etcdcl.Node) (updates []*update) {
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for _, v := range node.Nodes {
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updates = append(updates, getNode(v)...)
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}
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// getNode builds the key-value map starting from node recursively. It returns the
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// max etcdcl.Node.ModifiedIndex starting from that node.
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func getNode(node *etcdcl.Node, kv map[string]string) uint64 {
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if !node.Dir {
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u := &update{
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key: node.Key,
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val: node.Value,
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}
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updates = []*update{u}
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kv[node.Key] = node.Value
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return node.ModifiedIndex
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}
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return
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}
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type watcher struct {
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wr etcdcl.Watcher
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ctx context.Context
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cancel context.CancelFunc
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kv map[string]string
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}
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func (w *watcher) Next() (nu []*naming.Update, _ error) {
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for {
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resp, err := w.wr.Next(w.ctx)
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if err != nil {
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return nil, err
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}
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updates := getNode(resp.Node)
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for _, u := range updates {
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switch resp.Action {
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case "set":
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if resp.PrevNode == nil {
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w.kv[u.key] = u.val
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nu = append(nu, &naming.Update{
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Op: naming.Add,
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Addr: u.val,
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})
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} else {
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nu = append(nu, &naming.Update{
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Op: naming.Delete,
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Addr: w.kv[u.key],
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})
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nu = append(nu, &naming.Update{
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Op: naming.Add,
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Addr: u.val,
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})
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w.kv[u.key] = u.val
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}
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case "delete":
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nu = append(nu, &naming.Update{
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Op: naming.Delete,
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Addr: w.kv[u.key],
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})
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delete(w.kv, u.key)
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}
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}
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if len(nu) > 0 {
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break
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var max uint64
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for _, v := range node.Nodes {
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i := getNode(v, kv)
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if max < i {
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max = i
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}
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}
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return nu, nil
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}
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func (w *watcher) Stop() {
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w.cancel()
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return max
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}
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type resolver struct {
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kapi etcdcl.KeysAPI
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kv map[string]string
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}
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func (r *resolver) NewWatcher(target string) naming.Watcher {
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ctx, cancel := context.WithCancel(context.Background())
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w := &watcher{
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wr: r.kapi.Watcher(target, &etcdcl.WatcherOptions{Recursive: true}),
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ctx: ctx,
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cancel: cancel,
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}
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for k, v := range r.kv {
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w.kv[k] = v
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}
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return w
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}
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func (r *resolver) Resolve(target string) (nu []*naming.Update, _ error) {
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func (r *resolver) Resolve(target string) (naming.Watcher, error) {
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resp, err := r.kapi.Get(context.Background(), target, &etcdcl.GetOptions{Recursive: true})
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if err != nil {
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return nil, err
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}
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updates := getNode(resp.Node)
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for _, u := range updates {
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r.kv[u.key] = u.val
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nu = append(nu, &naming.Update{
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Op: naming.Add,
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Addr: u.val,
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})
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}
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return nu, nil
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kv := make(map[string]string)
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// Record the index in order to avoid missing updates between Get returning and
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// watch starting.
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index := getNode(resp.Node, kv)
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return &watcher{
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wr: r.kapi.Watcher(target, &etcdcl.WatcherOptions{
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AfterIndex: index,
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Recursive: true}),
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kv: kv,
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}, nil
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}
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// NewResolver creates an etcd-based naming.Resolver.
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@ -153,6 +87,68 @@ func NewResolver(cfg etcdcl.Config) (naming.Resolver, error) {
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}
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return &resolver{
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kapi: etcdcl.NewKeysAPI(c),
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kv: make(map[string]string),
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}, nil
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}
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type watcher struct {
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wr etcdcl.Watcher
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kv map[string]string
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}
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var once sync.Once
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func (w *watcher) Next(ctx context.Context) (nu []*naming.Update, err error) {
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once.Do(func() {
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select {
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case <-ctx.Done():
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err = ctx.Err()
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default:
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for _, v := range w.kv {
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nu = append(nu, &naming.Update{
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Op: naming.Add,
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Addr: v,
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})
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}
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}
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})
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if len(nu) > 0 || err != nil {
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// once.Do ran. Return directly.
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return
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}
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for {
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resp, err := w.wr.Next(ctx)
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if err != nil {
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return nil, err
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}
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if resp.Node.Dir {
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continue
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}
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switch resp.Action {
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case "set":
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if resp.PrevNode == nil {
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nu = append(nu, &naming.Update{
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Op: naming.Add,
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Addr: resp.Node.Value,
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})
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w.kv[resp.Node.Key] = resp.Node.Value
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} else {
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nu = append(nu, &naming.Update{
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Op: naming.Delete,
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Addr: w.kv[resp.Node.Key],
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})
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nu = append(nu, &naming.Update{
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Op: naming.Add,
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Addr: resp.Node.Value,
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})
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w.kv[resp.Node.Key] = resp.Node.Value
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}
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case "delete":
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nu = append(nu, &naming.Update{
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Op: naming.Delete,
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Addr: resp.Node.Value,
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})
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delete(w.kv, resp.Node.Key)
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}
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return nu, nil
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}
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}
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@ -35,40 +35,41 @@
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// The interface is EXPERIMENTAL and may be suject to change.
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package naming
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// OP defines the corresponding operations for a name resolution change.
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type OP uint8
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import (
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"golang.org/x/net/context"
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)
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// Operation defines the corresponding operations for a name resolution change.
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type Operation uint8
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const (
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// Add indicates a new address is added.
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Add = iota
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Add Operation = iota
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// Delete indicates an exisiting address is deleted.
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Delete
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)
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type ServiceConfig interface{}
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// Update defines a name resolution change.
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// Update defines a name resolution update. Notice that it is not valid having both
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// empty string Addr and nil Metadata in an Update.
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type Update struct {
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// Op indicates the operation of the update.
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Op OP
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Addr string
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Config ServiceConfig
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Op Operation
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// Addr is the updated address. It is empty string if there is no address update.
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Addr string
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// Metadata is the updated metadata. It is nil if there is no metadata update.
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// Metadata is not required for a custom naming implementation.
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Metadata interface{}
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}
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// Resolver does one-shot name resolution and creates a Watcher to
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// watch the future updates.
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// Resolver creates a Watcher for a target to track its resolution changes.
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type Resolver interface {
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// Resolve returns the name resolution results.
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Resolve(target string) ([]*Update, error)
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// NewWatcher creates a Watcher to watch the changes on target.
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NewWatcher(target string) Watcher
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// Resolve creates a Watcher for target.
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Resolve(target string) (Watcher, error)
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}
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// Watcher watches the updates for a particular target.
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// Watcher watches for the updates on the specified target.
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type Watcher interface {
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// Next blocks until an update or error happens. It may return one or more
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// updates.
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Next() ([]*Update, error)
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// Stop stops the Watcher.
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Stop()
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// updates. The first call should get the full set of the results.
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Next(ctx context.Context) ([]*Update, error)
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}
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