128 lines
2.1 KiB
Go
128 lines
2.1 KiB
Go
package discovery
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import (
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"context"
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"encoding/json"
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"github.com/coreos/etcd/clientv3"
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"github.com/google/uuid"
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"path"
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)
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type Registry struct {
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client *clientv3.Client
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path string
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}
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func New(endpoints []string) (*Registry, error) {
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client, err := clientv3.New(clientv3.Config{
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Endpoints: endpoints,
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})
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if err != nil {
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return nil, err
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}
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return &Registry{
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client: client,
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}, nil
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}
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func (r *Registry) Register(ctx context.Context, service string, host Host) error {
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resp, err := r.client.Grant(context.Background(), 30)
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if err != nil {
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return err
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}
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if host.UUID == "" {
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host.UUID = uuid.New().String()
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}
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b, err := json.Marshal(host)
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if err != nil {
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return err
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}
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key := path.Join(r.path, service, host.UUID)
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_, err = r.client.Put(context.Background(), key, string(b), clientv3.WithLease(resp.ID))
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if err != nil {
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return err
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}
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ch, err := r.client.KeepAlive(ctx, resp.ID)
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if err != nil {
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return err
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}
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go func() {
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for {
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select {
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case ka := <-ch:
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if ka == nil {
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return
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}
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// Removed
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}
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}
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}()
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return nil
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}
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func (r *Registry) Get(service string) ([]Host, error) {
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res, err := r.client.Get(context.Background(), path.Join(r.path, service), clientv3.WithPrefix())
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if err != nil {
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return nil, err
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}
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var host Host
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hosts := make([]Host, len(res.Kvs))
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for i, kv := range res.Kvs {
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host = Host{}
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if err = json.Unmarshal(kv.Value, &host); err != nil {
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continue
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}
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hosts[i] = host
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}
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return hosts, nil
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}
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func (r *Registry) Watch(service string) (chan Host, chan string) {
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ch := r.client.Watch(context.Background(), path.Join(r.path, service), clientv3.WithPrefix())
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upChan := make(chan Host)
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downChan := make(chan string)
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go func() {
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for resp := range ch {
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for _, e := range resp.Events {
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if e.Type == clientv3.EventTypeDelete {
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// Removed
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downChan <- string(e.Kv.Key)
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} else if e.IsCreate() || e.IsModify() {
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host := Host{}
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if err := json.Unmarshal(e.Kv.Value, &host); err != nil {
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continue
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}
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upChan <- host
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}
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}
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}
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}()
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return upChan, downChan
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}
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