add vault/etcd

config/source/etcd/watcher.go

@@ -0,0 +1,113 @@
+package etcd
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/micro/go-micro/config/source"
+	cetcd "go.etcd.io/etcd/clientv3"
+)
+
+type watcher struct {
+	opts        source.Options
+	name        string
+	stripPrefix string
+
+	sync.RWMutex
+	cs *source.ChangeSet
+
+	ch   chan *source.ChangeSet
+	exit chan bool
+}
+
+func newWatcher(key, strip string, wc cetcd.Watcher, cs *source.ChangeSet, opts source.Options) (source.Watcher, error) {
+	w := &watcher{
+		opts:        opts,
+		name:        "etcd",
+		stripPrefix: strip,
+		cs:          cs,
+		ch:          make(chan *source.ChangeSet),
+		exit:        make(chan bool),
+	}
+
+	ch := wc.Watch(context.Background(), key, cetcd.WithPrefix())
+
+	go w.run(wc, ch)
+
+	return w, nil
+}
+
+func (w *watcher) handle(evs []*cetcd.Event) {
+	w.RLock()
+	data := w.cs.Data
+	w.RUnlock()
+
+	var vals map[string]interface{}
+
+	// unpackage existing changeset
+	if err := w.opts.Encoder.Decode(data, &vals); err != nil {
+		return
+	}
+
+	// update base changeset
+	d := makeEvMap(w.opts.Encoder, vals, evs, w.stripPrefix)
+
+	// pack the changeset
+	b, err := w.opts.Encoder.Encode(d)
+	if err != nil {
+		return
+	}
+
+	// create new changeset
+	cs := &source.ChangeSet{
+		Timestamp: time.Now(),
+		Source:    w.name,
+		Data:      b,
+		Format:    w.opts.Encoder.String(),
+	}
+	cs.Checksum = cs.Sum()
+
+	// set base change set
+	w.Lock()
+	w.cs = cs
+	w.Unlock()
+
+	// send update
+	w.ch <- cs
+}
+
+func (w *watcher) run(wc cetcd.Watcher, ch cetcd.WatchChan) {
+	for {
+		select {
+		case rsp, ok := <-ch:
+			if !ok {
+				return
+			}
+			w.handle(rsp.Events)
+		case <-w.exit:
+			wc.Close()
+			return
+		}
+	}
+}
+
+func (w *watcher) Next() (*source.ChangeSet, error) {
+	select {
+	case cs := <-w.ch:
+		return cs, nil
+	case <-w.exit:
+		return nil, errors.New("watcher stopped")
+	}
+}
+
+func (w *watcher) Stop() error {
+	select {
+	case <-w.exit:
+		return nil
+	default:
+		close(w.exit)
+	}
+	return nil
+}