micro-config-consul/watcher.go

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package consul
import (
"fmt"
"reflect"
"github.com/hashicorp/consul/api"
"go.unistack.org/micro/v4/config"
"go.unistack.org/micro/v4/util/jitter"
rutil "go.unistack.org/micro/v4/util/reflect"
)
type consulWatcher struct {
cli *api.Client
path string
opts config.Options
wopts config.WatchOptions
done chan struct{}
vchan chan map[string]interface{}
echan chan error
}
func (w *consulWatcher) run() {
ticker := jitter.NewTicker(w.wopts.MinInterval, w.wopts.MaxInterval)
defer ticker.Stop()
src := w.opts.Struct
if w.wopts.Struct != nil {
src = w.wopts.Struct
}
for {
select {
case <-w.done:
return
case <-ticker.C:
dst, err := rutil.Zero(src)
if err != nil {
w.echan <- err
return
}
pair, _, err := w.cli.KV().Get(w.path, nil)
if err != nil {
w.echan <- err
return
}
if pair == nil {
w.echan <- fmt.Errorf("consul path %s not found", w.path)
return
}
err = w.opts.Codec.Unmarshal(pair.Value, dst)
if err != nil {
w.echan <- err
return
}
srcmp, err := rutil.StructFieldsMap(src)
if err != nil {
w.echan <- err
return
}
dstmp, err := rutil.StructFieldsMap(dst)
if err != nil {
w.echan <- err
return
}
for sk, sv := range srcmp {
if reflect.DeepEqual(dstmp[sk], sv) {
delete(dstmp, sk)
}
}
if len(dstmp) > 0 {
w.vchan <- dstmp
src = dst
}
}
}
}
func (w *consulWatcher) Next() (map[string]interface{}, error) {
select {
case <-w.done:
break
case err := <-w.echan:
return nil, err
case v, ok := <-w.vchan:
if !ok {
break
}
return v, nil
}
return nil, config.ErrWatcherStopped
}
func (w *consulWatcher) Stop() error {
close(w.done)
return nil
}