add otp service (#88)

pkg/cache/cache.go

@@ -0,0 +1,40 @@
+// Cache provides a simple marshaling layer on top of the store
+package cache
+
+import (
+	"encoding/json"
+	"time"
+
+	"github.com/micro/micro/v3/service/store"
+)
+
+func Get(key string, val interface{}) error {
+	recs, err := store.Read(key, store.ReadLimit(1))
+	if err != nil {
+		return err
+	}
+	if len(recs) == 0 {
+		return store.ErrNotFound
+	}
+	if err := json.Unmarshal(recs[0].Value, val); err != nil {
+		return err
+	}
+	return nil
+}
+
+func Put(key string, val interface{}, expires time.Time) error {
+	b, err := json.Marshal(val)
+	if err != nil {
+		return err
+	}
+	expiry := expires.Sub(time.Now())
+	return store.Write(&store.Record{
+		Key:    key,
+		Value:  b,
+		Expiry: expiry,
+	})
+}
+
+func Delete(key string) error {
+	return store.Delete(key)
+}