fix leveldb problems

Former-commit-id: f17fe73babf8910a2031323ffb2a28979082a4dd

monitor/queue.go

@@ -1,7 +1,9 @@
 package monitor
 
 import (
+	"fmt"
 	"local/rssmon3/config"
+	"local/storage"
 	"log"
 
 	"github.com/golang-collections/go-datastructures/queue"
@@ -17,13 +19,15 @@ func newQueue() (*Queue, error) {
 	q := queue.NewPriorityQueue(1)
 	db := config.Values().DB
 	keys, err := db.List([]string{nsQueued})
-	if err != nil {
+	if err == storage.ErrNotFound {
+		keys = []string{}
+	} else if err != nil {
 		return nil, err
 	}
 	for _, key := range keys {
 		b, err := db.Get(key, nsQueued)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("failed to get %s:%s: %v", nsQueued, key, err)
 		}
 		i := &Item{}
 		if err := i.Decode(b); err != nil {