diff --git a/middleware/torrentapproval/container/directory/directory.go b/middleware/torrentapproval/container/directory/directory.go
index c4063e1..41a30a3 100644
--- a/middleware/torrentapproval/container/directory/directory.go
+++ b/middleware/torrentapproval/container/directory/directory.go
@@ -1,3 +1,6 @@
+// Package directory implements container which
+// checks if hash present in any of *.torrent file
+// placed in some directory
 package directory
 
 import (
@@ -40,9 +43,8 @@ func build(confBytes []byte) (container.Container, error) {
 		dir = c.BlacklistPath
 	}
 	var w *dirwatch.Instance
-	w, err = dirwatch.New(dir)
 	if w, err = dirwatch.New(dir); err != nil {
-		return nil, fmt.Errorf("unable to initialize directory watch")
+		return nil, fmt.Errorf("unable to initialize directory watch: %v", err)
 	}
 	lst.watcher = w
 	go func() {
diff --git a/middleware/torrentapproval/container/list/list.go b/middleware/torrentapproval/container/list/list.go
index ad2df74..13f4bb9 100644
--- a/middleware/torrentapproval/container/list/list.go
+++ b/middleware/torrentapproval/container/list/list.go
@@ -1,3 +1,5 @@
+// Package list implements container with pre-defined
+// list of torrent hashes from config file
 package list
 
 import (
@@ -35,14 +37,13 @@ func build(confBytes []byte) (container.Container, error) {
 
 	hashList := c.Whitelist
 	if l.Invert {
-		l.Invert = true
 		hashList = c.Blacklist
 	}
 
 	for _, hashString := range hashList {
 		hashinfo, err := hex.DecodeString(hashString)
 		if err != nil {
-			return nil, fmt.Errorf("whitelist : invalid hash %s", hashString)
+			return nil, fmt.Errorf("whitelist : invalid hash %s, %v", hashString, err)
 		}
 		if len(hashinfo) != 20 {
 			return nil, fmt.Errorf("whitelist : hash %s is not 20 byes", hashString)
diff --git a/storage/memory/peer_store.go b/storage/memory/peer_store.go
index a3358b2..af66af9 100644
--- a/storage/memory/peer_store.go
+++ b/storage/memory/peer_store.go
@@ -147,23 +147,27 @@ func New(provided Config) (storage.PeerStore, error) {
 		}
 	}()
 
-	// Start a goroutine for reporting statistics to Prometheus.
-	ps.wg.Add(1)
-	go func() {
-		defer ps.wg.Done()
-		t := time.NewTicker(cfg.PrometheusReportingInterval)
-		for {
-			select {
-			case <-ps.closed:
-				t.Stop()
-				return
-			case <-t.C:
-				before := time.Now()
-				ps.populateProm()
-				log.Debug("storage: populateProm() finished", log.Fields{"timeTaken": time.Since(before)})
+	if cfg.PrometheusReportingInterval > 0 {
+		// Start a goroutine for reporting statistics to Prometheus.
+		ps.wg.Add(1)
+		go func() {
+			defer ps.wg.Done()
+			t := time.NewTicker(cfg.PrometheusReportingInterval)
+			for {
+				select {
+				case <-ps.closed:
+					t.Stop()
+					return
+				case <-t.C:
+					before := time.Now()
+					ps.populateProm()
+					log.Debug("storage: populateProm() finished", log.Fields{"timeTaken": time.Since(before)})
+				}
 			}
-		}
-	}()
+		}()
+	} else {
+		log.Info("prometheus disabled because of zero reporting interval")
+	}
 
 	return ps, nil
 }