adding the integer parser utility

index/scorch/persister.go

@@ -633,19 +633,14 @@ func (s *Scorch) removeOldBoltSnapshots() (numRemoved int, err error) {
 		return 0, err
 	}
 
-	numSnapshotsToKeep := NumSnapshotsToKeep
-	if val, ok := s.config["numSnapshotsToKeep"].(float64); ok && val > 0 {
-		numSnapshotsToKeep = int(val)
-	}
-
-	if len(persistedEpochs) <= numSnapshotsToKeep {
+	if len(persistedEpochs) <= s.numSnapshotsToKeep {
 		// we need to keep everything
 		return 0, nil
 	}
 
 	// make a map of epochs to protect from deletion
-	protectedEpochs := make(map[uint64]struct{}, numSnapshotsToKeep)
-	for _, epoch := range persistedEpochs[0:numSnapshotsToKeep] {
+	protectedEpochs := make(map[uint64]struct{}, s.numSnapshotsToKeep)
+	for _, epoch := range persistedEpochs[0:s.numSnapshotsToKeep] {
 		protectedEpochs[epoch] = struct{}{}
 	}
 

index/scorch/scorch.go

@@ -58,6 +58,7 @@ type Scorch struct {
 	nextSnapshotEpoch    uint64
 	eligibleForRemoval   []uint64        // Index snapshot epochs that are safe to GC.
 	ineligibleForRemoval map[string]bool // Filenames that should not be GC'ed yet.
+	numSnapshotsToKeep   int
 
 	closeCh            chan struct{}
 	introductions      chan *segmentIntroduction
@@ -191,6 +192,17 @@ func (s *Scorch) openBolt() error {
 		}
 	}
 
+	s.numSnapshotsToKeep = NumSnapshotsToKeep
+	if v, ok := s.config["numSnapshotsToKeep"]; ok {
+		var t int
+		if t, err = parseToInteger(v); err != nil {
+			return fmt.Errorf("numSnapshotsToKeep parse err: %v", err)
+		}
+		if t > 0 {
+			s.numSnapshotsToKeep = t
+		}
+	}
+
 	return nil
 }
 
@@ -503,3 +515,34 @@ func (s *Scorch) unmarkIneligibleForRemoval(filename string) {
 func init() {
 	registry.RegisterIndexType(Name, NewScorch)
 }
+
+func parseToInteger(v interface{}) (int, error) {
+	switch v.(type) {
+	case float32:
+		return int(v.(float32)), nil
+	case float64:
+		return int(v.(float64)), nil
+	case int:
+		return v.(int), nil
+	case int8:
+		return int(v.(int8)), nil
+	case int16:
+		return int(v.(int16)), nil
+	case int32:
+		return int(v.(int32)), nil
+	case int64:
+		return int(v.(int64)), nil
+	case uint:
+		return int(v.(uint)), nil
+	case uint8:
+		return int(v.(uint8)), nil
+	case uint16:
+		return int(v.(uint16)), nil
+	case uint32:
+		return int(v.(uint32)), nil
+	case uint64:
+		return int(v.(uint64)), nil
+	default:
+		return 0, fmt.Errorf("expects a numeric value")
+	}
+}