handle databases config

cmd/ledis-server/main.go

@@ -26,6 +26,7 @@ var readonly = flag.Bool("readonly", false, "set readonly mode, slave server is
 var rpl = flag.Bool("rpl", false, "enable replication or not, slave server is always enabled")
 var rplSync = flag.Bool("rpl_sync", false, "enable sync replication or not")
 var ttlCheck = flag.Int("ttl_check", 0, "TTL check interval")
+var databases = flag.Int("databases", 0, "ledisdb maximum database number")
 
 func main() {
 	runtime.GOMAXPROCS(runtime.NumCPU())
@@ -59,6 +60,10 @@ func main() {
 		cfg.DBName = *dbName
 	}
 
+	if *databases > 0 {
+		cfg.Databases = *databases
+	}
+
 	if len(*slaveof) > 0 {
 		cfg.SlaveOf = *slaveof
 		cfg.Readonly = true

ledis/ledis.go

@@ -48,8 +48,8 @@ func Open(cfg *config.Config) (*Ledis, error) {
 
 	if cfg.Databases == 0 {
 		cfg.Databases = 16
-	} else if cfg.Databases > 16 {
-		cfg.Databases = 16
+	} else if cfg.Databases > MaxDatabases {
+		cfg.Databases = MaxDatabases
 	}
 
 	os.MkdirAll(cfg.DataDir, 0755)
@@ -112,8 +112,8 @@ func (l *Ledis) Close() {
 }
 
 func (l *Ledis) Select(index int) (*DB, error) {
-	if index < 0 || index >= MaxDatabases {
-		return nil, fmt.Errorf("invalid db index %d, must in [0, %d]", index, MaxDatabases-1)
+	if index < 0 || index >= l.cfg.Databases {
+		return nil, fmt.Errorf("invalid db index %d, must in [0, %d]", index, l.cfg.Databases-1)
 	}
 
 	l.dbLock.Lock()