Command line arg for changing the number of background updaters

Default number of background updaters raised to 4

nameserver/zone.go

@@ -19,8 +19,8 @@ const (
 	DefaultLocalDomain     = "weave.local." // The default name used for the local domain
 	DefaultRefreshInterval = int(localTTL)  // Period for background updates with mDNS
 	DefaultRelevantTime    = 60             // When to forget info about remote info if nobody asks...
+	DefaultNumUpdaters     = 4              // Default number of background updaters
 
-	defaultNumUpdaters    = 1              // Number of background updaters
 	defaultRefreshMailbox = 1000           // Number of on-the-fly background queries
 	defaultRemoteIdent    = "weave:remote" // Ident used for info obtained from mDNS
 )
@@ -423,6 +423,8 @@ type ZoneConfig struct {
 	Iface *net.Interface
 	// Refresh interval for local names in the zone database (disabled by default) (in seconds)
 	RefreshInterval int
+	// Number of background updaters for names
+	RefreshWorkers int
 	// Forget about remote info if nobody asks for it in this time (in seconds)
 	RelevantTime int
 	// Max pending refresh requests
@@ -455,6 +457,7 @@ type zoneDb struct {
 	refreshCloseChan chan bool
 	refreshWg        sync.WaitGroup
 	refreshInterval  time.Duration
+	refreshWorkers   int
 }
 
 // Create a new zone database
@@ -475,6 +478,7 @@ func NewZoneDb(config ZoneConfig) (zone *zoneDb, err error) {
 		refreshChan:      make(chan refreshRequest, maxRefreshRequests),
 		refreshSchedChan: make(chan refreshRequest, maxRefreshRequests),
 		refreshCloseChan: make(chan bool),
+		refreshWorkers:   DefaultNumUpdaters,
 	}
 
 	// fix the default configuration parameters
@@ -490,6 +494,9 @@ func NewZoneDb(config ZoneConfig) (zone *zoneDb, err error) {
 	if config.RelevantTime > 0 {
 		zone.relevantLimit = time.Duration(config.RelevantTime) * time.Second
 	}
+	if config.RefreshWorkers > 0 {
+		zone.refreshWorkers = config.RefreshWorkers
+	}
 
 	// Create the mDNS client and server
 	if zone.mdnsCli == nil {
@@ -523,8 +530,8 @@ func (zone *zoneDb) Start() (err error) {
 
 	// Start some name refreshers...
 	if zone.refreshInterval > 0 {
-		Info.Printf("[zonedb] Starting %d background name updaters", defaultNumUpdaters)
-		for i := 0; i < defaultNumUpdaters; i++ {
+		Info.Printf("[zonedb] Starting %d background name updaters", zone.refreshWorkers)
+		for i := 0; i < zone.refreshWorkers; i++ {
 			zone.refreshWg.Add(1)
 			go zone.updater(i)
 		}

weavedns/main.go

@@ -25,6 +25,7 @@ func main() {
 		timeout         int
 		udpbuf          int
 		refreshInterval int
+		refreshWorkers  int
 		relevantTime    int
 		cacheLen        int
 		cacheDisabled   bool
@@ -45,6 +46,7 @@ func main() {
 	flag.BoolVar(&debug, "debug", false, "output debugging info to stderr")
 	// advanced options
 	flag.IntVar(&refreshInterval, "refresh", weavedns.DefaultRefreshInterval, "refresh interval (in secs) for local names (0=disable)")
+	flag.IntVar(&refreshWorkers, "refresh-workers", weavedns.DefaultNumUpdaters, "default number of background updaters")
 	flag.IntVar(&relevantTime, "relevant", weavedns.DefaultRelevantTime, "life time for info in the absence of queries (in secs)")
 	flag.IntVar(&udpbuf, "udpbuf", weavedns.DefaultUDPBuflen, "UDP buffer length")
 	flag.IntVar(&timeout, "timeout", weavedns.DefaultTimeout, "timeout for resolutions (in millisecs)")
@@ -76,6 +78,7 @@ func main() {
 		Domain:          domain,
 		Iface:           iface,
 		RefreshInterval: refreshInterval,
+		RefreshWorkers:  refreshWorkers,
 		RelevantTime:    relevantTime,
 	}
 	zone, err := weavedns.NewZoneDb(zoneConfig)