lib: Faster termination on exit (ref #6319) (#6329)

lib/discover/cache.go

@@ -7,6 +7,7 @@
 package discover
 
 import (
+	"context"
 	"sort"
 	stdsync "sync"
 	"time"
@@ -73,7 +74,7 @@ func (m *cachingMux) Add(finder Finder, cacheTime, negCacheTime time.Duration) {
 
 // Lookup attempts to resolve the device ID using any of the added Finders,
 // while obeying the cache settings.
-func (m *cachingMux) Lookup(deviceID protocol.DeviceID) (addresses []string, err error) {
+func (m *cachingMux) Lookup(ctx context.Context, deviceID protocol.DeviceID) (addresses []string, err error) {
 	m.mut.RLock()
 	for i, finder := range m.finders {
 		if cacheEntry, ok := m.caches[i].Get(deviceID); ok {
@@ -99,7 +100,7 @@ func (m *cachingMux) Lookup(deviceID protocol.DeviceID) (addresses []string, err
 		}
 
 		// Perform the actual lookup and cache the result.
-		if addrs, err := finder.Lookup(deviceID); err == nil {
+		if addrs, err := finder.Lookup(ctx, deviceID); err == nil {
 			l.Debugln("lookup for", deviceID, "at", finder)
 			l.Debugln("  addresses:", addrs)
 			addresses = append(addresses, addrs...)