Merge pull request #92 from marten-seemann/fix-browsing

don't stop querying when browsing

Author: grandcat

client.go

@@ -86,6 +86,7 @@ func (r *Resolver) Browse(ctx context.Context, service, domain string, entries c
 		params.Domain = domain
 	}
 	params.Entries = entries
+	params.isBrowsing = true
 	ctx, cancel := context.WithCancel(ctx)
 	go r.c.mainloop(ctx, params)
 
@@ -134,7 +135,7 @@ func (r *Resolver) Lookup(ctx context.Context, instance, service, domain string,
 
 // defaultParams returns a default set of QueryParams.
 func defaultParams(service string) *lookupParams {
-	return newLookupParams("", service, "local", make(chan *ServiceEntry))
+	return newLookupParams("", service, "local", false, make(chan *ServiceEntry))
 }
 
 // Client structure encapsulates both IPv4/IPv6 UDP connections.
@@ -293,7 +294,9 @@ func (c *client) mainloop(ctx context.Context, params *lookupParams) {
 				// service entry.
 				params.Entries <- e
 				sentEntries[k] = e
-				params.disableProbing()
+				if !params.isBrowsing {
+					params.disableProbing()
+				}
 			}
 			// reset entries
 			entries = make(map[string]*ServiceEntry)
@@ -368,10 +371,6 @@ func (c *client) recv(ctx context.Context, l interface{}, msgCh chan *dns.Msg) {
 // TODO: move error reporting to shutdown function as periodicQuery is called from
 // go routine context.
 func (c *client) periodicQuery(ctx context.Context, params *lookupParams) error {
-	if params.stopProbing == nil {
-		return nil
-	}
-
 	bo := backoff.NewExponentialBackOff()
 	bo.InitialInterval = 4 * time.Second
 	bo.MaxInterval = 60 * time.Second

service.go

@@ -70,18 +70,22 @@ type lookupParams struct {
 	ServiceRecord
 	Entries chan<- *ServiceEntry // Entries Channel
 
+	isBrowsing  bool
 	stopProbing chan struct{}
 	once        sync.Once
 }
 
 // newLookupParams constructs a lookupParams.
-func newLookupParams(instance, service, domain string, entries chan<- *ServiceEntry) *lookupParams {
-	return &lookupParams{
+func newLookupParams(instance, service, domain string, isBrowsing bool, entries chan<- *ServiceEntry) *lookupParams {
+	p := &lookupParams{
 		ServiceRecord: *NewServiceRecord(instance, service, domain),
 		Entries:       entries,
-
-		stopProbing: make(chan struct{}),
+		isBrowsing:    isBrowsing,
+	}
+	if !isBrowsing {
+		p.stopProbing = make(chan struct{})
 	}
+	return p
 }
 
 // Notify subscriber that no more entries will arrive. Mostly caused

service_test.go

@@ -152,10 +152,16 @@ func TestSubtype(t *testing.T) {
 		}
 		entries := make(chan *ServiceEntry)
 		var expectedResult []*ServiceEntry
-		go func(results <-chan *ServiceEntry) {
-			s := <-results
-			expectedResult = append(expectedResult, s)
-		}(entries)
+		go func() {
+			for {
+				select {
+				case s := <-entries:
+					expectedResult = append(expectedResult, s)
+				case <-ctx.Done():
+					return
+				}
+			}
+		}()
 
 		if err := resolver.Browse(ctx, mdnsService, mdnsDomain, entries); err != nil {
 			t.Fatalf("Expected browse success, but got %v", err)