subscriptions receive their context on Prepare().

relay.go

@@ -161,14 +161,13 @@ func (r *Relay) Connect(ctx context.Context) error {
 
 						// check if the event matches the desired filter, ignore otherwise
 						if !subscription.Filters.Match(&event) {
-							log.Printf("filter does not match\n")
+							log.Printf("filter does not match: %v ~ %v\n", subscription.Filters[0], event)
 							return
 						}
 
 						subscription.mutex.Lock()
 						defer subscription.mutex.Unlock()
 						if subscription.stopped {
-							log.Printf("subscription '%s' is stopped\n", subId)
 							return
 						}
 
@@ -360,9 +359,9 @@ func (r *Relay) Subscribe(ctx context.Context, filters Filters) *Subscription {
 		panic(fmt.Errorf("must call .Connect() first before calling .Subscribe()"))
 	}
 
-	sub := r.PrepareSubscription()
+	sub := r.PrepareSubscription(ctx)
 	sub.Filters = filters
-	sub.Fire(ctx)
+	sub.Fire()
 
 	return sub
 }
@@ -395,12 +394,16 @@ func (r *Relay) QuerySync(ctx context.Context, filter Filter) []*Event {
 	}
 }
 
-func (r *Relay) PrepareSubscription() *Subscription {
+func (r *Relay) PrepareSubscription(ctx context.Context) *Subscription {
 	current := subscriptionIdCounter
 	subscriptionIdCounter++
 
+	ctx, cancel := context.WithCancel(ctx)
+
 	return &Subscription{
 		Relay:             r,
+		Context:           ctx,
+		cancel:            cancel,
 		conn:              r.Connection,
 		counter:           current,
 		Events:            make(chan *Event),

subscription.go

@@ -17,6 +17,7 @@ type Subscription struct {
 	Events            chan *Event
 	EndOfStoredEvents chan struct{}
 	Context           context.Context
+	cancel            context.CancelFunc
 
 	stopped  bool
 	emitEose sync.Once
@@ -54,17 +55,13 @@ func (sub *Subscription) Unsub() {
 // Sub sets sub.Filters and then calls sub.Fire(ctx).
 func (sub *Subscription) Sub(ctx context.Context, filters Filters) {
 	sub.Filters = filters
-	sub.Fire(ctx)
+	sub.Fire()
 }
 
 // Fire sends the "REQ" command to the relay.
-// When ctx is cancelled, sub.Unsub() is called, closing the subscription.
+func (sub *Subscription) Fire() error {
-func (sub *Subscription) Fire(ctx context.Context) error {
 	sub.Relay.subscriptions.Store(sub.GetID(), sub)
 
-	ctx, cancel := context.WithCancel(ctx)
-	sub.Context = ctx
-
 	message := []interface{}{"REQ", sub.GetID()}
 	for _, filter := range sub.Filters {
 		message = append(message, filter)
@@ -72,13 +69,13 @@ func (sub *Subscription) Fire(ctx context.Context) error {
 
 	err := sub.conn.WriteJSON(message)
 	if err != nil {
-		cancel()
+		sub.cancel()
 		return err
 	}
 
 	// the subscription ends once the context is canceled
 	go func() {
-		<-ctx.Done()
+		<-sub.Context.Done()
 		sub.Unsub()
 	}()
 
@@ -87,7 +84,7 @@ func (sub *Subscription) Fire(ctx context.Context) error {
 		<-sub.Relay.ConnectionContext.Done()
 
 		// cancel the context -- this will cause the other context cancelation cause above to be called
-		cancel()
+		sub.cancel()
 	}()
 
 	return nil