move reply to request message type

Signed-off-by: Mike Mason <mimason@equinix.com>
infratographer · Aug 4, 2023 · b75f397 · b75f397
1 parent bdca5e2
commit b75f397
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Showing 6 changed files with 86 additions and 45 deletions.
diff --git a/events/connection.go b/events/connection.go
@@ -40,7 +40,7 @@ type Publisher interface {
 // AuthRelationshipSubscriber specifies the auth relationship subscriber methods.
 type AuthRelationshipSubscriber interface {
 	// SubscribeAuthRelationshipRequests subscribes to the provided topic responding with an AuthRelationshipRequest message.
-	SubscribeAuthRelationshipRequests(ctx context.Context, topic string) (<-chan Message[AuthRelationshipRequest], error)
+	SubscribeAuthRelationshipRequests(ctx context.Context, topic string) (<-chan Request[AuthRelationshipRequest, AuthRelationshipResponse], error)
 }
 
 // AuthRelationshipPublisher specifies the auth relationship publisher methods.

diff --git a/events/message.go b/events/message.go
@@ -53,14 +53,18 @@ type Message[T any] interface {
 	// Error returns any error encountered while decoding the message
 	Error() error
 
-	// ReplyAuthRelationshipRequest publishes an AuthRelationshipResponse message.
-	// An error is returned if the message is not an AuthRelationshipRequest.
-	ReplyAuthRelationshipRequest(ctx context.Context, message AuthRelationshipResponse) (Message[AuthRelationshipResponse], error)
-
 	// Source returns the underlying message object.
 	Source() any
 }
 
+// Request extends Message by allowing replies to be sent for the received message.
+type Request[TRequest, TResponse any] interface {
+	Message[TRequest]
+
+	// Reply publishes a response to the received message.
+	Reply(ctx context.Context, message TResponse) (Message[TResponse], error)
+}
+
 // ChangeType represents the possible event types for a ChangeMessage
 type ChangeType string
 

diff --git a/events/nats_message.go b/events/nats_message.go
@@ -34,6 +34,30 @@ func natsSubscriptionMessageChan[T any](ctx context.Context, conn *NATSConnectio
 	return msgCh
 }
 
+func natsSubscriptionAuthRelationshipRequestChan(ctx context.Context, conn *NATSConnection, batchSize int, natsCh <-chan *nats.Msg) chan Request[AuthRelationshipRequest, AuthRelationshipResponse] {
+	msgCh := make(chan Request[AuthRelationshipRequest, AuthRelationshipResponse], batchSize)
+
+	go func() {
+		defer close(msgCh)
+
+		for nMsg := range natsCh {
+			msg := natsDecodeMessage[AuthRelationshipRequest](conn, nMsg)
+
+			req := &NATSAuthRelationshipRequest{
+				NATSMessage: msg.(*NATSMessage[AuthRelationshipRequest]),
+			}
+
+			select {
+			case msgCh <- req:
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+
+	return msgCh
+}
+
 func natsDecodeMessage[T any](conn *NATSConnection, nMsg *nats.Msg) Message[T] {
 	msg := &NATSMessage[T]{
 		conn:   conn,
@@ -129,13 +153,49 @@ func (m *NATSMessage[T]) Error() error {
 	return nil
 }
 
-// ReplyAuthRelationshipRequest responds to an AuthRelationshipRequest with an AuthRelationshipResponse
-func (m *NATSMessage[T]) ReplyAuthRelationshipRequest(ctx context.Context, message AuthRelationshipResponse) (Message[AuthRelationshipResponse], error) {
-	ctx, span := m.conn.tracer.Start(ctx, "events.ReplyAuthRelationshipRequest")
+// Source returns the underlying nats message.
+func (m *NATSMessage[T]) Source() any {
+	return m.source
+}
 
-	defer span.End()
+func (m *NATSMessage[T]) publish() error {
+	return m.conn.conn.PublishMsg(m.source)
+}
 
+func (m *NATSMessage[T]) request(ctx context.Context) (Message[AuthRelationshipResponse], error) {
 	if m.source.Reply == "" {
+		m.source.Reply = m.conn.conn.NewRespInbox()
+	}
+
+	nMsg, err := m.conn.conn.RequestMsgWithContext(ctx, m.source)
+	if err != nil {
+		// ensure we wrap no responder errors with ErrRequestNoResponders.
+		if errors.Is(err, nats.ErrNoResponders) {
+			return nil, fmt.Errorf("%w: %w", ErrRequestNoResponders, err)
+		}
+
+		return nil, err
+	}
+
+	respMsg := natsDecodeMessage[AuthRelationshipResponse](m.conn, nMsg)
+
+	return respMsg, nil
+}
+
+var _ Request[AuthRelationshipRequest, AuthRelationshipResponse] = (*NATSAuthRelationshipRequest)(nil)
+
+// NATSAuthRelationshipRequest implements Request for AuthRelationshipRequest / AuthRelationshipResponse
+type NATSAuthRelationshipRequest struct {
+	*NATSMessage[AuthRelationshipRequest]
+}
+
+// Reply responds to an AuthRelationshipRequest with an AuthRelationshipResponse.
+func (r *NATSAuthRelationshipRequest) Reply(ctx context.Context, message AuthRelationshipResponse) (Message[AuthRelationshipResponse], error) {
+	ctx, span := r.conn.tracer.Start(ctx, "events.Reply")
+
+	defer span.End()
+
+	if r.source.Reply == "" {
 		span.RecordError(ErrNATSMessageNoReplySubject)
 		span.SetStatus(codes.Error, ErrNATSMessageNoReplySubject.Error())
 
@@ -156,43 +216,20 @@ func (m *NATSMessage[T]) ReplyAuthRelationshipRequest(ctx context.Context, messa
 
 	message.TraceContext = mapCarrier
 
-	respMsg, err := newNATSMessage(m.conn, m.source.Reply, message)
+	respMsg, err := newNATSMessage(r.conn, r.source.Reply, message)
 	if err != nil {
-		return nil, err
-	}
-
-	if err := m.source.RespondMsg(respMsg.source); err != nil {
-		return respMsg, err
-	}
-
-	return respMsg, nil
-}
-
-// Source returns the underlying nats message.
-func (m *NATSMessage[T]) Source() any {
-	return m.source
-}
-
-func (m *NATSMessage[T]) publish() error {
-	return m.conn.conn.PublishMsg(m.source)
-}
+		span.RecordError(err)
+		span.SetStatus(codes.Error, err.Error())
 
-func (m *NATSMessage[T]) request(ctx context.Context) (Message[AuthRelationshipResponse], error) {
-	if m.source.Reply == "" {
-		m.source.Reply = m.conn.conn.NewRespInbox()
+		return nil, err
 	}
 
-	nMsg, err := m.conn.conn.RequestMsgWithContext(ctx, m.source)
-	if err != nil {
-		// ensure we wrap no responder errors with ErrRequestNoResponders.
-		if errors.Is(err, nats.ErrNoResponders) {
-			return nil, fmt.Errorf("%w: %w", ErrRequestNoResponders, err)
-		}
+	if err := r.source.RespondMsg(respMsg.source); err != nil {
+		span.RecordError(err)
+		span.SetStatus(codes.Error, err.Error())
 
-		return nil, err
+		return respMsg, err
 	}
 
-	respMsg := natsDecodeMessage[AuthRelationshipResponse](m.conn, nMsg)
-
 	return respMsg, nil
 }
diff --git a/events/nats_subscribe.go b/events/nats_subscribe.go
@@ -138,7 +138,7 @@ func (c *NATSConnection) nextMessage(ctx context.Context, sub *nats.Subscription
 }
 
 // SubscribeAuthRelationshipRequests creates a new pull subscription parsing incoming messages as AuthRelationshipRequest messages and returning a new Message channel.
-func (c *NATSConnection) SubscribeAuthRelationshipRequests(ctx context.Context, topic string) (<-chan Message[AuthRelationshipRequest], error) {
+func (c *NATSConnection) SubscribeAuthRelationshipRequests(ctx context.Context, topic string) (<-chan Request[AuthRelationshipRequest, AuthRelationshipResponse], error) {
 	topic = c.buildSubscribeSubject("auth", "relationships", topic)
 
 	natsCh, err := c.coreSubscribe(ctx, topic)
@@ -148,7 +148,7 @@ func (c *NATSConnection) SubscribeAuthRelationshipRequests(ctx context.Context,
 
 	c.logger.Debugf("subscribing to auth relation request message on topic %s", topic)
 
-	return natsSubscriptionMessageChan[AuthRelationshipRequest](ctx, c, c.cfg.SubscriberFetchBatchSize, natsCh), nil
+	return natsSubscriptionAuthRelationshipRequestChan(ctx, c, c.cfg.SubscriberFetchBatchSize, natsCh), nil
 }
 
 // SubscribeChanges creates a new pull subscription parsing incoming messages as ChangeMessage messages and returning a new Message channel.

diff --git a/events/nats_test.go b/events/nats_test.go
@@ -130,7 +130,7 @@ func TestNATSRequestReply(t *testing.T) {
 
 			reqGot <- reqMsg
 
-			respMsg, err := reqMsg.ReplyAuthRelationshipRequest(ctx, authResponse)
+			respMsg, err := reqMsg.Reply(ctx, authResponse)
 			assert.NoError(t, err)
 			assert.NotNil(t, respMsg)
 		case <-time.After(time.Second * 2):

diff --git a/testing/eventtools/mock_connection.go b/testing/eventtools/mock_connection.go
@@ -51,10 +51,10 @@ func (c *MockConnection) Source() any {
 }
 
 // SubscribeAuthRelationshipRequests implements events.Connection
-func (c *MockConnection) SubscribeAuthRelationshipRequests(_ context.Context, topic string) (<-chan events.Message[events.AuthRelationshipRequest], error) {
+func (c *MockConnection) SubscribeAuthRelationshipRequests(_ context.Context, topic string) (<-chan events.Request[events.AuthRelationshipRequest, events.AuthRelationshipResponse], error) {
 	args := c.Called(topic)
 
-	return args.Get(0).(<-chan events.Message[events.AuthRelationshipRequest]), args.Error(1)
+	return args.Get(0).(<-chan events.Request[events.AuthRelationshipRequest, events.AuthRelationshipResponse]), args.Error(1)
 }
 
 // SubscribeChanges implements events.Connection