initial commit

internal/pubsub/doc.go

@@ -0,0 +1,2 @@
+// Package pubsub provides functions and data for a NATS consumer listening for resource lifecycle events.
+package pubsub

internal/pubsub/subscriber.go

@@ -0,0 +1,220 @@
+package pubsub
+
+import (
+	"context"
+	"sync"
+
+	nc "github.com/nats-io/nats.go"
+	"go.infratographer.com/x/events"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+	"go.uber.org/zap"
+
+	"go.equinixmetal.net/infra9-metal-bridge/internal/service"
+
+	"github.com/ThreeDotsLabs/watermill/message"
+)
+
+var tracer = otel.Tracer("go.infratographer.com/permissions-api/internal/pubsub")
+
+// Subscriber is the subscriber client
+type Subscriber struct {
+	ctx            context.Context
+	changeChannels []<-chan *message.Message
+	logger         *zap.SugaredLogger
+	subscriber     *events.Subscriber
+	subOpts        []nc.SubOpt
+	svc            service.Service
+}
+
+// SubscriberOption is a functional option for the Subscriber
+type SubscriberOption func(s *Subscriber)
+
+// WithLogger sets the logger for the Subscriber
+func WithLogger(l *zap.SugaredLogger) SubscriberOption {
+	return func(s *Subscriber) {
+		s.logger = l
+	}
+}
+
+// WithNatsSubOpts sets the logger for the Subscriber
+func WithNatsSubOpts(options ...nc.SubOpt) SubscriberOption {
+	return func(s *Subscriber) {
+		s.subOpts = append(s.subOpts, options...)
+	}
+}
+
+// NewSubscriber creates a new Subscriber
+func NewSubscriber(ctx context.Context, cfg events.SubscriberConfig, service service.Service, opts ...SubscriberOption) (*Subscriber, error) {
+	s := &Subscriber{
+		ctx:    ctx,
+		logger: zap.NewNop().Sugar(),
+		svc:    service,
+	}
+
+	for _, opt := range opts {
+		opt(s)
+	}
+
+	sub, err := events.NewSubscriber(cfg, s.subOpts...)
+	if err != nil {
+		return nil, err
+	}
+
+	s.subscriber = sub
+
+	s.logger.Debugw("subscriber configuration", "config", cfg)
+
+	return s, nil
+}
+
+// Subscribe subscribes to a nats subject
+func (s *Subscriber) Subscribe(topic string) error {
+	msgChan, err := s.subscriber.SubscribeChanges(s.ctx, topic)
+	if err != nil {
+		return err
+	}
+
+	s.changeChannels = append(s.changeChannels, msgChan)
+
+	s.logger.Infof("Subscribing to topic %s", topic)
+
+	return nil
+}
+
+// Listen start listening for messages on registered subjects and calls the registered message handler
+func (s Subscriber) Listen() error {
+	wg := &sync.WaitGroup{}
+
+	// goroutine for each change channel
+	for _, ch := range s.changeChannels {
+		wg.Add(1)
+
+		go s.listen(ch, wg)
+	}
+
+	wg.Wait()
+
+	return nil
+}
+
+// listen listens for messages on a channel and calls the registered message handler
+func (s Subscriber) listen(messages <-chan *message.Message, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	for msg := range messages {
+		s.logger.Infow("processing event", "event.id", msg.UUID)
+		if err := s.processEvent(msg); err != nil {
+			s.logger.Warn("Failed to process msg: ", err)
+
+			s.logger.Infow("message nacked", "event.id", msg.UUID)
+			msg.Nack()
+		} else {
+			s.logger.Infow("message acked", "event.id", msg.UUID)
+			msg.Ack()
+		}
+	}
+}
+
+// Close closes the subscriber connection and unsubscribes from all subscriptions
+func (s *Subscriber) Close() error {
+	return s.subscriber.Close()
+}
+
+// processEvent event message handler
+func (s *Subscriber) processEvent(msg *message.Message) error {
+	changeMsg, err := events.UnmarshalChangeMessage(msg.Payload)
+	if err != nil {
+		s.logger.Errorw("failed to process data in msg", zap.Error(err))
+
+		return err
+	}
+
+	ctx, span := tracer.Start(context.Background(), "pubsub.receive", trace.WithAttributes(attribute.String("pubsub.subject", changeMsg.SubjectID.String())))
+
+	defer span.End()
+
+	switch events.ChangeType(changeMsg.EventType) {
+	case events.CreateChangeType:
+		err = s.handleTouchEvent(ctx, msg, changeMsg)
+	case events.UpdateChangeType:
+		err = s.handleTouchEvent(ctx, msg, changeMsg)
+	case events.DeleteChangeType:
+		err = s.handleDeleteEvent(ctx, msg, changeMsg)
+	default:
+		s.logger.Warnw("ignoring msg, not a create, update or delete event", "event_type", changeMsg.EventType)
+	}
+
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (s *Subscriber) handleTouchEvent(ctx context.Context, msg *message.Message, changeMsg events.ChangeMessage) error {
+	if s.svc.IsOrganizationID(changeMsg.SubjectID) {
+		if err := s.svc.TouchOrganization(ctx, changeMsg.SubjectID); err != nil {
+			// TODO: only return errors on retryable errors
+			return err
+		}
+
+		return nil
+	}
+
+	if s.svc.IsProjectID(changeMsg.SubjectID) {
+		if err := s.svc.TouchProject(ctx, changeMsg.SubjectID); err != nil {
+			// TODO: only return errors on retryable errors
+			return err
+		}
+
+		return nil
+	}
+
+	if s.svc.IsUser(changeMsg.SubjectID) {
+		if err := s.svc.TouchUser(ctx, changeMsg.SubjectID); err != nil {
+			// TODO: only return errors on retryable errors
+			return err
+		}
+
+		return nil
+	}
+
+	s.logger.Warnw("unknown subject id", "subject.id", changeMsg.SubjectID)
+
+	return nil
+}
+
+func (s *Subscriber) handleDeleteEvent(ctx context.Context, msg *message.Message, changeMsg events.ChangeMessage) error {
+	if s.svc.IsOrganizationID(changeMsg.SubjectID) {
+		if err := s.svc.DeleteOrganization(ctx, changeMsg.SubjectID); err != nil {
+			// TODO: only return errors on retryable errors
+			return err
+		}
+
+		return nil
+	}
+
+	if s.svc.IsProjectID(changeMsg.SubjectID) {
+		if err := s.svc.DeleteProject(ctx, changeMsg.SubjectID); err != nil {
+			// TODO: only return errors on retryable errors
+			return err
+		}
+
+		return nil
+	}
+
+	if s.svc.IsUser(changeMsg.SubjectID) {
+		if err := s.svc.DeleteUser(ctx, changeMsg.SubjectID); err != nil {
+			// TODO: only return errors on retryable errors
+			return err
+		}
+
+		return nil
+	}
+
+	s.logger.Warnw("unknown subject id", "subject.id", changeMsg.SubjectID)
+
+	return nil
+}