borealis.go/bus.go

package borealis

import (
	"fmt"

	"github.com/nats-io/nats.go"
)

type Bus struct {
	NATS *nats.EncodedConn
}

type SubscriberHandler func(event *Event)

func Connect(url string) (*Bus, error) {
	nats.RegisterEncoder("v1", &V1MessageEncoder{})
	conn, err := nats.Connect(url)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to the broker: %w", err)
	}
	encodedConn, err := nats.NewEncodedConn(conn, "v1")
	if err != nil {
		return nil, fmt.Errorf("failed to configure the bus encoding: %w", err)
	}
	return &Bus{NATS: encodedConn}, nil
}

func (bus *Bus) SendEmail(request *SendEmail) error {
	return bus.Publish("email.outbound", request)
}

func (bus *Bus) RegisterID(request *RegisterID) error {
	return bus.Publish("id.register", request)
}

func (bus *Bus) VerifyEmail(request *VerifyEmail) error {
	return bus.Publish("id.verify", request)
}

func (bus *Bus) GrantAccess(request *GrantAccess) error {
	return bus.Publish("access.grant", request)
}

func (bus *Bus) RevokeAccess(request *RevokeAccess) error {
	return bus.Publish("access.revoke", request)
}

func (bus *Bus) Publish(stream string, request interface{}) error {
	rawEvent, err := NewRawEvent(0, request) // TODO
	if err != nil {
		return err
	}
	return bus.PublishRawEvent(stream, rawEvent)
}

func (bus *Bus) PublishRawEvent(stream string, rawEvent *RawEvent) error {
	if err := bus.NATS.Publish(stream, rawEvent); err != nil {
		return fmt.Errorf("failed to publish message: %w", err)
	}
	return nil
}

func (bus *Bus) Subscribe(stream string, handler SubscriberHandler) (*nats.Subscription, error) {
	return bus.NATS.Subscribe(stream, func(rawEvent RawEvent) {
		event, err := rawEvent.Check()
		if err == nil { // ignore invalid messages
			handler(event)
		}
	})
}