Files
upstream-watermill/_examples/basic/6-cqrs-ordered-events/subscribers.go
2026-09-15 21:27:46 +05:00

69 lines
1.3 KiB
Go

package main
import (
"context"
"log/slog"
"sync"
)
type SubscriberReadModel struct {
subscribers map[string]string // map[subscriberID]email
lock sync.RWMutex
}
func NewSubscriberReadModel() *SubscriberReadModel {
return &SubscriberReadModel{
subscribers: make(map[string]string),
}
}
func (m *SubscriberReadModel) OnSubscribed(ctx context.Context, event *SubscriberSubscribed) error {
m.lock.Lock()
defer m.lock.Unlock()
m.subscribers[event.SubscriberId] = event.Email
slog.Info(
"Subscriber added",
"subscriber_id", event.SubscriberId,
"email", event.Email,
)
return nil
}
func (m *SubscriberReadModel) OnUnsubscribed(ctx context.Context, event *SubscriberUnsubscribed) error {
m.lock.Lock()
defer m.lock.Unlock()
delete(m.subscribers, event.SubscriberId)
slog.Info(
"Subscriber removed",
"subscriber_id", event.SubscriberId,
)
return nil
}
func (m *SubscriberReadModel) OnEmailUpdated(ctx context.Context, event *SubscriberEmailUpdated) error {
m.lock.Lock()
defer m.lock.Unlock()
m.subscribers[event.SubscriberId] = event.NewEmail
slog.Info(
"Subscriber updated",
"subscriber_id", event.SubscriberId,
"email", event.NewEmail,
)
return nil
}
func (m *SubscriberReadModel) GetSubscriberCount() int {
m.lock.RLock()
defer m.lock.RUnlock()
return len(m.subscribers)
}