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Skills
Chapter 18 of 28
Asynchronous messaging in Encore Go via pubsub.NewTopic and pubsub.NewSubscription from encore.dev/pubsub — broadcast events, decouple producers from consumers, and run background…
1 minute · 132 words · 8 sections
Pub/Sub is for asynchronous messaging between services. Producers publish events to a Topic; consumers attach Subscriptions to react. Resources must be declared as package-level variables — never inside functions.
package events
import "encore.dev/pubsub"
type OrderCreatedEvent struct {
OrderID string `json:"order_id"`
UserID string `json:"user_id"`
Total int `json:"total"`
}
// Package level declaration
var OrderCreated = pubsub.NewTopic[*OrderCreatedEvent]("order-created", pubsub.TopicConfig{
DeliveryGuarantee: pubsub.AtLeastOnce,
})msgID, err := events.OrderCreated.Publish(ctx, &events.OrderCreatedEvent{
OrderID: "123",
UserID: "user-456",
Total: 9999,
})package notifications
import (
"context"
"myapp/events"
"encore.dev/pubsub"
)
var _ = pubsub.NewSubscription(events.OrderCreated, "send-confirmation-email",
pubsub.SubscriptionConfig[*events.OrderCreatedEvent]{
Handler: sendConfirmationEmail,
},
)
func sendConfirmationEmail(ctx context.Context, event *events.OrderCreatedEvent) error {
// Send email...
return nil
}Pass topic access to library code while maintaining static analysis:
// Create a reference with publish permission
ref := pubsub.TopicRef[pubsub.Publisher[*OrderCreatedEvent]](OrderCreated)
// Use the reference in library code
func publishEvent(ref pubsub.Publisher[*OrderCreatedEvent], event *OrderCreatedEvent) error {
_, err := ref.Publish(ctx, event)
return err
}pubsub.AtLeastOnce (default): may deliver duplicates → handlers must be idempotent.pubsub.ExactlyOnce: stricter, capped throughput (AWS 300 msg/s/topic, GCP 3000+ msg/s/region). Does not deduplicate on the publish side.context.Context and the event pointer; return an error to retry per the topic’s retry policy.Publish callers — Publish returns once the message is queued.Install this repository
npx skills add encoredev/skills/plugin marketplace add encoredev/skillsSkills install per repository, not per chapter — the CLI has no documented per-skill form, so we do not print one.
Asynchronous messaging in Encore Go via `pubsub.NewTopic` and `pubsub.NewSubscription` from `encore.dev/pubsub` — broadcast events, decouple producers from consumers, and run background handlers.
The verbatim description from this skill’s front matter — the string an agent matches on to decide whether to load it.
main, last pushed 15 May 2026.SKILL.md, not by matching a directory convention. One layout observed: encore/*/SKILL.md.h1 and no skipped levels:.claude-plugin/marketplace.json by Encore, declaring 1 plugin. It is read for editorial metadata only — never as the skill index, which is always the repository tree./encoredev/skills.md, and each chapter at its own .md URL.