Example: full app with Postgres store (multi-instance cluster, no NATS) #28

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opened 2026-02-19 22:28:39 +00:00 by ash · 2 comments

ash commented

2026-02-19 22:28:39 +00:00

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What

Complete working example app using Postgres store with clustering support. Multiple instances, no NATS.

Must Demonstrate

All 3 event modeling patterns
Single writer via pg_advisory_lock (distributed)
LISTEN/NOTIFY for real-time subscriptions
Competing projections (multiple instances, each event processed once)
OCC with gap handling
Multi-instance: run 3 copies, they coordinate via Postgres
Graceful shutdown + rebalancing
Connection pooling
Schema migration on startup
HTTP API + SSE live updates

Deployment

docker-compose with Postgres + 3 app instances
Or just go run main.go x3 pointing at same Postgres

Why

This is the "production without NATS" example. Many teams have Postgres and nothing else.

## What Complete working example app using Postgres store with clustering support. Multiple instances, no NATS. ## Must Demonstrate - All 3 event modeling patterns - Single writer via pg_advisory_lock (distributed) - LISTEN/NOTIFY for real-time subscriptions - Competing projections (multiple instances, each event processed once) - OCC with gap handling - Multi-instance: run 3 copies, they coordinate via Postgres - Graceful shutdown + rebalancing - Connection pooling - Schema migration on startup - HTTP API + SSE live updates ## Deployment - docker-compose with Postgres + 3 app instances - Or just `go run main.go` x3 pointing at same Postgres ## Why This is the "production without NATS" example. Many teams have Postgres and nothing else.

ash added the

enhancement

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2026-02-19 22:28:39 +00:00

ash referenced this issue from a commit

2026-02-20 08:15:21 +00:00

feat: add subscription.StoreAdapter to bridge store→subscription type gap

ash commented

2026-02-20 08:15:35 +00:00

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Implemented in commit 0b50908. Full working examples with end-to-end flow tested (HTTP → CommandBus → Decider → Store → Subscription → Projection → HTTP query).

Also fixed library gap: added subscription.StoreAdapter and pgstore.SubscriptionAdapter to bridge the type mismatch between store Event[E] and subscription GlobalEvent[E].

Implemented in commit 0b50908. Full working examples with end-to-end flow tested (HTTP → CommandBus → Decider → Store → Subscription → Projection → HTTP query). Also fixed library gap: added subscription.StoreAdapter and pgstore.SubscriptionAdapter to bridge the type mismatch between store Event[E] and subscription GlobalEvent[E].

ash closed this issue

2026-02-20 08:15:35 +00:00

ash commented

2026-02-20 08:15:40 +00:00

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Owner

Implemented. Full end-to-end flow tested.