Apa iku event-driven architecture ing microservices?

Question

Accepted Answer

Ing **event-driven architecture**, layanan berkomunikasi kanthi **ngasilake lan ngkonsumsine event** liwat broker (Kafka, RabbitMQ, lsp.). Sawijining layanan ngumumake yen ana-ana kedadean; layanan sing kasenggukan bisa ngreaksi — produser ora ngerti utawa ngenteni.

## Carane kerja

```text
Order Service ─publish→ [ Event Broker: "order.placed" ]
                              │
            ┌─────────────────┼──────────────────┐
            ▼                 ▼                  ▼
      Inventory         Notification          Analytics
      (reserve stock)   (send email)          (record metric)
```

## Conto event payload

```json
{
  "eventType": "order.placed",
  "eventId": "e-9f2c",          // unique → consumers dedupe
  "occurredAt": "2026-06-18T10:00:00Z",
  "data": { "orderId": "42", "total": 99.5 }
}
```

## Kauntungan

- **Loose coupling** — tambah consumer anyar tanpa nggubah producer.
- **Resilience** — broker menyimpan event nalika ana gangguan.
- **Scalability** — consumer bisa berkembang kanthi mandiri.

## Jebakan

```text
⚠️ Eventual consistency — readers may briefly see stale data
⚠️ Duplicate delivery — make consumers idempotent (use eventId)
⚠️ Ordering — only guaranteed within a partition/queue
⚠️ Hard to trace a flow across many consumers
```

## Kenapa penting

Desain event-driven iki sing ndadekne sampeyan bisa nambah kemampuan (analytics, fraud checks, notifications) kanthi mung melu, tanpa ana owah-owahan ing producer sing ana.

Ekstenibilitas lan resilience kuwi owah-owahan karo eventual consistency lan debugging sing luwih angel — pertukaran tengah sing sampeyan tanggap nalika mlayu event-driven.