Step Functions & EventBridge — Orchestration & Event-Driven

Tổng quan

Step Functions = orchestration (điều phối workflow phức tạp, có state). EventBridge = choreography (event-driven, loose coupling). Thường kết hợp: EventBridge trigger Step Functions workflow.

Step Functions Patterns

• Standard workflow: tối đa 1 năm, exactly-once, trả phí theo state transition.
• Express workflow: tối đa 5 phút, at-least-once, trả phí theo duration.
• Optimized integrations: gọi trực tiếp 200+ AWS service (DynamoDB, SQS, ECS...) không cần Lambda.
• Map state (Distributed): xử lý hàng triệu item song song (S3 inventory, CSV).
• Wait for Callback (.waitForTaskToken): chờ external system hoàn thành.
• Saga pattern: mỗi step có compensation transaction khi fail.

EventBridge Patterns

• Event Bus: default (AWS events), custom (app events), partner (SaaS).
• Rules: pattern matching trên event content (source, detail-type, detail fields).
• Targets: Lambda, SQS, SNS, Step Functions, API Gateway, Kinesis, ECS task...
• EventBridge Pipes: source → filter → enrich → target (point-to-point, no code).
• EventBridge Scheduler: cron/rate/one-time, thay CloudWatch Events.
• Archive & Replay: lưu events, replay lại cho debug/testing.
• Schema Registry: auto-discover event schema, generate code bindings.

Khi nào chọn gì

• Workflow có nhiều bước tuần tự, branching, retry → Step Functions.
• Event routing từ nhiều source tới nhiều target → EventBridge.
• Cron job / scheduled task → EventBridge Scheduler.
• Point-to-point transform → EventBridge Pipes.
• Long-running approval workflow → Step Functions + .waitForTaskToken.