Application integration
Decoupling components means a failure or slowdown in one does not take down the others. It is the keyword of this topic on the exam.
SQS
Simple Queue Service
Managed message queues: one component sends, another consumes at its own pace.
Key points
- Pull model: the consumer polls for messages.
- Keeps messages for up to 14 days.
- Standard queues (high throughput) and FIFO queues (guaranteed order).
On the exam
"Decouple components and hold messages until they are processed": SQS.
SNS
Simple Notification Service
Pub/sub messaging: a topic delivers the same message to many subscribers.
Key points
- Push model: the service delivers to subscribers.
- Targets: SQS, Lambda, HTTP, email, SMS and mobile notifications.
- Message filtering per subscriber.
On the exam
Send alerts by email or SMS, or fan a message out to many systems: SNS.
EventBridge
Amazon EventBridge
A serverless event bus that connects applications through events.
Key points
- Receives events from AWS services, SaaS apps and your own applications.
- Rules route each event to the right targets.
- The Scheduler schedules tasks, including in cron format.
On the exam
Event-driven architecture or reacting to events from AWS services and SaaS: EventBridge.
Step Functions
AWS Step Functions
Orchestrates services in visual workflows (state machines).
Key points
- Sequential, parallel and conditional steps.
- Built-in error handling and retries.
- Integrates with Lambda and more than 200 services.
On the exam
Coordinate several steps (e.g. several Lambda functions) in one workflow: Step Functions.
A managed message broker for Apache ActiveMQ and RabbitMQ.
Key points
- Compatible with standard protocols: AMQP, MQTT, STOMP, OpenWire.
- Eases migrating existing messaging systems.
- For new applications, SQS and SNS are usually the choice.
On the exam
Move an existing ActiveMQ or RabbitMQ without rewriting the application: Amazon MQ.