Scheduled tasks and event-driven architecture in Serverless are important features that enable automation and responsive applications:
Scheduled task implementation:
1. EventBridge (CloudWatch Events)
- Cron expressions: Use Cron expressions to define trigger rules
- Scheduled triggers: Trigger Lambda functions at fixed time intervals
- Applicable scenarios: Data backup, report generation, cleanup tasks
2. Scheduled trigger configuration
- Rate expressions: Use expressions like rate(1 minute), rate(1 hour)
- Cron expressions: Use expressions like cron(0 10 * * ? *)
- Timezone settings: Support setting specific timezones
3. Best practices
- Idempotency: Ensure tasks can be safely retried
- Timeout settings: Set reasonable timeout times
- Error handling: Implement comprehensive error handling and retry mechanisms
Event-driven architecture:
1. Event sources
- S3 events: File upload, deletion and other operations trigger
- DynamoDB Streams: Database changes trigger
- SNS/SQS: Message publishing and queue triggers
- API Gateway: HTTP requests trigger
2. Event processing patterns
- Direct trigger: Event sources directly trigger Lambda functions
- Asynchronous processing: Process events asynchronously through message queues
- Event routing: Use EventBridge to route events to multiple consumers
3. Event sourcing
- Event storage: Store events in event logs
- State reconstruction: Reconstruct application state by replaying events
- Audit trail: Completely record all state changes
Common application scenarios:
1. Data processing
- ETL processes: Scheduled data extraction, transformation, loading
- Data cleaning: Scheduled cleaning and transformation of data
- Data analysis: Scheduled generation of analysis reports
2. Operations automation
- Resource cleanup: Scheduled cleanup of expired resources
- Health checks: Scheduled checks of system health status
- Alert notifications: Scheduled sending of alert notifications
3. Business automation
- Order processing: Scheduled processing of pending orders
- Member management: Scheduled updates of member status
- Marketing campaigns: Scheduled start and end of marketing campaigns
Candidates should be able to share experience in implementing scheduled tasks and event-driven architecture from actual projects.