aws-eventbridge

# AWS EventBridge Amazon EventBridge is a serverless event bus that connects applications using events. Route events from AWS services, custom applications, and SaaS partners. ## Table of Contents - [Core Concepts](#core-concepts) - [Common Patterns](#common-patterns) - [CLI Reference](#cli-reference) - [Best Practices](#best-practices) - [Troubleshooting](#troubleshooting) - [References](#references) ## Core Concepts ### Event Bus Channel that receives events. Types: - **Default**: Receives AWS service events - **Custom**: Your application events - **Partner**: SaaS application events ### Rules Match incoming events and route to targets. Each rule can have up to 5 targets. ### Event Patterns JSON patterns that define which events match a rule. ### Targets AWS services that receive matched events (Lambda, SQS, SNS, Step Functions, etc.). ### Scheduler Schedule one-time or recurring events to invoke targets. ## Common Patterns ### Create Custom Event Bus and Rule **AWS CLI:** ```bash # Create custom event bus aws events create-event-bus --name my-app-events # Create rule aws events put-rule \ --name order-created-rule \ --event-bus-name my-app-events \ --event-pattern '{ "source": ["my-app.orders"], "detail-type": ["Order Created"] }' # Add Lambda target aws events put-targets \ --rule order-created-rule \ --event-bus-name my-app-events \ --targets '[{ "Id": "process-order", "Arn": "arn:aws:lambda:us-east-1:123456789012:function:ProcessOrder" }]' # Add Lambda permission aws lambda add-permission \ --function-name ProcessOrder \ --statement-id eventbridge-order-created \ --action lambda:InvokeFunction \ --principal events.amazonaws.com \ --source-arn arn:aws:events:us-east-1:123456789012:rule/my-app-events/order-created-rule ``` **boto3:** ```python import boto3 import json events = boto3.client('events') # Create rule events.put_rule( Name='order-created-rule', EventBusName='my-app-events', EventPattern=json.dumps({ 'source': ['my-app.orders'], 'detail-type': ['Order Created'] }), State='ENABLED' ) # Add target events.put_targets( Rule='order-created-rule', EventBusName='my-app-events', Targets=[{ 'Id': 'process-order', 'Arn': 'arn:aws:lambda:us-east-1:123456789012:function:ProcessOrder' }] ) ``` ### Publish Custom Events ```python import boto3 import json events = boto3.client('events') events.put_events( Entries=[ { 'Source': 'my-app.orders', 'DetailType': 'Order Created', 'Detail': json.dumps({ 'order_id': '12345', 'customer_id': 'cust-789', 'total': 99.99 }), 'EventBusName': 'my-app-events' } ] ) ``` ### Scheduled Events ```bash # Run every 5 minutes aws events put-rule \ --name every-5-minutes \ --schedule-expression "rate(5 minutes)" # Run at specific times (cron) aws events put-rule \ --name daily-cleanup \ --schedule-expression "cron(0 2 * * ? *)" # Add target aws events put-targets \ --rule every-5-minutes \ --targets '[{ "Id": "cleanup-function", "Arn": "arn:aws:lambda:us-east-1:123456789012:function:Cleanup" }]' ``` ### EventBridge Scheduler (One-Time and Flexible) ```bash # One-time schedule aws scheduler create-schedule \ --name send-reminder \ --schedule-expression "at(2024-12-25T09:00:00)" \ --target '{ "Arn": "arn:aws:lambda:us-east-1:123456789012:function:SendReminder", "RoleArn": "arn:aws:iam::123456789012:role/scheduler-role", "Input": "{\"message\": \"Happy Holidays!\"}" }' \ --flexible-time-window '{"Mode": "OFF"}' # Recurring with flexible window aws scheduler create-schedule \ --name hourly-sync \ --schedule-expression "rate(1 hour)" \ --target '{ "Arn": "arn:aws:lambda:us-east-1:123456789012:function:SyncData", "RoleArn": "arn:aws:iam::123456789012:role/scheduler-role" }' \ --flexible-time-window '{"Mode": "FLEXIBLE", "MaximumWindowInMinutes": 15}' ``` ### AWS Service Events ```bash # EC2 state changes aws events put-rule \ --name ec2-state-change \ --event-pattern '{ "source": ["aws.ec2"], "detail-type": ["EC2 Instance State-change Notification"], "detail": { "state": ["stopped", "terminated"] } }' # S3 object created aws events put-rule \ --name s3-upload \ --event-pattern '{ "source": ["aws.s3"], "detail-type": ["Object Created"], "detail": { "bucket": {"name": ["my-bucket"]}, "object": {"key": [{"prefix": "uploads/"}]} } }' ``` ### Good Event Structure ```python events.put_events( Entries=[{ 'Source': 'mycompany.orders.api', 'DetailType': 'Order Created', 'Detail': json.dumps({ 'version': '1.0', 'correlation_id': 'req-abc-123', 'timestamp': '2024-01-15T10:30:00Z', 'order_id': '12345', 'data': {'total': 99.99} }), 'EventBusName': 'my-app-events' }] ) ``` ## CLI Reference ### Event Buses | Command | Description | |---------|-------------| | `aws events create-event-bus` | Create event bus | | `aws events delete-event-bus` | Delete event bus | | `aws events list-event-buses` | List event buses | | `aws events describe-event-bus` | Get event bus details | ### Rules | Command | Description | |---------|-------------| | `aws events put-rule` | Create or update rule | | `aws events delete-rule` | Delete rule | | `aws events list-rules` | List rules | | `aws events describe-rule` | Get rule details | | `aws events enable-rule` | Enable rule | | `aws events disable-rule` | Disable rule | ### Targets | Command | Description | |---------|-------------| | `aws events put-targets` | Add targets to rule | | `aws events remove-targets` | Remove targets | | `aws events list-targets-by-rule` | List rule targets | ### Events | Command | Description | |---------|-------------| | `aws events put-events` | Publish events | ## Best Practices ### Event Design - **Use meaningful source names** — `company.service.component` - **Use descriptive detail-types** — `Order Created`, `User Signed Up` - **Include correlation IDs** for tracing - **Keep events small** (< 256 KB) - **Use versioning** for event schemas ### Reliability - **Use DLQs** for failed deliveries - **Implement idempotency** in consumers - **Monitor failed invocations** - **Use archive and replay** for recovery ### Security - **Use resource policies** to control access - **Enable encryption** with KMS - **Use IAM roles** for targets ### Cost Optimization - **Use specific event patterns** to reduce matches - **Batch events** when publishing (up to 10 per call) ## Troubleshooting ### Rule Not Triggering **Debug:** ```bash # Check rule status aws events describe-rule --name my-rule # Test event pattern aws events test-event-pattern \ --event-pattern '{"source": ["my-app"]}' \ --event '{"source": "my-app", "detail-type": "Test"}' ``` **Common causes:** - Rule disabled - Event pattern doesn't match - Target permissions missing ### Lambda Not Invoked **Check Lambda permissions:** ```bash aws lambda get-policy --function-name MyFunction ``` **Required permission:** ```json { "Principal": "events.amazonaws.com", "Action": "lambda:InvokeFunction", "Resource": "function-arn", "Condition": { "ArnLike": { "AWS:SourceArn": "rule-arn" } } } ``` ### Viewing Failed Events ```bash # Check FailedInvocations metric aws cloudwatch get-metric-statistics \ --namespace AWS/Events \ --metric-name FailedInvocations \ --dimensions Name=RuleName,Value=my-rule \ --start-time $(date -d '1 hour ago' -u +%Y-%m-%dT%H:%M:%SZ) \ --end-time $(date -u +%Y-%m-%dT%H:%M:%SZ) \ --period 300 \ --statistics Sum ``` ## References - [EventBridge User Guide](https://docs.aws.amazon.com/eventbridge/latest/userguide/) - [EventBridge API Reference](https://docs.aws.amazon.com/eventbridge/latest/APIReference/) - [EventBridge CLI Reference](https://docs.aws.amazon.com/cli/latest/reference/events/) - [boto3 EventBridge](https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/events.html) - [Event Pattern Reference](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-event-patterns.html)