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Event-driven architecture (EDA) is often misunderstood, with many teams equating it to simply dumping database changes onto a message broker. However, there’s a critical distinction between broadcasting what changed (Change Data Capture – CDC) and why it changed (Domain Events).
🔗 Read the full article here: https://lnkd.in/eqyqwMKE
You Should Know:
1. Domain Events (Business Intent)
Domain Events represent meaningful business occurrences, such as:
– `OrderPlaced`
– `PaymentProcessed`
– `UserRegistered`
Example Kafka Command (Producer):
kafka-console-producer --broker-list localhost:9092 --topic order-events <<EOF
{ "eventType": "OrderPlaced", "orderId": "12345", "userId": "67890", "timestamp": "2025-04-19T12:00:00Z" }
EOF
2. Change Data Capture (CDC) (DB Change Tracking)
CDC captures low-level database changes (inserts, updates, deletes) without business context.
Debezium (CDC Tool) Setup:
Start Zookeeper
bin/zookeeper-server-start.sh config/zookeeper.properties
Start Kafka
bin/kafka-server-start.sh config/server.properties
Configure Debezium MySQL Connector
curl -i -X POST -H "Accept:application/json" -H "Content-Type:application/json" localhost:8083/connectors/ -d '{
"name": "inventory-connector",
"config": {
"connector.class": "io.debezium.connector.mysql.MySqlConnector",
"database.hostname": "mysql",
"database.port": "3306",
"database.user": "debezium",
"database.password": "dbz",
"database.server.id": "184054",
"database.server.name": "dbserver1",
"database.include.list": "inventory",
"database.history.kafka.bootstrap.servers": "kafka:9092",
"database.history.kafka.topic": "schema-changes.inventory"
}
}'
When to Use Which?
| Scenario | Use Domain Events | Use CDC |
|-|-|-|
| Business process tracking | ✅ Yes | ❌ No |
| Data replication/sync | ❌ No | ✅ Yes |
| Audit logging | ❌ No | ✅ Yes |
Linux & Windows Commands for Event-Driven Systems
- Kafka Topic Creation:
kafka-topics --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 3 --topic domain-events
Windows Event Log (For CDC-like tracking):
Get-WinEvent -LogName "Application" -MaxEvents 10 | Format-Table -AutoSize
RabbitMQ (Alternative to Kafka):
rabbitmqctl list_queues rabbitmqadmin publish exchange=amq.default routing_key=test payload="Hello, World!"
What Undercode Say
Event-driven architectures require careful consideration of business intent vs data synchronization. Misusing CDC as a replacement for Domain Events leads to tightly coupled systems. Always start simple but ensure teams understand the difference.
For deeper implementation, explore:
- Kafka Streams for event processing
- Debezium for real-time CDC
- AsyncAPI for event documentation
Expected Output:
A well-structured event-driven system separates business events from database changes, ensuring scalability and maintainability. Use the right tool for the right job!
References:
Reported By: Raul Junco – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
