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How to connect BE service to Local Kafka

Background​

In the Navida Pro backend architecture, services communicate using:

  • HTTP (synchronous)
  • Kafka (asynchronous)

Kafka is primarily used for non-blocking async communication and persistent event processing in higher environments. Initially, each microservice managed its own Kafka utility code — leading to duplication and inconsistency.

To address this, all reusable Kafka components were centralized and migrated to the Open Contract library.

What Kafka Utilities Are in Open Contract?​

Open Contract now provides standardized Kafka support for all services, including:

  • Common Kafka producer and consumer configurations
  • Shared serializers and deserializers
  • Utility methods for message publishing
  • Property-driven behavior switches for different environments

This ensures consistency, reusability, and simplifies onboarding Kafka across services.

How to Run Kafka Locally for Development​

Step 1: Download and Extract Kafka​

Download and extract the Kafka locally.

Step 2: Start Zookeeper and Kafka Server​

# Start Zookeeper
bin/zookeeper-server-start.sh config/zookeeper.properties

# In a new terminal, start Kafka server
bin/kafka-server-start.sh config/server.properties

Kafka is now up and running on your machine.

Step 3: Configure Your Spring Boot Service​

In your application.properties or application.yml, set the following properties:

spring.profiles.active=local
aok.data.process.method=kafka-implementation

Why spring.profiles.active=local?

This setting tells your application to use local Kafka configuration. Higher environments require certificates and keys, which are not required or configured locally. A custom configuration bean in Open Contract ensures the correct Kafka setup is loaded when local is active.

Why aok.data.process.method=kafka-implementation?

We have a conditional check in the business logic to switch between:

  • data-process-implementation → uses Feign client (sync)
  • kafka-implementation → uses Kafka (async)

Set this to kafka-implementation to ensure all write operations go through Kafka.

Summary for Local Kafka Setup​

  1. Integrate Open Contract (see integration guide)
  2. Start local Kafka server (Zookeeper + Kafka broker)
  3. Ensure these properties are configured: 
    spring.profiles.active=local
    aok.data.process.method=kafka-implementation

Once these steps are complete, your service will successfully connect to Kafka running on your local machine.

Final Note​

Centralizing Kafka logic into Open Contract has simplified Kafka integration across all backend services. It enables:

  • Easier onboarding for developers
  • Cleaner codebase
  • Environment-specific flexibility
  • Improved debugging and observability