jEAP Messaging

jEAP Messaging is a library for sending and receiving messages over Apache Kafka in Spring Boot applications. It builds on Spring for Apache Kafka and Avro, and lets a microservice produce and consume strongly-typed events and commands with minimal boilerplate. It provides:

• A structured definition of message types using Avro schemas and message-type descriptors
• Avro serialization of message types to Kafka records
• Pre-configured Spring Kafka beans for producers and consumers (single- and multi-cluster)
• Declaration of consumed/produced message types on topics using Java annotations (message contracts)
• Built-in error handling that never loses a message (integration with a jeap-error-handling-service)
• Idempotent message handling, message signing and encryption, and a Kafka broker health indicator

For the transactional outbox pattern see the separate jeap-messaging-outbox library.

Documentation

Start with Getting started, then follow the links below.

Topic	File
Getting started (add the dependency, produce & consume)	docs/getting-started.md
Architecture & three-layer model	docs/architecture.md
Choosing dependencies	docs/dependencies.md
Configuration reference (jeap.messaging.kafka.*)	docs/configuration.md
Message types (events & commands)	docs/message-types.md
Defining messages in Avro	docs/defining-messages.md
Avro Maven plugin	docs/avro-maven-plugin.md
Schema evolution	docs/message-evolution.md
Message Type Registry	docs/message-type-registry.md
Publishing messages	docs/publishing-messages.md
Consuming messages	docs/consuming-messages.md
Kafka how-to (integrate Kafka into a service)	docs/kafka-how-to.md
Kafka topics & client configuration	docs/kafka-topics-and-configuration.md
Message contracts	docs/message-contracts.md
Idempotent message handler	docs/idempotent-message-handler.md
Error handling	docs/error-handling.md
Confluent Schema Registry	docs/schema-registry-confluent.md
AWS Glue Schema Registry	docs/schema-registry-aws-glue.md
AWS MSK IAM authentication	docs/aws-msk-iam-authentication.md
Signing messages	docs/signing-messages.md
Encrypting messages	docs/encrypting-messages.md
Message filtering	docs/message-filtering.md
Health indicators	docs/health-indicators.md
Testing	docs/testing.md

Modules

The artifact most consumers depend on is jeap-messaging-infrastructure-kafka. Group id for all modules is ch.admin.bit.jeap; the version is managed by the jEAP Spring Boot parent.

Module	Purpose
jeap-messaging-model	Infrastructure-independent interfaces for domain events and commands
jeap-messaging-api	MessageListener / MessagePublisher interfaces
jeap-messaging-avro	Avro implementation of the model: AvroMessage, builders, AvroSerializationHelper
jeap-messaging-avro-maven-plugin	Generates Java classes from Avro schemas / the Message Type Registry
jeap-messaging-avro-compiler, -validator, -test	Internal Avro compilation, validation and test support
jeap-messaging-avro-errorevent	Avro types for the error-handling integration
jeap-messaging-infrastructure	Core Kafka infrastructure: serialization, signing, crypto, tracing, metrics, health, error handling
jeap-messaging-infrastructure-kafka	Spring Boot auto-configuration; the main consumer-facing artifact
jeap-messaging-infrastructure-kafka-test	Test fixtures: TestMessageSender, TestKafkaListener, KafkaIntegrationTestBase
jeap-messaging-infrastructure-kafka-without-tracing-test	Test fixtures for services that do not use tracing
jeap-messaging-confluent-schema-registry	Confluent Schema Registry integration
jeap-messaging-glue-schema-registry	AWS Glue Schema Registry integration
jeap-messaging-aws-msk-iam-auth	AWS MSK IAM authentication
jeap-messaging-idempotence	@IdempotentMessageHandler with a JPA-backed processing store and housekeeping
jeap-messaging-contract-annotations	Message-contract annotations
jeap-messaging-contract-annotation-processor	Annotation processor generating the contract JSON uploaded during the build
jeap-messaging-contract-maven-plugin	Maven plugin for message contracts
jeap-messaging-registry-maven-plugin	Verifies and exports a Message Type Registry

Changes

This library is versioned using Semantic Versioning and all changes are documented in CHANGELOG.md following the format defined in Keep a Changelog.

Note

This repository is part the open source distribution of jEAP. See github.com/jeap-admin-ch/jeap for more information.

License

This repository is Open Source Software licensed under the Apache License 2.0.