Message Broker Adapter Generator

Creates unified message broker abstraction with adapter implementations for multiple broker technologies.

When to Use

Scenario	Example
Broker abstraction	Switch between RabbitMQ/Kafka/SQS without code changes
Multi-broker support	Different brokers for different bounded contexts
Testing isolation	InMemory adapter for tests
Migration path	Gradual migration from one broker to another
Vendor independence	Avoid lock-in to specific message broker

Component Characteristics

MessageBrokerInterface

• Domain layer port
• publish(Message): void
• consume(string queue, callable handler): void
• acknowledge(Message): void
• reject(Message, bool requeue): void

Message

• Immutable value object
• Body (string), headers (array), routingKey, metadata
• Correlation ID and message ID
• Timestamp and content type

MessageSerializerInterface

• Serialize/deserialize messages
• JSON implementation by default
• Extensible for Avro, Protobuf

RabbitMqAdapter

• php-amqplib based
• Exchange and queue declaration
• Publish confirm mode
• Consumer with prefetch

KafkaAdapter

• RdKafka based
• Topic partitioning
• Consumer groups
• Offset management

SqsAdapter

• AWS SDK based
• FIFO and standard queues
• Long polling
• Visibility timeout

InMemoryAdapter

• For testing only
• Tracks published messages
• Synchronous consumption

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Generation Process

Step 1: Analyze Request

Determine:

• Which broker adapters needed (RabbitMQ, Kafka, SQS, or all)
• Queue/topic naming conventions
• Serialization format

Step 2: Generate Core Components

1. Domain Layer (src/Domain/Shared/Messaging/)

   • Message.php — Immutable message value object
   • MessageBrokerInterface.php — Broker port
   • MessageSerializerInterface.php — Serialization contract
   • MessageId.php — Message identity value object

2. Infrastructure Layer (src/Infrastructure/Messaging/)

   • JsonMessageSerializer.php — JSON serializer
   • RabbitMq/RabbitMqAdapter.php — RabbitMQ implementation
   • Kafka/KafkaAdapter.php — Kafka implementation
   • Sqs/SqsAdapter.php — AWS SQS implementation
   • InMemory/InMemoryAdapter.php — Testing adapter
   • MessageBrokerFactory.php — Config-based adapter factory

3. Tests

   • MessageTest.php
   • JsonMessageSerializerTest.php
   • InMemoryAdapterTest.php
   • MessageBrokerFactoryTest.php

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File Placement

Layer	Path
Domain Types	src/Domain/Shared/Messaging/
Infrastructure	src/Infrastructure/Messaging/
Broker Adapters	src/Infrastructure/Messaging/{Broker}/
Unit Tests	tests/Unit/{Layer}/{Path}/

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Naming Conventions

Component	Pattern	Example
Interface	MessageBrokerInterface	MessageBrokerInterface
Message VO	Message	Message
Adapter	{Broker}Adapter	RabbitMqAdapter
Serializer	{Format}MessageSerializer	JsonMessageSerializer
Factory	MessageBrokerFactory	MessageBrokerFactory
Test	{ClassName}Test	RabbitMqAdapterTest

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Quick Template Reference

MessageBrokerInterface

interface MessageBrokerInterface
{
    public function publish(Message $message, string $routingKey = ''): void;
    public function consume(string $queue, callable $handler): void;
    public function acknowledge(Message $message): void;
    public function reject(Message $message, bool $requeue = false): void;
}

Message

final readonly class Message
{
    public function __construct(
        public MessageId $id,
        public string $body,
        public string $routingKey = '',
        public array $headers = [],
        public ?string $correlationId = null,
        public ?string $contentType = 'application/json',
        public ?\DateTimeImmutable $timestamp = null,
    ) {}

    public static function create(string $body, string $routingKey = '', array $headers = []): self;
    public function withHeader(string $key, string $value): self;
    public function withCorrelationId(string $correlationId): self;
}

---

Usage Example

// Publish
$message = Message::create(
    body: json_encode(['order_id' => $orderId, 'total' => $total]),
    routingKey: 'orders.created'
);
$broker->publish($message);

// Consume
$broker->consume('order_processing', function (Message $message) use ($handler) {
    $handler->handle($message);
    $this->broker->acknowledge($message);
});

---

DI Configuration

Domain\Shared\Messaging\MessageBrokerInterface:
    factory: ['@Infrastructure\Messaging\MessageBrokerFactory', 'create']
    arguments:
        $driver: '%env(MESSAGE_BROKER_DRIVER)%'

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References

For complete PHP templates and test examples, see:

• references/templates.md — All component templates
• references/examples.md — Order event publishing example and unit tests