Symfony Messenger Kafka Transport

This bundle aims to provide a simple Kafka transport for Symfony Messenger. Kafka REST Proxy support coming soon.

Installation

Applications that use Symfony Flex

Open a command console, enter your project directory and execute:

$ composer require koco/messenger-kafka

Applications that don't use Symfony Flex

After adding the composer requirement, enable the bundle by adding it to the list of registered bundles in the config/bundles.php file of your project:

return [
    // ...
    Koco\Kafka\KocoKafkaBundle::class => ['all' => true],
];

Configuration

DSN

Specify a DSN starting with either kafka:// or kafka+ssl://. Multiple brokers are separated by ,.

• kafka://my-local-kafka:9092
• kafka+ssl://my-staging-kafka:9093
• kafka+ssl://prod-kafka-01:9093,kafka+ssl://prod-kafka-02:9093,kafka+ssl://prod-kafka-03:9093

Example

The configuration options for kafka_conf and topic_conf can be found here. It is highly recommended to set enable.auto.offset.store to false for consumers. Otherwise, every message will be acknowledged, regardless of any error thrown by the message handlers.

framework:
    messenger:
        transports:
            producer:
                dsn: '%env(KAFKA_URL)%'
                # serializer: App\Infrastructure\Messenger\MySerializer
                options:
                    flushTimeout: 10000
                    flushRetries: 5
                    topic:
                        name: 'events'
                    kafka_conf:
                        security.protocol: 'sasl_ssl'
                        ssl.ca.location: '%kernel.project_dir%/config/kafka/ca.pem'
                        sasl.username: '%env(KAFKA_SASL_USERNAME)%'
                        sasl.password: '%env(KAFKA_SASL_PASSWORD)%'
                        sasl.mechanisms: 'SCRAM-SHA-256'
            consumer:
                dsn: '%env(KAFKA_URL)%'
                # serializer: App\Infrastructure\Messenger\MySerializer
                options:
                    commitAsync: true
                    receiveTimeout: 10000
                    topic:
                        name: "events"
                    kafka_conf:
                        enable.auto.offset.store: 'false'
                        group.id: 'my-group-id' # should be unique per consumer
                        security.protocol: 'sasl_ssl'
                        ssl.ca.location: '%kernel.project_dir%/config/kafka/ca.pem'
                        sasl.username: '%env(KAFKA_SASL_USERNAME)%'
                        sasl.password: '%env(KAFKA_SASL_PASSWORD)%'
                        sasl.mechanisms: 'SCRAM-SHA-256'
                        max.poll.interval.ms: '45000'
                    topic_conf:
                        auto.offset.reset: 'earliest'

Serializer

You will most likely want to implement your own Serializer. Please see: https://symfony.com/doc/current/messenger.html#serializing-messages

The fields key, headers, and body are available in the decode() and encode() methods.

<?php
namespace App\Infrastructure\Messenger;

use App\Catalogue\Domain\Model\Event\ProductCreated;
use Symfony\Component\Messenger\Envelope;
use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;

final class MySerializer implements SerializerInterface
{
    public function decode(array $encodedEnvelope): Envelope
    {
        $record = json_decode($encodedEnvelope['body'], true);

        return new Envelope(new ProductCreated(
            $record['id'],
            $record['name'],
            $record['description'],
        ));
    }

    public function encode(Envelope $envelope): array
    {
        /** @var ProductCreated $event */
        $event = $envelope->getMessage();
        
        return [
            'key' => $event->getId(),
            'headers' => [],
            'body' => json_encode([
                'id' => $event->getId(),
                'name' => $event->getName(),
                'description' => $event->getDescription(),
            ]),
        ];
    }

}

How do I work with Avro?

Same as with the basic example above, you need to build your own serializer. Within the decode() and encode() you can make use of flix-tech/avro-serde-php.

What about the Confluent Schema Registry?

To connect with Schema Registry and control various settings, you can use this bundle:

$ composer require koco/avro-regy

And configure it to match your setup:

avro_regy:
  base_uri: '%env(SCHEMA_REGISTRY_URL)%'
  file_naming_strategy: subject
  options:
    register_missing_schemas: true
    register_missing_subjects: true
  serializers:
    catalogue:
      schema_dir: '%kernel.project_dir%/src/Catalogue/Domain/Model/Event/Avro/'
    orders:
      schema_dir: '%kernel.project_dir%/src/Orders/Domain/Model/Event/Avro/'
      file_naming_strategy: qualified_name
      options:
        register_missing_schemas: false
        register_missing_subjects: false

Please see https://github.com/KonstantinCodes/avro-regy for the full documentation.