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  • About
  • Installation
  • How to use
    • CQRS PHP
    • Event Handling PHP
    • Aggregates & Sagas
    • Scheduling in PHP
    • Asynchronous PHP
    • Event Sourcing PHP
    • Microservices PHP
    • Resiliency and Error Handling
    • Laravel Demos
    • Symfony Demos
      • Doctrine ORM
  • Tutorial
    • Before we start tutorial
    • Lesson 1: Messaging Concepts
    • Lesson 2: Tactical DDD
    • Lesson 3: Converters
    • Lesson 4: Metadata and Method Invocation
    • Lesson 5: Interceptors
    • Lesson 6: Asynchronous Handling
  • Enterprise
  • Modelling
    • Introduction
    • Message Bus and CQRS
      • CQRS Introduction - Commands
        • Query Handling
        • Event Handling
      • Aggregate Introduction
        • Aggregate Command Handlers
        • Aggregate Query Handlers
        • Aggregate Event Handlers
        • Advanced Aggregate creation
      • Repositories Introduction
      • Business Interface
        • Introduction
        • Business Repository
        • Database Business Interface
          • Converting Parameters
          • Converting Results
      • Saga Introduction
      • Identifier Mapping
    • Extending Messaging (Middlewares)
      • Message Headers
      • Interceptors (Middlewares)
        • Additional Scenarios
      • Intercepting Asynchronous Endpoints
      • Extending Message Buses (Gateways)
    • Event Sourcing
      • Installation
      • Event Sourcing Introduction
        • Working with Event Streams
        • Event Sourcing Aggregates
          • Working with Aggregates
          • Applying Events
          • Different ways to Record Events
        • Working with Metadata
        • Event versioning
        • Event Stream Persistence
          • Event Sourcing Repository
          • Making Stream immune to changes
          • Snapshoting
          • Persistence Strategies
          • Event Serialization and PII Data (GDPR)
      • Projection Introduction
        • Configuration
        • Choosing Event Streams for Projection
        • Executing and Managing
          • Running Projections
          • Projection CLI Actions
          • Access Event Store
        • Projections with State
        • Emitting events
    • Recovering, Tracing and Monitoring
      • Resiliency
        • Retries
        • Error Channel and Dead Letter
          • Dbal Dead Letter
        • Idempotent Consumer (Deduplication)
        • Resilient Sending
        • Outbox Pattern
        • Concurrency Handling
      • Message Handling Isolation
      • Ecotone Pulse (Service Dashboard)
    • Asynchronous Handling and Scheduling
      • Asynchronous Message Handlers
      • Asynchronous Message Bus (Gateways)
      • Delaying Messages
      • Time to Live
      • Message Priority
      • Scheduling
      • Dynamic Message Channels
    • Distributed Bus and Microservices
      • Distributed Bus
        • Distributed Bus with Service Map
          • Configuration
          • Custom Features
          • Non-Ecotone Application integration
          • Testing
        • AMQP Distributed Bus (RabbitMQ)
          • Configuration
        • Distributed Bus Interface
      • Message Consumer
      • Message Publisher
    • Business Workflows
      • The Basics - Stateless Workflows
      • Stateful Workflows - Saga
      • Handling Failures
    • Testing Support
      • Testing Messaging
      • Testing Aggregates and Sagas with Message Flows
      • Testing Event Sourcing Applications
      • Testing Asynchronous Messaging
  • Messaging and Ecotone In Depth
    • Overview
    • Multi-Tenancy Support
      • Getting Started
        • Any Framework Configuration
        • Symfony and Doctrine ORM
        • Laravel
      • Different Scenarios
        • Hooking into Tenant Switch
        • Shared and Multi Database Tenants
        • Accessing Current Tenant in Message Handler
        • Events and Tenant Propagation
        • Multi-Tenant aware Dead Letter
      • Advanced Queuing Strategies
    • Document Store
    • Console Commands
    • Messaging concepts
      • Message
      • Message Channel
      • Message Endpoints/Handlers
        • Internal Message Handler
        • Message Router
        • Splitter
      • Consumer
      • Messaging Gateway
      • Inbound/Outbound Channel Adapter
    • Method Invocation And Conversion
      • Method Invocation
      • Conversion
        • Payload Conversion
        • Headers Conversion
    • Service (Application) Configuration
    • Contributing to Ecotone
      • How Ecotone works under the hood
      • Ecotone Phases
      • Registering new Module Package
      • Demo Integration with SQS
        • Preparation
        • Inbound and Outbound Adapters and Message Channel
        • Message Consumer and Publisher
  • Modules
    • Overview
    • Symfony
      • Symfony Configuration
      • Symfony Database Connection (DBAL Module)
      • Doctrine ORM
      • Symfony Messenger Transport
    • Laravel
      • Laravel Configuration
      • Database Connection (DBAL Module)
      • Eloquent
      • Laravel Queues
      • Laravel Octane
    • Ecotone Lite
      • Logging
      • Database Connection (DBAL Module)
    • JMS Converter
    • OpenTelemetry (Tracing and Metrics)
      • Configuration
    • RabbitMQ Support
    • Kafka Support
      • Configuration
      • Message partitioning
      • Usage
    • DBAL Support
    • Amazon SQS Support
    • Redis Support
  • Other
    • Contact, Workshops and Support
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  • Context and Metadata Propagation
  • Database Message Channel

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  1. Messaging and Ecotone In Depth
  2. Multi-Tenancy Support
  3. Different Scenarios

Events and Tenant Propagation

When Customer is registered we may want to trigger side effects, like sending an Email with Welcome Message. For those situation we can define Events and Event Handlers.

final readonly class CustomerService
{
    #[CommandHandler]
    public function handle(RegisterCustomer $command, EventBus $eventBus)
    {
        // register Customer

        $eventBus->publish(new CustomerWasRegistered($command->customerId));
    }

    #[EventHandler]
    public function sendNotificationWhen(CustomerWasRegistered $event, NotificationSender $notificationSender)
    {
        $customer = Customer::find($event->customerId);

        $notificationSender->sendWelcomeNotification($customer);
    }
}

When Customer is registered, we publish CustomerWasRegistered Event Message using Event Bus. Then all methods marked with Event Handler that subscribe to it (First parameter indicates Event we subscribe too) will be executed as a result.

Context and Metadata Propagation

Ecotone by default propagate all Message Headers automatically. This as a result preserve context Tenant. In our case sending Notification will happen in context of the same Tenant, as Customer Registration was done:

This way we can of course access Tenant name in our Event Handlers too:

#[EventHandler]
public function audit(
  CustomerWasRegistered $event, 
  AuditRepository $auditRepository,
  #[Header('tenant')] string $tenantName
)
{
    $auditRepository->store($event, $tenantName);
}

Whatever metadata we send at the beginning of the flow (e.g. Register Customer Command), we will be able to access in any synchronous or asynchronous sub-flows (e.g. Customer was Registered Event Handlers). This means we can easily pass things that are not directly related to Customer Registration Command and access them, in context which make sense. For example we could pass HTTP Domain, IP Address in Metadata, and access it in Event Handler that stores those for auditing.

Database Message Channel

We can define our Event Handler as asynchronous and choose Database Queue as the Message Channel.

final readonly class CustomerService
{
    #[CommandHandler]
    public function handle(RegisterCustomer $command, EventBus $eventBus)
    {
        Customer::register($command)->save();

        $eventBus->publish(new CustomerWasRegistered($command->customerId));
    }

    // We will be using notifications Message Channel (Database Queue)
    #[Asynchronous('notifications')]
    #[EventHandler(endpointId: "notificationSender")]
    public function sendNotificationWhen(
        CustomerWasRegistered $event,
        NotificationSender $notificationSender
    )
    {
        $notificationSender->sendWelcomeNotification(
           Customer::find($event->customerId)
        );
    }
}

and then define Database Queue as Message Channel:

final readonly class EcotoneConfiguration
{
    #[ServiceContext]
    public function databaseChannel(): DbalBackedMessageChannelBuilder
    {
        return DbalBackedMessageChannelBuilder::create('notifications');
    }
}

When we publish Message to Asynchronous Database Message Channel, Ecotone will publish it to the Database related to given Tenant by default. However this means that we need to consume Messages from multiple Databases.

Depending on Business Domain we work in, we may have hundreds of Tenants, so running hundreds of Message Consumers may be far from ideal. For those situations, Ecotone by default use Round-Robin strategy to consume using single process. This means that we will be fetching from each Tenant in order:

This way of consuming works out of the box, we don’t need to do any customer configuration to make it happen.

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Last updated 1 year ago

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Metadata is automatically propagated from Command to published Event
Ecotone using Round Robin Strategy to consume Messages from multiple Tenants