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Connection Config Reference ​

Reference for connection detection options in Extraction Config.

Overview ​

OptionDescription
connections.eventPublishersEvent publisher declarations for convention-based async Links
connections.httpLinksHTTP link resolution for cross-domain and external service calls

connections.eventPublishers ​

Declares custom component types that publish Events using metadata. Used with convention decorators:

  • @EventPublisherContainer on publisher classes
  • @Event on published event classes
  • @EventHandlerContainer on subscriber handlers consuming those Events

The extractor matches publisher components (by fromType) to Event components (by the metadata value in metadataKey), creating async Links.

Parameters:

FieldTypeRequiredDescription
connections.eventPublishers[].fromTypestringYesCustom component type name matching the eventPublisher type defined in customTypes. This is the type used by @EventPublisherContainer classes.
connections.eventPublishers[].metadataKeystringYesMetadata key containing the published Event type name. Must match an extracted field on the custom type (e.g., publishedEventType from @Event classes).

Example:

json
{
  "connections": {
    "eventPublishers": [
      {
        "fromType": "eventPublisher",
        "metadataKey": "publishedEventType"
      }
    ]
  }
}

fromType: "eventPublisher" matches the eventPublisher custom type defined in customTypes. The extractor reads the publishedEventType metadata value from each publisher component and finds the Event component with a matching eventName.

View config in ecommerce-demo-app →

Resolves cross-domain HTTP calls into Links targeting API components in other domains. When a component calls a method on an httpCall component, the extractor uses the HTTP client's metadata to find the target API component.

Parameters:

FieldTypeRequiredDescription
connections.httpLinks[].fromCustomTypestringYesCustom component type name for HTTP clients (must exist in customTypes)
connections.httpLinks[].matchDomainBystringYesMetadata key whose value identifies the target domain
connections.httpLinks[].matchApiBystring[]YesMetadata keys used to match the target API component

Full example:

Config:

yaml
modules:
  - domain: orders
    name: orders
    path: ../../orders
    modules: /src/{module}
    extends: '@living-architecture/riviere-extract-conventions'

  - domain: bff
    name: bff
    path: ../../bff
    modules: /src/{module}
    extends: '@living-architecture/riviere-extract-conventions'

connections:
  eventPublishers:
    - fromType: eventPublisher
      metadataKey: publishedEventType
  httpLinks:
    - fromCustomType: httpCall
      matchDomainBy: serviceName
      matchApiBy: [route, method]

BFF HTTP client:

typescript
/** @httpClient */
export class OrdersServiceClient {
  readonly serviceName = 'orders'
  readonly route = '/orders'
  readonly method = 'POST'

  async placeOrder(request: PlaceOrderRequest): Promise<PlaceOrderResponse> {
    return fetch('http://localhost:3000/orders', {
      method: 'POST',
      body: JSON.stringify(request),
    })
  }
}

Orders domain API:

typescript
@APIContainer
export class OrdersEndpoint {
  @Post('/orders')
  async createOrder(req: Request): Promise<Response> { /* ... */ }
}

The call graph detects PlaceOrderBFFUseCase → OrdersServiceClient.placeOrder(). The httpLinks config resolves this: serviceName: 'orders' matches the orders domain, route: '/orders' + method: 'POST' matches createOrder. The link becomes:

json
{
  "source": "bff:bff:useCase:placeorderbffusecase",
  "target": "orders:orders:api:createorder",
  "type": "sync"
}

When serviceName doesn't match any domain (e.g., 'Fraud Detection Service'), the link becomes an external link:

json
{
  "source": "bff:bff:useCase:placeorderbffusecase",
  "target": { "name": "Fraud Detection Service", "route": "/api/check", "method": "POST" },
  "type": "sync"
}

See Also ​