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Event Publisher

Description​

A component in the Infrastructure layer responsible for publishing messages/events to a message bus or queue.

Definition Schema​

The definition for a event_publisher component expects the following structure:

{
  "$defs": {
    "ServiceDependencyInputDTO": {
      "description": "Defines a dependency to be injected into the Service's __init__.",
      "example": {
        "assigned_attribute_name": "_emailer",
        "param_name": "email_service",
        "param_type_str": "EmailService"
      },
      "example_with_explicit_import": {
        "param_import_from_module": "sqlalchemy.ext.asyncio",
        "param_import_names": [
          "AsyncSession"
        ],
        "param_name": "async_session_factory",
        "param_type_str": "AsyncSession"
      },
      "properties": {
        "param_name": {
          "description": "Name of the parameter in __init__ (e.g., 'user_repository')",
          "title": "Param Name",
          "type": "string"
        },
        "param_type_str": {
          "description": "Type hint string for the parameter (e.g., 'UserRepository')",
          "title": "Param Type Str",
          "type": "string"
        },
        "assigned_attribute_name": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "description": "Name of the attribute to assign the dependency to on self (e.g., '_repo'). Defaults to '_' + param_name if None.",
          "title": "Assigned Attribute Name"
        },
        "param_import_from_module": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "description": "Optional: Explicit module to import the dependency type from (e.g., 'sqlalchemy.ext.asyncio').",
          "title": "Param Import From Module"
        },
        "param_import_names": {
          "anyOf": [
            {
              "items": {
                "type": "string"
              },
              "type": "array"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "description": "Optional: Explicit list of names to import from the module (e.g., ['AsyncSession']). Used if param_import_from_module is set.",
          "title": "Param Import Names"
        }
      },
      "required": [
        "param_name",
        "param_type_str"
      ],
      "title": "ServiceDependencyInputDTO",
      "type": "object"
    }
  },
  "description": "DTO for defining an Event Publisher class.",
  "example": {
    "dependencies": [
      {
        "assigned_attribute_name": "_producer",
        "param_name": "kafka_producer",
        "param_type_str": "aiokafka.AIOKafkaProducer"
      }
    ],
    "name": "AuditLogEventPublisher"
  },
  "properties": {
    "name": {
      "description": "Name of the event publisher class (e.g., 'KafkaPostEventPublisher')",
      "title": "Name",
      "type": "string"
    },
    "dependencies": {
      "description": "List of dependencies for the __init__ method.",
      "items": {
        "$ref": "#/$defs/ServiceDependencyInputDTO"
      },
      "title": "Dependencies",
      "type": "array"
    }
  },
  "required": [
    "name"
  ],
  "title": "EventPublisherInputDTO",
  "type": "object"
}

Naming and Location Conventions​

Class: PascalCase, typically ends with 'EventPublisher'. File: ${event_publisher_name}.py (based on ${event_publisher_name}). Location: app/infrastructure/messaging.

Example Definition​

{
  "name": "AuditLogEventPublisher",
  "dependencies": [
    {
      "param_name": "kafka_producer",
      "param_type_str": "aiokafka.AIOKafkaProducer",
      "assigned_attribute_name": "_producer"
    }
  ]
}