Shared Event Sourced Aggregate

Description

An Event Sourced Aggregate that is part of the Shared Kernel.

Definition Schema

The definition for a shared_event_sourced_aggregate component expects the following structure:

{
  "$defs": {
    "AggregateCreationParameterInputDTO": {
      "description": "Defines a parameter for the initiate_creation class method.",
      "example": {
        "param_name": "title",
        "param_type_str": "str"
      },
      "properties": {
        "param_name": {
          "title": "Param Name",
          "type": "string"
        },
        "param_type_str": {
          "title": "Param Type Str",
          "type": "string"
        }
      },
      "required": [
        "param_name",
        "param_type_str"
      ],
      "title": "AggregateCreationParameterInputDTO",
      "type": "object"
    },
    "AggregateStateParameterInputDTO": {
      "description": "Defines a state field within the aggregate.",
      "example": {
        "param_name": "title",
        "param_type_str": "str"
      },
      "properties": {
        "param_name": {
          "title": "Param Name",
          "type": "string"
        },
        "param_type_str": {
          "title": "Param Type Str",
          "type": "string"
        }
      },
      "required": [
        "param_name",
        "param_type_str"
      ],
      "title": "AggregateStateParameterInputDTO",
      "type": "object"
    },
    "EventToApplierMappingDTO": {
      "properties": {
        "event_name_str": {
          "description": "Name of the event class (e.g., 'OrderCreated')",
          "title": "Event Name Str",
          "type": "string"
        },
        "event_module_str": {
          "description": "Module path for the event (e.g., 'app_root_name.domain.ordering.events')",
          "title": "Event Module Str",
          "type": "string"
        },
        "applier_method_name": {
          "description": "Name of the method in the aggregate that applies this event (e.g., '_apply_order_created')",
          "title": "Applier Method Name",
          "type": "string"
        }
      },
      "required": [
        "event_name_str",
        "event_module_str",
        "applier_method_name"
      ],
      "title": "EventToApplierMappingDTO",
      "type": "object"
    },
    "SnapshotStateFieldDTO": {
      "properties": {
        "param_name": {
          "title": "Param Name",
          "type": "string"
        },
        "param_type_str": {
          "title": "Param Type Str",
          "type": "string"
        }
      },
      "required": [
        "param_name",
        "param_type_str"
      ],
      "title": "SnapshotStateFieldDTO",
      "type": "object"
    }
  },
  "example": {
    "creation_event_module": "app_root_name.domain.ticketing.events",
    "creation_event_name": "TicketOpenedEvent",
    "creation_parameters": [
      {
        "param_name": "title",
        "param_type_str": "str"
      },
      {
        "param_name": "reported_by_id",
        "param_type_str": "uuid.UUID"
      }
    ],
    "event_appliers": [
      {
        "applier_method_name": "_apply_ticket_opened",
        "event_module_str": "app_root_name.domain.ticketing.events",
        "event_name_str": "TicketOpenedEvent"
      },
      {
        "applier_method_name": "_apply_ticket_closed",
        "event_module_str": "app_root_name.domain.ticketing.events",
        "event_name_str": "TicketClosedEvent"
      }
    ],
    "id_type_str": "uuid.UUID",
    "map_aggregate_id_to_event_field": "ticket_id",
    "name": "TicketAggregate",
    "snapshot_fields": [
      {
        "param_name": "title",
        "param_type_str": "str"
      },
      {
        "param_name": "status",
        "param_type_str": "str"
      }
    ],
    "state_parameters": [
      {
        "param_name": "title",
        "param_type_str": "str"
      },
      {
        "param_name": "status",
        "param_type_str": "str"
      }
    ]
  },
  "properties": {
    "name": {
      "description": "Name of the Event-Sourced Aggregate class (e.g., 'OrderAggregate')",
      "title": "Name",
      "type": "string"
    },
    "id_type_str": {
      "description": "Type hint for the aggregate's ID (e.g., 'uuid.UUID', 'int')",
      "title": "Id Type Str",
      "type": "string"
    },
    "state_parameters": {
      "description": "Fields representing the aggregate's mutable state.",
      "items": {
        "$ref": "#/$defs/AggregateStateParameterInputDTO"
      },
      "title": "State Parameters",
      "type": "array"
    },
    "event_appliers": {
      "description": "Mappings of events to their applier methods.",
      "items": {
        "$ref": "#/$defs/EventToApplierMappingDTO"
      },
      "title": "Event Appliers",
      "type": "array"
    },
    "snapshot_fields": {
      "description": "Fields to include in the snapshot state.",
      "items": {
        "$ref": "#/$defs/SnapshotStateFieldDTO"
      },
      "title": "Snapshot Fields",
      "type": "array"
    },
    "creation_event_name": {
      "description": "Name of the event raised upon creation (e.g., 'OrderCreated')",
      "title": "Creation Event Name",
      "type": "string"
    },
    "creation_event_module": {
      "description": "Module path for the creation event (e.g., 'app_root_name.domain.ordering.events')",
      "title": "Creation Event Module",
      "type": "string"
    },
    "creation_parameters": {
      "description": "Parameters for the 'create' classmethod.",
      "items": {
        "$ref": "#/$defs/AggregateCreationParameterInputDTO"
      },
      "title": "Creation Parameters",
      "type": "array"
    },
    "map_aggregate_id_to_event_field": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Name of the field in the creation event that should be populated with the aggregate's ID (e.g., 'ticket_id', 'aggregate_id').",
      "title": "Map Aggregate Id To Event Field"
    }
  },
  "required": [
    "name",
    "id_type_str",
    "creation_event_name",
    "creation_event_module"
  ],
  "title": "EventSourcedAggregateEngineInputDTO",
  "type": "object"
}

Naming and Location Conventions

Class: PascalCase, typically ends with 'EventSourcedAggregate'. File: ${shared_event_sourced_aggregate_name}.py (based on ${shared_event_sourced_aggregate_name}). Location: app/domain/shared_kernel/event_sourced_aggregates.

Example Definition

{
  "name": "TicketAggregate",
  "id_type_str": "uuid.UUID",
  "state_parameters": [
    {
      "param_name": "title",
      "param_type_str": "str"
    },
    {
      "param_name": "status",
      "param_type_str": "str"
    }
  ],
  "event_appliers": [
    {
      "event_name_str": "TicketOpenedEvent",
      "event_module_str": "app_root_name.domain.ticketing.events",
      "applier_method_name": "_apply_ticket_opened"
    },
    {
      "event_name_str": "TicketClosedEvent",
      "event_module_str": "app_root_name.domain.ticketing.events",
      "applier_method_name": "_apply_ticket_closed"
    }
  ],
  "snapshot_fields": [
    {
      "param_name": "title",
      "param_type_str": "str"
    },
    {
      "param_name": "status",
      "param_type_str": "str"
    }
  ],
  "creation_event_name": "TicketOpenedEvent",
  "creation_event_module": "app_root_name.domain.ticketing.events",
  "creation_parameters": [
    {
      "param_name": "title",
      "param_type_str": "str"
    },
    {
      "param_name": "reported_by_id",
      "param_type_str": "uuid.UUID"
    }
  ],
  "map_aggregate_id_to_event_field": "ticket_id"
}