[Data Contracts] Contract Events Integration

[carlesarnal]

Parent Epic

Part of #6192

Priority

P3 (Low)

Phase

Phase 4 - Audit & Events

Blocked By

• Contract Lifecycle Status Management
• Promotion Workflow

Description

Integrate contract events with the existing event system and webhook infrastructure.

Requirements

• Define contract event types in events package:

  Event	Trigger
  ContractCreated	Contract metadata first added to artifact
  ContractMetadataUpdated	Contract metadata fields changed
  ContractStatusChanged	Status transition (DRAFT->STABLE, etc.)
  ContractPromoted	Promotion stage changed
  ContractDeleted	Contract metadata removed from artifact

• Event record definitions:

  public record ContractCreated(
      String groupId,
      String artifactId,
      ContractMetadata metadata,
      String createdBy,
      Instant createdOn
  ) implements RegistryEvent {}
  
  public record ContractMetadataUpdated(
      String groupId,
      String artifactId,
      ContractMetadata previousMetadata,
      ContractMetadata newMetadata,
      String updatedBy,
      Instant updatedOn
  ) implements RegistryEvent {}

• Ensure events are published via CDI @Observes pattern

• Add event types to webhook event type filter configuration

• Document webhook payload format for contract events

Webhook Payload Example

{
  "type": "CONTRACT_STATUS_CHANGED",
  "timestamp": "2025-01-15T10:30:00Z",
  "data": {
    "groupId": "com.example",
    "artifactId": "order-events",
    "previousStatus": "DRAFT",
    "newStatus": "STABLE",
    "changedBy": "user@example.com",
    "comment": "Ready for production"
  }
}

Acceptance Criteria

• All contract events are published
• Webhooks can subscribe to contract events
• Event payloads are documented in OpenAPI spec
• Integration tests verify event publishing

Technical Notes

Events location: app/src/main/java/io/apicurio/registry/events/