CloudEvent

A standardized event envelope following the CloudEvents specification. Used for external event consumption and integration.

Structure

message CloudEvent {
  string type = 1;                    // Event type
  google.protobuf.Any payload = 2;    // Event data
  map<string, string> extensions = 3; // Custom attributes

  // Optional overrides
  optional string id = 4;
  optional string source = 5;
  optional string subject = 6;
}

Default Values

When not explicitly set:

• id: {domain}:{root_id}:{sequence}
• source: angzarr/{domain}

CloudEventsResponse

Return type from projectors that emit external events:

message CloudEventsResponse {
  repeated CloudEvent events = 1;
}

Projectors can emit:

• 0 events: Skip/filter
• 1 event: Typical case
• N events: Fan-out pattern

Use Cases

• External system integration
• Webhook delivery
• Message queue publishing
• Cross-system event sharing

Relationship to Internal Events

Aspect	Internal Event	CloudEvent
Format	Protobuf Any	CloudEvents spec
Audience	Angzarr components	External systems
Produced by	Aggregates	Projectors