Documentation
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Overview ¶
Package events is the generic event contract: the Event interface, the metadata every event carries, and a Registry a consumer fills with its own event catalog to parse payloads.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
This section is empty.
Types ¶
type Event ¶
type Event interface {
// Type returns the event's type discriminator.
Type() EventType
// Metadata returns the common metadata shared by all events.
Metadata() EventMetadata
}
Event is the interface all events implement.
type EventMetadata ¶
type EventMetadata struct {
// EventID is the unique identifier of the event.
EventID string `json:"event_id"`
// EventType is the type discriminator for the event.
EventType EventType `json:"event_type"`
// OccurredAt is the timestamp when the event occurred.
OccurredAt time.Time `json:"occurred_at"`
// TenantID is the tenant the event belongs to.
TenantID string `json:"tenant_id"`
// UserID is the user who triggered the event, if applicable.
UserID string `json:"user_id,omitempty"`
// CorrelationID links related events across services.
CorrelationID string `json:"correlation_id,omitempty"`
// TraceParent carries the W3C trace context (traceparent header) captured when
// the event was produced, so a consumer can continue the originating trace —
// e.g. request → outbox → relay publish → consumer — as one distributed
// trace. Empty when no active trace context was present.
TraceParent string `json:"traceparent,omitempty"`
}
EventMetadata holds common fields for all events.
type EventType ¶
type EventType string
EventType is an event's type discriminator (e.g. "widget.created"); the consumer defines its own values.
type Factory ¶
type Factory func() Event
Factory returns a new, zero-valued event of one type, for Registry.Parse to decode a payload into. It must return a non-nil pointer.
type Registry ¶
type Registry struct {
// contains filtered or unexported fields
}
Registry maps event types to factories, so a consumer parses its own event catalog: register each type once at the composition root, then Parse payloads. EventMetadata is the envelope every event shares; its event_type field selects the factory. The zero value is an empty Registry ready to use (NewRegistry is equivalent), and a Registry is safe for concurrent use.
func (*Registry) Parse ¶
Parse decodes a JSON event payload into the event registered for its event_type. A malformed payload, a missing event_type, an unregistered type or a body that does not decode into the event returns a CodeInvalidInput error. The payload is decoded twice (once to read the type, once into the concrete event); a consumer whose catalog is fixed and hot can keep a single-pass parser of its own.
func (*Registry) Register ¶
Register adds the factory for eventType. It returns a CodeInvalidInput error, registering nothing, for an empty eventType, a type registered twice, a nil factory, or a factory that does not return a non-nil pointer (Parse decodes into the factory's value, so anything else would fail every message of that type).
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