Documentation
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Overview ¶
Package events provides an in-process event dispatcher modelled on Laravel's Event facade.
Events are arbitrary values (typically structs). Listeners are functions that receive the dispatched event and an error. Dispatch is synchronous — listeners run in registration order on the calling goroutine. Background fan-out is left to the caller (spawn a goroutine inside a listener, or use a queue package).
Type-safe registration uses Go generics so listeners don't need to type-assert:
type UserRegistered struct{ ID uint64; Email string }
d := events.New()
events.Listen(d, func(ctx context.Context, e UserRegistered) error {
return sendWelcomeEmail(ctx, e.Email)
})
_ = d.Dispatch(ctx, UserRegistered{ID: 42, Email: "a@b.co"})
If a listener returns an error, the dispatcher records it and (by default) continues with the remaining listeners. Use StopOnError(true) to short-circuit instead. Errors are joined with errors.Join so callers can inspect each one.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Forget ¶
func Forget[E any](d *Dispatcher) bool
Forget removes every listener registered for events of type E. The returned bool is true if anything was removed.
func HasListeners ¶
func HasListeners[E any](d *Dispatcher) bool
HasListeners reports whether at least one listener is registered for events of type E. Handy for unit tests and conditional dispatch.
Types ¶
type Dispatcher ¶
type Dispatcher struct {
// contains filtered or unexported fields
}
Dispatcher routes events to registered listeners.
func (*Dispatcher) Dispatch ¶
func (d *Dispatcher) Dispatch(ctx context.Context, event any) error
Dispatch fans the event out to its listeners. Returns the joined errors from listeners (or nil).
func (*Dispatcher) StopOnError ¶
func (d *Dispatcher) StopOnError(v bool) *Dispatcher
StopOnError toggles short-circuit behaviour. Default false: every listener runs, errors are joined and returned together.
Source Files