feat(core): specify event listener API #14735
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| type HasEventListeners interface { | ||
| AppModule | ||
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| // RegisterEventListeners registers the module's events listeners. | ||
| RegisterEventListeners(registrar *EventListenerRegistrar) | ||
| } |
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I have a question on why to expose EventListenerRegistrar in core, shouldn't that be runtime?
The core interface could simply be:
| type HasEventListeners interface { | |
| AppModule | |
| // RegisterEventListeners registers the module's events listeners. | |
| RegisterEventListeners(registrar *EventListenerRegistrar) | |
| } | |
| type HasEventListeners interface { | |
| AppModule | |
| RegisterEventListeners() []func(context.Context, protoiface.MessageV1) | |
| RegisterEventInterceptors() []func(context.Context, protoiface.MessageV1) error | |
| } |
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It's just a more ergonomic API this way I think
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EventListenerRegistrar is just a dummy struct to make using generics easy
aaronc
changed the title
| // RegisterEventListener registers an event listener for event type E. If a non-nil error is returned by the listener, | ||
| // it will cause the process which emitted the event to fail. | ||
| func RegisterEventListener[E protoiface.MessageV1](registrar *EventListenerRegistrar, listener func(context.Context, E) error) { | ||
| registrar.listeners = append(registrar.listeners, listener) |
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why not this instead of using []any.
| registrar.listeners = append(registrar.listeners, listener) | |
| listenerF := func(ctx context.Context, iMsg protoiface.MessageV1) error { | |
| concrete, ok := iMsg.(E) | |
| if !ok { return fmt.Errorf("...") | |
| return listener(ctx, concrete) | |
| } | |
| registrar.listeners = append(registrar.listeners, listenerF) |
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Because the caller will be doing a type check anyway. I think this would just add extra type checking. Also in core we don't want to add any implementation details. This should be defer all those details to runtime
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| // EventListenerRegistrar allows registering event listeners. | ||
| type EventListenerRegistrar struct { | ||
| listeners []any |
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| listeners []any | |
| listeners []func(ctx context.Context, iMsg protoiface.MessageV1) error |
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Are we okay to merge this? I think this should have a standalone ADR by the way. I can work on that after #12972. |
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I'm taking the 👍 as a yes |
Description
Ref #14683
This adds an API for modules to register event listeners in core.
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