Original PIP : https://github.com/apache/pulsar/issues/13628
Pasted bellow for quoting convenience.
——
## Motivation
In some case or for better observability. We can support Pulsar event
notification mechanism, that can let user subscribe this system topic to
receive some **"we need notice to user"** event.
## Goal
Enable users to receive Pulsar system event.
## API Changes
1. Add config ``pulsarSystemEventEnabled``
```java
pulsarSystemEventEnabled=false
```
2. Add ``SystemEventMessageBuilder``
```java
public interface SystemEventMessageBuilder {
SystemEventMessageBuilder eventType(SystemEvent event);
SystemEventMessageBuilder properties(Map<String,Object> properties);
SystemEventMessageBuilder addProperty(String key, Object value);
SystemEventMessage build();
}
```
3. Add ``SystemEventService``
```java
public interface SystemEventService {
void init();
CompletableFuture<MessageId> trigger(SystemEventMessage message);
void close();
}
```
## Implementation
This PIP just is a simple version, it's purpose is to discuss what event we
need to trigger? how to trigger? and what is the event message structure.
I think we need to trigger some event as bellow:
- [ ] Client connected
- [ ] Client disconnected
- [ ] Consumer subscribe
- [ ] Consumer unsubscribe
- [ ] Producer publish
- [ ] Message delivered
- [ ] Message acked
These are far from enough, and we need to continue to make supplements here.
Please fell free to give me more advice for this PIP.
## Reject Alternatives
none.
Thanks,
Mattisonchao
