Files
DECNET/decnet_web/src/components/MazeNET/useTopologyStream.ts
anti 8ecb9e6c2d feat(web/mazenet): subscribe to topology SSE stream in editor
Wire the MazeNET editor to the new /topologies/{id}/events SSE route
so live (active|degraded) topologies reflect mutator state transitions
without reload:

- useTopologyStream hook opens an EventSource against
  /topologies/{id}/events?token=<jwt>, with 3s reconnect matching the
  dashboard's /stream consumer. Callback refs avoid tearing down the
  connection on consumer rerenders.
- useMazeApi gains enqueueMutation(topologyId, op, payload,
  expectedVersion?) — thin wrapper over POST /mutations.
- MazeNET.tsx opens the stream only when topoStatus is active|degraded
  (pending editors have nothing to stream) and refetches on
  mutation.applied|failed|status events. Header shows a LIVE /
  CONNECTING… indicator.

Phase A slice — Apply (N changes) with an optimistic staged buffer
lands in a follow-up; the hooks + API method it'll need are already
here.
2026-04-21 14:38:58 -04:00

108 lines
3.2 KiB
TypeScript

/**
* Topology event stream — opens an SSE connection to
* `/topologies/{id}/events` and dispatches typed events to the caller.
*
* Mirrors the reconnect shape used by the dashboard's `/stream` consumer:
* on any error we close the current EventSource and retry after 3s. The
* hook is inert until `topologyId` is non-empty and `enabled` is true —
* typical usage is to gate on `topoStatus === 'active' || 'degraded'` so
* pending topologies don't open a useless channel.
*/
import { useEffect, useRef } from 'react';
export type TopologyStreamEventName =
| 'snapshot'
| 'mutation.enqueued'
| 'mutation.applying'
| 'mutation.applied'
| 'mutation.failed'
| 'status';
export interface TopologyStreamEvent {
name: TopologyStreamEventName | string;
topic?: string;
type?: string;
ts?: string;
payload: Record<string, unknown>;
}
export interface UseTopologyStreamOptions {
topologyId: string | null;
enabled: boolean;
onEvent: (event: TopologyStreamEvent) => void;
onError?: () => void;
}
const NAMED_EVENTS: TopologyStreamEventName[] = [
'snapshot',
'mutation.enqueued',
'mutation.applying',
'mutation.applied',
'mutation.failed',
'status',
];
export function useTopologyStream({
topologyId,
enabled,
onEvent,
onError,
}: UseTopologyStreamOptions): void {
const esRef = useRef<EventSource | null>(null);
const reconnectRef = useRef<ReturnType<typeof setTimeout> | null>(null);
// Keep the latest callbacks in refs so reconnect logic doesn't tear
// down and rebuild the connection every time the consumer rerenders.
const onEventRef = useRef(onEvent);
const onErrorRef = useRef(onError);
useEffect(() => { onEventRef.current = onEvent; }, [onEvent]);
useEffect(() => { onErrorRef.current = onError; }, [onError]);
useEffect(() => {
if (!enabled || !topologyId) return;
const connect = () => {
if (esRef.current) esRef.current.close();
const token = localStorage.getItem('token') ?? '';
const baseUrl = import.meta.env.VITE_API_URL || 'http://localhost:8000/api/v1';
const url = `${baseUrl}/topologies/${topologyId}/events?token=${encodeURIComponent(token)}`;
const es = new EventSource(url);
esRef.current = es;
const dispatch = (name: string) => (event: MessageEvent) => {
try {
const parsed = JSON.parse(event.data) as Partial<TopologyStreamEvent>;
onEventRef.current({
name,
topic: parsed.topic,
type: parsed.type,
ts: parsed.ts,
payload: (parsed.payload ?? {}) as Record<string, unknown>,
});
} catch (err) {
console.error('useTopologyStream: parse failed', err);
}
};
for (const name of NAMED_EVENTS) {
es.addEventListener(name, dispatch(name) as EventListener);
}
es.onerror = () => {
es.close();
esRef.current = null;
onErrorRef.current?.();
reconnectRef.current = setTimeout(connect, 3000);
};
};
connect();
return () => {
if (reconnectRef.current) clearTimeout(reconnectRef.current);
if (esRef.current) esRef.current.close();
esRef.current = null;
};
}, [topologyId, enabled]);
}