feat: add shared runtime and PI datasource handlers

src/lib/runtime.ts

@@ -0,0 +1,48 @@
+import { EventFeed } from "./event-feed";
+import { InflightTracker } from "./inflight-tracker";
+import { MetricsPoller } from "./metrics-poller";
+import { type LlamaSwapConfig } from "./util";
+
+class Runtime {
+  readonly tracker = new InflightTracker();
+  offline = true;
+  private feed?: EventFeed;
+  private poller?: MetricsPoller;
+  private listeners = new Set<() => void>();
+
+  ensureConnections(cfg: LlamaSwapConfig): void {
+    if (!this.feed) {
+      this.feed = new EventFeed(cfg, (ev) => {
+        this.tracker.apply(ev);
+        this.emit();
+      });
+      this.feed.setStatusHandler((connected) => {
+        this.offline = !connected;
+        this.emit();
+      });
+      this.feed.start();
+    }
+    if (!this.poller) {
+      this.poller = new MetricsPoller(cfg);
+      this.poller.on(() => this.emit());
+      this.poller.start();
+    }
+  }
+
+  get pollerInstance(): MetricsPoller | undefined {
+    return this.poller;
+  }
+
+  subscribe(listener: () => void): () => void {
+    this.listeners.add(listener);
+    return () => {
+      this.listeners.delete(listener);
+    };
+  }
+
+  private emit(): void {
+    for (const listener of this.listeners) listener();
+  }
+}
+
+export const runtime = new Runtime();