feat(streamer): pcm tcp tap with reconnect backoff

streamer/src/pcm-tap.ts

@@ -0,0 +1,51 @@
+import { EventEmitter } from "node:events";
+import { Socket, connect } from "node:net";
+
+export interface PcmTapOpts {
+  host: string;
+  port: number;
+  reconnectInitialMs?: number;
+  reconnectMaxMs?: number;
+}
+
+export class PcmTap extends EventEmitter {
+  private socket: Socket | null = null;
+  private stopped = false;
+  private backoff: number;
+
+  constructor(private opts: PcmTapOpts) {
+    super();
+    this.backoff = opts.reconnectInitialMs ?? 1000;
+  }
+
+  start(): void {
+    if (this.stopped) return;
+    this.connect();
+  }
+
+  stop(): void {
+    this.stopped = true;
+    this.socket?.destroy();
+  }
+
+  private connect(): void {
+    this.emit("connecting");
+    const sock = connect({ host: this.opts.host, port: this.opts.port });
+    this.socket = sock;
+
+    sock.on("connect", () => {
+      this.emit("connected");
+      this.backoff = this.opts.reconnectInitialMs ?? 1000;
+    });
+    sock.on("data", (chunk) => this.emit("data", chunk));
+    sock.on("error", (err) => this.emit("warn", err));
+    sock.on("close", () => {
+      if (this.stopped) return;
+      this.emit("disconnected");
+      const max = this.opts.reconnectMaxMs ?? 30000;
+      const wait = Math.min(this.backoff, max);
+      this.backoff = Math.min(this.backoff * 2, max);
+      setTimeout(() => this.connect(), wait);
+    });
+  }
+}