feat(rcon): add admin server console

apps/web/src/lib/rcon-gateway.ts

@@ -0,0 +1,104 @@
+import { Rcon } from "rcon-client";
+import { sanitizeRconOutput } from "./rcon-validation";
+
+const TIMEOUT_MS = 5_000;
+const CLEANUP_TIMEOUT_MS = 1_000;
+const MAX_ACTIVE_CONNECTIONS = 8;
+const activeConnections = new Set<string>();
+
+type Connection = { id?: string; host: string; port: number; password: string };
+type FailureReason = "busy" | "timeout" | "unavailable";
+
+export interface RconTransport {
+  connect(): Promise<unknown>;
+  send(command: string): Promise<string>;
+  end(): Promise<unknown>;
+  destroy?(): void;
+}
+
+type TransportFactory = (connection: Connection) => RconTransport;
+
+class RconDeadlineError extends Error {}
+
+async function deadline<T>(operation: Promise<T>, timeout: () => void, timeoutMs = TIMEOUT_MS) {
+  let timer: ReturnType<typeof setTimeout> | undefined;
+  try {
+    return await Promise.race([
+      operation,
+      new Promise<never>((_, reject) => {
+        timer = setTimeout(() => {
+          timeout();
+          reject(new RconDeadlineError("RCON operation timed out"));
+        }, timeoutMs);
+      }),
+    ]);
+  } finally {
+    if (timer) clearTimeout(timer);
+  }
+}
+
+function defaultTransport(connection: Connection): RconTransport {
+  const client = new Rcon({
+    host: connection.host,
+    port: connection.port,
+    password: connection.password,
+    timeout: TIMEOUT_MS,
+    maxPending: 1,
+  });
+  return {
+    connect: () => client.connect(),
+    send: (command) => client.send(command),
+    end: async () => {
+      if (!client.socket) return;
+      if (client.socket.connecting || !client.socket.writable) {
+        client.socket.destroy();
+        return;
+      }
+      await client.end();
+    },
+    destroy: () => client.socket?.destroy(),
+  };
+}
+
+function failure(error: unknown): { ok: false; reason: FailureReason } {
+  return { ok: false, reason: error instanceof RconDeadlineError ? "timeout" : "unavailable" };
+}
+
+async function withTransport<T>(
+  connection: Connection,
+  operation: (transport: RconTransport) => Promise<T>,
+  factory: TransportFactory,
+): Promise<T | { ok: false; reason: FailureReason }> {
+  const key = connection.id ?? `${connection.host}:${connection.port}`;
+  if (activeConnections.has(key) || activeConnections.size >= MAX_ACTIVE_CONNECTIONS) {
+    return { ok: false, reason: "busy" };
+  }
+  activeConnections.add(key);
+  let transport: RconTransport | null = null;
+  try {
+    transport = factory(connection);
+    return await deadline(operation(transport), () => transport?.destroy?.());
+  } catch (error) {
+    return failure(error);
+  } finally {
+    if (transport) {
+      await deadline(transport.end(), () => transport?.destroy?.(), CLEANUP_TIMEOUT_MS).catch(() => undefined);
+    }
+    activeConnections.delete(key);
+  }
+}
+
+export async function testRconConnection(connection: Connection, factory: TransportFactory = defaultTransport) {
+  return withTransport(connection, async (transport) => {
+    await transport.connect();
+    return { ok: true as const };
+  }, factory);
+}
+
+export async function executeRcon(connection: Connection, command: string, factory: TransportFactory = defaultTransport) {
+  return withTransport(connection, async (transport) => {
+    await transport.connect();
+    const response = await transport.send(command);
+    return { ok: true as const, response: sanitizeRconOutput(response) };
+  }, factory);
+}