fix(WebSocketManager#connect): check if we have enough sessions (#8481)

* fix(WebSocketManager#connect): check if we have enough sessions

* fix: more useful error message

* fix: tests

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/ws/__tests__/ws/WebSocketManager.test.ts

@@ -183,6 +183,34 @@ test('strategies', async () => {
 	const strategy = new MockStrategy();
 	manager.setStrategy(strategy);
 
+	const data: APIGatewayBotInfo = {
+		shards: 1,
+		session_start_limit: {
+			max_concurrency: 3,
+			reset_after: 60,
+			remaining: 3,
+			total: 3,
+		},
+		url: 'wss://gateway.discord.gg',
+	};
+
+	const fetch = vi.fn(() => ({
+		data,
+		statusCode: 200,
+		responseOptions: {
+			headers: {
+				'content-type': 'application/json',
+			},
+		},
+	}));
+
+	mockPool
+		.intercept({
+			path: '/api/v10/gateway/bot',
+			method: 'GET',
+		})
+		.reply(fetch);
+
 	await manager.connect();
 	expect(strategy.spawn).toHaveBeenCalledWith(shardIds);
 	expect(strategy.connect).toHaveBeenCalled();

packages/ws/src/ws/WebSocketManager.ts

@@ -271,6 +271,16 @@ export class WebSocketManager extends AsyncEventEmitter<ManagerShardEventsMap> {
 
 	public async connect() {
 		const shardCount = await this.getShardCount();
+
+		const data = await this.fetchGatewayInformation();
+		if (data.session_start_limit.remaining < shardCount) {
+			throw new Error(
+				`Not enough sessions remaining to spawn ${shardCount} shards; only ${
+					data.session_start_limit.remaining
+				} remaining; resets at ${new Date(Date.now() + data.session_start_limit.reset_after).toISOString()}`,
+			);
+		}
+
 		// First, make sure all our shards are spawned
 		await this.updateShardCount(shardCount);
 		await this.strategy.connect();