refactor(core): Centralize SSH Tunnel management (#9906)

Co-authored-by: Michael Kret <michael.k@radency.com>

packages/core/test/SSHClientsManager.test.ts

@@ -0,0 +1,67 @@
+import { Client } from 'ssh2';
+import type { SSHCredentials } from 'n8n-workflow';
+import { SSHClientsManager } from '@/SSHClientsManager';
+
+describe('SSHClientsManager', () => {
+	const credentials: SSHCredentials = {
+		sshAuthenticateWith: 'password',
+		sshHost: 'example.com',
+		sshPort: 22,
+		sshUser: 'username',
+		sshPassword: 'password',
+	};
+
+	let sshClientsManager: SSHClientsManager;
+	const connectSpy = jest.spyOn(Client.prototype, 'connect');
+	const endSpy = jest.spyOn(Client.prototype, 'end');
+
+	beforeEach(() => {
+		jest.clearAllMocks();
+		jest.useFakeTimers();
+
+		sshClientsManager = new SSHClientsManager();
+		connectSpy.mockImplementation(function (this: Client) {
+			this.emit('ready');
+			return this;
+		});
+	});
+
+	it('should create a new SSH client', async () => {
+		const client = await sshClientsManager.getClient(credentials);
+
+		expect(client).toBeInstanceOf(Client);
+	});
+
+	it('should not create a new SSH client when connect fails', async () => {
+		connectSpy.mockImplementation(function (this: Client) {
+			throw new Error('Failed to connect');
+		});
+		await expect(sshClientsManager.getClient(credentials)).rejects.toThrow('Failed to connect');
+	});
+
+	it('should reuse an existing SSH client', async () => {
+		const client1 = await sshClientsManager.getClient(credentials);
+		const client2 = await sshClientsManager.getClient(credentials);
+
+		expect(client1).toBe(client2);
+	});
+
+	it('should close all SSH connections on process exit', async () => {
+		await sshClientsManager.getClient(credentials);
+		sshClientsManager.onShutdown();
+
+		expect(endSpy).toHaveBeenCalledTimes(1);
+	});
+
+	it('should cleanup stale SSH connections', async () => {
+		await sshClientsManager.getClient({ ...credentials, sshHost: 'host1' });
+		await sshClientsManager.getClient({ ...credentials, sshHost: 'host2' });
+		await sshClientsManager.getClient({ ...credentials, sshHost: 'host3' });
+
+		jest.advanceTimersByTime(6 * 60 * 1000);
+		sshClientsManager.cleanupStaleConnections();
+
+		expect(endSpy).toHaveBeenCalledTimes(3);
+		expect(sshClientsManager.clients.size).toBe(0);
+	});
+});