SSH Tunnel Support

import { PostgresWarehouseClient } from '@lightdash/warehouses';

const client = new PostgresWarehouseClient({
  type: 'postgres',
  host: 'internal-db.local',
  port: 5432,
  user: 'dbuser',
  password: 'dbpass',
  dbname: 'warehouse',
  schema: 'public',
  sslmode: 'disable',
  // SSH tunnel config
  useSshTunnel: true,
  sshTunnelHost: 'bastion.example.com',
  sshTunnelPort: 22,
  sshTunnelUser: 'sshuser',
  sshTunnelPrivateKey: '-----BEGIN RSA PRIVATE KEY-----\n...',
});

await client.test(); // Tunnel created automatically

import { SshTunnel } from '@lightdash/warehouses';

const tunnel = new SshTunnel(credentials);
const modifiedCreds = await tunnel.connect();
console.log('Tunnel port:', tunnel.localPort);

const client = new PostgresWarehouseClient(modifiedCreds);
await client.test();

await tunnel.disconnect();

Original:  Client -> internal-db.local:5432 (blocked)

With SSH:  Client -> 127.0.0.1:random_port
           -> [SSH Tunnel] -> bastion.example.com:22
           -> internal-db.local:5432 (accessible)

{
  useSshTunnel: true,
  sshTunnelHost: 'bastion.example.com',
  sshTunnelPort: 22, // Default: 22
  sshTunnelUser: 'sshuser',
  sshTunnelPrivateKey: '-----BEGIN RSA PRIVATE KEY-----\n...',
  sshTunnelPublicKey: '...', // Optional, for reference
}

const privateKey = `-----BEGIN RSA PRIVATE KEY-----
MIIEpAIBAAKCAQEA1234567890...
[multiple lines]
-----END RSA PRIVATE KEY-----`;

class SshTunnel<T extends CreateWarehouseCredentials> {
  readonly originalCredentials: T;
  overrideCredentials: T;
  localPort: number | undefined;

  constructor(credentials: T);
  connect(): Promise<T>;
  disconnect(): Promise<void>;
}

try {
  const tunnel = new SshTunnel(credentials);
  const modifiedCreds = await tunnel.connect();
  const client = new PostgresWarehouseClient(modifiedCreds);
  await client.test();
} catch (error) {
  console.error('SSH tunnel failed:', error.message);
} finally {
  await tunnel.disconnect();
}

Error: SSH tunnel connection timeout

Error: SSH authentication failed

Error: Failed to establish port forward

const pgTunnel = new SshTunnel(pgCredentials);
const rsTunnel = new SshTunnel(rsCredentials);

const pgCreds = await pgTunnel.connect();
const rsCreds = await rsTunnel.connect();

const pgClient = new PostgresWarehouseClient(pgCreds);
const rsClient = new RedshiftWarehouseClient(rsCreds);

// Use both clients...

await pgTunnel.disconnect();
await rsTunnel.disconnect();