I have a Node.js app running on an ES2 instance which I can connect successfully to an AWS RDS Postgres database and run a SQL statement to return the results. Now I want to run that same app but on my local machine instead of the EC2 instance. Can it be done?

I tried using the same key pair instance as I am using for the EC2 instance and created an SSH tunnel with this command
(true endpoints replaced with XXX for security):

ssh -i ec2-db-keypair.pem -N -L localhost:8080:database-test-1.XXX.eu-west-2.rds.amazonaws.com:5432 [email protected]

My Node server is listening on 8081 and when the user lands on the route /db I want it to connect to the database and run some SQL statements.

The connection pool below works from within the EC2 instance, but not from my local machine:

server.listen({ port: 8081 }, (err, address) => {
  if (err) {
    console.error(err);
    process.exit(1);
  }
  console.log(`Server listening at ${address}`);
});

server.get("/db", async (request, reply) => {
  console.log("connect to db using slonik");

  const pem = fs
    .readFileSync(path.join(__dirname, "../../eu-west-2-bundle.pem"))
    .toString();

  const pool = createPool(
// ec2 instance instead of localhost:8080 I use: database-test-1.XXX.eu-west-2.rds.amazonaws.com:5432
    `postgresql://postges:mydbpassword@$localhost:8080/postgres`,
    {
      ssl: {
        ca: pem,
        rejectUnauthorized: true,
      },
    }
  );

  pool.connect(async (connection) => {
    try {
      const resultNodejsMyTableRows = await connection.query(
        sql`SELECT * FROM nodejs_mytable ORDER BY id ASC`
      );
      console.log("nodejs_mytable=", { resultNodejsMyTableRows });
    } catch (err) {
      console.log(err);
    }
  });

  return "look at console for responsesn";
});

Currently I get:

Hostname/IP does not match certificate's altnames: Host: localhost. is not in the cert's altnames: DNS:database-test-1.XXX.eu-west-2.rds.amazonaws.com

Is this the correct way that the SSH tunnel works and if not can someone advise on the correct way?