[FEATURE] Add more context in error messages

[kellyselden]

What / Why

It would be great if the reason the lock couldn't be acquired could be included in the error message. I thought there was something wrong with my implementation because I would intermittently see Error: EEXIST: file already exists, open 'xxx' in my logs. After extensive debugging, I realised it was working as designed, it was just timing out after the wait has expired.

I added the following workaround code:

  let wait = 60e3;

  let before = new Date();

  try {
    await lock(lockFilePath, { wait });
  } catch (err) {
    let elapsed = new Date() - before;

    if (err.code === 'EEXIST' && elapsed >= wait) {
      err = new Error(`\`${lock.name}\` failed to acquire lock after ${elapsed}ms. ${err.message}`);
    }

    throw err;
  }

It would be great if we could include all this context as to why it failed into the error message.