Clump the delay to maxPossibleDelay

[erlichmen]

according to https://www.rabbitmq.com/ttl.html the max value for x-expires is 2^32-1.
Make sure that we don't overflow the value as it will throw precondition_failed error.

[oroce]

first of all: thanks for your contribution

yes we are aware of that.
we never put bigger value than 2^32-1 in case we have to (for example we want to schedule something for 30 days) we do it in two steps (20 days + 10 days delay).

I think we shouldn't silently change the delay but should throw an error.

@madbence?

[erlichmen]

I got the actual problem from the retry packages that uses schedule for the backoff delay.
The problem is that if the error is not catch here it will throw an error on the amqp connection and most probably crash your application.

I don't think that the schedule module should handle splitting the tasks since that might cause different problems (what happens if someone by mistake schedule something for a millions years away?)

error can be nice but how would a user handle it?, most likely the user would not handle it and we are back to square one (app crashing).

most certainly the retry package needs to be fixed as well, but this is a one size fits all solution that at least doesn't crash the apps for existing users.

[madbence]

You're right, amqp-schedule should not handle task-splitting, but it should also not modify the delay silently. The best solution would be an exception. I will look into this problem this evening.

[oroce]

sure scheduler shouldn't handle splitting the task, we are using an internal module for that.

I think we could do something like this:

...
return function publish(exchange, route, message, delay, options, fn) {
   if(delay instanceof Date) {
     delay = delay.getTime() - Date.now();
   }

  if (delay + opt.threshold > maxPossibleDelay) {
    var err = new Error('Delay is bigger than 2^32-1');
    if (fn) {
      return fn(err);
    } else {
      return conn.emit('error', err);
    }
  }
....

Basically we can reuse fn or emit an error on connection.