Add ability in task spec to wait for a lock before proceeding about orquesta HOT 4 OPEN

List of locks could potentially be dangerous and cause deadlock scenarios, in my opinion.

Classic deadlock scenario is:

# Thread A

Lock X
Lock Y

Unlock Y
Unlock X


# Thread B
Lock X
Lock Y

Unlock X
Unlock Y

If locks are not obtained and released in the exact same order in all code paths, you risk the chance of a deadlock scenario. It's much safer to just have one single lock and ensure it is always released in the face of an exception or return from your code path (In this case a workflow success or failure).

from orquesta.

Small question, would it make sense to support a list of locks rather than a single lock? Could people want to acquire locks on different resources with different timeouts but still want the executing workflow to depend one or both of them?

from orquesta.

Fair enough, I was coming from a specific use case where I needed a lock for a group of servers and another lock for individual server within that group when I asked if it made sense to support a list of locks.

If Orquesta would suffer from the same deadlock/livelock issues as OS threads, then I agree it's a dangerous feature to allow.

from orquesta.

This is a good point on deadlock. I think for the time being we will keep this simple. The engine should detect that a lock is already acquired and will not allow additional lock requests in subworkflow(s) since that is possible.

from orquesta.