Ray: [ray] Usage of @property in an actor class

[51616]

What is the problem?

Seems like the use of @property in actor class cannot be used with ray actor.

Reproduction (REQUIRED)

@ray.remote
class A:
    def __init__(self,x):
        self.x = x

    @property
    def x_square(self):
        return x**2

a_instance = a.remote(x=5)
ray.get(a_instance.x_square.remote())

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[rkooo567]

cc @ericl

I think it is an expected behavior because you cannot access the member variables of actors with a remote call. Afaik, @property makes a class member variables that are aliases to getter and setter, so it is expected that it doesn't work.

[rkooo567]

If this is a hard requirement, please create a feature request! I will close it for now.

[winni2k]

I am running into this issue. I have a class that has several @property methods. I have found myself working around this by creating a derived "ray" class and creating getter and setter methods for all the properties. Quite verbose and ugly I must say. Here's what the derived class looks like:

@ray.remote
class PhyloTreeLikelihoodMoverActor(PhyloTreeLikelihoodMover):
    def set_seed(self, seed):
        self.prng.seed(seed)

    def get_attachment_log_like(self):
        return self.attachment_log_like

    def get_has_changed_nodes(self):
        return self.has_changed_nodes

    def get_double_check_ll_calculations(self):
        return self.double_check_ll_calculations

    def set_double_check_ll_calculations(self, val):
        self.double_check_ll_calculations = val

    def get_check_logsumexp_accuracy(self):
        return self.check_logsumexp_accuracy

    def set_check_logsumexp_accuracy(self, val):
        self.check_logsumexp_accuracy = val

    def get_logsumexp_refresh_rate(self):
        return self.logsumexp_refresh_rate

    def set_logsumexp_refresh_rate(self, val):
        self.logsumexp_refresh_rate = val

    def get_g(self):
        return self.g

    def get_mh_correction(self):
        return self.mover.mh_correction

As far as I can tell, only the first method would be needed otherwise. I would also be happy to hear suggestions on how to rationalize code.

However, this is still way better than any other library I have tried...

[ericl]

Hmm, this is an interesting issue. I'm not sure it's possible in general to generate all possible attribute accessors so that they can be called with .remote(). For example, a class might define __getattribute__ to return computed attribute values.

As a workaround, you could probably define a method like this:

def getattr(self, attr):
   return getattr(self, attr)

Then on the actor you can actor.getattr.remote("attachment_log_like") to dynamically get the attribute.

[winni2k]

Nice! That worked for me!