Service.get_payload as an instance method

[johny-b]

This would be nice:

Golem.run_service(
    ...,
    instance_params=[{'foo': 'bar'}]
)

class MyService(Service):
    def __init__(self, *, foo):
        self.foo = foo
        
    async def get_payload(self):
        image_hash = 'aaa' if self.foo == 'bar' else 'bbb'
        return await vm.repo(image_hash=image_hash)

I understand this could be solved by providing payload in Golem.run_service, instead of async def get_payload(), but I think it's convenient to have all such logic in a single place.

This is not important. But maybe this is easy? Could be useful.

(I found this doesn't work because I wrote this code & it didn't work, so that's not a 100% abstract thing).

[shadeofblue]

hmm.... there's an inherent problem here

1. payload determines the demand
2. the demand is published once per Cluster and is independent from the number of instances that end up being spawned
3. plus, honestly, if we want to differ the image hash, it doesn't seem like it's still the same service ...

anyway, to sum up, I'd say it's by design that the payload cannot differ on a per-instance basis

[shadeofblue]

you could create a factory that creates classes with an overridden class attribute which determines which image is deployed and use that in the Golem.run_service call ...

[johny-b]

OK, I more-or-less understand.

I have a feeling this somehow corresponds to #560.
If we instantiated the Service-based class immediately in golem.run_service() - and I think this would be the best solution for #560 - this should also work.

[shadeofblue]

OK, I more-or-less understand.

I have a feeling this somehow corresponds to #560.
If we instantiated the Service-based class immediately in golem.run_service() - and I think this would be the best solution for #560 - this should also work.

hmm, I don't really see an overlap between payload definition and the instance's lifecycle ...

[shadeofblue]

and I do believe that, if you really want to differentiate payload based some parameter, you do want to differentiate the Service ... and if you don't want to specify those classes explicitly but rather insist on having them created programatically, such a class factory would be the best solution ...

[johny-b]

I no longer think this is worth considering.