Files
pytorch/torch/_library/opaque_object.py
angelayi 3be9c86c74 [opaque obj] Initial OpaqueObject (#162660)
A big pain point ppl have with custom ops is that they do not accept arbitrary input/outputs. In this PR we create the concept of an "OpaqueObject" which allows users to pass arbitrary python objects into custom operators.

Some still slightly annoying parts with this implementation:
- The schema of the operator is `__torch__.torch.classes.aten.OpaqueObject` instead of whatever python type
- `@torch.library.custom_op` doesn't work.. yet?

UX:
```python
from torch._library.opaque_object import make_opaque, get_payload

# your custom python class
class OpaqueQueue:
    def __init__(self, queue: list[torch.Tensor], init_tensor_: torch.Tensor) -> None:
        super().__init__()
        self.queue = queue
        self.init_tensor_ = init_tensor_

    def push(self, tensor: torch.Tensor) -> None:
        self.queue.append(tensor)

    def pop(self) -> torch.Tensor:
        if len(self.queue) > 0:
            return self.queue.pop(0)
        return self.init_tensor_

    def size(self) -> int:
        return len(self.queue)

queue = OpaqueQueue([], torch.zeros(3))
obj: torch._C.ScriptObject = make_opaque(queue)

# obj.payload stores a direct reference to this python queue object
self.assertEqual(get_payload(obj), queue)

# This is able to be passed through the dispatcher
torch.ops._TestOpaqueObject.queue_push(obj, torch.ones(3))
self.assertTrue(queue.size(), 1)
```

Authoring a custom op:

```python
lib = torch.library.Library("_TestOpaqueObject", "FRAGMENT")

torch.library.define(
    f"_TestOpaqueObject::queue_push",
    "(__torch__.torch.classes.aten.OpaqueObject a, Tensor b) -> ()",
    tags=torch.Tag.pt2_compliant_tag,
    lib=lib,
)

@torch.library.impl(f"{libname}::queue_push", "CompositeExplicitAutograd", lib=lib)
def push_impl(q: torch._C.ScriptObject, b: torch.Tensor) -> None:
    # We can get the payload directly by get_payload(q)
    queue = get_payload(q)
    assert isinstance(queue, OpaqueQueue)
    queue.push(b)
```

Pull Request resolved: https://github.com/pytorch/pytorch/pull/162660
Approved by: https://github.com/zou3519
2025-09-22 18:30:28 +00:00

17 lines
526 B
Python

from typing import Any
import torch
def make_opaque(payload: Any) -> torch._C.ScriptObject:
"""
Creates an opaque object which stores the given Python object.
This opaque object can be passed to any custom operator as an argument.
The Python object can then be accessed from the opaque object using the `get_payload()` API.
"""
return torch._C._make_opaque_object(payload)
def get_payload(opaque_object: torch._C.ScriptObject) -> Any:
return torch._C._get_opaque_object_payload(opaque_object)