adding required wrapper

CHANGELOG.md

@@ -8,7 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
--
+- Added `requires` wrapper ([#1056](https://github.com/PyTorchLightning/pytorch-lightning-bolts/pull/1056))
 
 
 ### Changed

src/pl_bolts/utils/_dependency.py

@@ -0,0 +1,28 @@
+import functools
+import os
+from typing import Any, Callable
+
+from lightning_utilities.core.imports import ModuleAvailableCache, RequirementCache
+
+
+# ToDo: replace with utils wrapper after 0.10 is released
+def requires(*module_path_version: str) -> Callable:
+ """Wrapper for enforcing certain requirements for a particular class or function."""
+
+ def decorator(func: Callable) -> Callable:
+ reqs = [
+ ModuleAvailableCache(mod_ver) if "." in mod_ver else RequirementCache(mod_ver)
+ for mod_ver in module_path_version
+ ]
+ available = all(map(bool, reqs))
+ if not available:
+
+ @functools.wraps(func)
+ def wrapper(*args: Any, **kwargs: Any) -> Any:
+ msg = os.linesep.join([repr(r) for r in reqs if not bool(r)])
+ raise ModuleNotFoundError(f"Required dependencies not available: \n{msg}")
+
+ return wrapper
+ return func
+
+ return decorator

tests/utils/test_dependency.py

@@ -0,0 +1,28 @@
+import pytest
+from pl_bolts.utils._dependency import requires
+
+
+@requires("torch")
+def using_torch():
+ return True
+
+
+@requires("torch.anything.wrong")
+def using_torch_wrong_path():
+ return True
+
+
+@requires("torch>99.0")
+def using_torch_bad_version():
+ return True
+
+
+def test_requires_pass():
+ assert using_torch() is True
+
+
+def test_requires_fail():
+ with pytest.raises(ModuleNotFoundError, match="Required dependencies not available"):
+ assert using_torch_wrong_path()
+ with pytest.raises(ModuleNotFoundError, match="Required dependencies not available"):
+ assert using_torch_bad_version()