Changing how optional dependencies are import state are checked (#551)

* adding initial check

* adding check_module_enabled func

* silly typo "module" instead of module

* switch all optionals to check_module_enabled

* changing to c/longdouble for tests

* cleaning up old code and adding noqa

* Revert "changing to c/longdouble for tests"

This reverts commit 06534b1.

* numpydoc style docstring

* adding cupy/cusignal import tests and how enables are set

* adding message to be optional

* fixing logic in cupy/cusignal_enabled

* cleaning up old code snippets and typos

* small format changes

* more formatting changes

* changing import to import_module for pylint

* minor: restyling deps.py

* minor: added alex-rakowski to contributors

---------

Co-authored-by: mrava87 <[email protected]>

Author: alex-rakowski

README.md

@@ -149,3 +149,4 @@ A list of video tutorials to learn more about PyLops:
 * Rohan Babbar, rohanbabbar04
 * Wei Zhang, ZhangWeiGeo
 * Fedor Goncharov, fedor-goncharov
+* Alex Rakowski, alex-rakowski

docs/source/credits.rst

@@ -20,4 +20,5 @@ Contributors
 *  `Aniket Singh Rawat <https://github.com/dikwickley>`_, dikwickley
 *  `Rohan Babbar <https://github.com/rohanbabbar04>`_, rohanbabbar04
 *  `Wei Zhang <https://github.com/ZhangWeiGeo>`_, ZhangWeiGeo
-*  `Fedor Goncharov <https://github.com/fedor-goncharov>`_, fedor-goncharov
+*  `Fedor Goncharov <https://github.com/fedor-goncharov>`_, fedor-goncharov
+*  `Alex Rakowski <https://github.com/alex-rakowski>`_, alex-rakowski

pylops/utils/deps.py

@@ -12,30 +12,78 @@
 ]
 
 import os
-from importlib import util
-
-# check package availability
-cupy_enabled = (
-    util.find_spec("cupy") is not None and int(os.getenv("CUPY_PYLOPS", 1)) == 1
-)
-cusignal_enabled = (
-    util.find_spec("cusignal") is not None and int(os.getenv("CUSIGNAL_PYLOPS", 1)) == 1
-)
-devito_enabled = util.find_spec("devito") is not None
-numba_enabled = util.find_spec("numba") is not None
-pyfftw_enabled = util.find_spec("pyfftw") is not None
-pywt_enabled = util.find_spec("pywt") is not None
-skfmm_enabled = util.find_spec("skfmm") is not None
-spgl1_enabled = util.find_spec("spgl1") is not None
-sympy_enabled = util.find_spec("sympy") is not None
-torch_enabled = util.find_spec("torch") is not None
+from importlib import import_module, util
+from typing import Optional
 
 
 # error message at import of available package
-def devito_import(message):
+def cupy_import(message: Optional[str] = None) -> str:
+    # detect if cupy is available and the user is expecting to be used
+    cupy_test = (
+        util.find_spec("cupy") is not None and int(os.getenv("CUPY_PYLOPS", 1)) == 1
+    )
+    # if cupy should be importable
+    if cupy_test:
+        # try importing it
+        try:
+            import_module("cupy")  # noqa: F401
+
+            # if successful set the message to None.
+            cupy_message = None
+        # if unable to import but the package is installed
+        except (ImportError, ModuleNotFoundError) as e:
+            cupy_message = (
+                f"Failed to import cupy, Falling back to CPU (error: {e}). "
+                "Please ensure your CUDA environment is set up correctly "
+                "for more details visit 'https://docs.cupy.dev/en/stable/install.html'"
+            )
+            print(UserWarning(cupy_message))
+    # if cupy_test is False, it means not installed or environment variable set to 0
+    else:
+        cupy_message = (
+            "Cupy package not installed or os.getenv('CUPY_PYLOPS') == 0. "
+            f"In order to be able to use {message} "
+            "ensure 'os.getenv('CUPY_PYLOPS') == 1' and run "
+            "'pip install cupy'; "
+            "for more details visit 'https://docs.cupy.dev/en/stable/install.html'"
+        )
+
+    return cupy_message
+
+
+def cusignal_import(message: Optional[str] = None) -> str:
+    cusignal_test = (
+        util.find_spec("cusignal") is not None
+        and int(os.getenv("CUSIGNAL_PYLOPS", 1)) == 1
+    )
+    if cusignal_test:
+        try:
+            import_module("cusignal")  # noqa: F401
+
+            cusignal_message = None
+        except (ImportError, ModuleNotFoundError) as e:
+            cusignal_message = (
+                f"Failed to import cusignal. Falling back to CPU (error: {e}) . "
+                "Please ensure your CUDA environment is set up correctly; "
+                "for more details visit 'https://github.com/rapidsai/cusignal#installation'"
+            )
+            print(UserWarning(cusignal_message))
+    else:
+        cusignal_message = (
+            "Cusignal not installed or os.getenv('CUSIGNAL_PYLOPS') == 0. "
+            f"In order to be able to use {message} "
+            "ensure 'os.getenv('CUSIGNAL_PYLOPS') == 1' and run "
+            "'conda install cusignal'; "
+            "for more details visit ''https://github.com/rapidsai/cusignal#installation''"
+        )
+
+    return cusignal_message
+
+
+def devito_import(message: Optional[str] = None) -> str:
     if devito_enabled:
         try:
-            import devito  # noqa: F401
+            import_module("devito")  # noqa: F401
 
             devito_message = None
         except Exception as e:
@@ -49,10 +97,10 @@ def devito_import(message):
     return devito_message
 
 
-def numba_import(message):
+def numba_import(message: Optional[str] = None) -> str:
     if numba_enabled:
         try:
-            import numba  # noqa: F401
+            import_module("numba")  # noqa: F401
 
             numba_message = None
         except Exception as e:
@@ -68,10 +116,10 @@ def numba_import(message):
     return numba_message
 
 
-def pyfftw_import(message):
+def pyfftw_import(message: Optional[str] = None) -> str:
     if pyfftw_enabled:
         try:
-            import pyfftw  # noqa: F401
+            import_module("pyfftw")  # noqa: F401
 
             pyfftw_message = None
         except Exception as e:
@@ -87,10 +135,10 @@ def pyfftw_import(message):
     return pyfftw_message
 
 
-def pywt_import(message):
+def pywt_import(message: Optional[str] = None) -> str:
     if pywt_enabled:
         try:
-            import pywt  # noqa: F401
+            import_module("pywt")  # noqa: F401
 
             pywt_message = None
         except Exception as e:
@@ -106,10 +154,10 @@ def pywt_import(message):
     return pywt_message
 
 
-def skfmm_import(message):
+def skfmm_import(message: Optional[str] = None) -> str:
     if skfmm_enabled:
         try:
-            import skfmm  # noqa: F401
+            import_module("skfmm")  # noqa: F401
 
             skfmm_message = None
         except Exception as e:
@@ -124,10 +172,10 @@ def skfmm_import(message):
     return skfmm_message
 
 
-def spgl1_import(message):
+def spgl1_import(message: Optional[str] = None) -> str:
     if spgl1_enabled:
         try:
-            import spgl1  # noqa: F401
+            import_module("spgl1")  # noqa: F401
 
             spgl1_message = None
         except Exception as e:
@@ -141,10 +189,10 @@ def spgl1_import(message):
     return spgl1_message
 
 
-def sympy_import(message):
+def sympy_import(message: Optional[str] = None) -> str:
     if sympy_enabled:
         try:
-            import sympy  # noqa: F401
+            import_module("sympy")  # noqa: F401
 
             sympy_message = None
         except Exception as e:
@@ -156,3 +204,28 @@ def sympy_import(message):
             f'"pip install sympy".'
         )
     return sympy_message
+
+
+# Set package availability booleans
+# cupy and cusignal: the package is imported to check everything is working correctly,
+# if not the package is disabled. We do this here as both libraries are used as drop-in
+# replacement for many numpy and scipy routines when cupy arrays are provided.
+# all other libraries: we simply check if the package is available and postpone its import
+# to check everything is working correctly when a user tries to create an operator that requires
+# such a package
+cupy_enabled: bool = (
+    True if (cupy_import() is None and int(os.getenv("CUPY_PYLOPS", 1)) == 1) else False
+)
+cusignal_enabled: bool = (
+    True
+    if (cusignal_import() is None and int(os.getenv("CUSIGNAL_PYLOPS", 1)) == 1)
+    else False
+)
+devito_enabled = util.find_spec("devito") is not None
+numba_enabled = util.find_spec("numba") is not None
+pyfftw_enabled = util.find_spec("pyfftw") is not None
+pywt_enabled = util.find_spec("pywt") is not None
+skfmm_enabled = util.find_spec("skfmm") is not None
+spgl1_enabled = util.find_spec("spgl1") is not None
+sympy_enabled = util.find_spec("sympy") is not None
+torch_enabled = util.find_spec("torch") is not None