Cryptic message while importing CUDA version of onnxruntime Python package when one of dependencies is missing

[ivanst0]

Describe the bug
If one of native dependencies of onnxruntime-gpu package (CUDA, cuDNN, C++ Runtime) is missing the following error message is printed before the process terminates:

<python_env>\lib\site-packages\onnxruntime\capi\_pybind_state.py:14: UserWarning: Cannot load onnxruntime.capi. Error: 'DLL load failed: The specified module could not be found.'.
  warnings.warn("Cannot load onnxruntime.capi. Error: '{0}'.".format(str(e)))
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "<python_env>\lib\site-packages\onnxruntime\__init__.py", line 13, in <module>
    from onnxruntime.capi._pybind_state import get_all_providers, get_available_providers, get_device, set_seed, \
ImportError: cannot import name 'get_all_providers' from 'onnxruntime.capi._pybind_state' (<python_env>\lib\site-packages\onnxruntime\capi\_pybind_state.py)

Based on this message the user can't figure out which dependency is missing, or which version of particular dependency is required.

System information

• OS Platform and Distribution: Windows 10
• ONNX Runtime installed from: PyPI
• ONNX Runtime version: 1.6.0
• Python version: any

Expected behavior
The error message should inform the user which dependency is missing (and which version of it).

[snnn]

Yes, your concern is valid. And I suggest our users use windbg to get more detailed information.

To identify the problem:

1. Install windbg

2. Find the gflags.exe in the windbg install folder and start it,

3. Select the image file tab
   

4. Type python.exe then press the "tab" key, check "Show loader snaps" box

5. Put your python commands into a script file, named "test.py"

import torch
import onnxruntime

6. Start windbg, run python.exe with arguments of "test.py"
   

7. in the command windows, type "g", then press the enter key
   

8. You'll see a lot of outputs in the debugging windows. Please search the lines that have "LdrpProcessWork - ERROR: Unable to load DLL", and put the result here.
   e.g.
   "cublas64_100.dll", Parent Module: "C:\intelpython3\lib\site-packages\onnxruntime\capi\onnxruntime_pybind11_state.pyd", Status: 0xc0000135

Please post the log here if you can't find the problematic DLL by yourself.

[ivanst0]

The user can also use Dependency Walker, Dependencies or a similar tool to identify the actual dependencies of onnxruntime\capi\onnxruntime_pybind11_state.pyd, or use Process Monitor to see where python.exe is looking for (and not finding) dependency DLLs.

However, none of these options is user-friendly. The error message should simply tell the user which dependency is missing.