Adam Roderick

05/26/2020, 12:44 PM
The version of pendulum you are using will not install on windows.
Here is the relevant error from running `pip install prefect`:
Building wheels for collected packages: pendulum
  Building wheel for pendulum (PEP 517) ... error
  ERROR: Command errored out with exit status 1:
   command: 'c:\python38\python.exe' 'c:\python38\lib\site-packages\pip\_vendor\pep517\' build_wheel 'C:\Users\adam\AppData\Local\Temp\tmpj19tpk5a'
       cwd: C:\Users\adam\AppData\Local\Temp\pip-install-g0l9pvd_\pendulum
  Complete output (24 lines):
  Traceback (most recent call last):
    File "", line 2, in <module>
      from setuptools import setup
  ModuleNotFoundError: No module named 'setuptools'
  Traceback (most recent call last):
    File "c:\python38\lib\site-packages\pip\_vendor\pep517\", line 280, in <module>
    File "c:\python38\lib\site-packages\pip\_vendor\pep517\", line 263, in main
      json_out['return_val'] = hook(**hook_input['kwargs'])
    File "c:\python38\lib\site-packages\pip\_vendor\pep517\", line 204, in build_wheel
      return _build_backend().build_wheel(wheel_directory, config_settings,
    File "C:\Users\adam\AppData\Local\Temp\pip-build-env-g8_9u9_d\overlay\Lib\site-packages\poetry\core\masonry\", line 57, in build_wheel
      return unicode(WheelBuilder.make_in(poetry, Path(wheel_directory)))
    File "C:\Users\adam\AppData\Local\Temp\pip-build-env-g8_9u9_d\overlay\Lib\site-packages\poetry\core\masonry\builders\", line 56, in make_in
    File "C:\Users\adam\AppData\Local\Temp\pip-build-env-g8_9u9_d\overlay\Lib\site-packages\poetry\core\masonry\builders\", line 82, in build
    File "C:\Users\adam\AppData\Local\Temp\pip-build-env-g8_9u9_d\overlay\Lib\site-packages\poetry\core\masonry\builders\", line 101, in _build
    File "C:\Users\adam\AppData\Local\Temp\pip-build-env-g8_9u9_d\overlay\Lib\site-packages\poetry\core\masonry\builders\", line 129, in _run_build_command
    File "c:\python38\lib\", line 364, in check_call
      raise CalledProcessError(retcode, cmd)
  subprocess.CalledProcessError: Command '['c:\\python38\\python.exe', '', 'build', '-b', 'build']' returned non-zero exit status 1.
  ERROR: Failed building wheel for pendulum
Failed to build pendulum
ERROR: Could not build wheels for pendulum which use PEP 517 and cannot be installed directly
Workaround for me was to install specific version
pip install pendulum==2.0.4
, which is the minimum allowed in prefect's requirements.txt. After installing that version,
pip install prefect

Jim Crist-Harif

05/26/2020, 2:25 PM
Thanks for the heads up Adam, glad you figured it out. We see this as an issue with pendulum/pip, not a bug in prefect, but we'll definitely be tracking that issue for a resolution.

Adam Roderick

05/26/2020, 5:28 PM
Agreed, it's definitely to do with pendulum. Just FYI