RPC proxy not working with implicit start from Rhino/Grasshopper

Describe the bug

Using compas_rpc.Proxy as a contextmanager raises an exception. This only happens if a RPC server is not already running. (Same/similar to #265)

To Reproduce Steps to reproduce the behavior:

Context: Grasshopper GHPython node or Rhino python editor.

Sample script

from compas.rpc import Proxy
from compas.geometry import Point

pt1 = Point(1, 2, 3)

with Proxy("compas.geometry", max_conn_attempts=5) as proxy:
    pt2 = proxy.Point(1, 2, 3)

if list(pt1) == pt2:
    print("Success")

1. Traceback

Message: Traceback (most recent call last):
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\compas\rpc\dispatcher.py", line 100, in _dispatch
    module = importlib.import_module(modulename)
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\compas\geometry\__init__.py", line 497, in <module>
    from .bbox import *  # noqa: F401 F403
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\compas\geometry\bbox\__init__.py", line 10, in <module>
    from .bbox_numpy import *  # noqa: F401 F403
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\compas\geometry\bbox\bbox_numpy.py", line 24, in <module>
    from compas.numerical import pca_numpy
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\compas\numerical\__init__.py", line 109, in <module>
    from .isolines import *  # noqa: F401 F403
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\compas\numerical\isolines\__init__.py", line 8, in <module>
    from .isolines_numpy import *  # noqa: F401 F403
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\compas\numerical\isolines\isolines_numpy.py", line 11, in <module>
    import matplotlib.pyplot as plt
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\matplotlib\__init__.py", line 174, in <module>
    _check_versions()
  File "C:\Users\a\scoop\apps\miniconda3\4.7.12.1\envs\compas_rr_ts-dev\lib\site-packages\matplotlib\__init__.py", line 159, in _check_versions
    from . import ft2font
ImportError: DLL load failed while importing ft2font: %1 is not a valid Win32 application.


Traceback:
  line 345, in _proxy, "C:\Users\a\AppData\Roaming\McNeel\Rhinoceros\6.0\scripts\compas\rpc\proxy.py"
  line 4, in <module>, "C:\Users\a\AppData\Local\Temp\TempScript.py"

Expected behavior Print “Success”.

Desktop (please complete the following information):

• OS: Win10
• Python version 2.7.8 (IronPython 2.7.8 (2.7.8.0) on .NET 4.0.30319.42000 (64-bit))
• Python package manager: Anaconda
• compas version: 0.19.1

[tetov]

• You are using a dev environment (based on the name), so the first thing I would try is to create a brand new env with compas 0.19.1, to rule out interference from other stuff

That environment only had a compas 0.19.1 and an editable install of a package I tested compas.plugin with.

• You have miniconda instead of Anaconda, I don’t think that is the source of the problem, but perhaps miniconda does take a different priority for some of the packages that normally are found on the anaconda channel (eg. matplotlib)

• Since the error seems to be coming from matplotlib, could you verify that 1) it works without RPC, 2) a --force-reinstall conda installation of the matplotlib-base package does not fix it ?

Just tested this on another computer with miniconda and it worked. Seems like my plugin package is the culprit.

I’ll investigate further, I’ll reopen if necessary.

[tetov]

    if PYTHON_DIRECTORY:
        lib_bin = os.path.join(PYTHON_DIRECTORY, 'Library', 'bin')
        if os.path.exists(lib_bin) and lib_bin not in env['PATH']:
            env['PATH'] = lib_bin + os.pathsep + env['PATH']

        lib_bin = os.path.join(PYTHON_DIRECTORY, 'lib')
        if os.path.exists(lib_bin) and lib_bin not in env['PATH']:
            env['PATH'] = lib_bin + os.pathsep + env['PATH']

This fixed it for me.