Include developer instructions for installing in editable mode

[mofojed]

As a developer, I want to be able to install these python modules in editable mode so I can make change without build and reinstall a wheel every time. https://pip.pypa.io/en/stable/topics/local-project-installs/#editable-installs

[mofojed]

I currently can't get Python editable mode to work with deephaven.ui or plotly-express. I'm wondering if we're using namespace packages incorrectly and that may be the reason why? https://peps.python.org/pep-0420/#specification

I tried installing the package in editable, like:

pip install -e  ~/dev/deephaven/iris-oss/deephaven-plugins/plugins/ui

And they show up in the pip list correctly:

(.venv) ➜  main git:(main) pip list | grep deep                                                 
deephaven-core                  0.29.0
deephaven-plugin                0.5.0
deephaven-plugin-matplotlib     0.3.0.dev0
deephaven-plugin-plotly-express 0.0.7.dev0   /home/bender/dev/deephaven/iris-oss/deephaven-plugins/plugins/plotly-express
deephaven-plugin-ui             0.0.1.dev1   /home/bender/dev/deephaven/iris-oss/deephaven-plugins/plugins/ui
deephaven-server                0.29.0

But then starting up the server I get a ModuleNotFoundError on plugin registration:

2023-10-18T17:33:32.850Z | main                 |  INFO | .d.s.p.PluginRegistration | Invoking registration: io.deephaven.server.plugin.python.PythonPluginsRegistration@2acbc859
Initiating shutdown due to: Uncaught exception in thread main
java.lang.RuntimeException: Error in Python interpreter:
Type: <class 'ModuleNotFoundError'>
Value: No module named 'deephaven.ui'
Line: 1004
Namespace: _find_and_load_unlocked
File: <frozen importlib._bootstrap>
Traceback (most recent call last):
  File "/home/bender/dev/deephaven/iris-oss/core/main/.venv/lib/python3.10/site-packages/deephaven_internal/plugin/__init__.py", line 18, in initialize_all_and_register_into
  File "/home/bender/dev/deephaven/iris-oss/core/main/.venv/lib/python3.10/site-packages/deephaven_internal/plugin/register.py", line 18, in initialize_all_and_register_into
  File "/home/bender/dev/deephaven/iris-oss/core/main/.venv/lib/python3.10/site-packages/deephaven/plugin/__init__.py", line 94, in register_all_into
  File "/home/bender/dev/deephaven/iris-oss/core/main/.venv/lib/python3.10/site-packages/deephaven/plugin/__init__.py", line 90, in collect_registration_classes
  File "/home/bender/dev/deephaven/iris-oss/core/main/.venv/lib/python3.10/site-packages/deephaven/plugin/__init__.py", line 90, in <listcomp>
  File "/usr/lib/python3.10/importlib/metadata/__init__.py", line 171, in load
  File "/usr/lib/python3.10/importlib/__init__.py", line 126, in import_module
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1004, in _find_and_load_unlocked

[mattrunyon]

It's because of namespaces. I ran into issues when trying to use deephaven-plugin in editable mode with core

[devinrsmith]

Editable mode may also be tricky if we want to package js plugins in python environments. It may be a better tack to take to configure the deephaven server to point to the NPM packages (deephaven.jsPlugins.<name>=/path/to/package_root) as opposed to trying to plumb in through a Plugin.