python binding: install and fix CI

Install:

- As of Python 3.3+, `__init__.py` is not required in site-package
  folders. Those folders are seen as module by default.
- Helps with file ownership when installing the binding
  wrapper via pip as part of the villas-node package and the bindings from the codebase.

CI:

- Fixed wrong variable name in the CI script.
- .so file should be found and symlinked properly into `/python/villas/node` for testing purposes.

Signed-off-by: Kevin Vu te Laar <vu.te@rwth-aachen.de>

Author: Kevin Vu te Laar

.gitlab-ci.yml

@@ -181,11 +181,11 @@ test:python_unit_integration:
     - cmake --build build ${CMAKE_BUILD_OPTS} --target python_binding
 
     - binding_path=$(find ${PWD}/build/python/binding/ -name "python_binding*.so" | head -n1)
-    - link_path=${PWD}/python/villas/node/$(basename $python_binding)
+    - link_path=${PWD}/python/villas/node/$(basename $binding_path)
     - ln -sf $binding_path $link_path
 
     - cmake --build build ${CMAKE_BUILD_OPTS} --target run-python-unit-tests run-python-integration-tests
-    - rm $node_path
+    - rm $link_path
   needs:
     - job: "build:source: [fedora]"
       artifacts: true

python/binding/CMakeLists.txt

@@ -28,13 +28,6 @@ if(pybind11_FOUND)
     COMPONENT lib
     LIBRARY DESTINATION ${PYTHON_SITE_PACKAGES}/villas/node/
   )
-  file(WRITE "${CMAKE_BINARY_DIR}/python/villas/__init__.py" "")
-  file(WRITE "${CMAKE_BINARY_DIR}/python/villas/node/__init__.py" "")
-  install(
-    DIRECTORY "${CMAKE_BINARY_DIR}/python/villas"
-    DESTINATION "${PYTHON_SITE_PACKAGES}"
-    FILES_MATCHING PATTERN "__init__.py"
-  )
 else()
   message(STATUS "pybind11 not found. Skipping Python wrapper build.")
 endif()