Merge pull request #3711 from nilsvu/py_main_entry

Add a main entry point to the Python package

.github/workflows/Tests.yaml

@@ -456,6 +456,7 @@ ${{ env.CACHE_KEY_SUFFIX }}"
           -D SPECTRE_UNIT_TEST_TIMEOUT_FACTOR=${TEST_TIMEOUT_FACTOR:-'1'}
           -D SPECTRE_INPUT_FILE_TEST_TIMEOUT_FACTOR=${TEST_TIMEOUT_FACTOR:-'1'}
           -D SPECTRE_PYTHON_TEST_TIMEOUT_FACTOR=${TEST_TIMEOUT_FACTOR:-'1'}
+          -D CMAKE_INSTALL_PREFIX=/work/spectre_install
           --warn-uninitialized
           $GITHUB_WORKSPACE 2>&1 | tee CMakeOutput.txt 2>&1
       - name: Check for CMake warnings
@@ -522,6 +523,17 @@ ${{ env.CACHE_KEY_SUFFIX }}"
           # We get occasional random timeouts, repeat tests to see if
           # it is a random timeout or systematic
           ctest -j2 -LE unit --output-on-failure --repeat after-timeout:3
+      - name: Install
+        working-directory: /work/build
+        # Make sure the `install` target runs without error. We could add some
+        # basic smoke tests here to make sure the installation worked.
+        run: |
+          make install
+      - name: Print size of install directory
+        working-directory: /work/spectre_install
+        run: |
+          ls | xargs du -sh
+          du -sh .
       - name: Test formaline tar can be built
         if: matrix.build_type == 'Debug'
         working-directory: /work/build
@@ -716,6 +728,7 @@ ${{ env.CACHE_KEY_SUFFIX }}"
             -D USE_PCH=ON \
             -D USE_CCACHE=ON \
             -D SPECTRE_TEST_TIMEOUT_FACTOR=5 \
+            -D CMAKE_INSTALL_PREFIX=../install \
             $GITHUB_WORKSPACE
       - name: Build tests
         working-directory: build
@@ -739,6 +752,15 @@ ${{ env.CACHE_KEY_SUFFIX }}"
         working-directory: build
         run: |
           ctest -j3 --repeat after-timeout:3 --output-on-failure
+      - name: Install
+        working-directory: build
+        run: |
+          make install
+      - name: Print size of install directory
+        working-directory: install
+        run: |
+          ls | xargs du -sh
+          du -sh .
       # Retain caches only on the 'develop' branch (see unit_tests job)
       - name: Clear caches
         if: github.ref != 'refs/heads/develop'

cmake/SpectrePythonExecutable.sh

@@ -4,4 +4,4 @@
 # See LICENSE.txt for details.
 
 PYTHONPATH="@CMAKE_BINARY_DIR@/bin/python:$PYTHONPATH" @Python_EXECUTABLE@ \
-  -m @PYTHON_MODULE_LOCATION@.@PYTHON_FILE_JUST_NAME_WE@ "$@"
+  -m @PYTHON_SCRIPT_LOCATION@ "$@"

cmake/SpectreSetupPythonPackage.cmake

@@ -1,11 +1,6 @@
 # Distributed under the MIT License.
 # See LICENSE.txt for details.
 
-set(SPECTRE_PYTHON_INSTALL_LIBDIR
-  "lib/python${Python_VERSION_MAJOR}.${Python_VERSION_MINOR}/site-packages"
-  CACHE STRING "Location where the Python package is installed. Defaults to \
-CMAKE_INSTALL_PREFIX/lib/pythonX.Y/site-packages/.")
-
 spectre_define_test_timeout_factor_option(PYTHON "Python")
 
 set(SPECTRE_PYTHON_PREFIX "${CMAKE_BINARY_DIR}/bin/python/spectre/")
@@ -23,10 +18,28 @@ if(NOT EXISTS "${SPECTRE_PYTHON_PREFIX}/__init__.py")
     "__all__ = []")
 endif()
 
-# Write a file for installing the Python modules
+# Create the root __main__.py entry point
+configure_file(
+  "${CMAKE_SOURCE_DIR}/support/Python/__main__.py"
+  "${SPECTRE_PYTHON_PREFIX}/__main__.py"
+)
+# Also link the main entry point to bin/
+set(PYTHON_SCRIPT_LOCATION "spectre")
+configure_file(
+  "${CMAKE_SOURCE_DIR}/cmake/SpectrePythonExecutable.sh"
+  "${CMAKE_BINARY_DIR}/tmp/spectre")
+file(COPY "${CMAKE_BINARY_DIR}/tmp/spectre"
+  DESTINATION "${CMAKE_BINARY_DIR}/bin"
+  FILE_PERMISSIONS OWNER_READ OWNER_WRITE OWNER_EXECUTE GROUP_READ
+    GROUP_EXECUTE WORLD_READ WORLD_EXECUTE)
+
+# Write configuration files for installing the Python modules
+configure_file(
+  "${CMAKE_SOURCE_DIR}/src/PythonBindings/pyproject.toml"
+  "${SPECTRE_PYTHON_PREFIX_PARENT}/pyproject.toml")
 configure_file(
-  "${CMAKE_SOURCE_DIR}/src/PythonBindings/setup.py"
-  "${SPECTRE_PYTHON_PREFIX_PARENT}/setup.py")
+  "${CMAKE_SOURCE_DIR}/src/PythonBindings/setup.cfg"
+  "${SPECTRE_PYTHON_PREFIX_PARENT}/setup.cfg")
 
 set(_JEMALLOC_MESSAGE "")
 if(BUILD_PYTHON_BINDINGS AND "${JEMALLOC_LIB_TYPE}" STREQUAL SHARED)
@@ -47,10 +60,17 @@ configure_file(
   "${CMAKE_BINARY_DIR}/tmp/LoadPython.sh"
   "${CMAKE_BINARY_DIR}/bin/LoadPython.sh")
 
-# Install the SpECTRE Python package to the user-specified location.
+# Install the SpECTRE Python package to the CMAKE_INSTALL_PREFIX, using pip.
+# This will install the package into the expected subdirectory, typically
+# `lib/pythonX.Y/site-packages/`. It also creates symlinks to entry points
+# specified in `setup.py`.
 install(
-  DIRECTORY ${SPECTRE_PYTHON_PREFIX}
-  DESTINATION ${SPECTRE_PYTHON_INSTALL_LIBDIR}
+  CODE "execute_process(\
+    COMMAND ${Python_EXECUTABLE} -m pip install \
+      --no-deps --no-input --no-cache-dir --no-index --ignore-installed \
+      --disable-pip-version-check --no-build-isolation \
+      --prefix ${CMAKE_INSTALL_PREFIX} ${SPECTRE_PYTHON_PREFIX_PARENT} \
+    )"
   )
 
 add_custom_target(all-pybindings)
@@ -257,6 +277,8 @@ function(SPECTRE_PYTHON_ADD_MODULE MODULE_NAME)
     # Write an executable in `${CMAKE_BINARY_DIR}/bin` that runs the Python
     # script in the correct Python environment
     if(${PYTHON_FILE} IN_LIST ARG_PYTHON_EXECUTABLES)
+      set(PYTHON_SCRIPT_LOCATION
+        "${PYTHON_MODULE_LOCATION}.${PYTHON_FILE_JUST_NAME_WE}")
       configure_file(
         "${CMAKE_SOURCE_DIR}/cmake/SpectrePythonExecutable.sh"
         "${CMAKE_BINARY_DIR}/tmp/${PYTHON_FILE_JUST_NAME_WE}")

docs/DevGuide/BuildSystem.md

@@ -198,10 +198,6 @@ cmake -D FLAG1=OPT1 ... -D FLAGN=OPTN <SPECTRE_ROOT>
   - Location where the `install` target copies executables, libraries, etc. Make
     sure to set this variable before you `install`, or a default location such
     as `/usr/local` is used.
-- SPECTRE_PYTHON_INSTALL_LIBDIR
-  - Location where the `install` target copies the SpECTRE Python package.
-    Defaults to `CMAKE_INSTALL_PREFIX/lib/pythonX.Y/site-packages/`, which is a
-    location where Python packages are often expected.
 - DEBUG_SYMBOLS
   - Whether or not to use debug symbols (default is `ON`)
   - Disabling debug symbols will reduce compile time and total size of the build

src/PythonBindings/pyproject.toml

@@ -0,0 +1,6 @@
+# Distributed under the MIT License.
+# See LICENSE.txt for details.
+
+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"

src/PythonBindings/setup.cfg

@@ -0,0 +1,25 @@
+# Distributed under the MIT License.
+# See LICENSE.txt for details.
+
+[metadata]
+name = spectre
+version = @SPECTRE_VERSION@
+description = Python bindings for SpECTRE
+author = SXS collaboration
+url = @SPECTRE_HOMEPAGE@
+license = MIT
+
+[options]
+packages = find:
+install_requires =
+    h5py >= 3.0.0
+    numpy
+    scipy
+
+[options.package_data]
+# Install Python bindings libs alongside the Python code
+* = *.so
+
+[options.entry_points]
+console_scripts =
+    spectre = spectre.__main__:main

support/Python/__main__.py

@@ -0,0 +1,27 @@
+# Distributed under the MIT License.
+# See LICENSE.txt for details.
+
+SPECTRE_VERSION = "@SPECTRE_VERSION@"
+
+
+def main():
+    import argparse
+
+    class HelpFormatter(argparse.ArgumentDefaultsHelpFormatter,
+                        argparse.RawDescriptionHelpFormatter):
+        pass
+
+    parser = argparse.ArgumentParser(
+        prog='spectre',
+        description="SpECTRE version: {}".format(SPECTRE_VERSION),
+        formatter_class=HelpFormatter)
+
+    # Version endpoint
+    parser.add_argument('--version', action='version', version=SPECTRE_VERSION)
+
+    parser.parse_args()
+    raise NotImplementedError("No subprograms are implemented yet.")
+
+
+if __name__ == '__main__':
+    main()

tests/CMakeLists.txt

@@ -1,4 +1,5 @@
 # Distributed under the MIT License.
 # See LICENSE.txt for details.
 
+add_subdirectory(support)
 add_subdirectory(Unit)

tests/support/CMakeLists.txt

@@ -0,0 +1,4 @@
+# Distributed under the MIT License.
+# See LICENSE.txt for details.
+
+add_subdirectory(Python)

tests/support/Python/CMakeLists.txt

@@ -0,0 +1,11 @@
+# Distributed under the MIT License.
+# See LICENSE.txt for details.
+
+if (BUILD_PYTHON_BINDINGS)
+  add_test(NAME "support.Python.main"
+    COMMAND ${CMAKE_BINARY_DIR}/bin/spectre --version)
+  set_tests_properties(
+    "support.Python.main" PROPERTIES
+    PASS_REGULAR_EXPRESSION "${SPECTRE_VERSION}"
+    LABELS "python")
+endif()