Include .py file migration in build_py packaging step; perform build_clib and build_ext before build_py packaging step

pkg/pypi/build.py

@@ -6,6 +6,7 @@ See: https://stackoverflow.com/questions/60073711/how-to-build-c-extensions-via-
 import os
 import shutil
 import subprocess
+from distutils.command.build_py import build_py
 from distutils.command.build_ext import build_ext
 from distutils.errors import DistutilsPlatformError, CCompilerError, DistutilsExecError
 from distutils.extension import Extension
@@ -52,6 +53,7 @@ class LibztModule(Extension):
             "libzt._libzt",
             sources=sources,
             include_dirs=INCLUDE_DIRS,
+            # depends = ...  # TODO: specify dependencies for recompile
             extra_compile_args=[
                 "-std=c++11",
                 "-DZTS_ENABLE_PYTHON=1",
@@ -95,21 +97,42 @@ def cstuff():
     })
 
 
+def copy_python_files(src_dir: str, dst_dir: str):
+    """ Copy all Python files from `src_dir` to `dst_dir`"""
+    for filename in {os.path.basename(filepath) for filepath in glob(os.path.join(src_dir, "*.py"))}:
+        shutil.copy(os.path.join(src_dir, filename), os.path.join(dst_dir, filename))
+
+
 class BuildFailed(Exception):
     pass
 
 
+class PyBuilder(build_py):
+
+    def run(self):
+        # Build extension module first since libzt.py is generated by SWIG
+        self.run_command("build_clib")
+        self.run_command("build_ext")
+        return super().run()
+
+    def build_packages(self):
+        # Copy Python files into packaging directory
+        copy_python_files(src_dir=os.path.join(ROOT_DIR, "src/bindings/python"),
+                          dst_dir=os.path.join(DIR, "libzt"))
+        super().build_packages()
+
+
 class ExtBuilder(build_ext):
 
     def run(self):
         try:
-            build_ext.run(self)
+            super().run()
         except (DistutilsPlatformError, FileNotFoundError):
             raise BuildFailed('File not found. Could not compile C extension.')
 
     def build_extension(self, ext):
         try:
-            build_ext.build_extension(self, ext)
+            super().build_extension(ext)
         except (CCompilerError, DistutilsExecError, DistutilsPlatformError, ValueError):
             raise BuildFailed('Could not compile C extension.')
 
@@ -122,18 +145,10 @@ def build(setup_kwargs):
     # Ensure git submodules are loaded
     subprocess.run(["git", "submodule", "update", "--init"])
 
-    # Copy Python files into packaging directory
-    src_dir = os.path.join(ROOT_DIR, "src", "bindings", "python")
-    dst_dir = os.path.join(DIR, "libzt")
-    for filename in os.listdir(src_dir):
-        if os.path.isfile(os.path.join(src_dir, filename)) and filename.endswith(".py"):
-            shutil.copy(os.path.join(src_dir, filename), os.path.join(dst_dir, filename))
-
     # LICENSE file
     shutil.copy(os.path.join(ROOT_DIR, "LICENSE.txt"), os.path.join(DIR, "LICENSE"))
 
     # Pass up extensions information
     setup_kwargs["libraries"] = [cstuff()]
     setup_kwargs["ext_modules"] = [LibztModule()]
-    setup_kwargs["py_modules"] = ["libzt"]
-    setup_kwargs["cmdclass"] = {"build_ext": ExtBuilder}
+    setup_kwargs["cmdclass"] = {"build_py": PyBuilder, "build_ext": ExtBuilder}