feat: preparatory work for cleaning up code generator

1.  Modify `codegen/__init__.py` and `./setup.py` so that
    `python setup.py --reformat=false` disables reformatting.
2.  Add `bin/get_size.py` so that `python bin/get_size.py plotly build`
    reports the number of files and total size in bytes of the `plotly`
    directory (where generated code is put) and the `build` directory
    that is populated by `python setup.py build`.

```
$ python bin/get_size.py plotly build
which   num_files       num_bytes
src        15110        47664264
build      14982        45870886
```

Author: gvwilson

packages/python/plotly/bin/get_size.py

@@ -0,0 +1,27 @@
+"""Calculate total size and total number of files of package."""
+
+from pathlib import Path
+import sys
+
+
+def main():
+    """Main driver."""
+    assert len(sys.argv) == 3, "Usage: get_size.py src_dir build_dir"
+    src_files, src_bytes = get_size(sys.argv[1])
+    build_files, build_bytes = get_size(sys.argv[2])
+    print(f"which\t{'num_files':8s}\t{'num_bytes':8s}")
+    print(f"src\t{src_files:8d}\t{src_bytes:8d}")
+    print(f"build\t{build_files:8d}\t{build_bytes:8d}")
+
+
+def get_size(root_dir):
+    """Count files and size in bytes."""
+    num_files, num_bytes = 0, 0
+    for f in Path(root_dir).glob("**/*.*"):
+        num_files += 1
+        num_bytes += f.stat().st_size
+    return num_files, num_bytes
+
+
+if __name__ == "__main__":
+    main()

packages/python/plotly/codegen/__init__.py

@@ -85,7 +85,7 @@ def preprocess_schema(plotly_schema):
         items["colorscale"] = items.pop("concentrationscales")
 
 
-def perform_codegen():
+def perform_codegen(reformat=True):
     # Set root codegen output directory
     # ---------------------------------
     # (relative to project root)
@@ -337,9 +337,12 @@ def __getattr__(import_name):
         f.write(graph_objects_init_source)
 
     # ### Run black code formatter on output directories ###
-    subprocess.call(["black", "--target-version=py36", validators_pkgdir])
-    subprocess.call(["black", "--target-version=py36", graph_objs_pkgdir])
-    subprocess.call(["black", "--target-version=py36", graph_objects_path])
+    if reformat:
+        subprocess.call(["black", "--target-version=py36", validators_pkgdir])
+        subprocess.call(["black", "--target-version=py36", graph_objs_pkgdir])
+        subprocess.call(["black", "--target-version=py36", graph_objects_path])
+    else:
+        print("skipping reformatting")
 
 
 if __name__ == "__main__":

packages/python/plotly/setup.py

@@ -176,21 +176,23 @@ def run(self):
 
 class CodegenCommand(Command):
     description = "Generate class hierarchy from Plotly JSON schema"
-    user_options = []
+    user_options = [
+        ("reformat=", None, "reformat "),
+    ]
 
     def initialize_options(self):
-        pass
+        self.reformat = "true"
 
     def finalize_options(self):
-        pass
+        self.reformat = self.reformat.lower() in {"true", "t", "yes", "y", "1"}
 
     def run(self):
         if sys.version_info < (3, 8):
             raise ImportError("Code generation must be executed with Python >= 3.8")
 
         from codegen import perform_codegen
 
-        perform_codegen()
+        perform_codegen(self.reformat)
 
 
 def overwrite_schema_local(uri):