Allow to load pages from package

dash/_pages.py

@@ -1,6 +1,7 @@
 import collections
 import importlib
 import os
+import pkgutil
 import re
 import sys
 from fnmatch import fnmatch
@@ -411,6 +412,15 @@ def _page_meta_tags(app):
     ]
 
 
+def _ensure_layout_is_loaded(module_name, page_module):
+    if (
+        module_name in PAGE_REGISTRY
+        and not PAGE_REGISTRY[module_name]["supplied_layout"]
+    ):
+        _validate.validate_pages_layout(module_name, page_module)
+        PAGE_REGISTRY[module_name]["layout"] = getattr(page_module, "layout")
+
+
 def _import_layouts_from_pages(pages_folder):
     for root, dirs, files in os.walk(pages_folder):
         dirs[:] = [d for d in dirs if not d.startswith(".") and not d.startswith("_")]
@@ -428,10 +438,13 @@ def _import_layouts_from_pages(pages_folder):
             page_module = importlib.util.module_from_spec(spec)
             spec.loader.exec_module(page_module)
             sys.modules[module_name] = page_module
+            _ensure_layout_is_loaded(module_name, page_module)
 
-            if (
-                module_name in PAGE_REGISTRY
-                and not PAGE_REGISTRY[module_name]["supplied_layout"]
-            ):
-                _validate.validate_pages_layout(module_name, page_module)
-                PAGE_REGISTRY[module_name]["layout"] = getattr(page_module, "layout")
+
+def _import_layouts_from_package(pages_package):
+    modules = pkgutil.walk_packages(
+        pages_package.__path__, prefix=pages_package.__name__ + "."
+    )
+    for module in modules:
+        page_module = importlib.import_module(module.name)
+        _ensure_layout_is_loaded(module.name, page_module)

dash/dash.py

@@ -67,6 +67,7 @@
     _page_meta_tags,
     _path_to_page,
     _import_layouts_from_pages,
+    _import_layouts_from_package,
 )
 
 # Add explicit mapping for map files
@@ -345,6 +346,7 @@ def __init__(  # pylint: disable=too-many-statements
         server=True,
         assets_folder="assets",
         pages_folder="pages",
+        pages_package=None,
         use_pages=None,
         assets_url_path="assets",
         assets_ignore="",
@@ -444,6 +446,7 @@ def __init__(  # pylint: disable=too-many-statements
         _get_paths.CONFIG = self.config
         _pages.CONFIG = self.config
 
+        self.pages_package = pages_package
         self.pages_folder = str(pages_folder)
         self.use_pages = (pages_folder != "pages") if use_pages is None else use_pages
 
@@ -1959,6 +1962,8 @@ def enable_pages(self):
             return
         if self.pages_folder:
             _import_layouts_from_pages(self.config.pages_folder)
+        if self.pages_package:
+            _import_layouts_from_package(self.pages_package)
 
         @self.server.before_request
         def router():

tests/conftest.py

@@ -1,4 +1,5 @@
 import os
+import sys
 
 import pytest
 import dash
@@ -21,6 +22,9 @@ def clear_pages_state():
 
 def init_pages_state():
     """Clear all global state that is used by pages feature."""
+    for page in dash._pages.PAGE_REGISTRY.values():
+        if page["module"] in sys.modules:
+            sys.modules.pop(page["module"])
     dash._pages.PAGE_REGISTRY.clear()
     dash._pages.CONFIG.clear()
     dash._pages.CONFIG.__dict__.clear()

tests/unit/pages/test_pages.py

@@ -76,3 +76,12 @@ def test_import_layouts_from_pages(
 
     page_entry = list(dash.page_registry.values())[0]
     assert page_entry["module"] == expected_module_name
+
+
+def test_import_layouts_from_package(clear_pages_state):
+    from . import custom_pages
+
+    _ = Dash(__package__, use_pages=True, pages_folder="", pages_package=custom_pages)
+    page_entries = list(dash.page_registry.values())
+    assert len(page_entries) == 1
+    assert page_entries[0]["module"] == "pages.custom_pages.page"