cache packages_distributions (#11453)

* cache packages_distributions

* remove unused exception reference

* make style

Signed-off-by: Vladimir Mandic <[email protected]>

* change name to _package_map

---------

Signed-off-by: Vladimir Mandic <[email protected]>
Co-authored-by: DN6 <[email protected]>

Author: vladmandic

src/diffusers/utils/import_utils.py

@@ -36,7 +36,10 @@
     import importlib_metadata
 else:
     import importlib.metadata as importlib_metadata
-
+try:
+    _package_map = importlib_metadata.packages_distributions()  # load-once to avoid expensive calls
+except Exception:
+    _package_map = None
 
 logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
 
@@ -56,35 +59,32 @@
 
 
 def _is_package_available(pkg_name: str, get_dist_name: bool = False) -> Tuple[bool, str]:
+    global _package_map
     pkg_exists = importlib.util.find_spec(pkg_name) is not None
     pkg_version = "N/A"
 
     if pkg_exists:
+        if _package_map is None:
+            _package_map = defaultdict(list)
+            try:
+                # Fallback for Python < 3.10
+                for dist in importlib_metadata.distributions():
+                    _top_level_declared = (dist.read_text("top_level.txt") or "").split()
+                    _infered_opt_names = {
+                        f.parts[0] if len(f.parts) > 1 else inspect.getmodulename(f) for f in (dist.files or [])
+                    } - {None}
+                    _top_level_inferred = filter(lambda name: "." not in name, _infered_opt_names)
+                    for pkg in _top_level_declared or _top_level_inferred:
+                        _package_map[pkg].append(dist.metadata["Name"])
+            except Exception as _:
+                pass
         try:
-            package_map = importlib_metadata.packages_distributions()
-        except Exception as e:
-            package_map = defaultdict(list)
-            if isinstance(e, AttributeError):
-                try:
-                    # Fallback for Python < 3.10
-                    for dist in importlib_metadata.distributions():
-                        _top_level_declared = (dist.read_text("top_level.txt") or "").split()
-                        _infered_opt_names = {
-                            f.parts[0] if len(f.parts) > 1 else inspect.getmodulename(f) for f in (dist.files or [])
-                        } - {None}
-                        _top_level_inferred = filter(lambda name: "." not in name, _infered_opt_names)
-                        for pkg in _top_level_declared or _top_level_inferred:
-                            package_map[pkg].append(dist.metadata["Name"])
-                except Exception as _:
-                    pass
-
-        try:
-            if get_dist_name and pkg_name in package_map and package_map[pkg_name]:
-                if len(package_map[pkg_name]) > 1:
+            if get_dist_name and pkg_name in _package_map and _package_map[pkg_name]:
+                if len(_package_map[pkg_name]) > 1:
                     logger.warning(
-                        f"Multiple distributions found for package {pkg_name}. Picked distribution: {package_map[pkg_name][0]}"
+                        f"Multiple distributions found for package {pkg_name}. Picked distribution: {_package_map[pkg_name][0]}"
                     )
-                pkg_name = package_map[pkg_name][0]
+                pkg_name = _package_map[pkg_name][0]
             pkg_version = importlib_metadata.version(pkg_name)
             logger.debug(f"Successfully imported {pkg_name} version {pkg_version}")
         except (ImportError, importlib_metadata.PackageNotFoundError):