Adds progress bar using tqdm to directory_loader (#3349)

Approach copied from `WebBaseLoader`. Assumes the user doesn't have
`tqdm` installed.

docs/modules/indexes/document_loaders/examples/directory_loader.ipynb

@@ -68,6 +68,51 @@
     "len(docs)"
    ]
   },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "id": "e633d62f",
+   "metadata": {},
+   "source": [
+    "## Show a progress bar"
+   ]
+  },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "id": "43911860",
+   "metadata": {},
+   "source": [
+    "By default a progress bar will not be shown. To show a progress bar, install the `tqdm` library (e.g. `pip install tqdm`), and set the `show_progress` parameter to `True`."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "id": "bb93daac",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Requirement already satisfied: tqdm in /Users/jon/.pyenv/versions/3.9.16/envs/microbiome-app/lib/python3.9/site-packages (4.65.0)\n"
+     ]
+    },
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "0it [00:00, ?it/s]\n"
+     ]
+    }
+   ],
+   "source": [
+    "%pip install tqdm\n",
+    "loader = DirectoryLoader('../', glob=\"**/*.md\", show_progress=True)\n",
+    "docs = loader.load()"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "c5652850",

langchain/document_loaders/directory.py

@@ -35,6 +35,7 @@ class DirectoryLoader(BaseLoader):
         loader_cls: FILE_LOADER_TYPE = UnstructuredFileLoader,
         loader_kwargs: Union[dict, None] = None,
         recursive: bool = False,
+        show_progress: bool = False,
     ):
         """Initialize with path to directory and how to glob over it."""
         if loader_kwargs is None:
@@ -46,12 +47,30 @@ class DirectoryLoader(BaseLoader):
         self.loader_kwargs = loader_kwargs
         self.silent_errors = silent_errors
         self.recursive = recursive
+        self.show_progress = show_progress
 
     def load(self) -> List[Document]:
         """Load documents."""
         p = Path(self.path)
         docs = []
-        items = p.rglob(self.glob) if self.recursive else p.glob(self.glob)
+        items = list(p.rglob(self.glob) if self.recursive else p.glob(self.glob))
+
+        pbar = None
+        if self.show_progress:
+            try:
+                from tqdm import tqdm
+
+                pbar = tqdm(total=len(items))
+            except ImportError as e:
+                logger.warning(
+                    "To log the progress of DirectoryLoader you need to install tqdm, "
+                    "`pip install tqdm`"
+                )
+                if self.silent_errors:
+                    logger.warning(e)
+                else:
+                    raise e
+
         for i in items:
             if i.is_file():
                 if _is_visible(i.relative_to(p)) or self.load_hidden:
@@ -63,4 +82,11 @@ class DirectoryLoader(BaseLoader):
                             logger.warning(e)
                         else:
                             raise e
+                    finally:
+                        if pbar:
+                            pbar.update(1)
+
+        if pbar:
+            pbar.close()
+
         return docs