From c6dd0df0aebaee31056ea2cd20884bc001f4b3a1 Mon Sep 17 00:00:00 2001
From: David Brochart <david.brochart@gmail.com>
Date: Fri, 15 Apr 2022 12:35:59 +0200
Subject: [PATCH] Add watchfiles attribute to contents manager

---
 jupyter_server/services/contents/fileio.py    |  1 -
 .../services/contents/filemanager.py          |  5 +++++
 jupyter_server/services/contents/manager.py   | 21 +++++++++++++++++++
 setup.cfg                                     |  2 +-
 tests/services/contents/test_fileio.py        | 19 +----------------
 .../contents/test_largefilemanager.py         | 19 +++++++++++++++++
 6 files changed, 47 insertions(+), 20 deletions(-)

diff --git a/jupyter_server/services/contents/fileio.py b/jupyter_server/services/contents/fileio.py
index bba4d67a9d..d01bfd16dc 100644
--- a/jupyter_server/services/contents/fileio.py
+++ b/jupyter_server/services/contents/fileio.py
@@ -15,7 +15,6 @@
 from tornado.web import HTTPError
 from traitlets import Bool
 from traitlets.config import Configurable
-from watchfiles import *  # noqa
 
 from jupyter_server.utils import to_api_path, to_os_path
 
diff --git a/jupyter_server/services/contents/filemanager.py b/jupyter_server/services/contents/filemanager.py
index 88aa0e3620..b18a19efd9 100644
--- a/jupyter_server/services/contents/filemanager.py
+++ b/jupyter_server/services/contents/filemanager.py
@@ -35,6 +35,8 @@
 
 class FileContentsManager(FileManagerMixin, ContentsManager):
 
+    import watchfiles
+
     root_dir = Unicode(config=True)
 
     @default("root_dir")
@@ -546,6 +548,9 @@ def get_kernel_path(self, path, model=None):
 
 
 class AsyncFileContentsManager(FileContentsManager, AsyncFileManagerMixin, AsyncContentsManager):
+
+    import watchfiles
+
     @default("checkpoints_class")
     def _checkpoints_class_default(self):
         return AsyncFileCheckpoints
diff --git a/jupyter_server/services/contents/manager.py b/jupyter_server/services/contents/manager.py
index 7bd6450803..e4dd4b4b7f 100644
--- a/jupyter_server/services/contents/manager.py
+++ b/jupyter_server/services/contents/manager.py
@@ -34,6 +34,13 @@
 copy_pat = re.compile(r"\-Copy\d*\.")
 
 
+class NoWatchfilesAPI:
+    pass
+
+
+NOWATCHFILESAPI = NoWatchfilesAPI()
+
+
 class ContentsManager(LoggingConfigurable):
     """Base class for serving files and directories.
 
@@ -409,6 +416,20 @@ def rename_file(self, old_path, new_path):
     # ContentsManager API part 2: methods that have useable default
     # implementations, but can be overridden in subclasses.
 
+    @property
+    def watchfiles(self):
+        """File system change notifyer
+
+        Override this method in subclasses if the file system supports change notifications.
+
+        Returns
+        -------
+        api : class
+            The supported API for file system change notifications. Loosely follows the API of the
+            watchfiles Python package (can be a subset of it).
+        """
+        return NOWATCHFILESAPI
+
     def delete(self, path):
         """Delete a file/directory and any associated checkpoints."""
         path = path.strip("/")
diff --git a/setup.cfg b/setup.cfg
index 2efdd71469..db168f08bd 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -53,7 +53,7 @@ install_requires =
     terminado>=0.8.3
     tornado>=6.1.0
     traitlets>=5.1
-    watchfiles>=0.12
+    watchfiles>=0.13
     websocket-client
 
 [options.extras_require]
diff --git a/tests/services/contents/test_fileio.py b/tests/services/contents/test_fileio.py
index 5f5716c53d..017916ce07 100644
--- a/tests/services/contents/test_fileio.py
+++ b/tests/services/contents/test_fileio.py
@@ -1,11 +1,10 @@
-import asyncio
 import os
 import stat
 import sys
 
 import pytest
 
-from jupyter_server.services.contents.fileio import Change, atomic_writing, awatch
+from jupyter_server.services.contents.fileio import atomic_writing
 
 umask = 0
 
@@ -122,19 +121,3 @@ def test_atomic_writing_newlines(tmp_path):
     with open(path, newline="") as f:
         read = f.read()
     assert read == text
-
-
-async def test_watch_directory(tmp_path):
-    file_path = tmp_path / "file.txt"
-
-    async def change_dir():
-        # let the watcher start
-        await asyncio.sleep(0.1)
-        # add file to directory
-        file_path.write_text("foo")
-
-    asyncio.create_task(change_dir())
-    stop_event = asyncio.Event()
-    async for change in awatch(tmp_path, stop_event=stop_event):
-        assert change == {(Change.added, str(file_path))}
-        stop_event.set()
diff --git a/tests/services/contents/test_largefilemanager.py b/tests/services/contents/test_largefilemanager.py
index 82c5e54e78..ba2e8122c8 100644
--- a/tests/services/contents/test_largefilemanager.py
+++ b/tests/services/contents/test_largefilemanager.py
@@ -1,3 +1,5 @@
+import asyncio
+
 import pytest
 import tornado
 
@@ -110,3 +112,20 @@ async def test_save_in_subdirectory(jp_large_contents_manager, tmp_path):
     assert "path" in model
     assert model["name"] == "Untitled.ipynb"
     assert model["path"] == "foo/Untitled.ipynb"
+
+
+async def test_watch_directory(tmp_path):
+    cm = AsyncLargeFileManager(root_dir=str(tmp_path))
+    file_path = tmp_path / "file.txt"
+
+    async def change_dir():
+        # let the watcher start
+        await asyncio.sleep(0.1)
+        # add file to directory
+        file_path.write_text("foo")
+
+    asyncio.create_task(change_dir())
+    stop_event = asyncio.Event()
+    async for change in cm.watchfiles.awatch(tmp_path, stop_event=stop_event):
+        assert (cm.watchfiles.Change.added, str(file_path)) in change
+        stop_event.set()