Core: Implement walk api

tosfs/core.py

@@ -18,7 +18,7 @@
 import mimetypes
 import os
 import time
-from typing import Any, BinaryIO, List, Optional, Tuple, Union
+from typing import Any, BinaryIO, Generator, List, Optional, Tuple, Union
 
 import tos
 from fsspec import AbstractFileSystem
@@ -65,6 +65,7 @@ class TosFileSystem(AbstractFileSystem):
     abstract super-class for pythonic file-systems.
     """
 
+    protocol = ("tos", "tosfs")
     retries = 5
     default_block_size = 5 * 2**20
 
@@ -676,6 +677,42 @@ def _read_chunks(body: BinaryIO, f: BinaryIO) -> None:
                     e,
                 )
 
+    def walk(
+        self,
+        path: str,
+        maxdepth: Optional[int] = None,
+        topdown: bool = True,
+        on_error: str = "omit",
+        **kwargs: Any,
+    ) -> Generator[str, List[str], List[str]]:
+        """List objects under the given path.
+
+        Parameters
+        ----------
+        path : str
+            The path to list.
+        maxdepth : int, optional
+            The maximum depth to walk to (default is None).
+        topdown : bool, optional
+            Whether to walk top-down or bottom-up (default is True).
+        on_error : str, optional
+            How to handle errors (default is 'omit').
+        **kwargs : Any, optional
+            Additional arguments.
+
+        Raises
+        ------
+        ValueError
+            If the path is an invalid path.
+
+        """
+        if path in ["", "*"] + ["{}://".format(p) for p in self.protocol]:
+            raise ValueError("Cannot access all of TOS via path {}.".format(path))
+
+        return super().walk(
+            path, maxdepth=maxdepth, topdown=topdown, on_error=on_error, **kwargs
+        )
+
     def _open_remote_file(
         self,
         bucket: str,

tosfs/tests/test_tosfs.py

@@ -343,6 +343,79 @@ def test_get_file(tosfs: TosFileSystem, bucket: str, temporary_workspace: str) -
     tosfs.rm_file(rpath)
 
 
+def test_walk(tosfs: TosFileSystem, bucket: str, temporary_workspace: str) -> None:
+    with pytest.raises(ValueError, match="Cannot access all of TOS via path ."):
+        tosfs.walk(path="")
+
+    with pytest.raises(ValueError, match="Cannot access all of TOS via path *."):
+        tosfs.walk(path="*")
+
+    with pytest.raises(ValueError, match="Cannot access all of TOS via path tos://."):
+        tosfs.walk("tos://")
+
+    for root, dirs, files in list(tosfs.walk("/", maxdepth=1)):
+        assert root == ""
+        assert len(dirs) > 0
+        assert files == []
+
+    for root, dirs, files in tosfs.walk(bucket, maxdepth=1):
+        assert root == bucket
+        assert len(dirs) > 0
+        assert len(files) > 0
+
+    dir_name = random_str()
+    sub_dir_name = random_str()
+    file_name = random_str()
+    sub_file_name = random_str()
+
+    tosfs.makedirs(f"{bucket}/{temporary_workspace}/{dir_name}/{sub_dir_name}")
+    tosfs.touch(f"{bucket}/{temporary_workspace}/{dir_name}/{file_name}")
+    tosfs.touch(
+        f"{bucket}/{temporary_workspace}/{dir_name}/{sub_dir_name}/{sub_file_name}"
+    )
+
+    walk_results = list(tosfs.walk(f"{bucket}/{temporary_workspace}"))
+
+    assert walk_results[0][0] == f"{bucket}/{temporary_workspace}"
+    assert dir_name in walk_results[0][1]
+    assert walk_results[0][2] == []
+
+    assert walk_results[1][0] == f"{bucket}/{temporary_workspace}/{dir_name}"
+    assert sub_dir_name in walk_results[1][1]
+    assert file_name in walk_results[1][2]
+
+    assert (
+        walk_results[2][0]
+        == f"{bucket}/{temporary_workspace}/{dir_name}/{sub_dir_name}"
+    )
+    assert walk_results[2][1] == []
+    assert sub_file_name in walk_results[2][2]
+
+    walk_results = list(tosfs.walk(f"{bucket}/{temporary_workspace}", topdown=False))
+    assert (
+        walk_results[0][0]
+        == f"{bucket}/{temporary_workspace}/{dir_name}/{sub_dir_name}"
+    )
+    assert walk_results[0][1] == []
+    assert sub_file_name in walk_results[0][2]
+
+    assert walk_results[1][0] == f"{bucket}/{temporary_workspace}/{dir_name}"
+    assert sub_dir_name in walk_results[1][1]
+    assert file_name in walk_results[1][2]
+
+    assert walk_results[2][0] == f"{bucket}/{temporary_workspace}"
+    assert dir_name in walk_results[2][1]
+    assert walk_results[2][2] == []
+
+    tosfs.rm_file(
+        f"{bucket}/{temporary_workspace}/{dir_name}/{sub_dir_name}/{sub_file_name}"
+    )
+    tosfs.rm_file(f"{bucket}/{temporary_workspace}/{dir_name}/{file_name}")
+    tosfs.rmdir(f"{bucket}/{temporary_workspace}/{dir_name}/{sub_dir_name}")
+    tosfs.rmdir(f"{bucket}/{temporary_workspace}/{dir_name}")
+    tosfs.rmdir(f"{bucket}/{temporary_workspace}")
+
+
 ###########################################################
 #                File operation tests                     #
 ###########################################################