localmemory: init

Author: milahu

fsspec/implementations/localmemory.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+import logging
+
+from fsspec.implementations.memory import MemoryFileSystem
+
+logger = logging.getLogger("fsspec.localmemoryfs")
+
+
+class LocalMemoryFileSystem(MemoryFileSystem):
+    """A filesystem based on a dict of BytesIO objects
+
+    This is a local filesystem so different instances of this class
+    point to different memory filesystems.
+    """
+
+    store = None
+    pseudo_dirs = None
+    protocol = "localmemory"
+    root_marker = "/"
+    _intrans = False
+    cachable = False  # same as: skip_instance_cache = True
+
+    def __init__(self, *args, **kwargs):
+        self.logger = logger  # global
+        self.store: dict[str, Any] = {}  # local
+        self.pseudo_dirs = [""]  # local
+        super().__init__(*args, **kwargs)

fsspec/implementations/tests/test_localmemory.py

@@ -0,0 +1,24 @@
+import pytest
+
+import fsspec
+from fsspec.implementations.localmemory import LocalMemoryFileSystem
+
+
+def test_protocol():
+    # this should not throw: ValueError: Protocol not known: localmemory
+    fsspec.filesystem("localmemory")
+
+
+def test_init():
+    fs1 = LocalMemoryFileSystem()
+    fs2 = LocalMemoryFileSystem()
+
+    # check that fs1 and fs2 are different instances of LocalMemoryFileSystem
+    assert id(fs1) != id(fs2)
+    assert id(fs1.store) != id(fs2.store)
+    assert id(fs1.pseudo_dirs) != id(fs2.pseudo_dirs)
+
+    fs1.touch("/fs1.txt")
+    fs2.touch("/fs2.txt")
+    assert fs1.ls("/", detail=False) == ["/fs1.txt"]
+    assert fs2.ls("/", detail=False) == ["/fs2.txt"]

fsspec/registry.py

@@ -171,6 +171,7 @@ def register_implementation(name, cls, clobber=False, errtxt=None):
         "err": "LibArchive requires to be installed",
     },
     "local": {"class": "fsspec.implementations.local.LocalFileSystem"},
+    "localmemory": {"class": "fsspec.implementations.localmemory.LocalMemoryFileSystem"},
     "memory": {"class": "fsspec.implementations.memory.MemoryFileSystem"},
     "oci": {
         "class": "ocifs.OCIFileSystem",