FromConfigMixin.from_config now supports fsspec config loading (#918)

Author: mauvilsa

CHANGELOG.rst

@@ -15,6 +15,12 @@ paths are considered internals and can change in minor and patch releases.
 v4.50.0 (unreleased)
 --------------------
 
+Added
+^^^^^
+- ``FromConfigMixin.from_config`` with ``config_read_mode_fsspec_enabled=True``
+  now supports fsspec config loading including the resolving of relative paths
+  (`#918 <https://github.com/omni-us/jsonargparse/pull/918>`__).
+
 Changed
 ^^^^^^^
 - Drop support for Python 3.9. The minimum supported Python version is now

DOCUMENTATION.rst

@@ -744,10 +744,11 @@ If you import ``from jsonargparse import set_parsing_settings`` and then run
 functions and classes will also support loading from URLs: :meth:`parse_path
 <.ArgumentParser.parse_path>`, :meth:`get_defaults
 <.ArgumentParser.get_defaults>` (``default_config_files`` argument),
-``action="config"``, :class:`.ActionJsonSchema`, :class:`.ActionJsonnet` and
-:class:`.ActionParser`. This means that a tool that can receive a config file
-via ``action="config"`` is able to get the content from a URL, thus something
-like the following would work:
+``action="config"``, :py:meth:`.FromConfigMixin.from_config`,
+:class:`.ActionJsonSchema`, :class:`.ActionJsonnet` and :class:`.ActionParser`.
+This means that a tool that can receive a config file via ``action="config"`` is
+able to get the content from a URL, thus something like the following would
+work:
 
 .. code-block:: bash
 

jsonargparse/_from_config.py

@@ -8,9 +8,10 @@
 from ._core import ArgumentParser
 from ._loaders_dumpers import get_loader_exceptions, load_value
 from ._optionals import _get_config_read_mode
+from ._paths import change_to_path_dir
 from ._required import clear_required, iter_required_keys
 from ._typehints import is_subclass_spec, resolve_class_path_by_name
-from ._util import import_object
+from ._util import import_object, load_config_path_context
 
 __all__ = ["FromConfigMixin"]
 
@@ -30,7 +31,9 @@ class FromConfigMixin:
            defaults.
 
         2. Adds a ``from_config`` ``@classmethod``, that instantiates the class
-           based on a config file or dict.
+           based on a config file or dict. If
+           ``config_read_mode_fsspec_enabled=True`` is set, then config paths
+           can be URLs.
 
     Attributes:
         __from_config_init_defaults__: Optional path to a config file for
@@ -61,12 +64,17 @@ def from_config(cls: type[T], config: str | PathLike | dict) -> T:
 def _parse_class_kwargs_from_config(cls: type[T], config: str | PathLike | dict, **kwargs) -> tuple[dict, type[T]]:
     """Parse the init kwargs for ``cls`` from a config file or dict."""
     parser = ArgumentParser(exit_on_error=False, **kwargs)
+    cfg_path = None
     if not isinstance(config, dict):
         from .typing import Path
 
         cfg_path = Path(config, mode=_get_config_read_mode())
-        cfg_str = cfg_path.read_text()
-        with parser_context(load_value_mode=parser.parser_mode):
+        with (
+            load_config_path_context(cfg_path),
+            change_to_path_dir(cfg_path),
+            parser_context(load_value_mode=parser.parser_mode),
+        ):
+            cfg_str = cfg_path.read_text()
             try:
                 config = load_value(cfg_str, path=str(config))
             except get_loader_exceptions() as ex:
@@ -86,7 +94,8 @@ def _parse_class_kwargs_from_config(cls: type[T], config: str | PathLike | dict,
     parser.add_class_arguments(cls)
     for required in iter_required_keys(parser):
         clear_required(parser, required)
-    cfg = parser.parse_object(config, defaults=False)
+    with load_config_path_context(cfg_path), change_to_path_dir(cfg_path):
+        cfg = parser.parse_object(config, defaults=False)
     return parser.instantiate(cfg).as_dict(), cls
 
 

jsonargparse_tests/test_from_config.py

@@ -2,9 +2,21 @@
 
 import pytest
 
-from jsonargparse import FromConfigMixin
+from jsonargparse import FromConfigMixin, set_parsing_settings
+from jsonargparse._optionals import fsspec_support
 from jsonargparse._paths import PathError
-from jsonargparse_tests.conftest import json_or_yaml_dump, skip_if_no_pyyaml, skip_if_omegaconf_unavailable
+from jsonargparse.typing import path_type
+from jsonargparse_tests.conftest import (
+    json_or_yaml_dump,
+    skip_if_fsspec_unavailable,
+    skip_if_no_pyyaml,
+    skip_if_omegaconf_unavailable,
+)
+
+if fsspec_support:
+    import fsspec
+
+Path_fsr = path_type("fsr")
 
 # __init__ defaults override tests
 
@@ -198,6 +210,29 @@ def test_from_config_method_path(tmp_cwd):
     assert instance.parent_param == "value_from_file"
 
 
+@skip_if_fsspec_unavailable
+def test_from_config_method_path_fsspec_relative_paths():
+    class FromConfigMethodFsspecRelativePath(FromConfigMixin):
+        def __init__(self, file: Path_fsr):
+            self.file = file
+
+    config_path = "memory://from_config/config.yaml"
+    file_path = "memory://from_config/file.txt"
+    with fsspec.open(config_path, "w") as f:
+        f.write(json_or_yaml_dump({"file": "file.txt"}))
+    with fsspec.open(file_path, "w") as f:
+        f.write("value_from_fsspec")
+
+    set_parsing_settings(config_read_mode_fsspec_enabled=True)
+    try:
+        instance = FromConfigMethodFsspecRelativePath.from_config(config_path)
+    finally:
+        set_parsing_settings(config_read_mode_fsspec_enabled=False)
+
+    assert instance.file.absolute == file_path
+    assert instance.file.read_text() == "value_from_fsspec"
+
+
 def test_from_config_method_path_does_not_exist(tmp_cwd):
     config_path = tmp_cwd / "config.yaml"