1from __future__ import annotations
2
3import importlib
4import sys
5import types
6import warnings
7from typing import Literal
8
9if sys.version_info >= (3, 12):
10 import importlib.metadata as importlib_metadata
11else:
12 import importlib_metadata
13from packaging.version import Version
14
15PY_VERSION = Version(".".join(map(str, sys.version_info[:3])))
16
17EMSCRIPTEN = sys.platform == "emscripten"
18
19LINUX = sys.platform == "linux"
20MACOS = sys.platform == "darwin"
21WINDOWS = sys.platform == "win32"
22
23
24def entry_points(group=None):
25 warnings.warn(
26 "`dask._compatibility.entry_points` has been replaced by `importlib_metadata.entry_points` and will be removed "
27 "in a future version. Please use `importlib_metadata.entry_points` instead.",
28 DeprecationWarning,
29 stacklevel=2,
30 )
31 return importlib_metadata.entry_points(group=group)
32
33
34VERSIONS = {
35 "numpy": "1.21.0",
36 "pandas": "2.0.0",
37 "bokeh": "3.1.0",
38 "jinja2": "2.10.3",
39 "pyarrow": "14.0.1",
40 "lz4": "4.3.2",
41}
42
43# A mapping from import name to package name (on PyPI) for packages where
44# these two names are different.
45
46INSTALL_MAPPING = {
47 "sqlalchemy": "SQLAlchemy",
48 "tables": "pytables",
49}
50
51
52def get_version(module: types.ModuleType) -> str:
53 version = getattr(module, "__version__", None)
54
55 if version is None:
56 raise ImportError(f"Can't determine version for {module.__name__}")
57 if module.__name__ == "psycopg2":
58 # psycopg2 appends " (dt dec pq3 ext lo64)" to it's version
59 version = version.split()[0]
60 return version
61
62
63def import_optional_dependency(
64 name: str,
65 extra: str = "",
66 min_version: str | None = None,
67 *,
68 errors: Literal["raise", "warn", "ignore"] = "raise",
69) -> types.ModuleType | None:
70 """
71 Import an optional dependency.
72
73 By default, if a dependency is missing an ImportError with a nice
74 message will be raised. If a dependency is present, but too old,
75 we raise.
76
77 Parameters
78 ----------
79 name : str
80 The module name.
81 extra : str
82 Additional text to include in the ImportError message.
83 errors : str {'raise', 'warn', 'ignore'}
84 What to do when a dependency is not found or its version is too old.
85
86 * raise : Raise an ImportError
87 * warn : Only applicable when a module's version is to old.
88 Warns that the version is too old and returns None
89 * ignore: If the module is not installed, return None, otherwise,
90 return the module, even if the version is too old.
91 It's expected that users validate the version locally when
92 using ``errors="ignore"`` (see. ``io/html.py``)
93 min_version : str, default None
94 Specify a minimum version that is different from the global pandas
95 minimum version required.
96 Returns
97 -------
98 maybe_module : Optional[ModuleType]
99 The imported module, when found and the version is correct.
100 None is returned when the package is not found and `errors`
101 is False, or when the package's version is too old and `errors`
102 is ``'warn'`` or ``'ignore'``.
103 """
104 assert errors in {"warn", "raise", "ignore"}
105
106 package_name = INSTALL_MAPPING.get(name)
107 install_name = package_name if package_name is not None else name
108
109 msg = (
110 f"Missing optional dependency '{install_name}'. {extra} "
111 f"Use pip or conda to install {install_name}."
112 )
113 try:
114 module = importlib.import_module(name)
115 except ImportError as err:
116 if errors == "raise":
117 raise ImportError(msg) from err
118 return None
119
120 # Handle submodules: if we have submodule, grab parent module from sys.modules
121 parent = name.split(".")[0]
122 if parent != name:
123 install_name = parent
124 module_to_get = sys.modules[install_name]
125 else:
126 module_to_get = module
127 minimum_version = min_version if min_version is not None else VERSIONS.get(parent)
128 if minimum_version:
129 version = get_version(module_to_get)
130 if version and Version(version) < Version(minimum_version):
131 msg = (
132 f"Dask requires version '{minimum_version}' or newer of '{parent}' "
133 f"(version '{version}' currently installed)."
134 )
135 if errors == "warn":
136 warnings.warn(msg, UserWarning)
137 return None
138 elif errors == "raise":
139 raise ImportError(msg)
140 else:
141 return None
142
143 return module