| import sys |
|
|
| from packaging import version as _version |
|
|
|
|
| def _check_version(actver, version, cmp_op): |
| """ |
| Check version string of an active module against a required version. |
| |
| If dev/prerelease tags result in TypeError for string-number comparison, |
| it is assumed that the dependency is satisfied. |
| Users on dev branches are responsible for keeping their own packages up to |
| date. |
| """ |
| try: |
| if cmp_op == '>': |
| return _version.parse(actver) > _version.parse(version) |
| elif cmp_op == '>=': |
| return _version.parse(actver) >= _version.parse(version) |
| elif cmp_op == '=': |
| return _version.parse(actver) == _version.parse(version) |
| elif cmp_op == '<': |
| return _version.parse(actver) < _version.parse(version) |
| else: |
| return False |
| except TypeError: |
| return True |
|
|
|
|
| def get_module_version(module_name): |
| """Return module version or None if version can't be retrieved.""" |
| mod = __import__(module_name, fromlist=[module_name.rpartition('.')[-1]]) |
| return getattr(mod, '__version__', getattr(mod, 'VERSION', None)) |
|
|
|
|
| def is_installed(name, version=None): |
| """Test if *name* is installed. |
| |
| Parameters |
| ---------- |
| name : str |
| Name of module or "python" |
| version : str, optional |
| Version string to test against. |
| If version is not None, checking version |
| (must have an attribute named '__version__' or 'VERSION') |
| Version may start with =, >=, > or < to specify the exact requirement |
| |
| Returns |
| ------- |
| out : bool |
| True if `name` is installed matching the optional version. |
| """ |
| if name.lower() == 'python': |
| actver = sys.version[:6] |
| else: |
| try: |
| actver = get_module_version(name) |
| except ImportError: |
| return False |
| if version is None: |
| return True |
| else: |
| |
| |
| import re |
|
|
| match = re.search('[0-9]', version) |
| assert match is not None, "Invalid version number" |
| symb = version[: match.start()] |
| if not symb: |
| symb = '=' |
| assert symb in ('>=', '>', '=', '<'), f"Invalid version condition '{symb}'" |
| version = version[match.start() :] |
| return _check_version(actver, version, symb) |
|
|
|
|
| def require(name, version=None): |
| """Return decorator that forces a requirement for a function or class. |
| |
| Parameters |
| ---------- |
| name : str |
| Name of module or "python". |
| version : str, optional |
| Version string to test against. |
| If version is not None, checking version |
| (must have an attribute named '__version__' or 'VERSION') |
| Version may start with =, >=, > or < to specify the exact requirement |
| |
| Returns |
| ------- |
| func : function |
| A decorator that raises an ImportError if a function is run |
| in the absence of the input dependency. |
| """ |
| |
| |
| import functools |
|
|
| def decorator(obj): |
| @functools.wraps(obj) |
| def func_wrapped(*args, **kwargs): |
| if is_installed(name, version): |
| return obj(*args, **kwargs) |
| else: |
| msg = f'"{obj}" in "{obj.__module__}" requires "{name}' |
| if version is not None: |
| msg += f" {version}" |
| raise ImportError(msg + '"') |
|
|
| return func_wrapped |
|
|
| return decorator |
|
|
|
|
| def get_module(module_name, version=None): |
| """Return a module object of name *module_name* if installed. |
| |
| Parameters |
| ---------- |
| module_name : str |
| Name of module. |
| version : str, optional |
| Version string to test against. |
| If version is not None, checking version |
| (must have an attribute named '__version__' or 'VERSION') |
| Version may start with =, >=, > or < to specify the exact requirement |
| |
| Returns |
| ------- |
| mod : module or None |
| Module if *module_name* is installed matching the optional version |
| or None otherwise. |
| """ |
| if not is_installed(module_name, version): |
| return None |
| return __import__(module_name, fromlist=[module_name.rpartition('.')[-1]]) |
|
|
