Source code for utils

# -*- coding: utf-8 -*-
import atexit
import inspect
import re
import subprocess

# import diaper for backward compatibility
import diaper

[docs]def lazycache(wrapped_method): """method decorator to create a lazily-evaluated and cached property ``lazycache``'d properties are complete object descriptors, supporting ``get``, ``set``, and ``del``, though ``del`` will clear a property's cache rather than destroy the property entirely Usage: >>> from utils import lazycache >>> class Example(object): ... @lazycache ... def lazyprop(self): ... return '42' ... >>> ex = Example() >>> value = ex.lazyprop >>> print value 42 >>> print value is ex.lazyprop # lazyprop guarantees this to be True, normal properties do not. True >>> ex.lazyprop = '99' >>> print ex.lazyprop # setting works! 99 >>> del(ex.lazyprop) >>> print ex.lazyprop # deleting clears the cache, so the value is recomputed on the next call 42 Values are stored in a private attribute of the same name as the method being decorated, e.g. a decorated method named ``lazyprop`` will store its cached value in an attr called ``_lazyprop`` """ attr = '_' + wrapped_method.__name__ if wrapped_method.__doc__: doc = wrapped_method.__doc__ + '\n\nThis attribute is lazily evaluated and cached.' else: doc = None def get_lazy(self): if not hasattr(self, attr): setattr(self, attr, wrapped_method(self)) return getattr(self, attr) def set_lazy(self, value): setattr(self, attr, value) def del_lazy(self): if hasattr(self, attr): delattr(self, attr) lazy = property(get_lazy, set_lazy, del_lazy, doc) return lazy
[docs]def property_or_none(wrapped, *args, **kwargs): """property_or_none([fget[, fset[, fdel[, doc]]]]) Property decorator that turns AttributeErrors into None returns Useful for chained attr lookups where some links in the chain are None Note: This delegates back to the :py:func:`property <python:property>` builtin and inherits its signature; thus it can be used interchangeably with ``property``. """ def wrapper(store): try: return wrapped(store) except AttributeError: pass return property(wrapper, *args, **kwargs)
class _classproperty(property): """Subclass property to make classmethod properties possible""" def __get__(self, cls, owner): return self.fget.__get__(None, owner)()
[docs]def classproperty(f): """Enables properties for whole classes: Usage: >>> class Foo(object): ... @classproperty ... def bar(cls): ... return "bar" ... >>> print baz """ return _classproperty(classmethod(f))
[docs]def at_exit(f, *args, **kwargs): """Diaper-protected atexit handler registering. Same syntax as atexit.register()""" return atexit.register(lambda: diaper(f, *args, **kwargs))
[docs]def normalize_text(text): text = re.sub(r"[^a-z0-9 ]", "", text.strip().lower()) return re.sub(r"\s+", " ", text)
[docs]class kwargify(object): def __init__(self, function): self._f = function self._defaults = {} self._args = inspect.getargspec(self._f).args f_defaults = inspect.getargspec(function).defaults if f_defaults is not None: for key, value in zip(self._args[-len(f_defaults):], f_defaults): self._defaults[key] = value def __call__(self, **kwargs): args = [] for arg in self._args: if arg in kwargs: args.append(kwargs[arg]) elif arg in self._defaults: args.append(self._defaults[arg]) else: raise TypeError("Required parameter {} not found in the context!".format(arg)) return self._f(*args) @property def __name__(self): return self._f.__name__
[docs]def tries(num_tries, exceptions, f, *args, **kwargs): """ Tries to call the function multiple times if specific exceptions occur. Args: num_tries: How many times to try if exception is raised exceptions: Tuple (or just single one) of exceptions that should be treated as repeat. f: Callable to be called. *args: Arguments to be passed through to the callable **kwargs: Keyword arguments to be passed through to the callable Returns: What ``f`` returns. Raises: What ``f`` raises if the try count is exceeded. """ tries = 0 while tries < num_tries: tries += 1 try: return f(*args, **kwargs) except exceptions as e: pass else: raise e
[docs]def read_env(file): """Given a py.path.Local file name, return a dict of exported shell vars and their values Note: This will only include shell variables that are exported from the file being parsed Returns a dict of varname: value pairs. If the file does not exist or bash could not parse the file, this dict will be empty. """ env_vars = {} if file.check(): with as f: content = # parse the file with bash, since it's pretty good at it, and dump the env command = ['bash', '-c', 'source {} && env'.format(file.strpath)] proc = subprocess.Popen(command, stdout=subprocess.PIPE, bufsize=1) # filter out vars not defined for line in iter(proc.stdout.readline, b''): try: key, value = line.split("=", 1) except ValueError: continue if '{}='.format(key) in content: env_vars[key] = value.strip() stdout, stderr = proc.communicate() return env_vars
[docs]def deferred_verpick(version_d): """This turns a dictionary for verpick to a class property. Useful for verpicked constants. """ from utils.version import pick as _version_pick @classproperty def getter(self): return _version_pick(version_d) return getter