Source code for reproman.utils

# ex: set sts=4 ts=4 sw=4 noet:
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#
#   See COPYING file distributed along with the reproman package for the
#   copyright and license terms.
#
# ## ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ##

import collections
from collections.abc import Mapping
import re

import builtins
from shlex import quote as shlex_quote
import time

import os.path as op
from os.path import curdir, basename, exists, realpath, islink, join as opj, isabs, normpath, expandvars, expanduser, abspath
from urllib.parse import quote as urlquote, unquote as urlunquote, urlsplit

import logging
import shutil
import stat
import os
import os.path as op
import sys
import tempfile
import platform
import gc
import glob

import attr
from functools import wraps
from time import sleep
import inspect
from itertools import tee

from reproman.support.exceptions import CommandError

lgr = logging.getLogger("reproman.utils")

lgr.log(5, "Importing reproman.utils")
#
# Some useful variables
#
_platform_system = platform.system().lower()
on_windows = _platform_system == 'windows'
on_osx = _platform_system == 'darwin'
on_linux = _platform_system == 'linux'
try:
    linux_distribution = platform.linux_distribution()
    on_debian_wheezy = on_linux \
                       and linux_distribution[0] == 'debian' \
                       and linux_distribution[1].startswith('7.')
except:  # pragma: no cover
    on_debian_wheezy = False

#
# Little helpers
#

# `getargspec` has been deprecated in Python 3.
if hasattr(inspect, "getfullargspec"):
[docs] def getargspec(func): """Backward-compatibility wrapper for inspect.getargspec. """ # The first four elements in getfullargspec's return value match # getargspec's. return inspect.getfullargspec(func)[:4]
else: getargspec = inspect.getargspec
[docs]def get_func_kwargs_doc(func): """ Provides args for a function Parameters ---------- func: str name of the function from which args are being requested Returns ------- list of the args that a function takes in """ return getargspec(func)[0]
# TODO: format error message with descriptions of args # return [repr(dict(get_docstring_split(func)[1]).get(x)) for x in getargspec(func)[0]]
[docs]def assure_tuple_or_list(obj): """Given an object, wrap into a tuple if not list or tuple """ if isinstance(obj, list) or isinstance(obj, tuple): return obj return (obj,)
[docs]def not_supported_on_windows(msg=None): """A little helper to be invoked to consistently fail whenever functionality is not supported (yet) on Windows """ if on_windows: raise NotImplementedError("This functionality is not yet implemented for Windows OS" + (": %s" % msg if msg else ""))
[docs]def shortened_repr(value, l=30): try: if hasattr(value, '__repr__') and (value.__repr__ is not object.__repr__): value_repr = repr(value) if not value_repr.startswith('<') and len(value_repr) > l: value_repr = "<<%s...>>" % (value_repr[:l-8]) elif value_repr.startswith('<') and value_repr.endswith('>') and ' object at 0x': raise ValueError("I hate those useless long reprs") else: raise ValueError("gimme class") except Exception as e: value_repr = "<%s>" % value.__class__.__name__.split('.')[-1] return value_repr
def __auto_repr__(obj): attr_names = tuple() if hasattr(obj, '__dict__'): attr_names += tuple(obj.__dict__.keys()) if hasattr(obj, '__slots__'): attr_names += tuple(obj.__slots__) items = [] for attr in sorted(set(attr_names)): if attr.startswith('_'): continue value = getattr(obj, attr) # TODO: should we add this feature to minimize some talktative reprs # such as of URL? #if value is None: # continue items.append("%s=%s" % (attr, shortened_repr(value))) return "%s(%s)" % (obj.__class__.__name__, ', '.join(items))
[docs]def auto_repr(cls): """Decorator for a class to assign it an automagic quick and dirty __repr__ It uses public class attributes to prepare repr of a class Original idea: http://stackoverflow.com/a/27799004/1265472 """ cls.__repr__ = __auto_repr__ return cls
[docs]def is_interactive(): """Return True if all in/outs are tty""" # TODO: check on windows if hasattr check would work correctly and add value: # return sys.stdin.isatty() and sys.stdout.isatty() and sys.stderr.isatty()
import hashlib
[docs]def md5sum(filename): with open(filename, 'rb') as f: return hashlib.md5(f.read()).hexdigest()
[docs]def sorted_files(dout): """Return a (sorted) list of files under dout """ return sorted(sum([[opj(r, f)[len(dout)+1:] for f in files] for r,d,files in os.walk(dout) if not '.git' in r], []))
from os.path import sep as dirsep _VCS_REGEX = '%s\.(?:git|gitattributes|svn|bzr|hg)(?:%s|$)' % (dirsep, dirsep) _REPROMAN_REGEX = '%s\.(?:reproman)(?:%s|$)' % (dirsep, dirsep)
[docs]def find_files(regex, topdir=curdir, exclude=None, exclude_vcs=True, exclude_reproman=False, dirs=False): """Generator to find files matching regex Parameters ---------- regex: basestring exclude: basestring, optional Matches to exclude exclude_vcs: If True, excludes commonly known VCS subdirectories. If string, used as regex to exclude those files (regex: `%r`) exclude_reproman: If True, excludes files known to be reproman meta-data files (e.g. under .reproman/ subdirectory) (regex: `%r`) topdir: basestring, optional Directory where to search dirs: bool, optional Either to match directories as well as files """ for dirpath, dirnames, filenames in os.walk(topdir): names = (dirnames + filenames) if dirs else filenames # TODO: might want to uniformize on windows to use '/' paths = (opj(dirpath, name) for name in names) for path in filter(re.compile(regex).search, paths): path = path.rstrip(dirsep) if exclude and re.search(exclude, path): continue if exclude_vcs and re.search(_VCS_REGEX, path): continue if exclude_reproman and re.search(_REPROMAN_REGEX, path): continue yield path
find_files.__doc__ %= (_VCS_REGEX, _REPROMAN_REGEX)
[docs]def expandpath(path, force_absolute=True): """Expand all variables and user handles in a path. By default return an absolute path """ path = expandvars(expanduser(path)) if force_absolute: path = abspath(path) return path
[docs]def is_explicit_path(path): """Return whether a path explicitly points to a location Any absolute path, or relative path starting with either '../' or './' is assumed to indicate a location on the filesystem. Any other path format is not considered explicit.""" path = expandpath(path, force_absolute=False) return isabs(path) \ or path.startswith(os.curdir + os.sep) \ or path.startswith(os.pardir + os.sep)
[docs]def rotree(path, ro=True, chmod_files=True): """To make tree read-only or writable Parameters ---------- path : string Path to the tree/directory to chmod ro : bool, optional Either to make it R/O (default) or RW chmod_files : bool, optional Either to operate also on files (not just directories) """ if ro: chmod = lambda f: os.chmod(f, os.stat(f).st_mode & ~stat.S_IWRITE) else: chmod = lambda f: os.chmod(f, os.stat(f).st_mode | stat.S_IWRITE | stat.S_IREAD) for root, dirs, files in os.walk(path, followlinks=False): if chmod_files: for f in files: fullf = opj(root, f) # might be the "broken" symlink which would fail to stat etc if exists(fullf): chmod(fullf) chmod(root)
[docs]def rmtree(path, chmod_files='auto', *args, **kwargs): """To remove git-annex .git it is needed to make all files and directories writable again first Parameters ---------- chmod_files : string or bool, optional Either to make files writable also before removal. Usually it is just a matter of directories to have write permissions. If 'auto' it would chmod files on windows by default `*args` : `**kwargs` : Passed into shutil.rmtree call """ # Give W permissions back only to directories, no need to bother with files if chmod_files == 'auto': chmod_files = on_windows if not os.path.islink(path): rotree(path, ro=False, chmod_files=chmod_files) shutil.rmtree(path, *args, **kwargs) else: # just remove the symlink os.unlink(path)
[docs]def rmtemp(f, *args, **kwargs): """Wrapper to centralize removing of temp files so we could keep them around It will not remove the temporary file/directory if REPROMAN_TESTS_KEEPTEMP environment variable is defined """ if not os.environ.get('REPROMAN_TESTS_KEEPTEMP'): if not os.path.lexists(f): lgr.debug("Path %s does not exist, so can't be removed" % f) return lgr.log(5, "Removing temp file: %s" % f) # Can also be a directory if os.path.isdir(f): rmtree(f, *args, **kwargs) else: for i in range(10): try: os.unlink(f) except OSError as e: if i < 9: sleep(0.1) continue else: raise break else: lgr.info("Keeping temp file: %s" % f)
[docs]def file_basename(name, return_ext=False): """ Strips up to 2 extensions of length up to 4 characters and starting with alpha not a digit, so we could get rid of .tar.gz etc """ bname = basename(name) fbname = re.sub('(\.[a-zA-Z_]\S{1,4}){0,2}$', '', bname) if return_ext: return fbname, bname[len(fbname)+1:] else: return fbname
[docs]def escape_filename(filename): """Surround filename in "" and escape " in the filename """ filename = filename.replace('"', r'\"').replace('`', r'\`') filename = '"%s"' % filename return filename
[docs]def encode_filename(filename): """Encode unicode filename """ if isinstance(filename, str): return filename.encode(sys.getfilesystemencoding()) else: return filename
if on_windows: def lmtime(filepath, mtime): """Set mtime for files. On Windows a merely adapter to os.utime """ os.utime(filepath, (time.time(), mtime)) else:
[docs] def lmtime(filepath, mtime): """Set mtime for files, while not de-referencing symlinks. To overcome absence of os.lutime Works only on linux and OSX ATM """ from .cmd import Runner # convert mtime to format touch understands [[CC]YY]MMDDhhmm[.SS] smtime = time.strftime("%Y%m%d%H%M.%S", time.localtime(mtime)) lgr.log(3, "Setting mtime for %s to %s == %s", filepath, mtime, smtime) Runner().run(['touch', '-h', '-t', '%s' % smtime, filepath]) rfilepath = realpath(filepath) if islink(filepath) and exists(rfilepath): # trust noone - adjust also of the target file # since it seemed like downloading under OSX (was it using curl?) # didn't bother with timestamps lgr.log(3, "File is a symlink to %s Setting mtime for it to %s", rfilepath, mtime) os.utime(rfilepath, (time.time(), mtime))
# doesn't work on OSX # Runner().run(['touch', '-h', '-d', '@%s' % mtime, filepath])
[docs]def assure_list(s): """Given not a list, would place it into a list. If None - empty list is returned Parameters ---------- s: list or anything """ if isinstance(s, list): return s elif s is None: return [] else: return [s]
[docs]def assure_list_from_str(s, sep='\n'): """Given a multiline string convert it to a list of return None if empty Parameters ---------- s: str or list """ if not s: return None if isinstance(s, list): return s return s.split(sep)
[docs]def assure_dict_from_str(s, **kwargs): """Given a multiline string with key=value items convert it to a dictionary Parameters ---------- s: str or dict Returns None if input s is empty """ if not s: return None if isinstance(s, dict): return s out = {} for value_str in assure_list_from_str(s, **kwargs): if '=' not in value_str: raise ValueError("{} is not in key=value format".format(repr(value_str))) k, v = value_str.split('=', 1) if k in out: err = "key {} was already defined in {}, but new value {} was provided".format(k, out, v) raise ValueError(err) out[k] = v return out
[docs]def only_with_values(d): """Given a dictionary, return the one only with entries which had non-null values""" # to maintain OrderedDict do explicit d.__class__ return d.__class__((k, v) for k,v in d.items() if v)
[docs]def assure_bytes(s, encoding='utf-8'): """Convert/encode unicode to bytes if of 'str' Parameters ---------- encoding: str, optional Encoding to use. "utf-8" is the default """ if not isinstance(s, str): return s return s.encode(encoding)
[docs]def assure_unicode(s, encoding=None, confidence=None): """Convert/decode to str if of 'bytes' Parameters ---------- encoding: str, optional Encoding to use. If None, "utf-8" is tried, and then if not a valid UTF-8, encoding will be guessed confidence: float, optional A value between 0 and 1, so if guessing of encoding is of lower than specified confidence, ValueError is raised """ if not isinstance(s, bytes): return s if encoding is None: # Figure out encoding, defaulting to 'utf-8' which is our common # target in contemporary digital society try: return s.decode('utf-8') except UnicodeDecodeError as exc: from .dochelpers import exc_str lgr.debug("Failed to decode a string as utf-8: %s", exc_str(exc)) # And now we could try to guess from chardet import detect enc = detect(s) denc = enc.get('encoding', None) if denc: denc_confidence = enc.get('confidence', 0) if confidence is not None and denc_confidence < confidence: raise ValueError( "Failed to auto-detect encoding with high enough " "confidence. Highest confidence was %s for %s" % (denc_confidence, denc) ) return s.decode(denc) else: raise ValueError( "Could not decode value as utf-8, or to guess its encoding: %s" % repr(s) ) else: return s.decode(encoding)
[docs]def unique(seq, key=None): """Given a sequence return a list only with unique elements while maintaining order This is the fastest solution. See https://www.peterbe.com/plog/uniqifiers-benchmark and http://stackoverflow.com/a/480227/1265472 for more information. Enhancement -- added ability to compare for uniqueness using a key function Parameters ---------- seq: Sequence to analyze key: callable, optional Function to call on each element so we could decide not on a full element, but on its member etc """ seen = set() seen_add = seen.add if not key: return [x for x in seq if not (x in seen or seen_add(x))] else: # OPT: could be optimized, since key is called twice, but for our cases # should be just as fine return [x for x in seq if not (key(x) in seen or seen_add(key(x)))]
[docs]def partition(items, predicate=bool): """Partition `items` by `predicate`. Parameters ---------- items : iterable predicate : callable A function that will be mapped over each element in `items`. The elements will partitioned based on whether the return value is false or true. Returns ------- A tuple with two generators, the first for 'false' items and the second for 'true' ones. Notes ----- Taken from Peter Otten's snippet posted at https://nedbatchelder.com/blog/201306/filter_a_list_into_two_parts.html """ a, b = tee((predicate(item), item) for item in items) return ((item for pred, item in a if not pred), (item for pred, item in b if pred))
# # Decorators # # Borrowed from pandas # Copyright: 2011-2014, Lambda Foundry, Inc. and PyData Development Team # Licese: BSD-3
[docs]def optional_args(decorator): """allows a decorator to take optional positional and keyword arguments. Assumes that taking a single, callable, positional argument means that it is decorating a function, i.e. something like this:: @my_decorator def function(): pass Calls decorator with decorator(f, `*args`, `**kwargs`)""" @wraps(decorator) def wrapper(*args, **kwargs): def dec(f): return decorator(f, *args, **kwargs) is_decorating = not kwargs and len(args) == 1 and isinstance(args[0], collections.Callable) if is_decorating: f = args[0] args = [] return dec(f) else: return dec return wrapper
# TODO: just provide decorators for tempfile.mk* functions. This is ugly!
[docs]def get_tempfile_kwargs(tkwargs={}, prefix="", wrapped=None): """Updates kwargs to be passed to tempfile. calls depending on env vars """ # operate on a copy of tkwargs to avoid any side-effects tkwargs_ = tkwargs.copy() # TODO: don't remember why I had this one originally # if len(targs)<2 and \ if not 'prefix' in tkwargs_: tkwargs_['prefix'] = '_'.join( ['reproman_temp'] + ([prefix] if prefix else []) + ([''] if (on_windows or not wrapped) else [wrapped.__name__])) directory = os.environ.get('REPROMAN_TESTS_TEMPDIR') if directory and 'dir' not in tkwargs_: tkwargs_['dir'] = directory return tkwargs_
[docs]@optional_args def line_profile(func): """Q&D helper to line profile the function and spit out stats """ import line_profiler prof = line_profiler.LineProfiler() @wraps(func) def newfunc(*args, **kwargs): try: pfunc = prof(func) return pfunc(*args, **kwargs) finally: prof.print_stats() return newfunc
[docs]def cached_property(prop): """Cache a property's return value. This avoids using `lru_cache`, which is more complicated than needed for simple properties and isn't available in Python 2's stdlib. Use this only if the property's return value is constant over the life of the object. This isn't appropriate for a property with a setter or a property whose getter value may change based some outside state. This should be positioned below the @property declaration. """ # Modified from MIT-licensed # https://code.activestate.com/recipes/576563-cached-property/ @wraps(prop) def wrapped(self): try: return self._property_cache[prop] except AttributeError: self._property_cache = {} x = self._property_cache[prop] = prop(self) return x except KeyError: x = self._property_cache[prop] = prop(self) return x return wrapped
# # Context Managers # from contextlib import contextmanager
[docs]@contextmanager def swallow_outputs(): """Context manager to help consuming both stdout and stderr, and print() stdout is available as cm.out and stderr as cm.err whenever cm is the yielded context manager. Internally uses temporary files to guarantee absent side-effects of swallowing into StringIO which lacks .fileno. print mocking is necessary for some uses where sys.stdout was already bound to original sys.stdout, thus mocking it later had no effect. Overriding print function had desired effect """ debugout = sys.stdout class StringIOAdapter(object): """Little adapter to help getting out/err values """ def __init__(self): kw = get_tempfile_kwargs({}, prefix="outputs") self._out = open(tempfile.mktemp(**kw), 'w') self._err = open(tempfile.mktemp(**kw), 'w') def _read(self, h): with open(h.name) as f: return f.read() @property def out(self): self._out.flush() return self._read(self._out) @property def err(self): self._err.flush() return self._read(self._err) @property def handles(self): return self._out, self._err def cleanup(self): self._out.close() self._err.close() out_name = self._out.name err_name = self._err.name del self._out del self._err gc.collect() rmtemp(out_name) rmtemp(err_name) def fake_print(*args, **kwargs): sep = kwargs.pop('sep', ' ') end = kwargs.pop('end', '\n') file = kwargs.pop('file', sys.stdout) if file in (oldout, olderr, sys.stdout, sys.stderr): # we mock sys.stdout.write(sep.join(args) + end) else: # must be some other file one -- leave it alone oldprint(*args, sep=sep, end=end, file=file) from .ui import ui # preserve -- they could have been mocked already oldprint = getattr(builtins, 'print') oldout, olderr = sys.stdout, sys.stderr olduiout = ui.out adapter = StringIOAdapter() try: sys.stdout, sys.stderr = adapter.handles ui.out = adapter.handles[0] setattr(builtins, 'print', fake_print) yield adapter finally: sys.stdout, sys.stderr, ui.out = oldout, olderr, olduiout setattr(builtins, 'print', oldprint) adapter.cleanup()
[docs]@contextmanager def swallow_logs(new_level=None): """Context manager to consume all logs. """ lgr = logging.getLogger("reproman") # Keep old settings old_level = lgr.level old_handlers = lgr.handlers # Let's log everything into a string # TODO: generalize with the one for swallow_outputs class StringIOAdapter(object): """Little adapter to help getting out values And to stay consistent with how swallow_outputs behaves """ def __init__(self): kw = dict() get_tempfile_kwargs(kw, prefix="logs") self._out = open(tempfile.mktemp(**kw), 'w') def _read(self, h): with open(h.name) as f: return f.read() @property def out(self): self._out.flush() return self._read(self._out) @property def lines(self): return self.out.split('\n') @property def handle(self): return self._out def cleanup(self): self._out.close() out_name = self._out.name del self._out gc.collect() rmtemp(out_name) adapter = StringIOAdapter() lgr.handlers = [logging.StreamHandler(adapter.handle)] if old_level < logging.DEBUG: # so if HEAVYDEBUG etc -- show them! lgr.handlers += old_handlers if isinstance(new_level, str): new_level = getattr(logging, new_level) if new_level is not None: lgr.setLevel(new_level) try: yield adapter finally: lgr.handlers, lgr.level = old_handlers, old_level adapter.cleanup()
# # Additional handlers # _sys_excepthook = sys.excepthook # Just in case we ever need original one
[docs]def setup_exceptionhook(ipython=False): """Overloads default sys.excepthook with our exceptionhook handler. If interactive, our exceptionhook handler will invoke pdb.post_mortem; if not interactive, then invokes default handler. """ def _reproman_pdb_excepthook(type, value, tb): import traceback traceback.print_exception(type, value, tb) print() if is_interactive(): import pdb pdb.post_mortem(tb) if ipython: from IPython.core import ultratb sys.excepthook = ultratb.FormattedTB(mode='Verbose', # color_scheme='Linux', call_pdb=is_interactive()) else: sys.excepthook = _reproman_pdb_excepthook
[docs]def assure_dir(*args): """Make sure directory exists. Joins the list of arguments to an os-specific path to the desired directory and creates it, if it not exists yet. """ dirname = opj(*args) if not exists(dirname): os.makedirs(dirname) return dirname
[docs]def updated(d, update): """Return a copy of the input with the 'update' Primarily for updating dictionaries """ d = d.copy() d.update(update) return d
[docs]def getpwd(): """Try to return a CWD without dereferencing possible symlinks If no PWD found in the env, output of getcwd() is returned """ try: return os.environ['PWD'] except KeyError: return os.getcwd()
[docs]class chpwd(object): """Wrapper around os.chdir which also adjusts environ['PWD'] The reason is that otherwise PWD is simply inherited from the shell and we have no ability to assess directory path without dereferencing symlinks. If used as a context manager it allows to temporarily change directory to the given path """ def __init__(self, path, mkdir=False, logsuffix=''): if path: pwd = getpwd() self._prev_pwd = pwd else: self._prev_pwd = None return if not isabs(path): path = normpath(opj(pwd, path)) if not os.path.exists(path) and mkdir: self._mkdir = True os.mkdir(path) else: self._mkdir = False lgr.debug("chdir %r -> %r %s", self._prev_pwd, path, logsuffix) os.chdir(path) # for grep people -- ok, to chdir here! os.environ['PWD'] = path def __enter__(self): # nothing more to do really, chdir was in the constructor pass def __exit__(self, exc_type, exc_val, exc_tb): if self._prev_pwd: # Need to use self.__class__ so this instance, if the entire # thing mocked during the test, still would use correct chpwd self.__class__(self._prev_pwd, logsuffix="(coming back)")
[docs]def knows_annex(path): """Returns whether at a given path there is information about an annex It is just a thin wrapper around GitRepo.is_with_annex() classmethod which also checks for `path` to exist first. This includes actually present annexes, but also uninitialized ones, or even the presence of a remote annex branch. """ from os.path import exists if not exists(path): lgr.debug("No annex: test path {0} doesn't exist".format(path)) return False from reproman.support.gitrepo import GitRepo return GitRepo(path, init=False, create=False).is_with_annex()
[docs]@contextmanager def make_tempfile(content=None, wrapped=None, **tkwargs): """Helper class to provide a temporary file name and remove it at the end (context manager) Parameters ---------- mkdir : bool, optional (default: False) If True, temporary directory created using tempfile.mkdtemp() content : str or bytes, optional Content to be stored in the file created wrapped : function, optional If set, function name used to prefix temporary file name `**tkwargs`: All other arguments are passed into the call to tempfile.mk{,d}temp(), and resultant temporary filename is passed as the first argument into the function t. If no 'prefix' argument is provided, it will be constructed using module and function names ('.' replaced with '_'). To change the used directory without providing keyword argument 'dir' set REPROMAN_TESTS_TEMPDIR. Examples -------- >>> from os.path import exists >>> from reproman.utils import make_tempfile >>> with make_tempfile() as fname: ... k = open(fname, 'w').write('silly test') >>> assert not exists(fname) # was removed >>> with make_tempfile(content="blah") as fname: ... assert open(fname).read() == "blah" """ if tkwargs.get('mkdir', None) and content is not None: raise ValueError("mkdir=True while providing content makes no sense") tkwargs_ = get_tempfile_kwargs(tkwargs, wrapped=wrapped) # if REPROMAN_TESTS_TEMPDIR is set, use that as directory, # let mktemp handle it otherwise. However, an explicitly provided # dir=... will override this. mkdir = tkwargs_.pop('mkdir', False) filename = {False: tempfile.mktemp, True: tempfile.mkdtemp}[mkdir](**tkwargs_) filename = realpath(filename) if content: with open(filename, 'w' + ('b' if isinstance(content, bytes) else '')) as f: f.write(content) if __debug__: # TODO mkdir lgr.debug('Created temporary thing named %s"' % filename) try: yield filename finally: # glob here for all files with the same name (-suffix) # would be useful whenever we requested .img filename, # and function creates .hdr as well lsuffix = len(tkwargs_.get('suffix', '')) filename_ = lsuffix and filename[:-lsuffix] or filename filenames = glob.glob(filename_ + '*') if len(filename_) < 3 or len(filenames) > 5: # For paranoid yoh who stepped into this already ones ;-) lgr.warning("It is unlikely that it was intended to remove all" " files matching %r. Skipping" % filename_) return for f in filenames: try: rmtemp(f) except OSError: pass
def _path_(p): """Given a path in POSIX" notation, regenerate one in native to the env one""" if on_windows: return opj(p.split('/')) else: # Assume that all others as POSIX compliant so nothing to be done return p
[docs]def is_unicode(s): """Return true if an object is unicode""" return isinstance(s, str)
[docs]def is_binarystring(s): """Return true if an object is a binary string (not unicode)""" return isinstance(s, bytes)
[docs]def to_unicode(s, encoding="utf-8"): """Converts any type string to unicode""" if is_unicode(s): return s else: return s.decode(encoding=encoding)
[docs]def to_binarystring(s, encoding="utf-8"): """Converts any type string to binarystring""" if is_binarystring(s): return s else: return s.encode(encoding=encoding)
[docs]def safe_write(ostream, s, encoding="utf-8"): """Safely write different string types to an output stream""" try: # Try unicode, and upon failure try binary_string ostream.write(to_unicode(s, encoding)) except (TypeError, UnicodeEncodeError): ostream.write(to_binarystring(s, encoding))
[docs]def generate_unique_name(pattern, nameset): """Create a unique numbered name from a pattern and a set Parameters ---------- pattern: basestring The pattern for the name (to be used with %) that includes one %d location nameset: collection Collection (set or list) of existing names. If the generated name is used, then add the name to the nameset. Returns ------- str The generated unique name """ i = 0 while True: n = pattern % i i += 1 if n not in nameset: return n
# http://stackoverflow.com/questions/1151658/python-hashable-dicts
[docs]class HashableDict(dict): """Dict that can be used as keys""" def __hash__(self): return hash(frozenset(self.values()))
[docs]def get_cmd_batch_len(arg_list, cmd_len): """Estimate the maximum batch length for a given argument list To make sure we don't call shell commands with too many arguments this function looks at an argument list and the command length without any arguments, and estimates the number of arguments we want to batch together at one time. Parameters ---------- arg_list : list The list to process in the command cmd_len : number The length of the command without arguments Returns ------- number The maximum number in a single batch """ if not arg_list: raise ValueError("Cannot batch an empty argument list") # Pick a conservative max command-line length try: _MAX_LEN_CMDLINE = os.sysconf(str("SC_ARG_MAX")) // 2 except (ValueError, AttributeError): _MAX_LEN_CMDLINE = 2048 # Find out how many files we can query at once max_len = max(map(len, arg_list)) return max((_MAX_LEN_CMDLINE - cmd_len) // (max_len + 1), 1)
[docs]def join_sequence_of_dicts(seq): """ Joins a sequence of dicts into a single dict Parameters ---------- seq: sequence Sequence of dicts to join Returns ------- dict Raises ------ RuntimeError if a duplicate key is encountered. """ r = {} for d in seq: for k, v in d.items(): if k in r: raise RuntimeError("Duplicate key %r (new value: %r, " "was: %r)" % (k, v, r[k])) r[k] = v return r
[docs]def cmd_err_filter(err_string): """ Creates a filter for CommandErrors that match a specific error string Parameters ---------- err_string: basestring The error string we want to match Returns ------- func object -> boolean """ return (lambda x: isinstance(x, CommandError) and err_string in to_unicode(x.stderr, "utf-8"))
[docs]def execute_command_batch(session, command, args, exception_filter=None): """ Generator that executes session.execute_command, with batches of args We want to call commands like "apt-cache policy" on a large number of packages, but risk creating command-lines that are too long. This function is a generator that will call execute_command but with batches of arguments (to stay within the command-line length limit) and yield the results. Parameters ---------- session Session object that implements the execute_command() member command : sequence The command that we wish to execute args : sequence The long list of additional arguments we wish to pass to the command exception_filter : func x -> bool A filter of exception types that the calling code will gracefully handle Returns ------- (out, err, exception) stdout of the command, stderr of the command, and an exception that is in the list of expected exceptions """ cmd_length = sum(map(len, command)) + len(command) num_args = get_cmd_batch_len(args, cmd_length) args = list(args) # we might get in with a set while args: batch, args = args[:num_args], args[num_args:] try: out, err = session.execute_command( command + batch ) out = to_unicode(out, "utf-8") yield (out, err, None) except Exception as e: if exception_filter and exception_filter(e): yield (None, None, e) else: raise
[docs]def items_to_dict(l, attrs='name', ordered=False): """Given a list of attr instances, return a dict using specified attrs as keys Parameters ---------- attrs : str or list of str Which attributes of the items to use to group ordered : bool, optional Either to return an ordered dictionary following the original order of items in the list Raises ------ ValueError If there is a conflict - multiple items with the same attrs used for key Returns ------- dict or collections.OrderedDict """ many = isinstance(attrs, (list, tuple)) out = (collections.OrderedDict if ordered else dict)() for i in l: k = tuple(getattr(i, a) for a in attrs) if many else getattr(i, attrs) if k in out: raise ValueError( "We already saw entry for %s: %s. Not adding %s", k, out[k], i ) out[k] = i return out
# TODO: just absorb into SpecObject __init__ but would require more handling # to allow *args as well
[docs]def instantiate_attr_object(item_type, items): """Instantiate item_type given items (for a list or dict) Provides a more informative exception message in case if some arguments are incorrect """ try: if issubclass(item_type, list): return item_type(items) else: return item_type(**items) except TypeError as exc: if "unexpected keyword" in str(exc): known_kws = [i.name for i in item_type.__attrs_attrs__] incorrect_kws = set(items.keys()).difference(known_kws) if incorrect_kws: # Provide a more informative message raise TypeError( "Following provided arguments are not known to %s: %s. " "Known but not yet provided are: %s" % (item_type.__name__, ', '.join(incorrect_kws), ', '.join(sorted(set(known_kws).difference(items)))) ) # if couldn't figure it out -- just raise original raise
[docs]def attrib(*args, **kwargs): """Extend the attr.ib to include our metadata elements. ATM we support additional keyword args which are then stored within `metadata`: - `doc` for documentation to describe the attribute (e.g. in --help) Also, when the `default` argument of attr.ib is unspecified, set it to None. """ doc = kwargs.pop('doc', None) metadata = kwargs.get('metadata', {}) if doc: metadata['doc'] = doc if metadata: kwargs['metadata'] = metadata return attr.ib(*args, default=kwargs.pop('default', None), **kwargs)
[docs]class PathRoot(object): """Find the root of paths based on a predicate function. The path -> root mapping is cached across calls. Parameters ---------- predicate : callable A callable that will be passed a path and should return true if that path should be considered a root. """ def __init__(self, predicate): self._pred = predicate self._cache = {} # path -> root def __call__(self, path): """Find root of `path` based on `predicate`. Parameters ---------- path : str Find this path's root. Returns ------- str or None """ to_cache = [] root = None for pth in self._walk_up(path): if pth in self._cache: root = self._cache[pth] break to_cache.append(pth) if self._pred(pth): root = pth break for pth in to_cache: self._cache[pth] = root return root @staticmethod def _walk_up(path): """Yield PATH, chopping off the right-most directory each iteration. Parameters ---------- path : string """ while path not in [os.path.pathsep, os.path.sep, ""]: yield path path = os.path.dirname(path)
[docs]def is_subpath(path, directory): """Test whether `path` is below (or is itself) `directory`. Symbolic links are not resolved before the check. """ return not os.path.relpath(path, directory).startswith(os.path.pardir)
SemanticVersion = collections.namedtuple("SemanticVersion", ["major", "minor", "patch", "tag"])
[docs]def parse_semantic_version(version): """Split version into major, minor, patch, and tag components. Parameters ---------- version : str A version string X.Y.Z. X, Y, and Z must be digits. Any remaining text is treated as a tag (e.g., "-rc1"). Returns ------- A namedtuple with the form (major, minor, patch, tag). """ m = re.match(r"(?P<major>[0-9]+)\.(?P<minor>[0-9]+)\.(?P<patch>[0-9]+)" r"(?P<tag>.*)", version) if m: return SemanticVersion(*m.groups()) else: raise ValueError( "{} does not appear to follow semantic versioning".format(version))
[docs]def command_as_string(command): """Convert `command` to the string representation. Parameters ---------- command : list or str If it is a list, convert it to a string, quoting each element as needed. If it is a string, it is returned as is. """ if isinstance(command, list): command = " ".join(map(shlex_quote, command)) return command
[docs]def merge_dicts(ds): """Convert an iterable of dictionaries. In the case of key collisions, the last value wins. Parameters ---------- ds : iterable of dicts Returns ------- dict """ merged = {} for d in ds: merged.update(d) return merged
[docs]def parse_kv_list(params): """Create a dict from a "key=value" list. Parameters ---------- params : sequence of str or mapping For a sequence, each item should have the form "<key>=<value". If `params` is a mapping, it will be returned as is. Returns ------- A mapping from backend key to value. Raises ------ ValueError if item in `params` does not match expected "key=value" format. """ if isinstance(params, Mapping): res = params elif params: def check_fmt(item): if "=" not in item: raise ValueError( "Expected 'key=value' format but got '{}'" .format(item)) return item res = dict(p.split("=", 1) for p in map(check_fmt, params)) else: res = {} return res
[docs]def write_update(fname, content, encoding=None): """Write `content` to `fname` unless it already has matching content. This is the same as simply writing the content, except no writing occurs if the content of the existing file matches, the write or update is logged, and the leading directories of `fname` are created if needed. Parameters ---------- fname : str Path to update. content : str Content to dump to path. encoding : str or None, optional Passed to `open`. """ existing_content = None if op.exists(fname): with open(fname, encoding=encoding) as fh: existing_content = fh.read() if content == existing_content: lgr.debug("File already has matching content: %s", fname) else: lgr.debug("%s content in %s", "Updating" if existing_content else "Creating", fname) os.makedirs(op.dirname(fname), exist_ok=True) with open(fname, "w", encoding=encoding) as fh: fh.write(content)
[docs]def pycache_source(path): """Map a pycache path to the original path. Parameters ---------- path : str A Python cache file. Returns ------- Path of cached Python file (str) or None if `path` doesn't look like a cache file. """ if not (path.endswith(".pyc") or path.endswith(".pyo")): lgr.debug("Path does not look like a Python cache file: %s", path) return if "__pycache__" not in path: # py2 pyfile = path[:-1] else: # It should be a py3-style path, e.g., "__pycache__/f.cpython-35.pyc" # or "__pycache__/f.cpython-35.opt-2.pyc". leading, base = op.split(path) name = base.split(".", 1)[0] pyfile = op.join(leading[:-len("__pycache__")], name + ".py") lgr.debug("Converted pycache file %s to source file %s", path, pyfile) return pyfile
lgr.log(5, "Done importing reproman.utils")