Source code for dask.utils

from datetime import datetime, timedelta
import functools
import inspect
import os
import shutil
import sys
import tempfile
import re
from errno import ENOENT
from collections.abc import Iterator
from contextlib import contextmanager
from importlib import import_module
from numbers import Integral, Number
from threading import Lock
from typing import Iterable, Optional
import uuid
from weakref import WeakValueDictionary
from functools import lru_cache

from .core import get_deps


system_encoding = sys.getdefaultencoding()
if system_encoding == "ascii":
    system_encoding = "utf-8"


def apply(func, args, kwargs=None):
    if kwargs:
        return func(*args, **kwargs)
    else:
        return func(*args)


def deepmap(func, *seqs):
    """Apply function inside nested lists

    >>> inc = lambda x: x + 1
    >>> deepmap(inc, [[1, 2], [3, 4]])
    [[2, 3], [4, 5]]

    >>> add = lambda x, y: x + y
    >>> deepmap(add, [[1, 2], [3, 4]], [[10, 20], [30, 40]])
    [[11, 22], [33, 44]]
    """
    if isinstance(seqs[0], (list, Iterator)):
        return [deepmap(func, *items) for items in zip(*seqs)]
    else:
        return func(*seqs)


def homogeneous_deepmap(func, seq):
    if not seq:
        return seq
    n = 0
    tmp = seq
    while isinstance(tmp, list):
        n += 1
        tmp = tmp[0]

    return ndeepmap(n, func, seq)


def ndeepmap(n, func, seq):
    """Call a function on every element within a nested container

    >>> def inc(x):
    ...     return x + 1
    >>> L = [[1, 2], [3, 4, 5]]
    >>> ndeepmap(2, inc, L)
    [[2, 3], [4, 5, 6]]
    """
    if n == 1:
        return [func(item) for item in seq]
    elif n > 1:
        return [ndeepmap(n - 1, func, item) for item in seq]
    elif isinstance(seq, list):
        return func(seq[0])
    else:
        return func(seq)


@contextmanager
def ignoring(*exceptions):
    try:
        yield
    except exceptions:
        pass


def import_required(mod_name, error_msg):
    """Attempt to import a required dependency.

    Raises a RuntimeError if the requested module is not available.
    """
    try:
        return import_module(mod_name)
    except ImportError as e:
        raise RuntimeError(error_msg) from e


@contextmanager
def tmpfile(extension="", dir=None):
    extension = "." + extension.lstrip(".")
    handle, filename = tempfile.mkstemp(extension, dir=dir)
    os.close(handle)
    os.remove(filename)

    try:
        yield filename
    finally:
        if os.path.exists(filename):
            if os.path.isdir(filename):
                shutil.rmtree(filename)
            else:
                with ignoring(OSError):
                    os.remove(filename)


@contextmanager
def tmpdir(dir=None):
    dirname = tempfile.mkdtemp(dir=dir)

    try:
        yield dirname
    finally:
        if os.path.exists(dirname):
            if os.path.isdir(dirname):
                with ignoring(OSError):
                    shutil.rmtree(dirname)
            else:
                with ignoring(OSError):
                    os.remove(dirname)


@contextmanager
def filetext(text, extension="", open=open, mode="w"):
    with tmpfile(extension=extension) as filename:
        f = open(filename, mode=mode)
        try:
            f.write(text)
        finally:
            try:
                f.close()
            except AttributeError:
                pass

        yield filename


@contextmanager
def changed_cwd(new_cwd):
    old_cwd = os.getcwd()
    os.chdir(new_cwd)
    try:
        yield
    finally:
        os.chdir(old_cwd)


@contextmanager
def tmp_cwd(dir=None):
    with tmpdir(dir) as dirname:
        with changed_cwd(dirname):
            yield dirname


@contextmanager
def noop_context():
    yield


class IndexCallable(object):
    """Provide getitem syntax for functions

    >>> def inc(x):
    ...     return x + 1

    >>> I = IndexCallable(inc)
    >>> I[3]
    4
    """

    __slots__ = ("fn",)

    def __init__(self, fn):
        self.fn = fn

    def __getitem__(self, key):
        return self.fn(key)


@contextmanager
def filetexts(d, open=open, mode="t", use_tmpdir=True):
    """Dumps a number of textfiles to disk

    d - dict
        a mapping from filename to text like {'a.csv': '1,1\n2,2'}

    Since this is meant for use in tests, this context manager will
    automatically switch to a temporary current directory, to avoid
    race conditions when running tests in parallel.
    """
    with (tmp_cwd() if use_tmpdir else noop_context()):
        for filename, text in d.items():
            try:
                os.makedirs(os.path.dirname(filename))
            except OSError:
                pass
            f = open(filename, "w" + mode)
            try:
                f.write(text)
            finally:
                try:
                    f.close()
                except AttributeError:
                    pass

        yield list(d)

        for filename in d:
            if os.path.exists(filename):
                with ignoring(OSError):
                    os.remove(filename)


def concrete(seq):
    """Make nested iterators concrete lists

    >>> data = [[1, 2], [3, 4]]
    >>> seq = iter(map(iter, data))
    >>> concrete(seq)
    [[1, 2], [3, 4]]
    """
    if isinstance(seq, Iterator):
        seq = list(seq)
    if isinstance(seq, (tuple, list)):
        seq = list(map(concrete, seq))
    return seq


def pseudorandom(n, p, random_state=None):
    """Pseudorandom array of integer indexes

    >>> pseudorandom(5, [0.5, 0.5], random_state=123)
    array([1, 0, 0, 1, 1], dtype=int8)

    >>> pseudorandom(10, [0.5, 0.2, 0.2, 0.1], random_state=5)
    array([0, 2, 0, 3, 0, 1, 2, 1, 0, 0], dtype=int8)
    """
    import numpy as np

    p = list(p)
    cp = np.cumsum([0] + p)
    assert np.allclose(1, cp[-1])
    assert len(p) < 256

    if not isinstance(random_state, np.random.RandomState):
        random_state = np.random.RandomState(random_state)

    x = random_state.random_sample(n)
    out = np.empty(n, dtype="i1")

    for i, (low, high) in enumerate(zip(cp[:-1], cp[1:])):
        out[(x >= low) & (x < high)] = i
    return out


def random_state_data(n, random_state=None):
    """Return a list of arrays that can initialize
    ``np.random.RandomState``.

    Parameters
    ----------
    n : int
        Number of arrays to return.
    random_state : int or np.random.RandomState, optional
        If an int, is used to seed a new ``RandomState``.
    """
    import numpy as np

    if not all(
        hasattr(random_state, attr) for attr in ["normal", "beta", "bytes", "uniform"]
    ):
        random_state = np.random.RandomState(random_state)

    random_data = random_state.bytes(624 * n * 4)  # `n * 624` 32-bit integers
    l = list(np.frombuffer(random_data, dtype=np.uint32).reshape((n, -1)))
    assert len(l) == n
    return l


def is_integer(i):
    """
    >>> is_integer(6)
    True
    >>> is_integer(42.0)
    True
    >>> is_integer('abc')
    False
    """
    return isinstance(i, Integral) or (isinstance(i, float) and i.is_integer())


ONE_ARITY_BUILTINS = set(
    [
        abs,
        all,
        any,
        ascii,
        bool,
        bytearray,
        bytes,
        callable,
        chr,
        classmethod,
        complex,
        dict,
        dir,
        enumerate,
        eval,
        float,
        format,
        frozenset,
        hash,
        hex,
        id,
        int,
        iter,
        len,
        list,
        max,
        min,
        next,
        oct,
        open,
        ord,
        range,
        repr,
        reversed,
        round,
        set,
        slice,
        sorted,
        staticmethod,
        str,
        sum,
        tuple,
        type,
        vars,
        zip,
        memoryview,
    ]
)
MULTI_ARITY_BUILTINS = set(
    [
        compile,
        delattr,
        divmod,
        filter,
        getattr,
        hasattr,
        isinstance,
        issubclass,
        map,
        pow,
        setattr,
    ]
)


def getargspec(func):
    """Version of inspect.getargspec that works with partial and warps."""
    if isinstance(func, functools.partial):
        return getargspec(func.func)

    func = getattr(func, "__wrapped__", func)
    if isinstance(func, type):
        return inspect.getfullargspec(func.__init__)
    else:
        return inspect.getfullargspec(func)


def takes_multiple_arguments(func, varargs=True):
    """Does this function take multiple arguments?

    >>> def f(x, y): pass
    >>> takes_multiple_arguments(f)
    True

    >>> def f(x): pass
    >>> takes_multiple_arguments(f)
    False

    >>> def f(x, y=None): pass
    >>> takes_multiple_arguments(f)
    False

    >>> def f(*args): pass
    >>> takes_multiple_arguments(f)
    True

    >>> class Thing(object):
    ...     def __init__(self, a): pass
    >>> takes_multiple_arguments(Thing)
    False

    """
    if func in ONE_ARITY_BUILTINS:
        return False
    elif func in MULTI_ARITY_BUILTINS:
        return True

    try:
        spec = getargspec(func)
    except Exception:
        return False

    try:
        is_constructor = spec.args[0] == "self" and isinstance(func, type)
    except Exception:
        is_constructor = False

    if varargs and spec.varargs:
        return True

    ndefaults = 0 if spec.defaults is None else len(spec.defaults)
    return len(spec.args) - ndefaults - is_constructor > 1


def get_named_args(func):
    """Get all non ``*args/**kwargs`` arguments for a function"""
    s = inspect.signature(func)
    return [
        n
        for n, p in s.parameters.items()
        if p.kind in [p.POSITIONAL_OR_KEYWORD, p.POSITIONAL_ONLY, p.KEYWORD_ONLY]
    ]


class Dispatch(object):
    """Simple single dispatch."""

    def __init__(self, name=None):
        self._lookup = {}
        self._lazy = {}
        if name:
            self.__name__ = name

    def register(self, type, func=None):
        """Register dispatch of `func` on arguments of type `type`"""

        def wrapper(func):
            if isinstance(type, tuple):
                for t in type:
                    self.register(t, func)
            else:
                self._lookup[type] = func
            return func

        return wrapper(func) if func is not None else wrapper

    def register_lazy(self, toplevel, func=None):
        """
        Register a registration function which will be called if the
        *toplevel* module (e.g. 'pandas') is ever loaded.
        """

        def wrapper(func):
            self._lazy[toplevel] = func
            return func

        return wrapper(func) if func is not None else wrapper

    def dispatch(self, cls):
        """Return the function implementation for the given ``cls``"""
        # Fast path with direct lookup on cls
        lk = self._lookup
        try:
            impl = lk[cls]
        except KeyError:
            pass
        else:
            return impl
        # Is a lazy registration function present?
        toplevel, _, _ = cls.__module__.partition(".")
        try:
            register = self._lazy.pop(toplevel)
        except KeyError:
            pass
        else:
            register()
            return self.dispatch(cls)  # recurse
        # Walk the MRO and cache the lookup result
        for cls2 in inspect.getmro(cls)[1:]:
            if cls2 in lk:
                lk[cls] = lk[cls2]
                return lk[cls2]
        raise TypeError("No dispatch for {0}".format(cls))

    def __call__(self, arg, *args, **kwargs):
        """
        Call the corresponding method based on type of argument.
        """
        meth = self.dispatch(type(arg))
        return meth(arg, *args, **kwargs)

    @property
    def __doc__(self):
        try:
            func = self.dispatch(object)
            return func.__doc__
        except TypeError:
            return "Single Dispatch for %s" % self.__name__


def ensure_not_exists(filename):
    """
    Ensure that a file does not exist.
    """
    try:
        os.unlink(filename)
    except OSError as e:
        if e.errno != ENOENT:
            raise


def _skip_doctest(line):
    # NumPy docstring contains cursor and comment only example
    stripped = line.strip()
    if stripped == ">>>" or stripped.startswith(">>> #"):
        return line
    elif ">>>" in stripped and "+SKIP" not in stripped:
        if "# doctest:" in line:
            return line + ", +SKIP"
        else:
            return line + "  # doctest: +SKIP"
    else:
        return line


def skip_doctest(doc):
    if doc is None:
        return ""
    return "\n".join([_skip_doctest(line) for line in doc.split("\n")])


def extra_titles(doc):
    lines = doc.split("\n")
    titles = {
        i: lines[i].strip()
        for i in range(len(lines) - 1)
        if lines[i + 1].strip() and all(c == "-" for c in lines[i + 1].strip())
    }

    seen = set()
    for i, title in sorted(titles.items()):
        if title in seen:
            new_title = "Extra " + title
            lines[i] = lines[i].replace(title, new_title)
            lines[i + 1] = lines[i + 1].replace("-" * len(title), "-" * len(new_title))
        else:
            seen.add(title)

    return "\n".join(lines)


def ignore_warning(doc, cls, name, extra="", skipblocks=0):
    """Expand docstring by adding disclaimer and extra text"""
    import inspect

    if inspect.isclass(cls):
        l1 = "This docstring was copied from %s.%s.%s.\n\n" % (
            cls.__module__,
            cls.__name__,
            name,
        )
    else:
        l1 = "This docstring was copied from %s.%s.\n\n" % (cls.__name__, name)
    l2 = "Some inconsistencies with the Dask version may exist."

    i = doc.find("\n\n")
    if i != -1:
        # Insert our warning
        head = doc[: i + 2]
        tail = doc[i + 2 :]
        while skipblocks > 0:
            i = tail.find("\n\n")
            head = tail[: i + 2]
            tail = tail[i + 2 :]
            skipblocks -= 1
        # Indentation of next line
        indent = re.match(r"\s*", tail).group(0)
        # Insert the warning, indented, with a blank line before and after
        if extra:
            more = [indent, extra.rstrip("\n") + "\n\n"]
        else:
            more = []
        bits = [head, indent, l1, indent, l2, "\n\n"] + more + [tail]
        doc = "".join(bits)

    return doc


def unsupported_arguments(doc, args):
    """ Mark unsupported arguments with a disclaimer """
    lines = doc.split("\n")
    for arg in args:
        subset = [
            (i, line)
            for i, line in enumerate(lines)
            if re.match(r"^\s*" + arg + " ?:", line)
        ]
        if len(subset) == 1:
            [(i, line)] = subset
            lines[i] = line + "  (Not supported in Dask)"
    return "\n".join(lines)


def _derived_from(cls, method, ua_args=[], extra="", skipblocks=0):
    """ Helper function for derived_from to ease testing """
    # do not use wraps here, as it hides keyword arguments displayed
    # in the doc
    original_method = getattr(cls, method.__name__)

    if isinstance(original_method, property):
        # some things like SeriesGroupBy.unique are generated.
        original_method = original_method.fget

    doc = original_method.__doc__
    if doc is None:
        doc = ""

    # Insert disclaimer that this is a copied docstring
    if doc:
        doc = ignore_warning(
            doc, cls, method.__name__, extra=extra, skipblocks=skipblocks
        )
    elif extra:
        doc += extra.rstrip("\n") + "\n\n"

    # Mark unsupported arguments
    try:
        method_args = get_named_args(method)
        original_args = get_named_args(original_method)
        not_supported = [m for m in original_args if m not in method_args]
    except ValueError:
        not_supported = []
    if len(ua_args) > 0:
        not_supported.extend(ua_args)
    if len(not_supported) > 0:
        doc = unsupported_arguments(doc, not_supported)

    doc = skip_doctest(doc)
    doc = extra_titles(doc)

    return doc


def derived_from(original_klass, version=None, ua_args=[], skipblocks=0):
    """Decorator to attach original class's docstring to the wrapped method.

    The output structure will be: top line of docstring, disclaimer about this
    being auto-derived, any extra text associated with the method being patched,
    the body of the docstring and finally, the list of keywords that exist in
    the original method but not in the dask version.

    Parameters
    ----------
    original_klass: type
        Original class which the method is derived from
    version : str
        Original package version which supports the wrapped method
    ua_args : list
        List of keywords which Dask doesn't support. Keywords existing in
        original but not in Dask will automatically be added.
    skipblocks : int
        How many text blocks (paragraphs) to skip from the start of the
        docstring. Useful for cases where the target has extra front-matter.
    """

    def wrapper(method):
        try:
            extra = getattr(method, "__doc__", None) or ""
            method.__doc__ = _derived_from(
                original_klass,
                method,
                ua_args=ua_args,
                extra=extra,
                skipblocks=skipblocks,
            )
            return method

        except AttributeError:
            module_name = original_klass.__module__.split(".")[0]

            @functools.wraps(method)
            def wrapped(*args, **kwargs):
                msg = "Base package doesn't support '{0}'.".format(method.__name__)
                if version is not None:
                    msg2 = " Use {0} {1} or later to use this method."
                    msg += msg2.format(module_name, version)
                raise NotImplementedError(msg)

            return wrapped

    return wrapper


def funcname(func):
    """Get the name of a function."""
    # functools.partial
    if isinstance(func, functools.partial):
        return funcname(func.func)
    # methodcaller
    if isinstance(func, methodcaller):
        return func.method[:50]

    module_name = getattr(func, "__module__", None) or ""
    type_name = getattr(type(func), "__name__", None) or ""

    # toolz.curry
    if "toolz" in module_name and "curry" == type_name:
        return func.func_name[:50]
    # multipledispatch objects
    if "multipledispatch" in module_name and "Dispatcher" == type_name:
        return func.name[:50]
    # numpy.vectorize objects
    if "numpy" in module_name and "vectorize" == type_name:
        return ("vectorize_" + funcname(func.pyfunc))[:50]

    # All other callables
    try:
        name = func.__name__
        if name == "<lambda>":
            return "lambda"
        return name[:50]
    except AttributeError:
        return str(func)[:50]


def typename(typ):
    """
    Return the name of a type

    Examples
    --------
    >>> typename(int)
    'int'

    >>> from dask.core import literal
    >>> typename(literal)
    'dask.core.literal'
    """
    if not typ.__module__ or typ.__module__ == "builtins":
        return typ.__name__
    else:
        return typ.__module__ + "." + typ.__name__


def ensure_bytes(s):
    """Turn string or bytes to bytes

    >>> ensure_bytes('123')
    b'123'
    >>> ensure_bytes('123')
    b'123'
    >>> ensure_bytes(b'123')
    b'123'
    """
    if isinstance(s, bytes):
        return s
    if hasattr(s, "encode"):
        return s.encode()
    msg = "Object %s is neither a bytes object nor has an encode method"
    raise TypeError(msg % s)


def ensure_unicode(s):
    """Turn string or bytes to bytes

    >>> ensure_unicode('123')
    '123'
    >>> ensure_unicode('123')
    '123'
    >>> ensure_unicode(b'123')
    '123'
    """
    if isinstance(s, str):
        return s
    if hasattr(s, "decode"):
        return s.decode()
    msg = "Object %s is neither a bytes object nor has an encode method"
    raise TypeError(msg % s)


def digit(n, k, base):
    """

    >>> digit(1234, 0, 10)
    4
    >>> digit(1234, 1, 10)
    3
    >>> digit(1234, 2, 10)
    2
    >>> digit(1234, 3, 10)
    1
    """
    return n // base ** k % base


def insert(tup, loc, val):
    """

    >>> insert(('a', 'b', 'c'), 0, 'x')
    ('x', 'b', 'c')
    """
    L = list(tup)
    L[loc] = val
    return tuple(L)


def dependency_depth(dsk):
    deps, _ = get_deps(dsk)

    @lru_cache(maxsize=None)
    def max_depth_by_deps(key):
        if not deps[key]:
            return 1

        d = 1 + max(max_depth_by_deps(dep_key) for dep_key in deps[key])
        return d

    return max(max_depth_by_deps(dep_key) for dep_key in deps.keys())


def memory_repr(num):
    for x in ["bytes", "KB", "MB", "GB", "TB"]:
        if num < 1024.0:
            return "%3.1f %s" % (num, x)
        num /= 1024.0


def asciitable(columns, rows):
    """Formats an ascii table for given columns and rows.

    Parameters
    ----------
    columns : list
        The column names
    rows : list of tuples
        The rows in the table. Each tuple must be the same length as
        ``columns``.
    """
    rows = [tuple(str(i) for i in r) for r in rows]
    columns = tuple(str(i) for i in columns)
    widths = tuple(max(max(map(len, x)), len(c)) for x, c in zip(zip(*rows), columns))
    row_template = ("|" + (" %%-%ds |" * len(columns))) % widths
    header = row_template % tuple(columns)
    bar = "+%s+" % "+".join("-" * (w + 2) for w in widths)
    data = "\n".join(row_template % r for r in rows)
    return "\n".join([bar, header, bar, data, bar])


def put_lines(buf, lines):
    if any(not isinstance(x, str) for x in lines):
        lines = [str(x) for x in lines]
    buf.write("\n".join(lines))


_method_cache = {}


class methodcaller(object):
    """
    Return a callable object that calls the given method on its operand.

    Unlike the builtin `operator.methodcaller`, instances of this class are
    serializable
    """

    __slots__ = ("method",)
    func = property(lambda self: self.method)  # For `funcname` to work

    def __new__(cls, method):
        if method in _method_cache:
            return _method_cache[method]
        self = object.__new__(cls)
        self.method = method
        _method_cache[method] = self
        return self

    def __call__(self, obj, *args, **kwargs):
        return getattr(obj, self.method)(*args, **kwargs)

    def __reduce__(self):
        return (methodcaller, (self.method,))

    def __str__(self):
        return "<%s: %s>" % (self.__class__.__name__, self.method)

    __repr__ = __str__


class itemgetter(object):
    """
    Return a callable object that gets an item from the operand

    Unlike the builtin `operator.itemgetter`, instances of this class are
    serializable
    """

    __slots__ = ("index",)

    def __init__(self, index):
        self.index = index

    def __call__(self, x):
        return x[self.index]

    def __reduce__(self):
        return (itemgetter, (self.index,))

    def __eq__(self, other):
        return type(self) is type(other) and self.index == other.index


class MethodCache(object):
    """Attribute access on this object returns a methodcaller for that
    attribute.

    Examples
    --------
    >>> a = [1, 3, 3]
    >>> M.count(a, 3) == a.count(3)
    True
    """

    __getattr__ = staticmethod(methodcaller)
    __dir__ = lambda self: list(_method_cache)


M = MethodCache()


class SerializableLock(object):
    _locks = WeakValueDictionary()
    """ A Serializable per-process Lock

    This wraps a normal ``threading.Lock`` object and satisfies the same
    interface.  However, this lock can also be serialized and sent to different
    processes.  It will not block concurrent operations between processes (for
    this you should look at ``multiprocessing.Lock`` or ``locket.lock_file``
    but will consistently deserialize into the same lock.

    So if we make a lock in one process::

        lock = SerializableLock()

    And then send it over to another process multiple times::

        bytes = pickle.dumps(lock)
        a = pickle.loads(bytes)
        b = pickle.loads(bytes)

    Then the deserialized objects will operate as though they were the same
    lock, and collide as appropriate.

    This is useful for consistently protecting resources on a per-process
    level.

    The creation of locks is itself not threadsafe.
    """

    def __init__(self, token=None):
        self.token = token or str(uuid.uuid4())
        if self.token in SerializableLock._locks:
            self.lock = SerializableLock._locks[self.token]
        else:
            self.lock = Lock()
            SerializableLock._locks[self.token] = self.lock

    def acquire(self, *args, **kwargs):
        return self.lock.acquire(*args, **kwargs)

    def release(self, *args, **kwargs):
        return self.lock.release(*args, **kwargs)

    def __enter__(self):
        self.lock.__enter__()

    def __exit__(self, *args):
        self.lock.__exit__(*args)

    def locked(self):
        return self.lock.locked()

    def __getstate__(self):
        return self.token

    def __setstate__(self, token):
        self.__init__(token)

    def __str__(self):
        return "<%s: %s>" % (self.__class__.__name__, self.token)

    __repr__ = __str__


def get_scheduler_lock(collection=None, scheduler=None):
    """Get an instance of the appropriate lock for a certain situation based on
    scheduler used."""
    from . import multiprocessing
    from .base import get_scheduler

    actual_get = get_scheduler(collections=[collection], scheduler=scheduler)

    if actual_get == multiprocessing.get:
        return multiprocessing.get_context().Manager().Lock()

    return SerializableLock()


def ensure_dict(d):
    if type(d) is dict:
        return d
    elif hasattr(d, "dicts"):
        result = {}
        seen = set()
        for dd in d.dicts.values():
            dd_id = id(dd)
            if dd_id not in seen:
                result.update(dd)
                seen.add(dd_id)
        return result
    return dict(d)


class OperatorMethodMixin(object):
    """A mixin for dynamically implementing operators"""

    @classmethod
    def _bind_operator(cls, op):
        """ bind operator to this class """
        name = op.__name__

        if name.endswith("_"):
            # for and_ and or_
            name = name[:-1]
        elif name == "inv":
            name = "invert"

        meth = "__{0}__".format(name)

        if name in ("abs", "invert", "neg", "pos"):
            setattr(cls, meth, cls._get_unary_operator(op))
        else:
            setattr(cls, meth, cls._get_binary_operator(op))

            if name in ("eq", "gt", "ge", "lt", "le", "ne", "getitem"):
                return

            rmeth = "__r{0}__".format(name)
            setattr(cls, rmeth, cls._get_binary_operator(op, inv=True))

    @classmethod
    def _get_unary_operator(cls, op):
        """ Must return a method used by unary operator """
        raise NotImplementedError

    @classmethod
    def _get_binary_operator(cls, op, inv=False):
        """ Must return a method used by binary operator """
        raise NotImplementedError


def partial_by_order(*args, **kwargs):
    """

    >>> from operator import add
    >>> partial_by_order(5, function=add, other=[(1, 10)])
    15
    """
    function = kwargs.pop("function")
    other = kwargs.pop("other")
    args2 = list(args)
    for i, arg in other:
        args2.insert(i, arg)
    return function(*args2, **kwargs)


def is_arraylike(x):
    """Is this object a numpy array or something similar?

    Examples
    --------
    >>> import numpy as np
    >>> is_arraylike(np.ones(5))
    True
    >>> is_arraylike(np.ones(()))
    True
    >>> is_arraylike(5)
    False
    >>> is_arraylike('cat')
    False
    """
    from .base import is_dask_collection

    return bool(
        hasattr(x, "shape")
        and isinstance(x.shape, tuple)
        and hasattr(x, "dtype")
        and not any(is_dask_collection(n) for n in x.shape)
    )


def is_dataframe_like(df):
    """ Looks like a Pandas DataFrame """
    typ = type(df)
    return (
        all(hasattr(typ, name) for name in ("groupby", "head", "merge", "mean"))
        and all(hasattr(df, name) for name in ("dtypes", "columns"))
        and not any(hasattr(typ, name) for name in ("name", "dtype"))
    )


def is_series_like(s):
    """ Looks like a Pandas Series """
    typ = type(s)
    return (
        all(hasattr(typ, name) for name in ("groupby", "head", "mean"))
        and all(hasattr(s, name) for name in ("dtype", "name"))
        and "index" not in typ.__name__.lower()
    )


def is_index_like(s):
    """ Looks like a Pandas Index """
    typ = type(s)
    return (
        all(hasattr(s, name) for name in ("name", "dtype"))
        and "index" in typ.__name__.lower()
    )


def natural_sort_key(s):
    """
    Sorting `key` function for performing a natural sort on a collection of
    strings

    See https://en.wikipedia.org/wiki/Natural_sort_order

    Parameters
    ----------
    s : str
        A string that is an element of the collection being sorted

    Returns
    -------
    tuple[str or int]
        Tuple of the parts of the input string where each part is either a
        string or an integer

    Examples
    --------
    >>> a = ['f0', 'f1', 'f2', 'f8', 'f9', 'f10', 'f11', 'f19', 'f20', 'f21']
    >>> sorted(a)
    ['f0', 'f1', 'f10', 'f11', 'f19', 'f2', 'f20', 'f21', 'f8', 'f9']
    >>> sorted(a, key=natural_sort_key)
    ['f0', 'f1', 'f2', 'f8', 'f9', 'f10', 'f11', 'f19', 'f20', 'f21']
    """
    return [int(part) if part.isdigit() else part for part in re.split(r"(\d+)", s)]


def factors(n):
    """Return the factors of an integer

    https://stackoverflow.com/a/6800214/616616
    """
    seq = ([i, n // i] for i in range(1, int(pow(n, 0.5) + 1)) if n % i == 0)
    return set(functools.reduce(list.__add__, seq))


[docs]def parse_bytes(s): """Parse byte string to numbers >>> from dask.utils import parse_bytes >>> parse_bytes('100') 100 >>> parse_bytes('100 MB') 100000000 >>> parse_bytes('100M') 100000000 >>> parse_bytes('5kB') 5000 >>> parse_bytes('5.4 kB') 5400 >>> parse_bytes('1kiB') 1024 >>> parse_bytes('1e6') 1000000 >>> parse_bytes('1e6 kB') 1000000000 >>> parse_bytes('MB') 1000000 >>> parse_bytes(123) 123 >>> parse_bytes('5 foos') # doctest: +SKIP ValueError: Could not interpret 'foos' as a byte unit """ if isinstance(s, (int, float)): return int(s) s = s.replace(" ", "") if not any(char.isdigit() for char in s): s = "1" + s for i in range(len(s) - 1, -1, -1): if not s[i].isalpha(): break index = i + 1 prefix = s[:index] suffix = s[index:] try: n = float(prefix) except ValueError as e: raise ValueError("Could not interpret '%s' as a number" % prefix) from e try: multiplier = byte_sizes[suffix.lower()] except KeyError as e: raise ValueError("Could not interpret '%s' as a byte unit" % suffix) from e result = n * multiplier return int(result)
byte_sizes = { "kB": 10 ** 3, "MB": 10 ** 6, "GB": 10 ** 9, "TB": 10 ** 12, "PB": 10 ** 15, "KiB": 2 ** 10, "MiB": 2 ** 20, "GiB": 2 ** 30, "TiB": 2 ** 40, "PiB": 2 ** 50, "B": 1, "": 1, } byte_sizes = {k.lower(): v for k, v in byte_sizes.items()} byte_sizes.update({k[0]: v for k, v in byte_sizes.items() if k and "i" not in k}) byte_sizes.update({k[:-1]: v for k, v in byte_sizes.items() if k and "i" in k})
[docs]def format_time(n): """format integers as time >>> from dask.utils import format_time >>> format_time(1) '1.00 s' >>> format_time(0.001234) '1.23 ms' >>> format_time(0.00012345) '123.45 us' >>> format_time(123.456) '123.46 s' """ if n >= 1: return "%.2f s" % n if n >= 1e-3: return "%.2f ms" % (n * 1e3) return "%.2f us" % (n * 1e6)
def format_time_ago(n: datetime) -> str: """Calculate a '3 hours ago' type string from a Python datetime. Examples -------- >>> from datetime import datetime, timedelta >>> now = datetime.now() >>> format_time_ago(now) 'Just now' >>> past = datetime.now() - timedelta(minutes=1) >>> format_time_ago(past) '1 minute ago' >>> past = datetime.now() - timedelta(minutes=2) >>> format_time_ago(past) '2 minutes ago' >>> past = datetime.now() - timedelta(hours=1) >>> format_time_ago(past) '1 hour ago' >>> past = datetime.now() - timedelta(hours=6) >>> format_time_ago(past) '6 hours ago' >>> past = datetime.now() - timedelta(days=1) >>> format_time_ago(past) '1 day ago' >>> past = datetime.now() - timedelta(days=5) >>> format_time_ago(past) '5 days ago' >>> past = datetime.now() - timedelta(days=8) >>> format_time_ago(past) '1 week ago' >>> past = datetime.now() - timedelta(days=16) >>> format_time_ago(past) '2 weeks ago' >>> past = datetime.now() - timedelta(days=190) >>> format_time_ago(past) '6 months ago' >>> past = datetime.now() - timedelta(days=800) >>> format_time_ago(past) '2 years ago' """ units = { "years": lambda diff: diff.days / 365, "months": lambda diff: diff.days / 30.436875, # Average days per month "weeks": lambda diff: diff.days / 7, "days": lambda diff: diff.days, "hours": lambda diff: diff.seconds / 3600, "minutes": lambda diff: diff.seconds % 3600 / 60, } diff = datetime.now() - n for unit in units: dur = int(units[unit](diff)) if dur > 0: if dur == 1: # De-pluralize unit = unit[:-1] return "%s %s ago" % (dur, unit) return "Just now"
[docs]def format_bytes(n): """Format bytes as text >>> from dask.utils import format_bytes >>> format_bytes(1) '1 B' >>> format_bytes(1234) '1.23 kB' >>> format_bytes(12345678) '12.35 MB' >>> format_bytes(1234567890) '1.23 GB' >>> format_bytes(1234567890000) '1.23 TB' >>> format_bytes(1234567890000000) '1.23 PB' """ if n > 1e15: return "%0.2f PB" % (n / 1e15) if n > 1e12: return "%0.2f TB" % (n / 1e12) if n > 1e9: return "%0.2f GB" % (n / 1e9) if n > 1e6: return "%0.2f MB" % (n / 1e6) if n > 1e3: return "%0.2f kB" % (n / 1000) return "%d B" % n
timedelta_sizes = { "s": 1, "ms": 1e-3, "us": 1e-6, "ns": 1e-9, "m": 60, "h": 3600, "d": 3600 * 24, } tds2 = { "second": 1, "minute": 60, "hour": 60 * 60, "day": 60 * 60 * 24, "millisecond": 1e-3, "microsecond": 1e-6, "nanosecond": 1e-9, } tds2.update({k + "s": v for k, v in tds2.items()}) timedelta_sizes.update(tds2) timedelta_sizes.update({k.upper(): v for k, v in timedelta_sizes.items()})
[docs]def parse_timedelta(s, default="seconds"): """Parse timedelta string to number of seconds Examples -------- >>> from datetime import timedelta >>> from dask.utils import parse_timedelta >>> parse_timedelta('3s') 3 >>> parse_timedelta('3.5 seconds') 3.5 >>> parse_timedelta('300ms') 0.3 >>> parse_timedelta(timedelta(seconds=3)) # also supports timedeltas 3 """ if s is None: return None if isinstance(s, timedelta): s = s.total_seconds() return int(s) if int(s) == s else s if isinstance(s, Number): s = str(s) s = s.replace(" ", "") if not s[0].isdigit(): s = "1" + s for i in range(len(s) - 1, -1, -1): if not s[i].isalpha(): break index = i + 1 prefix = s[:index] suffix = s[index:] or default n = float(prefix) multiplier = timedelta_sizes[suffix.lower()] result = n * multiplier if int(result) == result: result = int(result) return result
def has_keyword(func, keyword): try: return keyword in inspect.signature(func).parameters except Exception: return False def ndimlist(seq): if not isinstance(seq, (list, tuple)): return 0 elif not seq: return 1 else: return 1 + ndimlist(seq[0]) def iter_chunks(sizes, max_size): """Split sizes into chunks of total max_size each Parameters ---------- sizes : iterable of numbers The sizes to be chunked max_size : number Maximum total size per chunk. It must be greater or equal than each size in sizes """ chunk, chunk_sum = [], 0 iter_sizes = iter(sizes) size = next(iter_sizes, None) while size is not None: assert size <= max_size if chunk_sum + size <= max_size: chunk.append(size) chunk_sum += size size = next(iter_sizes, None) else: assert chunk yield chunk chunk, chunk_sum = [], 0 if chunk: yield chunk hex_pattern = re.compile("[a-f]+") def key_split(s): """ >>> key_split('x') 'x' >>> key_split('x-1') 'x' >>> key_split('x-1-2-3') 'x' >>> key_split(('x-2', 1)) 'x' >>> key_split("('x-2', 1)") 'x' >>> key_split('hello-world-1') 'hello-world' >>> key_split(b'hello-world-1') 'hello-world' >>> key_split('ae05086432ca935f6eba409a8ecd4896') 'data' >>> key_split('<module.submodule.myclass object at 0xdaf372') 'myclass' >>> key_split(None) 'Other' >>> key_split('x-abcdefab') # ignores hex 'x' >>> key_split('_(x)') # strips unpleasant characters 'x' """ if type(s) is bytes: s = s.decode() if type(s) is tuple: s = s[0] try: words = s.split("-") if not words[0][0].isalpha(): result = words[0].strip("_'()\"") else: result = words[0] for word in words[1:]: if word.isalpha() and not ( len(word) == 8 and hex_pattern.match(word) is not None ): result += "-" + word else: break if len(result) == 32 and re.match(r"[a-f0-9]{32}", result): return "data" else: if result[0] == "<": result = result.strip("<>").split()[0].split(".")[-1] return result except Exception: return "Other" def stringify(obj, exclusive: Optional[Iterable] = None): """Convert an object to a string If ``exclusive`` is specified, search through `obj` and convert values that are in ``exclusive``. Note that when searching through dictionaries, only values are converted, not the keys. Parameters ---------- obj : Any Object (or values within) to convert to string exclusive: Iterable, optional Set of values to search for when converting values to strings Returns ------- result : type(obj) Stringified copy of ``obj`` or ``obj`` itself if it is already a string or bytes. Examples -------- >>> stringify(b'x') b'x' >>> stringify('x') 'x' >>> stringify({('a',0):('a',0), ('a',1): ('a',1)}) "{('a', 0): ('a', 0), ('a', 1): ('a', 1)}" >>> stringify({('a',0):('a',0), ('a',1): ('a',1)}, exclusive={('a',0)}) {('a', 0): "('a', 0)", ('a', 1): ('a', 1)} """ typ = type(obj) if typ is str or typ is bytes: return obj elif exclusive is None: return str(obj) if typ is tuple and obj: from .optimization import SubgraphCallable obj0 = obj[0] if type(obj0) is SubgraphCallable: obj0 = obj0 return ( SubgraphCallable( stringify(obj0.dsk, exclusive), obj0.outkey, stringify(obj0.inkeys, exclusive), obj0.name, ), ) + tuple(stringify(x, exclusive) for x in obj[1:]) elif callable(obj0): return (obj0,) + tuple(stringify(x, exclusive) for x in obj[1:]) if typ is list: return [stringify(v, exclusive) for v in obj] if typ is dict: return {k: stringify(v, exclusive) for k, v in obj.items()} try: if obj in exclusive: return stringify(obj) except TypeError: # `obj` not hashable pass if typ is tuple: # If the tuple itself isn't a key, check its elements return tuple(stringify(v, exclusive) for v in obj) return obj def stringify_collection_keys(obj): """Convert all collection keys in ``obj`` to strings. This is a specialized version of ``stringify()`` that only converts keys of the form: ``("a string", ...)`` """ typ = type(obj) if typ is tuple and obj: obj0 = obj[0] if type(obj0) is str or type(obj0) is bytes: return stringify(obj) if callable(obj0): return (obj0,) + tuple(stringify_collection_keys(x) for x in obj[1:]) if typ is list: return [stringify_collection_keys(v) for v in obj] if typ is dict: return {k: stringify_collection_keys(v) for k, v in obj.items()} if typ is tuple: # If the tuple itself isn't a key, check its elements return tuple(stringify_collection_keys(v) for v in obj) return obj