Source code for plumbum.commands.base

import subprocess
import functools
from contextlib import contextmanager
from plumbum.commands.processes import run_proc, iter_lines
import plumbum.commands.modifiers
from plumbum.lib import six
from tempfile import TemporaryFile
from subprocess import PIPE, Popen
from types import MethodType


[docs]class RedirectionError(Exception): """Raised when an attempt is made to redirect an process' standard handle, which was already redirected to/from a file"""
#=================================================================================================== # Utilities #=================================================================================================== # modified from the stdlib pipes module for windows _safechars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@%_-+=:,./' _funnychars = '"`$\\'
[docs]def shquote(text): """Quotes the given text with shell escaping (assumes as syntax similar to ``sh``)""" if not text: return "''" text = six.str(text) if not text: return "''" for c in text: if c not in _safechars: break else: return text if "'" not in text: return "'" + text + "'" res = six.str("").join( (six.str('\\' + c) if c in _funnychars else c) for c in text) return six.str('"') + res + six.str('"')
def shquote_list(seq): return [shquote(item) for item in seq] #=================================================================================================== # Commands #===================================================================================================
[docs]class BaseCommand(object): """Base of all command objects""" __slots__ = ("cwd", "env", "custom_encoding", "__weakref__")
[docs] def __str__(self): return " ".join(self.formulate())
[docs] def __or__(self, other): """Creates a pipe with the other command""" return Pipeline(self, other)
[docs] def __gt__(self, file): """Redirects the process' stdout to the given file""" return StdoutRedirection(self, file)
[docs] def __rshift__(self, file): """Redirects the process' stdout to the given file (appending)""" return AppendingStdoutRedirection(self, file)
[docs] def __ge__(self, file): """Redirects the process' stderr to the given file""" return StderrRedirection(self, file)
[docs] def __lt__(self, file): """Redirects the given file into the process' stdin""" return StdinRedirection(self, file)
[docs] def __lshift__(self, data): """Redirects the given data into the process' stdin""" return StdinDataRedirection(self, data)
[docs] def __getitem__(self, args): """Creates a bound-command with the given arguments. Shortcut for bound_command.""" if not isinstance(args, (tuple, list)): args = [ args, ] return self.bound_command(*args)
[docs] def bound_command(self, *args): """Creates a bound-command with the given arguments""" if not args: return self if isinstance(self, BoundCommand): return BoundCommand(self.cmd, self.args + list(args)) else: return BoundCommand(self, args)
[docs] def __call__(self, *args, **kwargs): """A shortcut for `run(args)`, returning only the process' stdout""" return self.run(args, **kwargs)[1]
def _get_encoding(self): raise NotImplementedError()
[docs] def with_env(self, **envvars): """Returns a BoundEnvCommand with the given environment variables""" if not envvars: return self return BoundEnvCommand(self, envvars)
setenv = with_env @property def machine(self): raise NotImplementedError()
[docs] def formulate(self, level=0, args=()): """Formulates the command into a command-line, i.e., a list of shell-quoted strings that can be executed by ``Popen`` or shells. :param level: The nesting level of the formulation; it dictates how much shell-quoting (if any) should be performed :param args: The arguments passed to this command (a tuple) :returns: A list of strings """ raise NotImplementedError()
[docs] def popen(self, args=(), **kwargs): """Spawns the given command, returning a ``Popen``-like object. .. note:: When processes run in the **background** (either via ``popen`` or :class:`& BG <plumbum.commands.BG>`), their stdout/stderr pipes might fill up, causing them to hang. If you know a process produces output, be sure to consume it every once in a while, using a monitoring thread/reactor in the background. For more info, see `#48 <https://github.com/tomerfiliba/plumbum/issues/48>`_ :param args: Any arguments to be passed to the process (a tuple) :param kwargs: Any keyword-arguments to be passed to the ``Popen`` constructor :returns: A ``Popen``-like object """ raise NotImplementedError()
[docs] def nohup(self, command, cwd='.', stdout='nohup.out', stderr=None, append=True): """Runs a command detached.""" return self.machine.daemonic_popen(self, cwd, stdout, stderr, append)
[docs] @contextmanager def bgrun(self, args=(), **kwargs): """Runs the given command as a context manager, allowing you to create a `pipeline <http://en.wikipedia.org/wiki/Pipeline_(computing)>`_ (not in the UNIX sense) of programs, parallelizing their work. In other words, instead of running programs one after the other, you can start all of them at the same time and wait for them to finish. For a more thorough review, see `Lightweight Asynchronism <http://tomerfiliba.com/blog/Toying-with-Context-Managers/>`_. Example:: from plumbum.cmd import mkfs with mkfs["-t", "ext3", "/dev/sda1"] as p1: with mkfs["-t", "ext3", "/dev/sdb1"] as p2: pass .. note:: When processes run in the **background** (either via ``popen`` or :class:`& BG <plumbum.commands.BG>`), their stdout/stderr pipes might fill up, causing them to hang. If you know a process produces output, be sure to consume it every once in a while, using a monitoring thread/reactor in the background. For more info, see `#48 <https://github.com/tomerfiliba/plumbum/issues/48>`_ For the arguments, see :func:`run <BaseCommand.run>`. :returns: A Popen object, augmented with a ``.run()`` method, which returns a tuple of (return code, stdout, stderr) """ retcode = kwargs.pop("retcode", 0) timeout = kwargs.pop("timeout", None) p = self.popen(args, **kwargs) was_run = [False] def runner(): if was_run[0]: return # already done was_run[0] = True try: return run_proc(p, retcode, timeout) finally: del p.run # to break cyclic reference p -> cell -> p for f in [p.stdin, p.stdout, p.stderr]: try: f.close() except Exception: pass p.run = runner yield p runner()
[docs] def run(self, args=(), **kwargs): """Runs the given command (equivalent to popen() followed by :func:`run_proc <plumbum.commands.run_proc>`). If the exit code of the process does not match the expected one, :class:`ProcessExecutionError <plumbum.commands.ProcessExecutionError>` is raised. :param args: Any arguments to be passed to the process (a tuple) :param retcode: The expected return code of this process (defaults to 0). In order to disable exit-code validation, pass ``None``. It may also be a tuple (or any iterable) of expected exit codes. .. note:: this argument must be passed as a keyword argument. :param timeout: The maximal amount of time (in seconds) to allow the process to run. ``None`` means no timeout is imposed; otherwise, if the process hasn't terminated after that many seconds, the process will be forcefully terminated an exception will be raised .. note:: this argument must be passed as a keyword argument. :param kwargs: Any keyword-arguments to be passed to the ``Popen`` constructor :returns: A tuple of (return code, stdout, stderr) """ with self.bgrun(args, **kwargs) as p: return p.run()
def _use_modifier(self, modifier, args): """ Applies a modifier to the current object (e.g. FG, NOHUP) :param modifier: The modifier class to apply (e.g. FG) :param args: A dictionary of arguments to pass to this modifier :return: """ modifier_instance = modifier(**args) return self & modifier_instance
[docs] def run_bg(self, **kwargs): """ Run this command in the background. Uses all arguments from the BG construct :py:class: `plumbum.commands.modifiers.BG` """ return self._use_modifier(plumbum.commands.modifiers.BG, kwargs)
[docs] def run_fg(self, **kwargs): """ Run this command in the foreground. Uses all arguments from the FG construct :py:class: `plumbum.commands.modifiers.FG` """ return self._use_modifier(plumbum.commands.modifiers.FG, kwargs)
[docs] def run_tee(self, **kwargs): """ Run this command using the TEE construct. Inherits all arguments from TEE :py:class: `plumbum.commands.modifiers.TEE` """ return self._use_modifier(plumbum.commands.modifiers.TEE, kwargs)
[docs] def run_tf(self, **kwargs): """ Run this command using the TF construct. Inherits all arguments from TF :py:class: `plumbum.commands.modifiers.TF` """ return self._use_modifier(plumbum.commands.modifiers.TF, kwargs)
[docs] def run_retcode(self, **kwargs): """ Run this command using the RETCODE construct. Inherits all arguments from RETCODE :py:class: `plumbum.commands.modifiers.RETCODE` """ return self._use_modifier(plumbum.commands.modifiers.RETCODE, kwargs)
[docs] def run_nohup(self, **kwargs): """ Run this command using the NOHUP construct. Inherits all arguments from NOHUP :py:class: `plumbum.commands.modifiers.NOHUP` """ return self._use_modifier(plumbum.commands.modifiers.NOHUP, kwargs)
[docs]class BoundCommand(BaseCommand): __slots__ = ("cmd", "args")
[docs] def __init__(self, cmd, args): self.cmd = cmd self.args = list(args)
[docs] def __repr__(self): return "BoundCommand(%r, %r)" % (self.cmd, self.args)
def _get_encoding(self): return self.cmd._get_encoding()
[docs] def formulate(self, level=0, args=()): return self.cmd.formulate(level + 1, self.args + list(args))
@property def machine(self): return self.cmd.machine
[docs] def popen(self, args=(), **kwargs): if isinstance(args, six.string_types): args = [ args, ] return self.cmd.popen(self.args + list(args), **kwargs)
[docs]class BoundEnvCommand(BaseCommand): __slots__ = ("cmd", "envvars")
[docs] def __init__(self, cmd, envvars): self.cmd = cmd self.envvars = envvars
[docs] def __repr__(self): return "BoundEnvCommand(%r, %r)" % (self.cmd, self.envvars)
def _get_encoding(self): return self.cmd._get_encoding()
[docs] def formulate(self, level=0, args=()): return self.cmd.formulate(level, args)
@property def machine(self): return self.cmd.machine
[docs] def popen(self, args=(), **kwargs): with self.machine.env(**self.envvars): return self.cmd.popen(args, **kwargs)
[docs]class Pipeline(BaseCommand): __slots__ = ("srccmd", "dstcmd")
[docs] def __init__(self, srccmd, dstcmd): self.srccmd = srccmd self.dstcmd = dstcmd
[docs] def __repr__(self): return "Pipeline(%r, %r)" % (self.srccmd, self.dstcmd)
def _get_encoding(self): return self.srccmd._get_encoding() or self.dstcmd._get_encoding()
[docs] def formulate(self, level=0, args=()): return self.srccmd.formulate(level + 1) + ["|" ] + self.dstcmd.formulate( level + 1, args)
@property def machine(self): return self.srccmd.machine
[docs] def popen(self, args=(), **kwargs): src_kwargs = kwargs.copy() src_kwargs["stdout"] = PIPE if "stdin" in kwargs: src_kwargs["stdin"] = kwargs["stdin"] srcproc = self.srccmd.popen(args, **src_kwargs) kwargs["stdin"] = srcproc.stdout dstproc = self.dstcmd.popen(**kwargs) # allow p1 to receive a SIGPIPE if p2 exits srcproc.stdout.close() if srcproc.stderr is not None: dstproc.stderr = srcproc.stderr if srcproc.stdin and src_kwargs.get('stdin') != PIPE: srcproc.stdin.close() dstproc.srcproc = srcproc # monkey-patch .wait() to wait on srcproc as well (it's expected to die when dstproc dies) dstproc_wait = dstproc.wait @functools.wraps(Popen.wait) def wait2(*args, **kwargs): rc_dst = dstproc_wait(*args, **kwargs) rc_src = srcproc.wait(*args, **kwargs) dstproc.returncode = rc_dst or rc_src return dstproc.returncode dstproc._proc.wait = wait2 dstproc_verify = dstproc.verify def verify(proc, retcode, timeout, stdout, stderr): #TODO: right now it's impossible to specify different expected # return codes for different stages of the pipeline try: or_retcode = [0] + list(retcode) except TypeError: if (retcode is None): or_retcode = None # no-retcode-verification acts "greedily" else: or_retcode = [0, retcode] proc.srcproc.verify(or_retcode, timeout, stdout, stderr) dstproc_verify(retcode, timeout, stdout, stderr) dstproc.verify = MethodType(verify, dstproc) dstproc.stdin = srcproc.stdin return dstproc
[docs]class BaseRedirection(BaseCommand): __slots__ = ("cmd", "file") SYM = None # type: str KWARG = None # type: str MODE = None # type: str
[docs] def __init__(self, cmd, file): self.cmd = cmd self.file = file
def _get_encoding(self): return self.cmd._get_encoding()
[docs] def __repr__(self): return "%s(%r, %r)" % (self.__class__.__name__, self.cmd, self.file)
[docs] def formulate(self, level=0, args=()): return self.cmd.formulate(level + 1, args) + [ self.SYM, shquote(getattr(self.file, "name", self.file)) ]
@property def machine(self): return self.cmd.machine
[docs] def popen(self, args=(), **kwargs): from plumbum.machines.local import LocalPath from plumbum.machines.remote import RemotePath if self.KWARG in kwargs and kwargs[self.KWARG] not in (PIPE, None): raise RedirectionError("%s is already redirected" % (self.KWARG, )) if isinstance(self.file, RemotePath): raise TypeError("Cannot redirect to/from remote paths") if isinstance(self.file, six.string_types + (LocalPath, )): f = kwargs[self.KWARG] = open(str(self.file), self.MODE) else: kwargs[self.KWARG] = self.file f = None try: return self.cmd.popen(args, **kwargs) finally: if f: f.close()
[docs]class StdinRedirection(BaseRedirection): __slots__ = () SYM = "<" KWARG = "stdin" MODE = "r"
[docs]class StdoutRedirection(BaseRedirection): __slots__ = () SYM = ">" KWARG = "stdout" MODE = "w"
[docs]class AppendingStdoutRedirection(BaseRedirection): __slots__ = () SYM = ">>" KWARG = "stdout" MODE = "a"
[docs]class StderrRedirection(BaseRedirection): __slots__ = () SYM = "2>" KWARG = "stderr" MODE = "w"
class _ERROUT(int): def __repr__(self): return "ERROUT" def __str__(self): return "&1" ERROUT = _ERROUT(subprocess.STDOUT)
[docs]class StdinDataRedirection(BaseCommand): __slots__ = ("cmd", "data") CHUNK_SIZE = 16000
[docs] def __init__(self, cmd, data): self.cmd = cmd self.data = data
def _get_encoding(self): return self.cmd._get_encoding()
[docs] def formulate(self, level=0, args=()): return [ "echo %s" % (shquote(self.data), ), "|", self.cmd.formulate(level + 1, args) ]
@property def machine(self): return self.cmd.machine
[docs] def popen(self, args=(), **kwargs): if "stdin" in kwargs and kwargs["stdin"] != PIPE: raise RedirectionError("stdin is already redirected") data = self.data if isinstance(data, six.unicode_type) and self._get_encoding() is not None: data = data.encode(self._get_encoding()) f = TemporaryFile() while data: chunk = data[:self.CHUNK_SIZE] f.write(chunk) data = data[self.CHUNK_SIZE:] f.seek(0) # try: return self.cmd.popen(args, stdin=f, **kwargs)
# finally: # f.close()
[docs]class ConcreteCommand(BaseCommand): QUOTE_LEVEL = None # type: int __slots__ = ("executable", "custom_encoding")
[docs] def __init__(self, executable, encoding): self.executable = executable self.custom_encoding = encoding self.cwd = None self.env = None
[docs] def __str__(self): return str(self.executable)
[docs] def __repr__(self): return "{0}({1})".format(type(self).__name__, self.executable)
def _get_encoding(self): return self.custom_encoding
[docs] def formulate(self, level=0, args=()): argv = [six.str(self.executable)] for a in args: if a is None: continue if isinstance(a, BaseCommand): if level >= self.QUOTE_LEVEL: argv.extend(shquote_list(a.formulate(level + 1))) else: argv.extend(a.formulate(level + 1)) elif isinstance(a, (list, tuple)): argv.extend( shquote(b) if level >= self.QUOTE_LEVEL else six.str(b) for b in a) else: argv.append( shquote(a) if level >= self.QUOTE_LEVEL else six.str(a)) # if self.custom_encoding: # argv = [a.encode(self.custom_encoding) for a in argv if isinstance(a, six.string_types)] return argv