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# Copyright (C) 2011-2015 by Andrew Moffat
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
__version__ = "1.11"
__project_url__ = ""
import platform
if "windows" in platform.system().lower():
raise ImportError("sh %s is currently only supported on linux and osx. \
please install pbs 0.110 ( for windows \
support." % __version__)
import sys
IS_PY3 = sys.version_info[0] == 3
import traceback
import os
import re
from glob import glob as original_glob
import time
from types import ModuleType
from functools import partial
import inspect
from contextlib import contextmanager
from locale import getpreferredencoding
DEFAULT_ENCODING = getpreferredencoding() or "UTF-8"
if IS_PY3:
from io import StringIO
from io import BytesIO as cStringIO
from queue import Queue, Empty
# for some reason, python 3.1 removed the builtin "callable", wtf
if not hasattr(__builtins__, "callable"):
def callable(ob):
return hasattr(ob, "__call__")
from StringIO import StringIO
from cStringIO import OutputType as cStringIO
from Queue import Queue, Empty
IS_OSX = platform.system() == "Darwin"
THIS_DIR = os.path.dirname(os.path.realpath(__file__))
import errno
import warnings
import pty
import termios
import signal
import gc
import select
import threading
import tty
import fcntl
import struct
import resource
from collections import deque
import logging
import weakref
# TODO remove with contexts in next version
def with_context_warning():
with contexts are deprecated because they are not thread safe. they will be \
removed in the next version. use subcommands instead \ see \
""".strip(), stacklevel=3)
if IS_PY3:
raw_input = input
unicode = str
basestring = str
_unicode_methods = set(dir(unicode()))
def encode_to_py3bytes_or_py2str(s):
""" takes anything and attempts to return a py2 string or py3 bytes. this
is typically used when creating command + arguments to be executed via
os.exec* """
fallback_encoding = "utf8"
if IS_PY3:
# if we're already bytes, do nothing
if isinstance(s, bytes):
s = str(s)
s = bytes(s, DEFAULT_ENCODING)
except UnicodeEncodeError:
s = bytes(s, fallback_encoding)
# attempt to convert the thing to unicode from the system's encoding
s = unicode(s, DEFAULT_ENCODING)
# if the thing is already unicode, or it's a number, it can't be
# coerced to unicode with an encoding argument, but if we leave out
# the encoding argument, it will convert it to a string, then to unicode
except TypeError:
s = unicode(s)
# now that we have guaranteed unicode, encode to our system encoding,
# but attempt to fall back to something
s = s.encode(DEFAULT_ENCODING)
s = s.encode(fallback_encoding)
return s
class ErrorReturnCode(Exception):
""" base class for all exceptions as a result of a command's exit status
being deemed an error. this base class is dynamically subclassed into
derived classes with the format: ErrorReturnCode_NNN where NNN is the exit
code number. the reason for this is it reduces boiler plate code when
testing error return codes:
except ErrorReturnCode_12:
print("couldn't do X")
except ErrorReturnCode as e:
if e.exit_code == 12:
print("couldn't do X")
it's not much of a savings, but i believe it makes the code easier to read """
truncate_cap = 750
def __init__(self, full_cmd, stdout, stderr):
self.full_cmd = full_cmd
self.stdout = stdout
self.stderr = stderr
if self.stdout is None:
exc_stdout = "<redirected>"
exc_stdout = self.stdout[:self.truncate_cap]
out_delta = len(self.stdout) - len(exc_stdout)
if out_delta:
exc_stdout += ("... (%d more, please see e.stdout)" % out_delta).encode()
if self.stderr is None:
exc_stderr = "<redirected>"
exc_stderr = self.stderr[:self.truncate_cap]
err_delta = len(self.stderr) - len(exc_stderr)
if err_delta:
exc_stderr += ("... (%d more, please see e.stderr)" % err_delta).encode()
msg = "\n\n RAN: %r\n\n STDOUT:\n%s\n\n STDERR:\n%s" % \
(full_cmd, exc_stdout.decode(DEFAULT_ENCODING, "replace"),
exc_stderr.decode(DEFAULT_ENCODING, "replace"))
super(ErrorReturnCode, self).__init__(msg)
class SignalException(ErrorReturnCode): pass
class TimeoutException(Exception):
""" the exception thrown when a command is killed because a specified
timeout (via _timeout) was hit """
def __init__(self, exit_code):
self.exit_code = exit_code
super(Exception, self).__init__()
# we subclass AttributeError because:
class CommandNotFound(AttributeError): pass
rc_exc_regex = re.compile("(ErrorReturnCode|SignalException)_((\d+)|SIG\w+)")
rc_exc_cache = {}
def get_exc_from_name(name):
""" takes an exception name, like:
and returns the corresponding exception. this is primarily used for
importing exceptions from sh into user code, for instance, to capture those
exceptions """
exc = None
return rc_exc_cache[name]
except KeyError:
m = rc_exc_regex.match(name)
if m:
base =
rc_or_sig_name =
if base == "SignalException":
rc = -int(rc_or_sig_name)
except ValueError:
rc = -getattr(signal, rc_or_sig_name)
rc = int(rc_or_sig_name)
exc = get_rc_exc(rc)
return exc
def get_rc_exc(rc_or_sig_name):
""" takes a exit code, signal number, or signal name, and produces an
exception that corresponds to that return code. positive return codes yield
ErrorReturnCode exception, negative return codes yield SignalException
we also cache the generated exception so that only one signal of that type
exists, preserving identity """
rc = int(rc_or_sig_name)
except ValueError:
rc = -getattr(signal, rc_or_sig_name)
return rc_exc_cache[rc]
except KeyError:
if rc > 0:
name = "ErrorReturnCode_%d" % rc
base = ErrorReturnCode
name = "SignalException_%d" % abs(rc)
base = SignalException
exc = type(name, (base,), {"exit_code": rc})
rc_exc_cache[rc] = exc
return exc
def which(program):
def is_exe(fpath):
return (os.path.exists(fpath) and
os.access(fpath, os.X_OK) and
fpath, fname = os.path.split(program)
if fpath:
if is_exe(program):
return program
if "PATH" not in os.environ:
return None
for path in os.environ["PATH"].split(os.pathsep):
exe_file = os.path.join(path, program)
if is_exe(exe_file):
return exe_file
return None
def resolve_program(program):
path = which(program)
if not path:
# our actual command might have a dash in it, but we can't call
# that from python (we have to use underscores), so we'll check
# if a dash version of our underscore command exists and use that
# if it does
if "_" in program:
path = which(program.replace("_", "-"))
if not path:
return None
return path
# we add this thin wrapper to glob.glob because of a specific edge case where
# glob does not expand to anything. for example, if you try to do
# glob.glob("*.py") and there are no *.py files in the directory, glob.glob
# returns an empty list. this empty list gets passed to the command, and
# then the command fails with a misleading error message. this thin wrapper
# ensures that if there is no expansion, we pass in the original argument,
# so that when the command fails, the error message is clearer
def glob(arg):
return original_glob(arg) or arg
class Logger(object):
""" provides a memory-inexpensive logger. a gotcha about python's builtin
logger is that logger objects are never garbage collected. if you create a
thousand loggers with unique names, they'll sit there in memory until your
script is done. with sh, it's easy to create loggers with unique names if
we want our loggers to include our command arguments. for example, these
are all unique loggers:
ls -l
ls -l /tmp
ls /tmp
so instead of creating unique loggers, and without sacrificing logging
output, we use this class, which maintains as part of its state, the logging
"context", which will be the very unique name. this allows us to get a
logger with a very general name, eg: "command", and have a unique name
appended to it via the context, eg: "ls -l /tmp" """
def __init__(self, name, context=None): = name
if context:
context = context.replace("%", "%%")
self.context = context
self.log = logging.getLogger("%s.%s" % (SH_LOGGER_NAME, name))
def _format_msg(self, msg, *args):
if self.context:
msg = "%s: %s" % (self.context, msg)
return msg % args
def get_child(self, name, context):
new_name = + "." + name
new_context = self.context + "." + context
l = Logger(new_name, new_context)
return l
def info(self, msg, *args):, *args))
def debug(self, msg, *args):
self.log.debug(self._format_msg(msg, *args))
def error(self, msg, *args):
self.log.error(self._format_msg(msg, *args))
def exception(self, msg, *args):
self.log.exception(self._format_msg(msg, *args))
def friendly_truncate(s, max_len):
if len(s) > max_len:
s = "%s...(%d more)" % (s[:max_len], len(s) - max_len)
return s
class RunningCommand(object):
""" this represents an executing Command object. it is returned as the
result of __call__() being executed on a Command instance. this creates a
reference to a OProc instance, which is a low-level wrapper around the
process that was exec'd
this is the class that gets manipulated the most by user code, and so it
implements various convenience methods and logical mechanisms for the
underlying process. for example, if a user tries to access a
backgrounded-process's stdout/err, the RunningCommand object is smart enough
to know to wait() on the process to finish first. and when the process
finishes, RunningCommand is smart enough to translate exit codes to
exceptions. """
def __init__(self, cmd, call_args, stdin, stdout, stderr):
# self.ran is used for auditing what actually ran. for example, in
# exceptions, or if you just want to know what was ran after the
# command ran
if IS_PY3:
self.ran = " ".join([arg.decode(DEFAULT_ENCODING, "ignore") for arg in cmd])
self.ran = " ".join(cmd)
friendly_cmd = friendly_truncate(self.ran, 20)
friendly_call_args = friendly_truncate(str(call_args), 20)
# we're setting up the logger string here, instead of __repr__ because
# we reserve __repr__ to behave as if it was evaluating the child
# process's output
logger_str = "<Command %r call_args %s>" % (friendly_cmd,
self.log = Logger("command", logger_str)
self.call_args = call_args
self.cmd = cmd
self.process = None
self._process_completed = False
should_wait = True
spawn_process = True
# with contexts shouldn't run at all yet, they prepend
# to every command in the context
if call_args["with"]:
spawn_process = False
if call_args["piped"] or call_args["iter"] or call_args["iter_noblock"]:
should_wait = False
# we're running in the background, return self and let us lazily
# evaluate
if call_args["bg"]:
should_wait = False
# redirection
if call_args["err_to_out"]:
stderr = OProc.STDOUT
# set up which stream should write to the pipe
# TODO, make pipe None by default and limit the size of the Queue
# in oproc.OProc
pipe = OProc.STDOUT
if call_args["iter"] == "out" or call_args["iter"] is True:
pipe = OProc.STDOUT
elif call_args["iter"] == "err":
pipe = OProc.STDERR
if call_args["iter_noblock"] == "out" or call_args["iter_noblock"] is True:
pipe = OProc.STDOUT
elif call_args["iter_noblock"] == "err":
pipe = OProc.STDERR
# there's currently only one case where we wouldn't spawn a child
# process, and that's if we're using a with-context with our command
if spawn_process:"starting process")
self.process = OProc(self.log, cmd, stdin, stdout, stderr,
self.call_args, pipe)
if should_wait:
def wait(self):
if not self._process_completed:
self._process_completed = True
exit_code = self.process.wait()
if self.process.timed_out:
# if we timed out, our exit code represents a signal, which is
# negative, so let's make it positive to store in our
# TimeoutException
raise TimeoutException(-exit_code)
if self.call_args["done"]:
return self
def handle_command_exit_code(self, code):
""" here we determine if we had an exception, or an error code that we
weren't expecting to see. if we did, we create and raise an exception
if (code not in self.call_args["ok_code"] and (code > 0 or -code in
exc = get_rc_exc(code)
raise exc(self.ran, self.process.stdout, self.process.stderr)
def stdout(self):
return self.process.stdout
def stderr(self):
return self.process.stderr
def exit_code(self):
return self.process.exit_code
def pid(self):
def __len__(self):
return len(str(self))
def __enter__(self):
""" we don't actually do anything here because anything that should have
been done would have been done in the Command.__call__ call.
essentially all that has to happen is the comand be pushed on the
prepend stack. """
def __iter__(self):
return self
def next(self):
""" allow us to iterate over the output of our command """
# we do this because if get blocks, we can't catch a KeyboardInterrupt
# so the slight timeout allows for that.
while True:
chunk = self.process._pipe_queue.get(True, 0.001)
except Empty:
if self.call_args["iter_noblock"]:
return errno.EWOULDBLOCK
if chunk is None:
raise StopIteration()
return chunk.decode(self.call_args["encoding"],
except UnicodeDecodeError:
return chunk
# python 3
__next__ = next
def __exit__(self, typ, value, traceback):
if self.call_args["with"] and Command._prepend_stack:
def __str__(self):
""" in python3, should return unicode. in python2, should return a
string of bytes """
if IS_PY3:
return self.__unicode__()
return unicode(self).encode(self.call_args["encoding"])
def __unicode__(self):
""" a magic method defined for python2. calling unicode() on a
RunningCommand object will call this """
if self.process and self.stdout:
return self.stdout.decode(self.call_args["encoding"],
elif IS_PY3:
return ""
return unicode("")
def __eq__(self, other):
return unicode(self) == unicode(other)
__hash__ = None # Avoid DeprecationWarning in Python < 3
def __contains__(self, item):
return item in str(self)
def __getattr__(self, p):
# let these three attributes pass through to the OProc object
if p in ("signal", "terminate", "kill"):
if self.process:
return getattr(self.process, p)
raise AttributeError
# see if strings have what we're looking for. we're looking at the
# method names explicitly because we don't want to evaluate self unless
# we absolutely have to, the reason being, in python2, hasattr swallows
# exceptions, and if we try to run hasattr on a command that failed and
# is being run with _iter=True, the command will be evaluated, throw an
# exception, but hasattr will discard it
if p in _unicode_methods:
return getattr(unicode(self), p)
raise AttributeError
def __repr__(self):
""" in python3, should return unicode. in python2, should return a
string of bytes """
return str(self)
except UnicodeDecodeError:
if self.process:
if self.stdout:
return repr(self.stdout)
return repr("")
def __long__(self):
return long(str(self).strip())
def __float__(self):
return float(str(self).strip())
def __int__(self):
return int(str(self).strip())
def output_redirect_is_filename(out):
return out \
and not callable(out) \
and not hasattr(out, "write") \
and not isinstance(out, (cStringIO, StringIO))
class Command(object):
""" represents an un-run system program, like "ls" or "cd". because it
represents the program itself (and not a running instance of it), it should
hold very little state. in fact, the only state it does hold is baked
when a Command object is called, the result that is returned is a
RunningCommand object, which represents the Command put into an execution
state. """
_prepend_stack = []
_call_args = {
# currently unsupported
#"fg": False, # run command in foreground
# run a command in the background. commands run in the background
# ignore SIGHUP and do not automatically exit when the parent process
# ends
"bg": False,
"with": False, # prepend the command to every command after it
"in": None,
"out": None, # redirect STDOUT
"err": None, # redirect STDERR
"err_to_out": None, # redirect STDERR to STDOUT
# stdin buffer size
# 1 for line, 0 for unbuffered, any other number for that amount
"in_bufsize": 0,
# stdout buffer size, same values as above
"out_bufsize": 1,
"err_bufsize": 1,
# this is how big the output buffers will be for stdout and stderr.
# this is essentially how much output they will store from the process.
# we use a deque, so if it overflows past this amount, the first items
# get pushed off as each new item gets added.
# this is not a *BYTE* size, this is a *CHUNK* size...meaning, that if
# you're buffering out/err at 1024 bytes, the internal buffer size will
# be "internal_bufsize" CHUNKS of 1024 bytes
"internal_bufsize": 3 * 1024 ** 2,
"env": None,
"piped": None,
"iter": None,
"iter_noblock": None,
"ok_code": 0,
"cwd": None,
# the separator delimiting between a long-argument's name and its value
# for example, --arg=derp, '=' is the long_sep
"long_sep": "=",
# this is for programs that expect their input to be from a terminal.
# ssh is one of those programs
"tty_in": False,
"tty_out": True,
"decode_errors": "strict",
# how long the process should run before it is auto-killed
"timeout": 0,
"timeout_signal": signal.SIGKILL,
# TODO write some docs on "long-running processes"
# these control whether or not stdout/err will get aggregated together
# as the process runs. this has memory usage implications, so sometimes
# with long-running processes with a lot of data, it makes sense to
# set these to true
"no_out": False,
"no_err": False,
"no_pipe": False,
# if any redirection is used for stdout or stderr, internal buffering
# of that data is not stored. this forces it to be stored, as if
# the output is being T'd to both the redirected destination and our
# internal buffers
"tee": None,
# will be called when a process terminates without exception. this
# option also puts the command in the background, since it doesn't make
# sense to have an un-backgrounded command with a done callback
"done": None,
# a tuple (rows, columns) of the desired size of both the stdout and
# stdin ttys, if ttys are being used
"tty_size": (20, 80),
# these are arguments that cannot be called together, because they wouldn't
# make any sense
_incompatible_call_args = (
#("fg", "bg", "Command can't be run in the foreground and background"),
("err", "err_to_out", "Stderr is already being redirected"),
("piped", "iter", "You cannot iterate when this command is being piped"),
("piped", "no_pipe", "Using a pipe doesn't make sense if you've \
disabled the pipe"),
("no_out", "iter", "You cannot iterate over output if there is no \
# this method exists because of the need to have some way of letting
# manual object instantiation not perform the underscore-to-dash command
# conversion that resolve_program uses.
# there are 2 ways to create a Command object. using sh.Command(<program>)
# or by using sh.<program>. the method fed into sh.Command must be taken
# literally, and so no underscore-dash conversion is performed. the one
# for sh.<program> must do the underscore-dash converesion, because we
# can't type dashes in method names
def _create(cls, program, **default_kwargs):
path = resolve_program(program)
if not path:
raise CommandNotFound(program)
cmd = cls(path)
if default_kwargs:
cmd = cmd.bake(**default_kwargs)
return cmd
def __init__(self, path):
found = which(path)
if not found:
raise CommandNotFound(path)
self._path = encode_to_py3bytes_or_py2str(found)
self._partial = False
self._partial_baked_args = []
self._partial_call_args = {}
# bugfix for functools.wraps. issue #121
self.__name__ = str(self)
def __getattribute__(self, name):
# convenience
getattr = partial(object.__getattribute__, self)
if name.startswith("_"):
return getattr(name)
if name == "bake":
return getattr("bake")
if name.endswith("_"):
name = name[:-1]
return getattr("bake")(name)
def _extract_call_args(kwargs, to_override={}):
kwargs = kwargs.copy()
call_args = {}
for parg, default in Command._call_args.items():
key = "_" + parg
if key in kwargs:
call_args[parg] = kwargs[key]
del kwargs[key]
elif parg in to_override:
call_args[parg] = to_override[parg]
# test for incompatible call args
s1 = set(call_args.keys())
for args in Command._incompatible_call_args:
args = list(args)
error = args.pop()
if s1.issuperset(args):
raise TypeError("Invalid special arguments %r: %s" % (args, error))
return call_args, kwargs
def _aggregate_keywords(self, keywords, sep, raw=False):
processed = []
for k, v in keywords.items():
# we're passing a short arg as a kwarg, example:
# cut(d="\t")
if len(k) == 1:
if v is not False:
processed.append(encode_to_py3bytes_or_py2str("-" + k))
if v is not True:
# we're doing a long arg
if not raw:
k = k.replace("_", "-")
if v is True:
processed.append(encode_to_py3bytes_or_py2str("--" + k))
elif v is False:
arg = encode_to_py3bytes_or_py2str("--%s%s%s" % (k, sep, v))
return processed
def _compile_args(self, args, kwargs, sep):
processed_args = []
# aggregate positional args
for arg in args:
if isinstance(arg, (list, tuple)):
if not arg:
warnings.warn("Empty list passed as an argument to %r. \
If you're using glob.glob(), please use sh.glob() instead." % self._path, stacklevel=3)
for sub_arg in arg:
elif isinstance(arg, dict):
processed_args += self._aggregate_keywords(arg, sep, raw=True)
# aggregate the keyword arguments
processed_args += self._aggregate_keywords(kwargs, sep)
return processed_args
# TODO needs documentation
def bake(self, *args, **kwargs):
fn = Command(self._path)
fn._partial = True
call_args, kwargs = self._extract_call_args(kwargs)
pruned_call_args = call_args
for k, v in Command._call_args.items():
if pruned_call_args[k] == v:
del pruned_call_args[k]
except KeyError:
sep = pruned_call_args.get("long_sep", self._call_args["long_sep"])
fn._partial_baked_args.extend(self._compile_args(args, kwargs, sep))
return fn
def __str__(self):
""" in python3, should return unicode. in python2, should return a
string of bytes """
if IS_PY3:
return self.__unicode__()
return self.__unicode__().encode(DEFAULT_ENCODING)
def __eq__(self, other):
return str(self) == str(other)
return False
__hash__ = None # Avoid DeprecationWarning in Python < 3
def __repr__(self):
""" in python3, should return unicode. in python2, should return a
string of bytes """
return "<Command %r>" % str(self)
def __unicode__(self):
""" a magic method defined for python2. calling unicode() on a
self will call this """
baked_args = " ".join(item.decode(DEFAULT_ENCODING) for item in self._partial_baked_args)
if baked_args:
baked_args = " " + baked_args
return self._path.decode(DEFAULT_ENCODING) + baked_args
def __enter__(self):
def __exit__(self, typ, value, traceback):
def __call__(self, *args, **kwargs):
kwargs = kwargs.copy()
args = list(args)
cmd = []
# aggregate any 'with' contexts
call_args = Command._call_args.copy()
for prepend in self._prepend_stack:
# don't pass the 'with' call arg
pcall_args = prepend.call_args.copy()
del pcall_args["with"]
# here we extract the special kwargs and override any
# special kwargs from the possibly baked command
tmp_call_args, kwargs = self._extract_call_args(kwargs, self._partial_call_args)
if not getattr(call_args["ok_code"], "__iter__", None):
call_args["ok_code"] = [call_args["ok_code"]]
if call_args["done"]:
call_args["bg"] = True
# check if we're piping via composition
stdin = call_args["in"]
if args:
first_arg = args.pop(0)
if isinstance(first_arg, RunningCommand):
# it makes sense that if the input pipe of a command is running
# in the background, then this command should run in the
# background as well
if first_arg.call_args["bg"]:
call_args["bg"] = True
if first_arg.call_args["piped"] == "direct":
stdin = first_arg.process
stdin = first_arg.process._pipe_queue
args.insert(0, first_arg)
processed_args = self._compile_args(args, kwargs, call_args["long_sep"])
# makes sure our arguments are broken up correctly
split_args = self._partial_baked_args + processed_args
final_args = split_args
# stdout redirection
stdout = call_args["out"]
if output_redirect_is_filename(stdout):
stdout = open(str(stdout), "wb")
# stderr redirection
stderr = call_args["err"]
if output_redirect_is_filename(stderr):
stderr = open(str(stderr), "wb")
return RunningCommand(cmd, call_args, stdin, stdout, stderr)
def _start_daemon_thread(fn, *args):
thrd = threading.Thread(target=fn, args=args)
thrd.daemon = True
return thrd
def setwinsize(fd, rows_cols):
""" set the terminal size of a tty file descriptor. borrowed logic
from """
rows, cols = rows_cols
TIOCSWINSZ = getattr(termios, 'TIOCSWINSZ', -2146929561)
s = struct.pack('HHHH', rows, cols, 0, 0)
fcntl.ioctl(fd, TIOCSWINSZ, s)
def construct_streamreader_callback(process, handler):
""" here we're constructing a closure for our streamreader callback. this
is used in the case that we pass a callback into _out or _err, meaning we
want to our callback to handle each bit of output
we construct the closure based on how many arguments it takes. the reason
for this is to make it as easy as possible for people to use, without
limiting them. a new user will assume the callback takes 1 argument (the
data). as they get more advanced, they may want to terminate the process,
or pass some stdin back, and will realize that they can pass a callback of
more args """
# implied arg refers to the "self" that methods will pass in. we need to
# account for this implied arg when figuring out what function the user
# passed in based on number of args
implied_arg = 0
partial_args = 0
handler_to_inspect = handler
if isinstance(handler, partial):
partial_args = len(handler.args)
handler_to_inspect = handler.func
if inspect.ismethod(handler_to_inspect):
implied_arg = 1
num_args = len(inspect.getargspec(handler_to_inspect).args)
if inspect.isfunction(handler_to_inspect):
num_args = len(inspect.getargspec(handler_to_inspect).args)
# is an object instance with __call__ method
implied_arg = 1
num_args = len(inspect.getargspec(handler_to_inspect.__call__).args)
net_args = num_args - implied_arg - partial_args
handler_args = ()
# just the chunk
if net_args == 1:
handler_args = ()
# chunk, stdin
if net_args == 2:
handler_args = (process.stdin,)
# chunk, stdin, process
elif net_args == 3:
# notice we're only storing a weakref, to prevent cyclic references
# (where the process holds a streamreader, and a streamreader holds a
# handler-closure with a reference to the process
handler_args = (process.stdin, weakref.ref(process))
def fn(chunk):
# this is pretty ugly, but we're evaluating the process at call-time,
# because it's a weakref
args = handler_args
if len(args) == 2:
args = (handler_args[0], handler_args[1]())
return handler(chunk, *args)
return fn
def handle_process_exit_code(exit_code):
""" this should only ever be called once for each child process """
# if we exited from a signal, let our exit code reflect that
if os.WIFSIGNALED(exit_code):
return -os.WTERMSIG(exit_code)
# otherwise just give us a normal exit code
elif os.WIFEXITED(exit_code):
return os.WEXITSTATUS(exit_code)
raise RuntimeError("Unknown child exit status!")
class OProc(object):
""" this class is instantiated by RunningCommand for a command to be exec'd.
it handles all the nasty business involved with correctly setting up the
input/output to the child process. it gets its name for subprocess.Popen
(process open) but we're calling ours OProc (open process) """
_default_window_size = (24, 80)
# used in redirecting
def __init__(self, parent_log, cmd, stdin, stdout, stderr, call_args, pipe):
cmd is the full string that will be exec'd. it includes the program
name and all its arguments
stdin, stdout, stderr are what the child will use for standard
call_args is a mapping of all the special keyword arguments to apply
to the child process
self.call_args = call_args
# I had issues with getting 'Input/Output error reading stdin' from dd,
# until I set _tty_out=False
if self.call_args["piped"] == "direct":
self.call_args["tty_out"] = False
self._single_tty = self.call_args["tty_in"] and self.call_args["tty_out"]
# this logic is a little convoluted, but basically this top-level
# if/else is for consolidating input and output TTYs into a single
# TTY. this is the only way some secure programs like ssh will
# output correctly (is if stdout and stdin are both the same TTY)
if self._single_tty:
self._stdin_fd, self._slave_stdin_fd = pty.openpty()
self._stdout_fd = self._stdin_fd
self._slave_stdout_fd = self._slave_stdin_fd
self._stderr_fd = self._stdin_fd
self._slave_stderr_fd = self._slave_stdin_fd
# do not consolidate stdin and stdout. this is the most common use-
# case
# this check here is because we may be doing "direct" piping
# (_piped="direct"), and so our stdin might be an instance of
# OProc
if isinstance(stdin, OProc):
self._slave_stdin_fd = stdin._stdout_fd
self._stdin_fd = None
elif self.call_args["tty_in"]:
self._slave_stdin_fd, self._stdin_fd = pty.openpty()
# tty_in=False is the default
self._slave_stdin_fd, self._stdin_fd = os.pipe()
# tty_out=True is the default
if self.call_args["tty_out"]:
self._stdout_fd, self._slave_stdout_fd = pty.openpty()
self._stdout_fd, self._slave_stdout_fd = os.pipe()
# unless STDERR is going to STDOUT, it ALWAYS needs to be a pipe,
# and never a PTY. the reason for this is not totally clear to me,
# but it has to do with the fact that if STDERR isn't set as the
# CTTY (because STDOUT is), the STDERR buffer won't always flush
# by the time the process exits, and the data will be lost.
# i've only seen this on OSX.
if stderr is not OProc.STDOUT:
self._stderr_fd, self._slave_stderr_fd = os.pipe()
# this is a hack, but what we're doing here is intentionally throwing an
# OSError exception if our child processes's directory doesn't exist,
# but we're doing it BEFORE we fork. the reason for before the fork is
# error handling. i'm currently too lazy to implement what
# did and set up a error pipe to handle exceptions that
# happen in the child between fork and exec. it has only been seen in
# the wild for a missing cwd, so we'll handle it here.
cwd = self.call_args["cwd"]
if cwd is not None and not os.path.exists(cwd):
gc_enabled = gc.isenabled()
if gc_enabled:
gc.disable() = os.fork()
# child
if == 0: # pragma: no cover
# ignoring SIGHUP lets us persist even after the parent process
# exits. only ignore if we're backgrounded
if self.call_args["bg"] is True:
signal.signal(signal.SIGHUP, signal.SIG_IGN)
# this piece of ugliness is due to a bug where we can lose output
# if we do os.close(self._slave_stdout_fd) in the parent after
# the child starts writing.
# see
if IS_OSX:
if self.call_args["tty_out"]:
# set raw mode, so there isn't any weird translation of
# newlines to \r\n and other oddities. we're not outputting
# to a terminal anyways
# we HAVE to do this here, and not in the parent process,
# because we have to guarantee that this is set before the
# child process is run, and we can't do it twice.
# if the parent-side fd for stdin exists, close it. the case
# where it may not exist is if we're using piped="direct"
if self._stdin_fd:
if not self._single_tty:
if stderr is not OProc.STDOUT:
if cwd:
os.dup2(self._slave_stdin_fd, 0)
os.dup2(self._slave_stdout_fd, 1)
# we're not directing stderr to stdout? then set self._slave_stderr_fd to
# fd 2, the common stderr fd
if stderr is OProc.STDOUT:
os.dup2(self._slave_stdout_fd, 2)
os.dup2(self._slave_stderr_fd, 2)
# don't inherit file descriptors
max_fd = resource.getrlimit(resource.RLIMIT_NOFILE)[0]
os.closerange(3, max_fd)
# set our controlling terminal. tty_out defaults to true
if self.call_args["tty_out"]:
tmp_fd =, os.O_RDWR)
if self.call_args["tty_out"]:
setwinsize(1, self.call_args["tty_size"])
# actually execute the process
if self.call_args["env"] is None:
os.execv(cmd[0], cmd)
os.execve(cmd[0], cmd, self.call_args["env"])
# we must ensure that we ALWAYS exit the child process, otherwise
# the parent process code will be executed twice on exception
# if your parent process experiences an exit code 255, it is most
# likely that an exception occurred between the fork of the child
# and the exec. this should be reported.
# parent
if gc_enabled:
# used to determine what exception to raise. if our process was
# killed via a timeout counter, we'll raise something different than
# a SIGKILL exception
self.timed_out = False
self.started = time.time()
self.cmd = cmd
# exit code should only be manipulated from within self._wait_lock
# to prevent race conditions
self.exit_code = None
self.stdin = stdin or Queue()
# _pipe_queue is used internally to hand off stdout from one process
# to another. by default, all stdout from a process gets dumped
# into this pipe queue, to be consumed in real time (hence the
# thread-safe Queue), or at a potentially later time
self._pipe_queue = Queue()
# this is used to prevent a race condition when we're waiting for
# a process to end, and the OProc's internal threads are also checking
# for the processes's end
self._wait_lock = threading.Lock()
# these are for aggregating the stdout and stderr. we use a deque
# because we don't want to overflow
self._stdout = deque(maxlen=self.call_args["internal_bufsize"])
self._stderr = deque(maxlen=self.call_args["internal_bufsize"])
if self.call_args["tty_in"]:
setwinsize(self._stdin_fd, self.call_args["tty_size"])
self.log = parent_log.get_child("process", repr(self))
if not self._single_tty:
if stderr is not OProc.STDOUT:
self.log.debug("started process")
if self.call_args["tty_in"]:
attr = termios.tcgetattr(self._stdin_fd)
attr[3] &= ~termios.ECHO
termios.tcsetattr(self._stdin_fd, termios.TCSANOW, attr)
# this represents the connection from a Queue object (or whatever
# we're using to feed STDIN) to the process's STDIN fd
self._stdin_stream = None
if not isinstance(self.stdin, OProc):
self._stdin_stream = \
"stdin"), self._stdin_fd, self.stdin,
stdout_pipe = None
if pipe is OProc.STDOUT and not self.call_args["no_pipe"]:
stdout_pipe = self._pipe_queue
# this represents the connection from a process's STDOUT fd to
# wherever it has to go, sometimes a pipe Queue (that we will use
# to pipe data to other processes), and also an internal deque
# that we use to aggregate all the output
save_stdout = not self.call_args["no_out"] and \
(self.call_args["tee"] in (True, "out") or stdout is None)
# if we're piping directly into another process's filedescriptor, we
# bypass reading from the stdout stream altogether, because we've
# already hooked up this processes's stdout fd to the other
# processes's stdin fd
self._stdout_stream = None
if self.call_args["piped"] != "direct":
if callable(stdout):
stdout = construct_streamreader_callback(self, stdout)
self._stdout_stream = \
"stdout"), self._stdout_fd, stdout, self._stdout,
self.call_args["decode_errors"], stdout_pipe,
if stderr is OProc.STDOUT or self._single_tty:
self._stderr_stream = None
stderr_pipe = None
if pipe is OProc.STDERR and not self.call_args["no_pipe"]:
stderr_pipe = self._pipe_queue
save_stderr = not self.call_args["no_err"] and \
(self.call_args["tee"] in ("err",) or stderr is None)
if callable(stderr):
stderr = construct_streamreader_callback(self, stderr)
self._stderr_stream = StreamReader(Logger("streamreader"),
self._stderr_fd, stderr, self._stderr,
self.call_args["err_bufsize"], self.call_args["encoding"],
self.call_args["decode_errors"], stderr_pipe,
# start the main io threads
# stdin thread is not needed if we are connecting from another process's stdout pipe
self._input_thread = None
if self._stdin_stream:
self._input_thread = _start_daemon_thread(self.input_thread,
self._output_thread = _start_daemon_thread(self.output_thread,
self._stdout_stream, self._stderr_stream,
self.call_args["timeout"], self.started,
def __repr__(self):
return "<Process %d %r>" % (, self.cmd[:500])
def change_in_bufsize(self, buf):
def change_out_bufsize(self, buf):
def change_err_bufsize(self, buf):
def input_thread(self, stdin):
""" this is run in a separate thread. it writes into our process's
stdin (a streamwriter) and waits the process to end AND everything that
can be written to be written """
done = False
while not done and self.is_alive():
self.log.debug("%r ready for more input", stdin)
done = stdin.write()
def output_thread(self, stdout, stderr, timeout, started, timeout_exc):
""" this function is run in a separate thread. it reads from the
process's stdout stream (a streamreader), and waits for it to claim that
its done """
readers = []
errors = []
if stdout is not None:
if stderr is not None:
# this is our select loop for polling stdout or stderr that is ready to
# be read and processed. if one of those streamreaders indicate that it
# is done altogether being read from, we remove it from our list of
# things to poll. when no more things are left to poll, we leave this
# loop and clean up
while readers:
outputs, inputs, err =, [], errors, 0.1)
# stdout and stderr
for stream in outputs:
self.log.debug("%r ready to be read from", stream)
done =
if done:
for stream in err:
# test if the process has been running too long
if timeout:
now = time.time()
if now - started > timeout:
self.log.debug("we've been running too long")
self.timed_out = True
# this is here because stdout may be the controlling TTY, and
# we can't close it until the process has ended, otherwise the
# child will get SIGHUP. typically, if we've broken out of
# the above loop, and we're here, the process is just about to
# end, so it's probably ok to aggressively poll self.is_alive()
# the other option to this would be to do the CTTY close from
# the method that does the actual os.waitpid() call, but the
# problem with that is that the above loop might still be
# running, and closing the fd will cause some operation to
# fail. this is less complex than wrapping all the ops
# in the above loop with out-of-band fd-close exceptions
while self.is_alive():
if stdout:
if stderr:
def stdout(self):
return "".encode(self.call_args["encoding"]).join(self._stdout)
def stderr(self):
return "".encode(self.call_args["encoding"]).join(self._stderr)
def signal(self, sig):
self.log.debug("sending signal %d", sig)
os.kill(, sig)
except OSError:
def kill(self):
def terminate(self):
def is_alive(self):
""" polls if our child process has completed, without blocking. this
method has side-effects, such as setting our exit_code, if we happen to
see our child exit while this is running """
if self.exit_code is not None:
return False
# what we're doing here essentially is making sure that the main thread
# (or another thread), isn't calling .wait() on the process. because
# .wait() calls os.waitpid(, 0), we can't do an os.waitpid
# here...because if we did, and the process exited while in this
# thread, the main thread's os.waitpid(, 0) would raise OSError
# (because the process ended in another thread).
# so essentially what we're doing is, using this lock, checking if
# we're calling .wait(), and if we are, let .wait() get the exit code
# and handle the status, otherwise let us do it.
acquired = self._wait_lock.acquire(False)
if not acquired:
if self.exit_code is not None:
return False
return True
# WNOHANG is just that...we're calling waitpid without hanging...
# essentially polling the process. the return result is (0, 0) if
# there's no process status, so we check that pid == below
# in order to determine how to proceed
pid, exit_code = os.waitpid(, os.WNOHANG)
if pid ==
self.exit_code = handle_process_exit_code(exit_code)
return False
# no child process
except OSError:
return False
return True
def wait(self):
""" waits for the process to complete, handles the exit code """
self.log.debug("acquiring wait lock to wait for completion")
# using the lock in a with-context blocks, which is what we want if
# we're running wait()
with self._wait_lock:
self.log.debug("got wait lock")
if self.exit_code is None:
self.log.debug("exit code not set, waiting on pid")
pid, exit_code = os.waitpid(, 0) # blocks
self.exit_code = handle_process_exit_code(exit_code)
self.log.debug("exit code already set (%d), no need to wait", self.exit_code)
# we may not have a thread for stdin, if the pipe has been connected
# via _piped="direct"
if self._input_thread:
# wait for our stdout and stderr streamreaders to finish reading and
# aggregating the process output
return self.exit_code
class DoneReadingForever(Exception): pass
class NotYetReadyToRead(Exception): pass
def determine_how_to_read_input(input_obj):
""" given some kind of input object, return a function that knows how to
read chunks of that input object.
each reader function should return a chunk and raise a DoneReadingForever
exception, or return None, when there's no more data to read
NOTE: the function returned does not need to care much about the requested
buffering type (eg, unbuffered vs newline-buffered). the StreamBufferer
will take care of that. these functions just need to return a
reasonably-sized chunk of data. """
get_chunk = None
if isinstance(input_obj, Queue):
log_msg = "queue"
get_chunk = get_queue_chunk_reader(input_obj)
elif callable(input_obj):
log_msg = "callable"
get_chunk = get_callable_chunk_reader(input_obj)
# also handles stringio
elif hasattr(input_obj, "read"):
log_msg = "file descriptor"
get_chunk = get_file_chunk_reader(input_obj)
elif isinstance(input_obj, basestring):
log_msg = "string"
get_chunk = get_iter_string_reader(input_obj)
log_msg = "general iterable"
get_chunk = get_iter_chunk_reader(iter(input_obj))
return get_chunk, log_msg
def get_queue_chunk_reader(stdin):
def fn():
chunk = stdin.get(True, 0.01)
except Empty:
raise NotYetReadyToRead
if chunk is None:
raise DoneReadingForever
return chunk
return fn
def get_callable_chunk_reader(stdin):
def fn():
return stdin()
raise DoneReadingForever
return fn
def get_iter_string_reader(stdin):
""" return an iterator that returns a chunk of a string every time it is
called. notice that even though bufsize_type might be line buffered, we're
not doing any line buffering here. that's because our StreamBufferer
handles all buffering. we just need to return a reasonable-sized chunk. """
bufsize = 1024
iter_str = (stdin[i:i + bufsize] for i in range(0, len(stdin), bufsize))
return get_iter_chunk_reader(iter_str)
def get_iter_chunk_reader(stdin):
def fn():
if IS_PY3:
chunk = stdin.__next__()
chunk =
return chunk
except StopIteration:
raise DoneReadingForever
return fn
def get_file_chunk_reader(stdin):
bufsize = 1024
def fn():
chunk =
if not chunk:
raise DoneReadingForever
return chunk
return fn
def bufsize_type_to_bufsize(bf_type):
""" for a given bufsize type, return the actual bufsize we will read.
notice that although 1 means "newline-buffered", we're reading a chunk size
of 1024. this is because we have to read something. we let a
StreamBufferer instance handle splitting our chunk on newlines """
# newlines
if bf_type == 1:
bufsize = 1024
# unbuffered
elif bf_type == 0:
bufsize = 1
# or buffered by specific amount
bufsize = bf_type
return bufsize
class StreamWriter(object):
""" StreamWriter reads from some input (the stdin param) and writes to a fd
(the stream param). the stdin may be a Queue, a callable, something with
the "read" method, a string, or an iterable """
def __init__(self, log, stream, stdin, bufsize_type, encoding, tty_in): = stream
self.stdin = stdin
self.log = log
self.encoding = encoding
self.tty_in = tty_in
self.stream_bufferer = StreamBufferer(bufsize_type, self.encoding)
self.get_chunk, log_msg = determine_how_to_read_input(stdin)
self.log.debug("parsed stdin as a %s", log_msg)
def fileno(self):
""" defining this allows us to do on an instance of this
class """
def write(self):
""" attempt to get a chunk of data to write to our child process's
stdin, then write it. the return value answers the questions "are we
done writing forever?" """
# get_chunk may sometimes return bytes, and sometimes returns trings
# because of the nature of the different types of STDIN objects we
# support
chunk = self.get_chunk()
if chunk is None:
raise DoneReadingForever
except DoneReadingForever:
self.log.debug("done reading")
if self.tty_in:
# EOF time
char = termios.tcgetattr([6][termios.VEOF]
char = chr(4).encode()
os.write(, char)
return True
except NotYetReadyToRead:
self.log.debug("received no data")
return False
# if we're not bytes, make us bytes
if IS_PY3 and hasattr(chunk, "encode"):
chunk = chunk.encode(self.encoding)
for proc_chunk in self.stream_bufferer.process(chunk):
self.log.debug("got chunk size %d: %r", len(proc_chunk),
self.log.debug("writing chunk to process")
os.write(, proc_chunk)
except OSError:
self.log.debug("OSError writing stdin chunk")
return True
def close(self):
self.log.debug("closing, but flushing first")
chunk = self.stream_bufferer.flush()
self.log.debug("got chunk size %d to flush: %r", len(chunk), chunk[:30])
if chunk:
os.write(, chunk)
if not self.tty_in:
self.log.debug("we used a TTY, so closing the stream")
except OSError:
def determine_how_to_feed_output(handler, encoding, decode_errors):
if callable(handler):
process, finish = get_callback_chunk_consumer(handler, encoding,
elif isinstance(handler, cStringIO):
process, finish = get_cstringio_chunk_consumer(handler)
elif isinstance(handler, StringIO):
process, finish = get_stringio_chunk_consumer(handler, encoding,
elif hasattr(handler, "write"):
process, finish = get_file_chunk_consumer(handler)
process = lambda chunk: False
finish = lambda: None
return process, finish
def get_file_chunk_consumer(handler):
def process(chunk):
# we should flush on an fd. chunk is already the correctly-buffered
# size, so we don't need the fd buffering as well
return False
def finish():
if hasattr(handler, "flush"):
return process, finish
def get_callback_chunk_consumer(handler, encoding, decode_errors):
def process(chunk):
# try to use the encoding first, if that doesn't work, send
# the bytes, because it might be binary
chunk = chunk.decode(encoding, decode_errors)
except UnicodeDecodeError:
return handler(chunk)
def finish():
return process, finish
def get_cstringio_chunk_consumer(handler):
def process(chunk):
return False
def finish():
return process, finish
def get_stringio_chunk_consumer(handler, encoding, decode_errors):
def process(chunk):
handler.write(chunk.decode(encoding, decode_errors))
return False
def finish():
return process, finish
class StreamReader(object):
""" reads from some output (the stream) and sends what it just read to the
handler. """
def __init__(self, log, stream, handler, buffer, bufsize_type, encoding,
decode_errors, pipe_queue=None, save_data=True): = stream
self.buffer = buffer
self.save_data = save_data
self.encoding = encoding
self.decode_errors = decode_errors
self.pipe_queue = None
if pipe_queue:
self.pipe_queue = weakref.ref(pipe_queue)
self.log = log
self.stream_bufferer = StreamBufferer(bufsize_type, self.encoding,
self.bufsize = bufsize_type_to_bufsize(bufsize_type)
self.process_chunk, self.finish_chunk_processor = \
determine_how_to_feed_output(handler, encoding, decode_errors)
self.should_quit = False
def fileno(self):
""" defining this allows us to do on an instance of this
class """
def close(self):
chunk = self.stream_bufferer.flush()
self.log.debug("got chunk size %d to flush: %r", len(chunk), chunk[:30])
if chunk:
if self.pipe_queue and self.save_data:
except OSError:
def write_chunk(self, chunk):
# in PY3, the chunk coming in will be bytes, so keep that in mind
if not self.should_quit:
self.should_quit = self.process_chunk(chunk)
if self.save_data:
if self.pipe_queue:
self.log.debug("putting chunk onto pipe: %r", chunk[:30])
def read(self):
# if we're PY3, we're reading bytes, otherwise we're reading
# str
chunk =, self.bufsize)
except OSError as e:
self.log.debug("got errno %d, done reading", e.errno)
return True
if not chunk:
self.log.debug("got no chunk, done reading")
return True
self.log.debug("got chunk size %d: %r", len(chunk), chunk[:30])
for chunk in self.stream_bufferer.process(chunk):
class StreamBufferer(object):
""" this is used for feeding in chunks of stdout/stderr, and breaking it up
into chunks that will actually be put into the internal buffers. for
example, if you have two processes, one being piped to the other, and you
want that, first process to feed lines of data (instead of the chunks
however they come in), OProc will use an instance of this class to chop up
the data and feed it as lines to be sent down the pipe """
def __init__(self, buffer_type, encoding=DEFAULT_ENCODING,
# 0 for unbuffered, 1 for line, everything else for that amount
self.type = buffer_type
self.buffer = []
self.n_buffer_count = 0
self.encoding = encoding
self.decode_errors = decode_errors
# this is for if we change buffering types. if we change from line
# buffered to unbuffered, its very possible that our self.buffer list
# has data that was being saved up (while we searched for a newline).
# we need to use that up, so we don't lose it
self._use_up_buffer_first = False
# the buffering lock is used because we might chance the buffering
# types from a different thread. for example, if we have a stdout
# callback, we might use it to change the way stdin buffers. so we
# lock
self._buffering_lock = threading.RLock()
self.log = Logger("stream_bufferer")
def change_buffering(self, new_type):
# TODO, when we stop supporting 2.6, make this a with context
self.log.debug("acquiring buffering lock for changing buffering")
self.log.debug("got buffering lock for changing buffering")
if new_type == 0:
self._use_up_buffer_first = True
self.type = new_type
self.log.debug("released buffering lock for changing buffering")
def process(self, chunk):
# TODO, when we stop supporting 2.6, make this a with context
self.log.debug("acquiring buffering lock to process chunk (buffering: %d)", self.type)
self.log.debug("got buffering lock to process chunk (buffering: %d)", self.type)
# we've encountered binary, permanently switch to N size buffering
# since matching on newline doesn't make sense anymore
if self.type == 1:
chunk.decode(self.encoding, self.decode_errors)
self.log.debug("detected binary data, changing buffering")
# unbuffered
if self.type == 0:
if self._use_up_buffer_first:
self._use_up_buffer_first = False
to_write = self.buffer
self.buffer = []
return to_write
return [chunk]
# line buffered
# we must decode the bytes before we try to match on newline
elif self.type == 1:
total_to_write = []
chunk = chunk.decode(self.encoding, self.decode_errors)
while True:
newline = chunk.find("\n")
if newline == -1:
chunk_to_write = chunk[:newline + 1]
if self.buffer:
# this is ugly, but it's designed to take the existing
# bytes buffer, join it together, tack on our latest
# chunk, then convert the whole thing to a string.
# it's necessary, i'm sure. read the whole block to
# see why.
chunk_to_write = "".encode(self.encoding).join(self.buffer) \
+ chunk_to_write.encode(self.encoding)
chunk_to_write = chunk_to_write.decode(self.encoding)
self.buffer = []
self.n_buffer_count = 0
chunk = chunk[newline + 1:]
if chunk:
self.n_buffer_count += len(chunk)
return total_to_write
# N size buffered
total_to_write = []
while True:
overage = self.n_buffer_count + len(chunk) - self.type
if overage >= 0:
ret = "".encode(self.encoding).join(self.buffer) + chunk
chunk_to_write = ret[:self.type]
chunk = ret[self.type:]
self.buffer = []
self.n_buffer_count = 0
self.n_buffer_count += len(chunk)
return total_to_write
self.log.debug("released buffering lock for processing chunk (buffering: %d)", self.type)
def flush(self):
self.log.debug("acquiring buffering lock for flushing buffer")
self.log.debug("got buffering lock for flushing buffer")
ret = "".encode(self.encoding).join(self.buffer)
self.buffer = []
return ret
self.log.debug("released buffering lock for flushing buffer")
def pushd(path):
""" pushd is just a specialized form of args, where we're passing in the
current working directory """
with args(_cwd=path):
def args(*args, **kwargs):
""" allows us to temporarily override all the special keyword parameters in
a with context """
call_args = Command._call_args
old_args = call_args.copy()
for key,value in kwargs.items():
key = key.lstrip("_")
call_args[key] = value
class Environment(dict):
""" this allows lookups to names that aren't found in the global scope to be
searched for as a program name. for example, if "ls" isn't found in this
module's scope, we consider it a system program and try to find it.
we use a dict instead of just a regular object as the base class because the
exec() statement used in this file requires the "globals" argument to be a
dictionary """
# this is a list of all of the names that the sh module exports that will
# not resolve to functions. we don't want to accidentally shadow real
# commands with functions/imports that we define in for example,
# "import time" may override the time system program
whitelist = set([
def __init__(self, globs, baked_args={}):
self.globs = globs
self.baked_args = baked_args
self.disable_whitelist = False
def __setitem__(self, k, v):
self.globs[k] = v
def __getitem__(self, k):
# if we first import "_disable_whitelist" from sh, we can import
# anything defined in the global scope of this is useful for our
# tests
if k == "_disable_whitelist":
self.disable_whitelist = True
return None
# we're trying to import something real (maybe), see if it's in our
# global scope
if k in self.whitelist or self.disable_whitelist:
return self.globs[k]
except KeyError:
# somebody tried to be funny and do "from sh import *"
if k == "__all__":
raise AttributeError("Cannot import * from sh. \
Please import sh or import programs individually.")
# check if we're naming a dynamically generated ReturnCode exception
exc = get_exc_from_name(k)
if exc:
return exc
if k.startswith("__") and k.endswith("__"):
raise AttributeError
# how about an environment variable?
return os.environ[k]
except KeyError:
# is it a custom builtin?
builtin = getattr(self, "b_" + k, None)
if builtin:
return builtin
# it must be a command then
# we use _create instead of instantiating the class directly because
# _create uses resolve_program, which will automatically do underscore-
# to-dash conversions. instantiating directly does not use that
return Command._create(k, **self.baked_args)
# methods that begin with "b_" are custom builtins and will override any
# program that exists in our path. this is useful for things like
# common shell builtins that people are used to, but which aren't actually
# full-fledged system binaries
def b_cd(self, path):
def b_which(self, program):
return which(program)
def run_repl(env): # pragma: no cover
banner = "\n>> sh v{version}\n>>\n"
while True:
line = raw_input("sh> ")
except (ValueError, EOFError):
exec(compile(line, "<dummy>", "single"), env, env)
except SystemExit:
# cleans up our last line
# this is a thin wrapper around THIS module (we patch sys.modules[__name__]).
# this is in the case that the user does a "from sh import whatever"
# in other words, they only want to import certain programs, not the whole
# system PATH worth of commands. in this case, we just proxy the
# import lookup to our Environment class
class SelfWrapper(ModuleType):
def __init__(self, self_module, baked_args={}):
# this is super ugly to have to copy attributes like this,
# but it seems to be the only way to make reload() behave
# nicely. if i make these attributes dynamic lookups in
# __getattr__, reload sometimes chokes in weird ways...
for attr in ["__builtins__", "__doc__", "__name__", "__package__"]:
setattr(self, attr, getattr(self_module, attr, None))
# python 3.2 (2.7 and 3.3 work fine) breaks on osx (not ubuntu)
# if we set this to None. and 3.3 needs a value for __path__
self.__path__ = []
self.__self_module = self_module
self.__env = Environment(globals(), baked_args)
def __setattr__(self, name, value):
if hasattr(self, "__env"):
self.__env[name] = value
ModuleType.__setattr__(self, name, value)
def __getattr__(self, name):
if name == "__env":
raise AttributeError
return self.__env[name]
# accept special keywords argument to define defaults for all operations
# that will be processed with given by return SelfWrapper
def __call__(self, **kwargs):
return SelfWrapper(self.__self_module, kwargs)
# we're being run as a stand-alone script
if __name__ == "__main__": # pragma: no cover
arg = sys.argv.pop(1)
arg = None
if arg == "test":
import subprocess
def run_test(version, locale):
py_version = "python%s" % version
py_bin = which(py_version)
if py_bin:
print("Testing %s, locale %r" % (py_version.capitalize(),
env = os.environ.copy()
env["LANG"] = locale
p = subprocess.Popen([py_bin, os.path.join(THIS_DIR, "")]
+ sys.argv[1:], env=env)
return_code = p.wait()
if return_code != 0:
print("Couldn't find %s, skipping" % py_version.capitalize())
versions = ("2.6", "2.7", "3.1", "3.2", "3.3", "3.4")
locales = ("en_US.UTF-8", "C")
for locale in locales:
for version in versions:
run_test(version, locale)
env = Environment(globals())
# we're being imported from somewhere
self = sys.modules[__name__]
sys.modules[__name__] = SelfWrapper(self)
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