Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

file 525 lines (394 sloc) 14.557 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525
# -*- coding: utf-8 -*-
"""
celery.platforms
~~~~~~~~~~~~~~~~

Utilities dealing with platform specifics: signals, daemonization,
users, groups, and so on.

:copyright: (c) 2009 - 2011 by Ask Solem.
:license: BSD, see LICENSE for more details.

"""
from __future__ import absolute_import

import errno
import os
import platform as _platform
import shlex
import signal as _signal
import sys

from .local import try_import

_setproctitle = try_import("setproctitle")
resource = try_import("resource")
pwd = try_import("pwd")
grp = try_import("grp")

SYSTEM = _platform.system()
IS_OSX = SYSTEM == "Darwin"
IS_WINDOWS = SYSTEM == "Windows"

DAEMON_UMASK = 0
DAEMON_WORKDIR = "/"
DAEMON_REDIRECT_TO = getattr(os, "devnull", "/dev/null")


def pyimplementation():
    if hasattr(_platform, "python_implementation"):
        return _platform.python_implementation()
    elif sys.platform.startswith("java"):
        return "Jython %s" % (sys.platform, )
    elif hasattr(sys, "pypy_version_info"):
        v = ".".join(map(str, sys.pypy_version_info[:3]))
        if sys.pypy_version_info[3:]:
            v += "-" + "".join(map(str, sys.pypy_version_info[3:]))
        return "PyPy %s" % (v, )
    else:
        return "CPython"


class LockFailed(Exception):
    """Raised if a pidlock can't be acquired."""
    pass


def get_fdmax(default=None):
    """Returns the maximum number of open file descriptors
on this system.

:keyword default: Value returned if there's no file
descriptor limit.

"""
    fdmax = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
    if fdmax == resource.RLIM_INFINITY:
        return default
    return fdmax


class PIDFile(object):
    """PID lock file.

This is the type returned by :func:`create_pidlock`.

**Should not be used directly, use the :func:`create_pidlock`
context instead**

"""

    #: Path to the pid lock file.
    path = None

    def __init__(self, path):
        self.path = os.path.abspath(path)

    def acquire(self):
        """Acquire lock."""
        try:
            self.write_pid()
        except OSError, exc:
            raise LockFailed(str(exc))
        return self
    __enter__ = acquire

    def is_locked(self):
        """Returns true if the pid lock exists."""
        return os.path.exists(self.path)

    def release(self, *args):
        """Release lock."""
        self.remove()
    __exit__ = release

    def read_pid(self):
        """Reads and returns the current pid."""
        try:
            fh = open(self.path, "r")
        except IOError, exc:
            if exc.errno == errno.ENOENT:
                return
            raise

        line = fh.readline().strip()
        fh.close()

        try:
            return int(line)
        except ValueError:
            raise ValueError("PID file %r contents invalid." % self.path)

    def remove(self):
        """Removes the lock."""
        try:
            os.unlink(self.path)
        except OSError, exc:
            if exc.errno in (errno.ENOENT, errno.EACCES):
                return
            raise

    def remove_if_stale(self):
        """Removes the lock if the process is not running.
(does not respond to signals)."""
        try:
            pid = self.read_pid()
        except ValueError, exc:
            sys.stderr.write("Broken pidfile found. Removing it.\n")
            self.remove()
            return True
        if not pid:
            self.remove()
            return True

        try:
            os.kill(pid, 0)
        except os.error, exc:
            if exc.errno == errno.ESRCH:
                sys.stderr.write("Stale pidfile exists. Removing it.\n")
                self.remove()
                return True
        return False

    def write_pid(self):
        open_flags = (os.O_CREAT | os.O_EXCL | os.O_WRONLY)
        open_mode = (((os.R_OK | os.W_OK) << 6) |
                        ((os.R_OK) << 3) |
                        ((os.R_OK)))
        pidfile_fd = os.open(self.path, open_flags, open_mode)
        pidfile = os.fdopen(pidfile_fd, "w")
        try:
            pid = os.getpid()
            pidfile.write("%d\n" % (pid, ))
        finally:
            pidfile.close()


def create_pidlock(pidfile):
    """Create and verify pid file.

If the pid file already exists the program exits with an error message,
however if the process it refers to is not running anymore, the pid file
is deleted and the program continues.

The caller is responsible for releasing the lock before the program
exits.

:returns: :class:`PIDFile`.

**Example**:

.. code-block:: python

import atexit
pidlock = create_pidlock("/var/run/app.pid").acquire()
atexit.register(pidlock.release)

"""

    pidlock = PIDFile(pidfile)
    if pidlock.is_locked() and not pidlock.remove_if_stale():
        raise SystemExit(
                "ERROR: Pidfile (%s) already exists.\n"
                "Seems we're already running? (PID: %s)" % (
                    pidfile, pidlock.read_pid()))
    return pidlock


class DaemonContext(object):
    _is_open = False
    workdir = DAEMON_WORKDIR
    umask = DAEMON_UMASK

    def __init__(self, pidfile=None, workdir=None,
            umask=None, **kwargs):
        self.workdir = workdir or self.workdir
        self.umask = self.umask if umask is None else umask

    def open(self):
        if not self._is_open:
            self._detach()

            os.chdir(self.workdir)
            os.umask(self.umask)

            for fd in reversed(range(get_fdmax(default=2048))):
                try:
                    os.close(fd)
                except OSError, exc:
                    if exc.errno != errno.EBADF:
                        raise

            os.open(DAEMON_REDIRECT_TO, os.O_RDWR)
            os.dup2(0, 1)
            os.dup2(0, 2)

            self._is_open = True
    __enter__ = open

    def close(self, *args):
        if self._is_open:
            self._is_open = False
    __exit__ = close

    def _detach(self):
        if os.fork() == 0: # first child
            os.setsid() # create new session
            if os.fork() > 0: # second child
                os._exit(0)
        else:
            os._exit(0)
        return self


def detached(logfile=None, pidfile=None, uid=None, gid=None, umask=0,
             workdir=None, **opts):
    """Detach the current process in the background (daemonize).

:keyword logfile: Optional log file. The ability to write to this file
will be verified before the process is detached.
:keyword pidfile: Optional pid file. The pid file will not be created,
as this is the responsibility of the child. But the process will
exit if the pid lock exists and the pid written is still running.
:keyword uid: Optional user id or user name to change
effective privileges to.
:keyword gid: Optional group id or group name to change effective
privileges to.
:keyword umask: Optional umask that will be effective in the child process.
:keyword workdir: Optional new working directory.
:keyword \*\*opts: Ignored.

**Example**:

.. code-block:: python

import atexit
from celery.platforms import detached, create_pidlock

with detached(logfile="/var/log/app.log", pidfile="/var/run/app.pid",
uid="nobody"):
# Now in detached child process with effective user set to nobody,
# and we know that our logfile can be written to, and that
# the pidfile is not locked.
pidlock = create_pidlock("/var/run/app.pid").acquire()
atexit.register(pidlock.release)

# Run the program
program.run(logfile="/var/log/app.log")

"""

    if not resource:
        raise RuntimeError("This platform does not support detach.")
    workdir = os.getcwd() if workdir is None else workdir

    signals.reset("SIGCLD") # Make sure SIGCLD is using the default handler.
    set_effective_user(uid=uid, gid=gid)

    # Since without stderr any errors will be silently suppressed,
    # we need to know that we have access to the logfile.
    logfile and open(logfile, "a").close()
    # Doesn't actually create the pidfile, but makes sure it's not stale.
    pidfile and create_pidlock(pidfile)

    return DaemonContext(umask=umask, workdir=workdir)


def parse_uid(uid):
    """Parse user id.

uid can be an integer (uid) or a string (user name), if a user name
the uid is taken from the password file.

"""
    try:
        return int(uid)
    except ValueError:
        if pwd:
            try:
                return pwd.getpwnam(uid).pw_uid
            except KeyError:
                raise KeyError("User does not exist: %r" % (uid, ))
        raise


def parse_gid(gid):
    """Parse group id.

gid can be an integer (gid) or a string (group name), if a group name
the gid is taken from the password file.

"""
    try:
        return int(gid)
    except ValueError:
        if grp:
            try:
                return grp.getgrnam(gid).gr_gid
            except KeyError:
                raise KeyError("Group does not exist: %r" % (gid, ))
        raise


def setegid(gid):
    """Set effective group id."""
    gid = parse_gid(gid)
    if gid != os.getegid():
        os.setegid(gid)


def seteuid(uid):
    """Set effective user id."""
    uid = parse_uid(uid)
    if uid != os.geteuid():
        os.seteuid(uid)


def setgid(gid):
    os.setgid(parse_gid(gid))


def setuid(uid):
    os.setuid(parse_uid(uid))


def set_effective_user(uid=None, gid=None):
    """Change process privileges to new user/group.

If UID and GID is set the effective user/group is set.

If only UID is set, the effective user is set, and the group is
set to the users primary group.

If only GID is set, the effective group is set.

"""
    uid = uid and parse_uid(uid)
    gid = gid and parse_gid(gid)

    if uid:
        # If GID isn't defined, get the primary GID of the user.
        if not gid and pwd:
            gid = pwd.getpwuid(uid).pw_gid
            setgid(gid)
        setuid(uid)
    else:
        gid and setgid(gid)


class Signals(object):
    """Convenience interface to :mod:`signals`.

If the requested signal is not supported on the current platform,
the operation will be ignored.

**Examples**:

.. code-block:: python

>>> from celery.platforms import signals

>>> signals["INT"] = my_handler

>>> signals["INT"]
my_handler

>>> signals.supported("INT")
True

>>> signals.signum("INT")
2

>>> signals.ignore("USR1")
>>> signals["USR1"] == signals.ignored
True

>>> signals.reset("USR1")
>>> signals["USR1"] == signals.default
True

>>> signals.update(INT=exit_handler,
... TERM=exit_handler,
... HUP=hup_handler)

"""

    ignored = _signal.SIG_IGN
    default = _signal.SIG_DFL

    def supported(self, signal_name):
        """Returns true value if ``signal_name`` exists on this platform."""
        try:
            return self.signum(signal_name)
        except AttributeError:
            pass

    def signum(self, signal_name):
        """Get signal number from signal name."""
        if isinstance(signal_name, int):
            return signal_name
        if not isinstance(signal_name, basestring) \
                or not signal_name.isupper():
            raise TypeError("signal name must be uppercase string.")
        if not signal_name.startswith("SIG"):
            signal_name = "SIG" + signal_name
        return getattr(_signal, signal_name)

    def reset(self, *signal_names):
        """Reset signals to the default signal handler.

Does nothing if the platform doesn't support signals,
or the specified signal in particular.

"""
        self.update((sig, self.default) for sig in signal_names)

    def ignore(self, *signal_names):
        """Ignore signal using :const:`SIG_IGN`.

Does nothing if the platform doesn't support signals,
or the specified signal in particular.

"""
        self.update((sig, self.ignored) for sig in signal_names)

    def __getitem__(self, signal_name):
        return _signal.getsignal(self.signum(signal_name))

    def __setitem__(self, signal_name, handler):
        """Install signal handler.

Does nothing if the current platform doesn't support signals,
or the specified signal in particular.

"""
        try:
            _signal.signal(self.signum(signal_name), handler)
        except (AttributeError, ValueError):
            pass

    def update(self, _d_=None, **sigmap):
        """Set signal handlers from a mapping."""
        for signal_name, handler in dict(_d_ or {}, **sigmap).iteritems():
            self[signal_name] = handler


signals = Signals()
get_signal = signals.signum # compat
install_signal_handler = signals.__setitem__ # compat
reset_signal = signals.reset # compat
ignore_signal = signals.ignore # compat


def strargv(argv):
    arg_start = 2 if "manage" in argv[0] else 1
    if len(argv) > arg_start:
        return " ".join(argv[arg_start:])
    return ""


def set_process_title(progname, info=None):
    """Set the ps name for the currently running process.

Only works if :mod:`setproctitle` is installed.

"""
    proctitle = "[%s]" % progname
    proctitle = "%s %s" % (proctitle, info) if info else proctitle
    if _setproctitle:
        _setproctitle.setproctitle(proctitle)
    return proctitle


def set_mp_process_title(progname, info=None, hostname=None):
    """Set the ps name using the multiprocessing process name.

Only works if :mod:`setproctitle` is installed.

"""
    if hostname:
        progname = "%s@%s" % (progname, hostname.split(".")[0])
    try:
        from multiprocessing.process import current_process
    except ImportError:
        return set_process_title(progname, info=info)
    else:
        return set_process_title("%s:%s" % (progname,
                                            current_process().name), info=info)


def shellsplit(s, posix=True):
    # posix= option to shlex.split first available in Python 2.6+
    lexer = shlex.shlex(s, posix=not IS_WINDOWS)
    lexer.whitespace_split = True
    lexer.commenters = ''
    return list(lexer)
Something went wrong with that request. Please try again.