root / lib / utils.py @ cc4c9b91
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#
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#
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# Copyright (C) 2006, 2007 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Ganeti utility module.
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This module holds functions that can be used in both daemons (all) and
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the command line scripts.
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"""
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import os |
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import time |
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import subprocess |
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import re |
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import socket |
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import tempfile |
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import shutil |
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import errno |
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import pwd |
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import itertools |
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import select |
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import fcntl |
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import resource |
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import logging |
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import logging.handlers |
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import signal |
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from cStringIO import StringIO |
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try:
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from hashlib import sha1 |
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except ImportError: |
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import sha |
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sha1 = sha.new |
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from ganeti import errors |
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from ganeti import constants |
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_locksheld = [] |
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_re_shell_unquoted = re.compile('^[-.,=:/_+@A-Za-z0-9]+$')
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debug_locks = False
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#: when set to True, L{RunCmd} is disabled
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no_fork = False
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_RANDOM_UUID_FILE = "/proc/sys/kernel/random/uuid"
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class RunResult(object): |
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"""Holds the result of running external programs.
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@type exit_code: int
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@ivar exit_code: the exit code of the program, or None (if the program
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didn't exit())
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@type signal: int or None
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@ivar signal: the signal that caused the program to finish, or None
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(if the program wasn't terminated by a signal)
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@type stdout: str
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@ivar stdout: the standard output of the program
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@type stderr: str
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@ivar stderr: the standard error of the program
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@type failed: boolean
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@ivar failed: True in case the program was
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terminated by a signal or exited with a non-zero exit code
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@ivar fail_reason: a string detailing the termination reason
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"""
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__slots__ = ["exit_code", "signal", "stdout", "stderr", |
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"failed", "fail_reason", "cmd"] |
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def __init__(self, exit_code, signal_, stdout, stderr, cmd): |
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self.cmd = cmd
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self.exit_code = exit_code
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self.signal = signal_
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self.stdout = stdout
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self.stderr = stderr
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self.failed = (signal_ is not None or exit_code != 0) |
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if self.signal is not None: |
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self.fail_reason = "terminated by signal %s" % self.signal |
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elif self.exit_code is not None: |
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self.fail_reason = "exited with exit code %s" % self.exit_code |
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else:
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self.fail_reason = "unable to determine termination reason" |
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if self.failed: |
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logging.debug("Command '%s' failed (%s); output: %s",
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self.cmd, self.fail_reason, self.output) |
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def _GetOutput(self): |
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"""Returns the combined stdout and stderr for easier usage.
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"""
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return self.stdout + self.stderr |
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output = property(_GetOutput, None, None, "Return full output") |
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def RunCmd(cmd, env=None, output=None, cwd='/', reset_env=False): |
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"""Execute a (shell) command.
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The command should not read from its standard input, as it will be
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closed.
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@type cmd: string or list
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@param cmd: Command to run
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@type env: dict
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@param env: Additional environment
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@type output: str
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@param output: if desired, the output of the command can be
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saved in a file instead of the RunResult instance; this
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parameter denotes the file name (if not None)
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@type cwd: string
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@param cwd: if specified, will be used as the working
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directory for the command; the default will be /
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@type reset_env: boolean
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@param reset_env: whether to reset or keep the default os environment
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@rtype: L{RunResult}
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@return: RunResult instance
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@raise errors.ProgrammerError: if we call this when forks are disabled
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"""
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if no_fork:
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raise errors.ProgrammerError("utils.RunCmd() called with fork() disabled") |
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if isinstance(cmd, list): |
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cmd = [str(val) for val in cmd] |
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strcmd = " ".join(cmd)
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shell = False
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else:
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strcmd = cmd |
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shell = True
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logging.debug("RunCmd '%s'", strcmd)
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if not reset_env: |
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cmd_env = os.environ.copy() |
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cmd_env["LC_ALL"] = "C" |
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else:
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cmd_env = {} |
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if env is not None: |
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cmd_env.update(env) |
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try:
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if output is None: |
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out, err, status = _RunCmdPipe(cmd, cmd_env, shell, cwd) |
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else:
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status = _RunCmdFile(cmd, cmd_env, shell, output, cwd) |
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out = err = ""
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except OSError, err: |
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if err.errno == errno.ENOENT:
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raise errors.OpExecError("Can't execute '%s': not found (%s)" % |
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(strcmd, err)) |
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else:
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raise
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if status >= 0: |
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exitcode = status |
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signal_ = None
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else:
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exitcode = None
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signal_ = -status |
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return RunResult(exitcode, signal_, out, err, strcmd)
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def _RunCmdPipe(cmd, env, via_shell, cwd): |
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"""Run a command and return its output.
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@type cmd: string or list
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@param cmd: Command to run
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@type env: dict
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@param env: The environment to use
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@type via_shell: bool
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@param via_shell: if we should run via the shell
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@type cwd: string
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@param cwd: the working directory for the program
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@rtype: tuple
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@return: (out, err, status)
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"""
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poller = select.poll() |
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child = subprocess.Popen(cmd, shell=via_shell, |
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stderr=subprocess.PIPE, |
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stdout=subprocess.PIPE, |
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stdin=subprocess.PIPE, |
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close_fds=True, env=env,
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cwd=cwd) |
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child.stdin.close() |
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poller.register(child.stdout, select.POLLIN) |
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poller.register(child.stderr, select.POLLIN) |
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out = StringIO() |
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err = StringIO() |
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fdmap = { |
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child.stdout.fileno(): (out, child.stdout), |
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child.stderr.fileno(): (err, child.stderr), |
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} |
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for fd in fdmap: |
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status = fcntl.fcntl(fd, fcntl.F_GETFL) |
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fcntl.fcntl(fd, fcntl.F_SETFL, status | os.O_NONBLOCK) |
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while fdmap:
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try:
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pollresult = poller.poll() |
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except EnvironmentError, eerr: |
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if eerr.errno == errno.EINTR:
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continue
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raise
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except select.error, serr:
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if serr[0] == errno.EINTR: |
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continue
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raise
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for fd, event in pollresult: |
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if event & select.POLLIN or event & select.POLLPRI: |
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data = fdmap[fd][1].read()
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# no data from read signifies EOF (the same as POLLHUP)
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if not data: |
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poller.unregister(fd) |
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del fdmap[fd]
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continue
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fdmap[fd][0].write(data)
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if (event & select.POLLNVAL or event & select.POLLHUP or |
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event & select.POLLERR): |
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poller.unregister(fd) |
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del fdmap[fd]
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out = out.getvalue() |
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err = err.getvalue() |
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status = child.wait() |
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return out, err, status
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def _RunCmdFile(cmd, env, via_shell, output, cwd): |
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"""Run a command and save its output to a file.
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@type cmd: string or list
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@param cmd: Command to run
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@type env: dict
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@param env: The environment to use
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@type via_shell: bool
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@param via_shell: if we should run via the shell
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@type output: str
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@param output: the filename in which to save the output
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@type cwd: string
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@param cwd: the working directory for the program
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@rtype: int
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@return: the exit status
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"""
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fh = open(output, "a") |
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try:
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child = subprocess.Popen(cmd, shell=via_shell, |
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stderr=subprocess.STDOUT, |
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stdout=fh, |
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stdin=subprocess.PIPE, |
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close_fds=True, env=env,
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cwd=cwd) |
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child.stdin.close() |
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status = child.wait() |
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finally:
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fh.close() |
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return status
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def RunParts(dir_name, env=None, reset_env=False): |
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"""Run Scripts or programs in a directory
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@type dir_name: string
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@param dir_name: absolute path to a directory
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@type env: dict
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@param env: The environment to use
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@type reset_env: boolean
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@param reset_env: whether to reset or keep the default os environment
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@rtype: list of tuples
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@return: list of (name, (one of RUNDIR_STATUS), RunResult)
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"""
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rr = [] |
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try:
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dir_contents = ListVisibleFiles(dir_name) |
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except OSError, err: |
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logging.warning("RunParts: skipping %s (cannot list: %s)", dir_name, err)
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return rr
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for relname in sorted(dir_contents): |
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fname = PathJoin(dir_name, relname) |
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if not (os.path.isfile(fname) and os.access(fname, os.X_OK) and |
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constants.EXT_PLUGIN_MASK.match(relname) is not None): |
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rr.append((relname, constants.RUNPARTS_SKIP, None))
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else:
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try:
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result = RunCmd([fname], env=env, reset_env=reset_env) |
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except Exception, err: # pylint: disable-msg=W0703 |
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rr.append((relname, constants.RUNPARTS_ERR, str(err)))
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else:
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rr.append((relname, constants.RUNPARTS_RUN, result)) |
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return rr
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def RemoveFile(filename): |
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"""Remove a file ignoring some errors.
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Remove a file, ignoring non-existing ones or directories. Other
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errors are passed.
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@type filename: str
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@param filename: the file to be removed
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"""
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try:
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os.unlink(filename) |
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except OSError, err: |
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if err.errno not in (errno.ENOENT, errno.EISDIR): |
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raise
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def RenameFile(old, new, mkdir=False, mkdir_mode=0750): |
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"""Renames a file.
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@type old: string
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@param old: Original path
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@type new: string
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@param new: New path
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@type mkdir: bool
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@param mkdir: Whether to create target directory if it doesn't exist
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@type mkdir_mode: int
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@param mkdir_mode: Mode for newly created directories
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"""
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try:
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return os.rename(old, new)
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except OSError, err: |
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# In at least one use case of this function, the job queue, directory
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# creation is very rare. Checking for the directory before renaming is not
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# as efficient.
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if mkdir and err.errno == errno.ENOENT: |
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# Create directory and try again
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dirname = os.path.dirname(new) |
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try:
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os.makedirs(dirname, mode=mkdir_mode) |
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except OSError, err: |
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# Ignore EEXIST. This is only handled in os.makedirs as included in
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# Python 2.5 and above.
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if err.errno != errno.EEXIST or not os.path.exists(dirname): |
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raise
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return os.rename(old, new)
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raise
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def ResetTempfileModule(): |
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"""Resets the random name generator of the tempfile module.
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This function should be called after C{os.fork} in the child process to
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ensure it creates a newly seeded random generator. Otherwise it would
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generate the same random parts as the parent process. If several processes
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race for the creation of a temporary file, this could lead to one not getting
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a temporary name.
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"""
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# pylint: disable-msg=W0212
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if hasattr(tempfile, "_once_lock") and hasattr(tempfile, "_name_sequence"): |
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tempfile._once_lock.acquire() |
393 |
try:
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# Reset random name generator
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tempfile._name_sequence = None
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finally:
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tempfile._once_lock.release() |
398 |
else:
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logging.critical("The tempfile module misses at least one of the"
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" '_once_lock' and '_name_sequence' attributes")
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def _FingerprintFile(filename): |
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"""Compute the fingerprint of a file.
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If the file does not exist, a None will be returned
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instead.
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@type filename: str
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@param filename: the filename to checksum
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@rtype: str
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@return: the hex digest of the sha checksum of the contents
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of the file
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414 |
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415 |
"""
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416 |
if not (os.path.exists(filename) and os.path.isfile(filename)): |
417 |
return None |
418 |
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f = open(filename)
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420 |
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fp = sha1() |
422 |
while True: |
423 |
data = f.read(4096)
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if not data: |
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break
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fp.update(data) |
428 |
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return fp.hexdigest()
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def FingerprintFiles(files): |
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"""Compute fingerprints for a list of files.
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434 |
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@type files: list
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@param files: the list of filename to fingerprint
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@rtype: dict
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@return: a dictionary filename: fingerprint, holding only
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existing files
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"""
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ret = {} |
443 |
|
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for filename in files: |
445 |
cksum = _FingerprintFile(filename) |
446 |
if cksum:
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ret[filename] = cksum |
448 |
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return ret
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450 |
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451 |
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def ForceDictType(target, key_types, allowed_values=None): |
453 |
"""Force the values of a dict to have certain types.
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454 |
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455 |
@type target: dict
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@param target: the dict to update
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457 |
@type key_types: dict
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458 |
@param key_types: dict mapping target dict keys to types
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in constants.ENFORCEABLE_TYPES
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@type allowed_values: list
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@keyword allowed_values: list of specially allowed values
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|
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"""
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464 |
if allowed_values is None: |
465 |
allowed_values = [] |
466 |
|
467 |
if not isinstance(target, dict): |
468 |
msg = "Expected dictionary, got '%s'" % target
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raise errors.TypeEnforcementError(msg)
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470 |
|
471 |
for key in target: |
472 |
if key not in key_types: |
473 |
msg = "Unknown key '%s'" % key
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raise errors.TypeEnforcementError(msg)
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475 |
|
476 |
if target[key] in allowed_values: |
477 |
continue
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478 |
|
479 |
ktype = key_types[key] |
480 |
if ktype not in constants.ENFORCEABLE_TYPES: |
481 |
msg = "'%s' has non-enforceable type %s" % (key, ktype)
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482 |
raise errors.ProgrammerError(msg)
|
483 |
|
484 |
if ktype == constants.VTYPE_STRING:
|
485 |
if not isinstance(target[key], basestring): |
486 |
if isinstance(target[key], bool) and not target[key]: |
487 |
target[key] = ''
|
488 |
else:
|
489 |
msg = "'%s' (value %s) is not a valid string" % (key, target[key])
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490 |
raise errors.TypeEnforcementError(msg)
|
491 |
elif ktype == constants.VTYPE_BOOL:
|
492 |
if isinstance(target[key], basestring) and target[key]: |
493 |
if target[key].lower() == constants.VALUE_FALSE:
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494 |
target[key] = False
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495 |
elif target[key].lower() == constants.VALUE_TRUE:
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496 |
target[key] = True
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497 |
else:
|
498 |
msg = "'%s' (value %s) is not a valid boolean" % (key, target[key])
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raise errors.TypeEnforcementError(msg)
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500 |
elif target[key]:
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target[key] = True
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502 |
else:
|
503 |
target[key] = False
|
504 |
elif ktype == constants.VTYPE_SIZE:
|
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try:
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target[key] = ParseUnit(target[key]) |
507 |
except errors.UnitParseError, err:
|
508 |
msg = "'%s' (value %s) is not a valid size. error: %s" % \
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(key, target[key], err) |
510 |
raise errors.TypeEnforcementError(msg)
|
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elif ktype == constants.VTYPE_INT:
|
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try:
|
513 |
target[key] = int(target[key])
|
514 |
except (ValueError, TypeError): |
515 |
msg = "'%s' (value %s) is not a valid integer" % (key, target[key])
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raise errors.TypeEnforcementError(msg)
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517 |
|
518 |
|
519 |
def IsProcessAlive(pid): |
520 |
"""Check if a given pid exists on the system.
|
521 |
|
522 |
@note: zombie status is not handled, so zombie processes
|
523 |
will be returned as alive
|
524 |
@type pid: int
|
525 |
@param pid: the process ID to check
|
526 |
@rtype: boolean
|
527 |
@return: True if the process exists
|
528 |
|
529 |
"""
|
530 |
if pid <= 0: |
531 |
return False |
532 |
|
533 |
try:
|
534 |
os.stat("/proc/%d/status" % pid)
|
535 |
return True |
536 |
except EnvironmentError, err: |
537 |
if err.errno in (errno.ENOENT, errno.ENOTDIR): |
538 |
return False |
539 |
raise
|
540 |
|
541 |
|
542 |
def ReadPidFile(pidfile): |
543 |
"""Read a pid from a file.
|
544 |
|
545 |
@type pidfile: string
|
546 |
@param pidfile: path to the file containing the pid
|
547 |
@rtype: int
|
548 |
@return: The process id, if the file exists and contains a valid PID,
|
549 |
otherwise 0
|
550 |
|
551 |
"""
|
552 |
try:
|
553 |
raw_data = ReadFile(pidfile) |
554 |
except EnvironmentError, err: |
555 |
if err.errno != errno.ENOENT:
|
556 |
logging.exception("Can't read pid file")
|
557 |
return 0 |
558 |
|
559 |
try:
|
560 |
pid = int(raw_data)
|
561 |
except (TypeError, ValueError), err: |
562 |
logging.info("Can't parse pid file contents", exc_info=True) |
563 |
return 0 |
564 |
|
565 |
return pid
|
566 |
|
567 |
|
568 |
def MatchNameComponent(key, name_list, case_sensitive=True): |
569 |
"""Try to match a name against a list.
|
570 |
|
571 |
This function will try to match a name like test1 against a list
|
572 |
like C{['test1.example.com', 'test2.example.com', ...]}. Against
|
573 |
this list, I{'test1'} as well as I{'test1.example'} will match, but
|
574 |
not I{'test1.ex'}. A multiple match will be considered as no match
|
575 |
at all (e.g. I{'test1'} against C{['test1.example.com',
|
576 |
'test1.example.org']}), except when the key fully matches an entry
|
577 |
(e.g. I{'test1'} against C{['test1', 'test1.example.com']}).
|
578 |
|
579 |
@type key: str
|
580 |
@param key: the name to be searched
|
581 |
@type name_list: list
|
582 |
@param name_list: the list of strings against which to search the key
|
583 |
@type case_sensitive: boolean
|
584 |
@param case_sensitive: whether to provide a case-sensitive match
|
585 |
|
586 |
@rtype: None or str
|
587 |
@return: None if there is no match I{or} if there are multiple matches,
|
588 |
otherwise the element from the list which matches
|
589 |
|
590 |
"""
|
591 |
if key in name_list: |
592 |
return key
|
593 |
|
594 |
re_flags = 0
|
595 |
if not case_sensitive: |
596 |
re_flags |= re.IGNORECASE |
597 |
key = key.upper() |
598 |
mo = re.compile("^%s(\..*)?$" % re.escape(key), re_flags)
|
599 |
names_filtered = [] |
600 |
string_matches = [] |
601 |
for name in name_list: |
602 |
if mo.match(name) is not None: |
603 |
names_filtered.append(name) |
604 |
if not case_sensitive and key == name.upper(): |
605 |
string_matches.append(name) |
606 |
|
607 |
if len(string_matches) == 1: |
608 |
return string_matches[0] |
609 |
if len(names_filtered) == 1: |
610 |
return names_filtered[0] |
611 |
return None |
612 |
|
613 |
|
614 |
class HostInfo: |
615 |
"""Class implementing resolver and hostname functionality
|
616 |
|
617 |
"""
|
618 |
_VALID_NAME_RE = re.compile("^[a-z0-9._-]{1,255}$")
|
619 |
|
620 |
def __init__(self, name=None): |
621 |
"""Initialize the host name object.
|
622 |
|
623 |
If the name argument is not passed, it will use this system's
|
624 |
name.
|
625 |
|
626 |
"""
|
627 |
if name is None: |
628 |
name = self.SysName()
|
629 |
|
630 |
self.query = name
|
631 |
self.name, self.aliases, self.ipaddrs = self.LookupHostname(name) |
632 |
self.ip = self.ipaddrs[0] |
633 |
|
634 |
def ShortName(self): |
635 |
"""Returns the hostname without domain.
|
636 |
|
637 |
"""
|
638 |
return self.name.split('.')[0] |
639 |
|
640 |
@staticmethod
|
641 |
def SysName(): |
642 |
"""Return the current system's name.
|
643 |
|
644 |
This is simply a wrapper over C{socket.gethostname()}.
|
645 |
|
646 |
"""
|
647 |
return socket.gethostname()
|
648 |
|
649 |
@staticmethod
|
650 |
def LookupHostname(hostname): |
651 |
"""Look up hostname
|
652 |
|
653 |
@type hostname: str
|
654 |
@param hostname: hostname to look up
|
655 |
|
656 |
@rtype: tuple
|
657 |
@return: a tuple (name, aliases, ipaddrs) as returned by
|
658 |
C{socket.gethostbyname_ex}
|
659 |
@raise errors.ResolverError: in case of errors in resolving
|
660 |
|
661 |
"""
|
662 |
try:
|
663 |
result = socket.gethostbyname_ex(hostname) |
664 |
except socket.gaierror, err:
|
665 |
# hostname not found in DNS
|
666 |
raise errors.ResolverError(hostname, err.args[0], err.args[1]) |
667 |
|
668 |
return result
|
669 |
|
670 |
@classmethod
|
671 |
def NormalizeName(cls, hostname): |
672 |
"""Validate and normalize the given hostname.
|
673 |
|
674 |
@attention: the validation is a bit more relaxed than the standards
|
675 |
require; most importantly, we allow underscores in names
|
676 |
@raise errors.OpPrereqError: when the name is not valid
|
677 |
|
678 |
"""
|
679 |
hostname = hostname.lower() |
680 |
if (not cls._VALID_NAME_RE.match(hostname) or |
681 |
# double-dots, meaning empty label
|
682 |
".." in hostname or |
683 |
# empty initial label
|
684 |
hostname.startswith(".")):
|
685 |
raise errors.OpPrereqError("Invalid hostname '%s'" % hostname, |
686 |
errors.ECODE_INVAL) |
687 |
if hostname.endswith("."): |
688 |
hostname = hostname.rstrip(".")
|
689 |
return hostname
|
690 |
|
691 |
|
692 |
def GetHostInfo(name=None): |
693 |
"""Lookup host name and raise an OpPrereqError for failures"""
|
694 |
|
695 |
try:
|
696 |
return HostInfo(name)
|
697 |
except errors.ResolverError, err:
|
698 |
raise errors.OpPrereqError("The given name (%s) does not resolve: %s" % |
699 |
(err[0], err[2]), errors.ECODE_RESOLVER) |
700 |
|
701 |
|
702 |
def ListVolumeGroups(): |
703 |
"""List volume groups and their size
|
704 |
|
705 |
@rtype: dict
|
706 |
@return:
|
707 |
Dictionary with keys volume name and values
|
708 |
the size of the volume
|
709 |
|
710 |
"""
|
711 |
command = "vgs --noheadings --units m --nosuffix -o name,size"
|
712 |
result = RunCmd(command) |
713 |
retval = {} |
714 |
if result.failed:
|
715 |
return retval
|
716 |
|
717 |
for line in result.stdout.splitlines(): |
718 |
try:
|
719 |
name, size = line.split() |
720 |
size = int(float(size)) |
721 |
except (IndexError, ValueError), err: |
722 |
logging.error("Invalid output from vgs (%s): %s", err, line)
|
723 |
continue
|
724 |
|
725 |
retval[name] = size |
726 |
|
727 |
return retval
|
728 |
|
729 |
|
730 |
def BridgeExists(bridge): |
731 |
"""Check whether the given bridge exists in the system
|
732 |
|
733 |
@type bridge: str
|
734 |
@param bridge: the bridge name to check
|
735 |
@rtype: boolean
|
736 |
@return: True if it does
|
737 |
|
738 |
"""
|
739 |
return os.path.isdir("/sys/class/net/%s/bridge" % bridge) |
740 |
|
741 |
|
742 |
def NiceSort(name_list): |
743 |
"""Sort a list of strings based on digit and non-digit groupings.
|
744 |
|
745 |
Given a list of names C{['a1', 'a10', 'a11', 'a2']} this function
|
746 |
will sort the list in the logical order C{['a1', 'a2', 'a10',
|
747 |
'a11']}.
|
748 |
|
749 |
The sort algorithm breaks each name in groups of either only-digits
|
750 |
or no-digits. Only the first eight such groups are considered, and
|
751 |
after that we just use what's left of the string.
|
752 |
|
753 |
@type name_list: list
|
754 |
@param name_list: the names to be sorted
|
755 |
@rtype: list
|
756 |
@return: a copy of the name list sorted with our algorithm
|
757 |
|
758 |
"""
|
759 |
_SORTER_BASE = "(\D+|\d+)"
|
760 |
_SORTER_FULL = "^%s%s?%s?%s?%s?%s?%s?%s?.*$" % (_SORTER_BASE, _SORTER_BASE,
|
761 |
_SORTER_BASE, _SORTER_BASE, |
762 |
_SORTER_BASE, _SORTER_BASE, |
763 |
_SORTER_BASE, _SORTER_BASE) |
764 |
_SORTER_RE = re.compile(_SORTER_FULL) |
765 |
_SORTER_NODIGIT = re.compile("^\D*$")
|
766 |
def _TryInt(val): |
767 |
"""Attempts to convert a variable to integer."""
|
768 |
if val is None or _SORTER_NODIGIT.match(val): |
769 |
return val
|
770 |
rval = int(val)
|
771 |
return rval
|
772 |
|
773 |
to_sort = [([_TryInt(grp) for grp in _SORTER_RE.match(name).groups()], name) |
774 |
for name in name_list] |
775 |
to_sort.sort() |
776 |
return [tup[1] for tup in to_sort] |
777 |
|
778 |
|
779 |
def TryConvert(fn, val): |
780 |
"""Try to convert a value ignoring errors.
|
781 |
|
782 |
This function tries to apply function I{fn} to I{val}. If no
|
783 |
C{ValueError} or C{TypeError} exceptions are raised, it will return
|
784 |
the result, else it will return the original value. Any other
|
785 |
exceptions are propagated to the caller.
|
786 |
|
787 |
@type fn: callable
|
788 |
@param fn: function to apply to the value
|
789 |
@param val: the value to be converted
|
790 |
@return: The converted value if the conversion was successful,
|
791 |
otherwise the original value.
|
792 |
|
793 |
"""
|
794 |
try:
|
795 |
nv = fn(val) |
796 |
except (ValueError, TypeError): |
797 |
nv = val |
798 |
return nv
|
799 |
|
800 |
|
801 |
def IsValidIP(ip): |
802 |
"""Verifies the syntax of an IPv4 address.
|
803 |
|
804 |
This function checks if the IPv4 address passes is valid or not based
|
805 |
on syntax (not IP range, class calculations, etc.).
|
806 |
|
807 |
@type ip: str
|
808 |
@param ip: the address to be checked
|
809 |
@rtype: a regular expression match object
|
810 |
@return: a regular expression match object, or None if the
|
811 |
address is not valid
|
812 |
|
813 |
"""
|
814 |
unit = "(0|[1-9]\d{0,2})"
|
815 |
#TODO: convert and return only boolean
|
816 |
return re.match("^%s\.%s\.%s\.%s$" % (unit, unit, unit, unit), ip) |
817 |
|
818 |
|
819 |
def IsValidShellParam(word): |
820 |
"""Verifies is the given word is safe from the shell's p.o.v.
|
821 |
|
822 |
This means that we can pass this to a command via the shell and be
|
823 |
sure that it doesn't alter the command line and is passed as such to
|
824 |
the actual command.
|
825 |
|
826 |
Note that we are overly restrictive here, in order to be on the safe
|
827 |
side.
|
828 |
|
829 |
@type word: str
|
830 |
@param word: the word to check
|
831 |
@rtype: boolean
|
832 |
@return: True if the word is 'safe'
|
833 |
|
834 |
"""
|
835 |
return bool(re.match("^[-a-zA-Z0-9._+/:%@]+$", word)) |
836 |
|
837 |
|
838 |
def BuildShellCmd(template, *args): |
839 |
"""Build a safe shell command line from the given arguments.
|
840 |
|
841 |
This function will check all arguments in the args list so that they
|
842 |
are valid shell parameters (i.e. they don't contain shell
|
843 |
metacharacters). If everything is ok, it will return the result of
|
844 |
template % args.
|
845 |
|
846 |
@type template: str
|
847 |
@param template: the string holding the template for the
|
848 |
string formatting
|
849 |
@rtype: str
|
850 |
@return: the expanded command line
|
851 |
|
852 |
"""
|
853 |
for word in args: |
854 |
if not IsValidShellParam(word): |
855 |
raise errors.ProgrammerError("Shell argument '%s' contains" |
856 |
" invalid characters" % word)
|
857 |
return template % args
|
858 |
|
859 |
|
860 |
def FormatUnit(value, units): |
861 |
"""Formats an incoming number of MiB with the appropriate unit.
|
862 |
|
863 |
@type value: int
|
864 |
@param value: integer representing the value in MiB (1048576)
|
865 |
@type units: char
|
866 |
@param units: the type of formatting we should do:
|
867 |
- 'h' for automatic scaling
|
868 |
- 'm' for MiBs
|
869 |
- 'g' for GiBs
|
870 |
- 't' for TiBs
|
871 |
@rtype: str
|
872 |
@return: the formatted value (with suffix)
|
873 |
|
874 |
"""
|
875 |
if units not in ('m', 'g', 't', 'h'): |
876 |
raise errors.ProgrammerError("Invalid unit specified '%s'" % str(units)) |
877 |
|
878 |
suffix = ''
|
879 |
|
880 |
if units == 'm' or (units == 'h' and value < 1024): |
881 |
if units == 'h': |
882 |
suffix = 'M'
|
883 |
return "%d%s" % (round(value, 0), suffix) |
884 |
|
885 |
elif units == 'g' or (units == 'h' and value < (1024 * 1024)): |
886 |
if units == 'h': |
887 |
suffix = 'G'
|
888 |
return "%0.1f%s" % (round(float(value) / 1024, 1), suffix) |
889 |
|
890 |
else:
|
891 |
if units == 'h': |
892 |
suffix = 'T'
|
893 |
return "%0.1f%s" % (round(float(value) / 1024 / 1024, 1), suffix) |
894 |
|
895 |
|
896 |
def ParseUnit(input_string): |
897 |
"""Tries to extract number and scale from the given string.
|
898 |
|
899 |
Input must be in the format C{NUMBER+ [DOT NUMBER+] SPACE*
|
900 |
[UNIT]}. If no unit is specified, it defaults to MiB. Return value
|
901 |
is always an int in MiB.
|
902 |
|
903 |
"""
|
904 |
m = re.match('^([.\d]+)\s*([a-zA-Z]+)?$', str(input_string)) |
905 |
if not m: |
906 |
raise errors.UnitParseError("Invalid format") |
907 |
|
908 |
value = float(m.groups()[0]) |
909 |
|
910 |
unit = m.groups()[1]
|
911 |
if unit:
|
912 |
lcunit = unit.lower() |
913 |
else:
|
914 |
lcunit = 'm'
|
915 |
|
916 |
if lcunit in ('m', 'mb', 'mib'): |
917 |
# Value already in MiB
|
918 |
pass
|
919 |
|
920 |
elif lcunit in ('g', 'gb', 'gib'): |
921 |
value *= 1024
|
922 |
|
923 |
elif lcunit in ('t', 'tb', 'tib'): |
924 |
value *= 1024 * 1024 |
925 |
|
926 |
else:
|
927 |
raise errors.UnitParseError("Unknown unit: %s" % unit) |
928 |
|
929 |
# Make sure we round up
|
930 |
if int(value) < value: |
931 |
value += 1
|
932 |
|
933 |
# Round up to the next multiple of 4
|
934 |
value = int(value)
|
935 |
if value % 4: |
936 |
value += 4 - value % 4 |
937 |
|
938 |
return value
|
939 |
|
940 |
|
941 |
def AddAuthorizedKey(file_name, key): |
942 |
"""Adds an SSH public key to an authorized_keys file.
|
943 |
|
944 |
@type file_name: str
|
945 |
@param file_name: path to authorized_keys file
|
946 |
@type key: str
|
947 |
@param key: string containing key
|
948 |
|
949 |
"""
|
950 |
key_fields = key.split() |
951 |
|
952 |
f = open(file_name, 'a+') |
953 |
try:
|
954 |
nl = True
|
955 |
for line in f: |
956 |
# Ignore whitespace changes
|
957 |
if line.split() == key_fields:
|
958 |
break
|
959 |
nl = line.endswith('\n')
|
960 |
else:
|
961 |
if not nl: |
962 |
f.write("\n")
|
963 |
f.write(key.rstrip('\r\n'))
|
964 |
f.write("\n")
|
965 |
f.flush() |
966 |
finally:
|
967 |
f.close() |
968 |
|
969 |
|
970 |
def RemoveAuthorizedKey(file_name, key): |
971 |
"""Removes an SSH public key from an authorized_keys file.
|
972 |
|
973 |
@type file_name: str
|
974 |
@param file_name: path to authorized_keys file
|
975 |
@type key: str
|
976 |
@param key: string containing key
|
977 |
|
978 |
"""
|
979 |
key_fields = key.split() |
980 |
|
981 |
fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name)) |
982 |
try:
|
983 |
out = os.fdopen(fd, 'w')
|
984 |
try:
|
985 |
f = open(file_name, 'r') |
986 |
try:
|
987 |
for line in f: |
988 |
# Ignore whitespace changes while comparing lines
|
989 |
if line.split() != key_fields:
|
990 |
out.write(line) |
991 |
|
992 |
out.flush() |
993 |
os.rename(tmpname, file_name) |
994 |
finally:
|
995 |
f.close() |
996 |
finally:
|
997 |
out.close() |
998 |
except:
|
999 |
RemoveFile(tmpname) |
1000 |
raise
|
1001 |
|
1002 |
|
1003 |
def SetEtcHostsEntry(file_name, ip, hostname, aliases): |
1004 |
"""Sets the name of an IP address and hostname in /etc/hosts.
|
1005 |
|
1006 |
@type file_name: str
|
1007 |
@param file_name: path to the file to modify (usually C{/etc/hosts})
|
1008 |
@type ip: str
|
1009 |
@param ip: the IP address
|
1010 |
@type hostname: str
|
1011 |
@param hostname: the hostname to be added
|
1012 |
@type aliases: list
|
1013 |
@param aliases: the list of aliases to add for the hostname
|
1014 |
|
1015 |
"""
|
1016 |
# FIXME: use WriteFile + fn rather than duplicating its efforts
|
1017 |
# Ensure aliases are unique
|
1018 |
aliases = UniqueSequence([hostname] + aliases)[1:]
|
1019 |
|
1020 |
fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name)) |
1021 |
try:
|
1022 |
out = os.fdopen(fd, 'w')
|
1023 |
try:
|
1024 |
f = open(file_name, 'r') |
1025 |
try:
|
1026 |
for line in f: |
1027 |
fields = line.split() |
1028 |
if fields and not fields[0].startswith('#') and ip == fields[0]: |
1029 |
continue
|
1030 |
out.write(line) |
1031 |
|
1032 |
out.write("%s\t%s" % (ip, hostname))
|
1033 |
if aliases:
|
1034 |
out.write(" %s" % ' '.join(aliases)) |
1035 |
out.write('\n')
|
1036 |
|
1037 |
out.flush() |
1038 |
os.fsync(out) |
1039 |
os.chmod(tmpname, 0644)
|
1040 |
os.rename(tmpname, file_name) |
1041 |
finally:
|
1042 |
f.close() |
1043 |
finally:
|
1044 |
out.close() |
1045 |
except:
|
1046 |
RemoveFile(tmpname) |
1047 |
raise
|
1048 |
|
1049 |
|
1050 |
def AddHostToEtcHosts(hostname): |
1051 |
"""Wrapper around SetEtcHostsEntry.
|
1052 |
|
1053 |
@type hostname: str
|
1054 |
@param hostname: a hostname that will be resolved and added to
|
1055 |
L{constants.ETC_HOSTS}
|
1056 |
|
1057 |
"""
|
1058 |
hi = HostInfo(name=hostname) |
1059 |
SetEtcHostsEntry(constants.ETC_HOSTS, hi.ip, hi.name, [hi.ShortName()]) |
1060 |
|
1061 |
|
1062 |
def RemoveEtcHostsEntry(file_name, hostname): |
1063 |
"""Removes a hostname from /etc/hosts.
|
1064 |
|
1065 |
IP addresses without names are removed from the file.
|
1066 |
|
1067 |
@type file_name: str
|
1068 |
@param file_name: path to the file to modify (usually C{/etc/hosts})
|
1069 |
@type hostname: str
|
1070 |
@param hostname: the hostname to be removed
|
1071 |
|
1072 |
"""
|
1073 |
# FIXME: use WriteFile + fn rather than duplicating its efforts
|
1074 |
fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name)) |
1075 |
try:
|
1076 |
out = os.fdopen(fd, 'w')
|
1077 |
try:
|
1078 |
f = open(file_name, 'r') |
1079 |
try:
|
1080 |
for line in f: |
1081 |
fields = line.split() |
1082 |
if len(fields) > 1 and not fields[0].startswith('#'): |
1083 |
names = fields[1:]
|
1084 |
if hostname in names: |
1085 |
while hostname in names: |
1086 |
names.remove(hostname) |
1087 |
if names:
|
1088 |
out.write("%s %s\n" % (fields[0], ' '.join(names))) |
1089 |
continue
|
1090 |
|
1091 |
out.write(line) |
1092 |
|
1093 |
out.flush() |
1094 |
os.fsync(out) |
1095 |
os.chmod(tmpname, 0644)
|
1096 |
os.rename(tmpname, file_name) |
1097 |
finally:
|
1098 |
f.close() |
1099 |
finally:
|
1100 |
out.close() |
1101 |
except:
|
1102 |
RemoveFile(tmpname) |
1103 |
raise
|
1104 |
|
1105 |
|
1106 |
def RemoveHostFromEtcHosts(hostname): |
1107 |
"""Wrapper around RemoveEtcHostsEntry.
|
1108 |
|
1109 |
@type hostname: str
|
1110 |
@param hostname: hostname that will be resolved and its
|
1111 |
full and shot name will be removed from
|
1112 |
L{constants.ETC_HOSTS}
|
1113 |
|
1114 |
"""
|
1115 |
hi = HostInfo(name=hostname) |
1116 |
RemoveEtcHostsEntry(constants.ETC_HOSTS, hi.name) |
1117 |
RemoveEtcHostsEntry(constants.ETC_HOSTS, hi.ShortName()) |
1118 |
|
1119 |
|
1120 |
def CreateBackup(file_name): |
1121 |
"""Creates a backup of a file.
|
1122 |
|
1123 |
@type file_name: str
|
1124 |
@param file_name: file to be backed up
|
1125 |
@rtype: str
|
1126 |
@return: the path to the newly created backup
|
1127 |
@raise errors.ProgrammerError: for invalid file names
|
1128 |
|
1129 |
"""
|
1130 |
if not os.path.isfile(file_name): |
1131 |
raise errors.ProgrammerError("Can't make a backup of a non-file '%s'" % |
1132 |
file_name) |
1133 |
|
1134 |
prefix = '%s.backup-%d.' % (os.path.basename(file_name), int(time.time())) |
1135 |
dir_name = os.path.dirname(file_name) |
1136 |
|
1137 |
fsrc = open(file_name, 'rb') |
1138 |
try:
|
1139 |
(fd, backup_name) = tempfile.mkstemp(prefix=prefix, dir=dir_name) |
1140 |
fdst = os.fdopen(fd, 'wb')
|
1141 |
try:
|
1142 |
shutil.copyfileobj(fsrc, fdst) |
1143 |
finally:
|
1144 |
fdst.close() |
1145 |
finally:
|
1146 |
fsrc.close() |
1147 |
|
1148 |
return backup_name
|
1149 |
|
1150 |
|
1151 |
def ShellQuote(value): |
1152 |
"""Quotes shell argument according to POSIX.
|
1153 |
|
1154 |
@type value: str
|
1155 |
@param value: the argument to be quoted
|
1156 |
@rtype: str
|
1157 |
@return: the quoted value
|
1158 |
|
1159 |
"""
|
1160 |
if _re_shell_unquoted.match(value):
|
1161 |
return value
|
1162 |
else:
|
1163 |
return "'%s'" % value.replace("'", "'\\''") |
1164 |
|
1165 |
|
1166 |
def ShellQuoteArgs(args): |
1167 |
"""Quotes a list of shell arguments.
|
1168 |
|
1169 |
@type args: list
|
1170 |
@param args: list of arguments to be quoted
|
1171 |
@rtype: str
|
1172 |
@return: the quoted arguments concatenated with spaces
|
1173 |
|
1174 |
"""
|
1175 |
return ' '.join([ShellQuote(i) for i in args]) |
1176 |
|
1177 |
|
1178 |
def TcpPing(target, port, timeout=10, live_port_needed=False, source=None): |
1179 |
"""Simple ping implementation using TCP connect(2).
|
1180 |
|
1181 |
Check if the given IP is reachable by doing attempting a TCP connect
|
1182 |
to it.
|
1183 |
|
1184 |
@type target: str
|
1185 |
@param target: the IP or hostname to ping
|
1186 |
@type port: int
|
1187 |
@param port: the port to connect to
|
1188 |
@type timeout: int
|
1189 |
@param timeout: the timeout on the connection attempt
|
1190 |
@type live_port_needed: boolean
|
1191 |
@param live_port_needed: whether a closed port will cause the
|
1192 |
function to return failure, as if there was a timeout
|
1193 |
@type source: str or None
|
1194 |
@param source: if specified, will cause the connect to be made
|
1195 |
from this specific source address; failures to bind other
|
1196 |
than C{EADDRNOTAVAIL} will be ignored
|
1197 |
|
1198 |
"""
|
1199 |
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) |
1200 |
|
1201 |
success = False
|
1202 |
|
1203 |
if source is not None: |
1204 |
try:
|
1205 |
sock.bind((source, 0))
|
1206 |
except socket.error, (errcode, _):
|
1207 |
if errcode == errno.EADDRNOTAVAIL:
|
1208 |
success = False
|
1209 |
|
1210 |
sock.settimeout(timeout) |
1211 |
|
1212 |
try:
|
1213 |
sock.connect((target, port)) |
1214 |
sock.close() |
1215 |
success = True
|
1216 |
except socket.timeout:
|
1217 |
success = False
|
1218 |
except socket.error, (errcode, _):
|
1219 |
success = (not live_port_needed) and (errcode == errno.ECONNREFUSED) |
1220 |
|
1221 |
return success
|
1222 |
|
1223 |
|
1224 |
def OwnIpAddress(address): |
1225 |
"""Check if the current host has the the given IP address.
|
1226 |
|
1227 |
Currently this is done by TCP-pinging the address from the loopback
|
1228 |
address.
|
1229 |
|
1230 |
@type address: string
|
1231 |
@param address: the address to check
|
1232 |
@rtype: bool
|
1233 |
@return: True if we own the address
|
1234 |
|
1235 |
"""
|
1236 |
return TcpPing(address, constants.DEFAULT_NODED_PORT,
|
1237 |
source=constants.LOCALHOST_IP_ADDRESS) |
1238 |
|
1239 |
|
1240 |
def ListVisibleFiles(path): |
1241 |
"""Returns a list of visible files in a directory.
|
1242 |
|
1243 |
@type path: str
|
1244 |
@param path: the directory to enumerate
|
1245 |
@rtype: list
|
1246 |
@return: the list of all files not starting with a dot
|
1247 |
@raise ProgrammerError: if L{path} is not an absolue and normalized path
|
1248 |
|
1249 |
"""
|
1250 |
if not IsNormAbsPath(path): |
1251 |
raise errors.ProgrammerError("Path passed to ListVisibleFiles is not" |
1252 |
" absolute/normalized: '%s'" % path)
|
1253 |
files = [i for i in os.listdir(path) if not i.startswith(".")] |
1254 |
files.sort() |
1255 |
return files
|
1256 |
|
1257 |
|
1258 |
def GetHomeDir(user, default=None): |
1259 |
"""Try to get the homedir of the given user.
|
1260 |
|
1261 |
The user can be passed either as a string (denoting the name) or as
|
1262 |
an integer (denoting the user id). If the user is not found, the
|
1263 |
'default' argument is returned, which defaults to None.
|
1264 |
|
1265 |
"""
|
1266 |
try:
|
1267 |
if isinstance(user, basestring): |
1268 |
result = pwd.getpwnam(user) |
1269 |
elif isinstance(user, (int, long)): |
1270 |
result = pwd.getpwuid(user) |
1271 |
else:
|
1272 |
raise errors.ProgrammerError("Invalid type passed to GetHomeDir (%s)" % |
1273 |
type(user))
|
1274 |
except KeyError: |
1275 |
return default
|
1276 |
return result.pw_dir
|
1277 |
|
1278 |
|
1279 |
def NewUUID(): |
1280 |
"""Returns a random UUID.
|
1281 |
|
1282 |
@note: This is a Linux-specific method as it uses the /proc
|
1283 |
filesystem.
|
1284 |
@rtype: str
|
1285 |
|
1286 |
"""
|
1287 |
return ReadFile(_RANDOM_UUID_FILE, size=128).rstrip("\n") |
1288 |
|
1289 |
|
1290 |
def GenerateSecret(numbytes=20): |
1291 |
"""Generates a random secret.
|
1292 |
|
1293 |
This will generate a pseudo-random secret returning an hex string
|
1294 |
(so that it can be used where an ASCII string is needed).
|
1295 |
|
1296 |
@param numbytes: the number of bytes which will be represented by the returned
|
1297 |
string (defaulting to 20, the length of a SHA1 hash)
|
1298 |
@rtype: str
|
1299 |
@return: an hex representation of the pseudo-random sequence
|
1300 |
|
1301 |
"""
|
1302 |
return os.urandom(numbytes).encode('hex') |
1303 |
|
1304 |
|
1305 |
def EnsureDirs(dirs): |
1306 |
"""Make required directories, if they don't exist.
|
1307 |
|
1308 |
@param dirs: list of tuples (dir_name, dir_mode)
|
1309 |
@type dirs: list of (string, integer)
|
1310 |
|
1311 |
"""
|
1312 |
for dir_name, dir_mode in dirs: |
1313 |
try:
|
1314 |
os.mkdir(dir_name, dir_mode) |
1315 |
except EnvironmentError, err: |
1316 |
if err.errno != errno.EEXIST:
|
1317 |
raise errors.GenericError("Cannot create needed directory" |
1318 |
" '%s': %s" % (dir_name, err))
|
1319 |
if not os.path.isdir(dir_name): |
1320 |
raise errors.GenericError("%s is not a directory" % dir_name) |
1321 |
|
1322 |
|
1323 |
def ReadFile(file_name, size=-1): |
1324 |
"""Reads a file.
|
1325 |
|
1326 |
@type size: int
|
1327 |
@param size: Read at most size bytes (if negative, entire file)
|
1328 |
@rtype: str
|
1329 |
@return: the (possibly partial) content of the file
|
1330 |
|
1331 |
"""
|
1332 |
f = open(file_name, "r") |
1333 |
try:
|
1334 |
return f.read(size)
|
1335 |
finally:
|
1336 |
f.close() |
1337 |
|
1338 |
|
1339 |
def WriteFile(file_name, fn=None, data=None, |
1340 |
mode=None, uid=-1, gid=-1, |
1341 |
atime=None, mtime=None, close=True, |
1342 |
dry_run=False, backup=False, |
1343 |
prewrite=None, postwrite=None): |
1344 |
"""(Over)write a file atomically.
|
1345 |
|
1346 |
The file_name and either fn (a function taking one argument, the
|
1347 |
file descriptor, and which should write the data to it) or data (the
|
1348 |
contents of the file) must be passed. The other arguments are
|
1349 |
optional and allow setting the file mode, owner and group, and the
|
1350 |
mtime/atime of the file.
|
1351 |
|
1352 |
If the function doesn't raise an exception, it has succeeded and the
|
1353 |
target file has the new contents. If the function has raised an
|
1354 |
exception, an existing target file should be unmodified and the
|
1355 |
temporary file should be removed.
|
1356 |
|
1357 |
@type file_name: str
|
1358 |
@param file_name: the target filename
|
1359 |
@type fn: callable
|
1360 |
@param fn: content writing function, called with
|
1361 |
file descriptor as parameter
|
1362 |
@type data: str
|
1363 |
@param data: contents of the file
|
1364 |
@type mode: int
|
1365 |
@param mode: file mode
|
1366 |
@type uid: int
|
1367 |
@param uid: the owner of the file
|
1368 |
@type gid: int
|
1369 |
@param gid: the group of the file
|
1370 |
@type atime: int
|
1371 |
@param atime: a custom access time to be set on the file
|
1372 |
@type mtime: int
|
1373 |
@param mtime: a custom modification time to be set on the file
|
1374 |
@type close: boolean
|
1375 |
@param close: whether to close file after writing it
|
1376 |
@type prewrite: callable
|
1377 |
@param prewrite: function to be called before writing content
|
1378 |
@type postwrite: callable
|
1379 |
@param postwrite: function to be called after writing content
|
1380 |
|
1381 |
@rtype: None or int
|
1382 |
@return: None if the 'close' parameter evaluates to True,
|
1383 |
otherwise the file descriptor
|
1384 |
|
1385 |
@raise errors.ProgrammerError: if any of the arguments are not valid
|
1386 |
|
1387 |
"""
|
1388 |
if not os.path.isabs(file_name): |
1389 |
raise errors.ProgrammerError("Path passed to WriteFile is not" |
1390 |
" absolute: '%s'" % file_name)
|
1391 |
|
1392 |
if [fn, data].count(None) != 1: |
1393 |
raise errors.ProgrammerError("fn or data required") |
1394 |
|
1395 |
if [atime, mtime].count(None) == 1: |
1396 |
raise errors.ProgrammerError("Both atime and mtime must be either" |
1397 |
" set or None")
|
1398 |
|
1399 |
if backup and not dry_run and os.path.isfile(file_name): |
1400 |
CreateBackup(file_name) |
1401 |
|
1402 |
dir_name, base_name = os.path.split(file_name) |
1403 |
fd, new_name = tempfile.mkstemp('.new', base_name, dir_name)
|
1404 |
do_remove = True
|
1405 |
# here we need to make sure we remove the temp file, if any error
|
1406 |
# leaves it in place
|
1407 |
try:
|
1408 |
if uid != -1 or gid != -1: |
1409 |
os.chown(new_name, uid, gid) |
1410 |
if mode:
|
1411 |
os.chmod(new_name, mode) |
1412 |
if callable(prewrite): |
1413 |
prewrite(fd) |
1414 |
if data is not None: |
1415 |
os.write(fd, data) |
1416 |
else:
|
1417 |
fn(fd) |
1418 |
if callable(postwrite): |
1419 |
postwrite(fd) |
1420 |
os.fsync(fd) |
1421 |
if atime is not None and mtime is not None: |
1422 |
os.utime(new_name, (atime, mtime)) |
1423 |
if not dry_run: |
1424 |
os.rename(new_name, file_name) |
1425 |
do_remove = False
|
1426 |
finally:
|
1427 |
if close:
|
1428 |
os.close(fd) |
1429 |
result = None
|
1430 |
else:
|
1431 |
result = fd |
1432 |
if do_remove:
|
1433 |
RemoveFile(new_name) |
1434 |
|
1435 |
return result
|
1436 |
|
1437 |
|
1438 |
def FirstFree(seq, base=0): |
1439 |
"""Returns the first non-existing integer from seq.
|
1440 |
|
1441 |
The seq argument should be a sorted list of positive integers. The
|
1442 |
first time the index of an element is smaller than the element
|
1443 |
value, the index will be returned.
|
1444 |
|
1445 |
The base argument is used to start at a different offset,
|
1446 |
i.e. C{[3, 4, 6]} with I{offset=3} will return 5.
|
1447 |
|
1448 |
Example: C{[0, 1, 3]} will return I{2}.
|
1449 |
|
1450 |
@type seq: sequence
|
1451 |
@param seq: the sequence to be analyzed.
|
1452 |
@type base: int
|
1453 |
@param base: use this value as the base index of the sequence
|
1454 |
@rtype: int
|
1455 |
@return: the first non-used index in the sequence
|
1456 |
|
1457 |
"""
|
1458 |
for idx, elem in enumerate(seq): |
1459 |
assert elem >= base, "Passed element is higher than base offset" |
1460 |
if elem > idx + base:
|
1461 |
# idx is not used
|
1462 |
return idx + base
|
1463 |
return None |
1464 |
|
1465 |
|
1466 |
def all(seq, pred=bool): # pylint: disable-msg=W0622 |
1467 |
"Returns True if pred(x) is True for every element in the iterable"
|
1468 |
for _ in itertools.ifilterfalse(pred, seq): |
1469 |
return False |
1470 |
return True |
1471 |
|
1472 |
|
1473 |
def any(seq, pred=bool): # pylint: disable-msg=W0622 |
1474 |
"Returns True if pred(x) is True for at least one element in the iterable"
|
1475 |
for _ in itertools.ifilter(pred, seq): |
1476 |
return True |
1477 |
return False |
1478 |
|
1479 |
|
1480 |
def UniqueSequence(seq): |
1481 |
"""Returns a list with unique elements.
|
1482 |
|
1483 |
Element order is preserved.
|
1484 |
|
1485 |
@type seq: sequence
|
1486 |
@param seq: the sequence with the source elements
|
1487 |
@rtype: list
|
1488 |
@return: list of unique elements from seq
|
1489 |
|
1490 |
"""
|
1491 |
seen = set()
|
1492 |
return [i for i in seq if i not in seen and not seen.add(i)] |
1493 |
|
1494 |
|
1495 |
def NormalizeAndValidateMac(mac): |
1496 |
"""Normalizes and check if a MAC address is valid.
|
1497 |
|
1498 |
Checks whether the supplied MAC address is formally correct, only
|
1499 |
accepts colon separated format. Normalize it to all lower.
|
1500 |
|
1501 |
@type mac: str
|
1502 |
@param mac: the MAC to be validated
|
1503 |
@rtype: str
|
1504 |
@return: returns the normalized and validated MAC.
|
1505 |
|
1506 |
@raise errors.OpPrereqError: If the MAC isn't valid
|
1507 |
|
1508 |
"""
|
1509 |
mac_check = re.compile("^([0-9a-f]{2}(:|$)){6}$", re.I)
|
1510 |
if not mac_check.match(mac): |
1511 |
raise errors.OpPrereqError("Invalid MAC address specified: %s" % |
1512 |
mac, errors.ECODE_INVAL) |
1513 |
|
1514 |
return mac.lower()
|
1515 |
|
1516 |
|
1517 |
def TestDelay(duration): |
1518 |
"""Sleep for a fixed amount of time.
|
1519 |
|
1520 |
@type duration: float
|
1521 |
@param duration: the sleep duration
|
1522 |
@rtype: boolean
|
1523 |
@return: False for negative value, True otherwise
|
1524 |
|
1525 |
"""
|
1526 |
if duration < 0: |
1527 |
return False, "Invalid sleep duration" |
1528 |
time.sleep(duration) |
1529 |
return True, None |
1530 |
|
1531 |
|
1532 |
def _CloseFDNoErr(fd, retries=5): |
1533 |
"""Close a file descriptor ignoring errors.
|
1534 |
|
1535 |
@type fd: int
|
1536 |
@param fd: the file descriptor
|
1537 |
@type retries: int
|
1538 |
@param retries: how many retries to make, in case we get any
|
1539 |
other error than EBADF
|
1540 |
|
1541 |
"""
|
1542 |
try:
|
1543 |
os.close(fd) |
1544 |
except OSError, err: |
1545 |
if err.errno != errno.EBADF:
|
1546 |
if retries > 0: |
1547 |
_CloseFDNoErr(fd, retries - 1)
|
1548 |
# else either it's closed already or we're out of retries, so we
|
1549 |
# ignore this and go on
|
1550 |
|
1551 |
|
1552 |
def CloseFDs(noclose_fds=None): |
1553 |
"""Close file descriptors.
|
1554 |
|
1555 |
This closes all file descriptors above 2 (i.e. except
|
1556 |
stdin/out/err).
|
1557 |
|
1558 |
@type noclose_fds: list or None
|
1559 |
@param noclose_fds: if given, it denotes a list of file descriptor
|
1560 |
that should not be closed
|
1561 |
|
1562 |
"""
|
1563 |
# Default maximum for the number of available file descriptors.
|
1564 |
if 'SC_OPEN_MAX' in os.sysconf_names: |
1565 |
try:
|
1566 |
MAXFD = os.sysconf('SC_OPEN_MAX')
|
1567 |
if MAXFD < 0: |
1568 |
MAXFD = 1024
|
1569 |
except OSError: |
1570 |
MAXFD = 1024
|
1571 |
else:
|
1572 |
MAXFD = 1024
|
1573 |
maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
|
1574 |
if (maxfd == resource.RLIM_INFINITY):
|
1575 |
maxfd = MAXFD |
1576 |
|
1577 |
# Iterate through and close all file descriptors (except the standard ones)
|
1578 |
for fd in range(3, maxfd): |
1579 |
if noclose_fds and fd in noclose_fds: |
1580 |
continue
|
1581 |
_CloseFDNoErr(fd) |
1582 |
|
1583 |
|
1584 |
def Daemonize(logfile): |
1585 |
"""Daemonize the current process.
|
1586 |
|
1587 |
This detaches the current process from the controlling terminal and
|
1588 |
runs it in the background as a daemon.
|
1589 |
|
1590 |
@type logfile: str
|
1591 |
@param logfile: the logfile to which we should redirect stdout/stderr
|
1592 |
@rtype: int
|
1593 |
@return: the value zero
|
1594 |
|
1595 |
"""
|
1596 |
# pylint: disable-msg=W0212
|
1597 |
# yes, we really want os._exit
|
1598 |
UMASK = 077
|
1599 |
WORKDIR = "/"
|
1600 |
|
1601 |
# this might fail
|
1602 |
pid = os.fork() |
1603 |
if (pid == 0): # The first child. |
1604 |
os.setsid() |
1605 |
# this might fail
|
1606 |
pid = os.fork() # Fork a second child.
|
1607 |
if (pid == 0): # The second child. |
1608 |
os.chdir(WORKDIR) |
1609 |
os.umask(UMASK) |
1610 |
else:
|
1611 |
# exit() or _exit()? See below.
|
1612 |
os._exit(0) # Exit parent (the first child) of the second child. |
1613 |
else:
|
1614 |
os._exit(0) # Exit parent of the first child. |
1615 |
|
1616 |
for fd in range(3): |
1617 |
_CloseFDNoErr(fd) |
1618 |
i = os.open("/dev/null", os.O_RDONLY) # stdin |
1619 |
assert i == 0, "Can't close/reopen stdin" |
1620 |
i = os.open(logfile, os.O_WRONLY|os.O_CREAT|os.O_APPEND, 0600) # stdout |
1621 |
assert i == 1, "Can't close/reopen stdout" |
1622 |
# Duplicate standard output to standard error.
|
1623 |
os.dup2(1, 2) |
1624 |
return 0 |
1625 |
|
1626 |
|
1627 |
def DaemonPidFileName(name): |
1628 |
"""Compute a ganeti pid file absolute path
|
1629 |
|
1630 |
@type name: str
|
1631 |
@param name: the daemon name
|
1632 |
@rtype: str
|
1633 |
@return: the full path to the pidfile corresponding to the given
|
1634 |
daemon name
|
1635 |
|
1636 |
"""
|
1637 |
return PathJoin(constants.RUN_GANETI_DIR, "%s.pid" % name) |
1638 |
|
1639 |
|
1640 |
def EnsureDaemon(name): |
1641 |
"""Check for and start daemon if not alive.
|
1642 |
|
1643 |
"""
|
1644 |
result = RunCmd([constants.DAEMON_UTIL, "check-and-start", name])
|
1645 |
if result.failed:
|
1646 |
logging.error("Can't start daemon '%s', failure %s, output: %s",
|
1647 |
name, result.fail_reason, result.output) |
1648 |
return False |
1649 |
|
1650 |
return True |
1651 |
|
1652 |
|
1653 |
def WritePidFile(name): |
1654 |
"""Write the current process pidfile.
|
1655 |
|
1656 |
The file will be written to L{constants.RUN_GANETI_DIR}I{/name.pid}
|
1657 |
|
1658 |
@type name: str
|
1659 |
@param name: the daemon name to use
|
1660 |
@raise errors.GenericError: if the pid file already exists and
|
1661 |
points to a live process
|
1662 |
|
1663 |
"""
|
1664 |
pid = os.getpid() |
1665 |
pidfilename = DaemonPidFileName(name) |
1666 |
if IsProcessAlive(ReadPidFile(pidfilename)):
|
1667 |
raise errors.GenericError("%s contains a live process" % pidfilename) |
1668 |
|
1669 |
WriteFile(pidfilename, data="%d\n" % pid)
|
1670 |
|
1671 |
|
1672 |
def RemovePidFile(name): |
1673 |
"""Remove the current process pidfile.
|
1674 |
|
1675 |
Any errors are ignored.
|
1676 |
|
1677 |
@type name: str
|
1678 |
@param name: the daemon name used to derive the pidfile name
|
1679 |
|
1680 |
"""
|
1681 |
pidfilename = DaemonPidFileName(name) |
1682 |
# TODO: we could check here that the file contains our pid
|
1683 |
try:
|
1684 |
RemoveFile(pidfilename) |
1685 |
except: # pylint: disable-msg=W0702 |
1686 |
pass
|
1687 |
|
1688 |
|
1689 |
def KillProcess(pid, signal_=signal.SIGTERM, timeout=30, |
1690 |
waitpid=False):
|
1691 |
"""Kill a process given by its pid.
|
1692 |
|
1693 |
@type pid: int
|
1694 |
@param pid: The PID to terminate.
|
1695 |
@type signal_: int
|
1696 |
@param signal_: The signal to send, by default SIGTERM
|
1697 |
@type timeout: int
|
1698 |
@param timeout: The timeout after which, if the process is still alive,
|
1699 |
a SIGKILL will be sent. If not positive, no such checking
|
1700 |
will be done
|
1701 |
@type waitpid: boolean
|
1702 |
@param waitpid: If true, we should waitpid on this process after
|
1703 |
sending signals, since it's our own child and otherwise it
|
1704 |
would remain as zombie
|
1705 |
|
1706 |
"""
|
1707 |
def _helper(pid, signal_, wait): |
1708 |
"""Simple helper to encapsulate the kill/waitpid sequence"""
|
1709 |
os.kill(pid, signal_) |
1710 |
if wait:
|
1711 |
try:
|
1712 |
os.waitpid(pid, os.WNOHANG) |
1713 |
except OSError: |
1714 |
pass
|
1715 |
|
1716 |
if pid <= 0: |
1717 |
# kill with pid=0 == suicide
|
1718 |
raise errors.ProgrammerError("Invalid pid given '%s'" % pid) |
1719 |
|
1720 |
if not IsProcessAlive(pid): |
1721 |
return
|
1722 |
|
1723 |
_helper(pid, signal_, waitpid) |
1724 |
|
1725 |
if timeout <= 0: |
1726 |
return
|
1727 |
|
1728 |
def _CheckProcess(): |
1729 |
if not IsProcessAlive(pid): |
1730 |
return
|
1731 |
|
1732 |
try:
|
1733 |
(result_pid, _) = os.waitpid(pid, os.WNOHANG) |
1734 |
except OSError: |
1735 |
raise RetryAgain()
|
1736 |
|
1737 |
if result_pid > 0: |
1738 |
return
|
1739 |
|
1740 |
raise RetryAgain()
|
1741 |
|
1742 |
try:
|
1743 |
# Wait up to $timeout seconds
|
1744 |
Retry(_CheckProcess, (0.01, 1.5, 0.1), timeout) |
1745 |
except RetryTimeout:
|
1746 |
pass
|
1747 |
|
1748 |
if IsProcessAlive(pid):
|
1749 |
# Kill process if it's still alive
|
1750 |
_helper(pid, signal.SIGKILL, waitpid) |
1751 |
|
1752 |
|
1753 |
def FindFile(name, search_path, test=os.path.exists): |
1754 |
"""Look for a filesystem object in a given path.
|
1755 |
|
1756 |
This is an abstract method to search for filesystem object (files,
|
1757 |
dirs) under a given search path.
|
1758 |
|
1759 |
@type name: str
|
1760 |
@param name: the name to look for
|
1761 |
@type search_path: str
|
1762 |
@param search_path: location to start at
|
1763 |
@type test: callable
|
1764 |
@param test: a function taking one argument that should return True
|
1765 |
if the a given object is valid; the default value is
|
1766 |
os.path.exists, causing only existing files to be returned
|
1767 |
@rtype: str or None
|
1768 |
@return: full path to the object if found, None otherwise
|
1769 |
|
1770 |
"""
|
1771 |
# validate the filename mask
|
1772 |
if constants.EXT_PLUGIN_MASK.match(name) is None: |
1773 |
logging.critical("Invalid value passed for external script name: '%s'",
|
1774 |
name) |
1775 |
return None |
1776 |
|
1777 |
for dir_name in search_path: |
1778 |
# FIXME: investigate switch to PathJoin
|
1779 |
item_name = os.path.sep.join([dir_name, name]) |
1780 |
# check the user test and that we're indeed resolving to the given
|
1781 |
# basename
|
1782 |
if test(item_name) and os.path.basename(item_name) == name: |
1783 |
return item_name
|
1784 |
return None |
1785 |
|
1786 |
|
1787 |
def CheckVolumeGroupSize(vglist, vgname, minsize): |
1788 |
"""Checks if the volume group list is valid.
|
1789 |
|
1790 |
The function will check if a given volume group is in the list of
|
1791 |
volume groups and has a minimum size.
|
1792 |
|
1793 |
@type vglist: dict
|
1794 |
@param vglist: dictionary of volume group names and their size
|
1795 |
@type vgname: str
|
1796 |
@param vgname: the volume group we should check
|
1797 |
@type minsize: int
|
1798 |
@param minsize: the minimum size we accept
|
1799 |
@rtype: None or str
|
1800 |
@return: None for success, otherwise the error message
|
1801 |
|
1802 |
"""
|
1803 |
vgsize = vglist.get(vgname, None)
|
1804 |
if vgsize is None: |
1805 |
return "volume group '%s' missing" % vgname |
1806 |
elif vgsize < minsize:
|
1807 |
return ("volume group '%s' too small (%s MiB required, %d MiB found)" % |
1808 |
(vgname, minsize, vgsize)) |
1809 |
return None |
1810 |
|
1811 |
|
1812 |
def SplitTime(value): |
1813 |
"""Splits time as floating point number into a tuple.
|
1814 |
|
1815 |
@param value: Time in seconds
|
1816 |
@type value: int or float
|
1817 |
@return: Tuple containing (seconds, microseconds)
|
1818 |
|
1819 |
"""
|
1820 |
(seconds, microseconds) = divmod(int(value * 1000000), 1000000) |
1821 |
|
1822 |
assert 0 <= seconds, \ |
1823 |
"Seconds must be larger than or equal to 0, but are %s" % seconds
|
1824 |
assert 0 <= microseconds <= 999999, \ |
1825 |
"Microseconds must be 0-999999, but are %s" % microseconds
|
1826 |
|
1827 |
return (int(seconds), int(microseconds)) |
1828 |
|
1829 |
|
1830 |
def MergeTime(timetuple): |
1831 |
"""Merges a tuple into time as a floating point number.
|
1832 |
|
1833 |
@param timetuple: Time as tuple, (seconds, microseconds)
|
1834 |
@type timetuple: tuple
|
1835 |
@return: Time as a floating point number expressed in seconds
|
1836 |
|
1837 |
"""
|
1838 |
(seconds, microseconds) = timetuple |
1839 |
|
1840 |
assert 0 <= seconds, \ |
1841 |
"Seconds must be larger than or equal to 0, but are %s" % seconds
|
1842 |
assert 0 <= microseconds <= 999999, \ |
1843 |
"Microseconds must be 0-999999, but are %s" % microseconds
|
1844 |
|
1845 |
return float(seconds) + (float(microseconds) * 0.000001) |
1846 |
|
1847 |
|
1848 |
def GetDaemonPort(daemon_name): |
1849 |
"""Get the daemon port for this cluster.
|
1850 |
|
1851 |
Note that this routine does not read a ganeti-specific file, but
|
1852 |
instead uses C{socket.getservbyname} to allow pre-customization of
|
1853 |
this parameter outside of Ganeti.
|
1854 |
|
1855 |
@type daemon_name: string
|
1856 |
@param daemon_name: daemon name (in constants.DAEMONS_PORTS)
|
1857 |
@rtype: int
|
1858 |
|
1859 |
"""
|
1860 |
if daemon_name not in constants.DAEMONS_PORTS: |
1861 |
raise errors.ProgrammerError("Unknown daemon: %s" % daemon_name) |
1862 |
|
1863 |
(proto, default_port) = constants.DAEMONS_PORTS[daemon_name] |
1864 |
try:
|
1865 |
port = socket.getservbyname(daemon_name, proto) |
1866 |
except socket.error:
|
1867 |
port = default_port |
1868 |
|
1869 |
return port
|
1870 |
|
1871 |
|
1872 |
def SetupLogging(logfile, debug=0, stderr_logging=False, program="", |
1873 |
multithreaded=False, syslog=constants.SYSLOG_USAGE):
|
1874 |
"""Configures the logging module.
|
1875 |
|
1876 |
@type logfile: str
|
1877 |
@param logfile: the filename to which we should log
|
1878 |
@type debug: integer
|
1879 |
@param debug: if greater than zero, enable debug messages, otherwise
|
1880 |
only those at C{INFO} and above level
|
1881 |
@type stderr_logging: boolean
|
1882 |
@param stderr_logging: whether we should also log to the standard error
|
1883 |
@type program: str
|
1884 |
@param program: the name under which we should log messages
|
1885 |
@type multithreaded: boolean
|
1886 |
@param multithreaded: if True, will add the thread name to the log file
|
1887 |
@type syslog: string
|
1888 |
@param syslog: one of 'no', 'yes', 'only':
|
1889 |
- if no, syslog is not used
|
1890 |
- if yes, syslog is used (in addition to file-logging)
|
1891 |
- if only, only syslog is used
|
1892 |
@raise EnvironmentError: if we can't open the log file and
|
1893 |
syslog/stderr logging is disabled
|
1894 |
|
1895 |
"""
|
1896 |
fmt = "%(asctime)s: " + program + " pid=%(process)d" |
1897 |
sft = program + "[%(process)d]:"
|
1898 |
if multithreaded:
|
1899 |
fmt += "/%(threadName)s"
|
1900 |
sft += " (%(threadName)s)"
|
1901 |
if debug:
|
1902 |
fmt += " %(module)s:%(lineno)s"
|
1903 |
# no debug info for syslog loggers
|
1904 |
fmt += " %(levelname)s %(message)s"
|
1905 |
# yes, we do want the textual level, as remote syslog will probably
|
1906 |
# lose the error level, and it's easier to grep for it
|
1907 |
sft += " %(levelname)s %(message)s"
|
1908 |
formatter = logging.Formatter(fmt) |
1909 |
sys_fmt = logging.Formatter(sft) |
1910 |
|
1911 |
root_logger = logging.getLogger("")
|
1912 |
root_logger.setLevel(logging.NOTSET) |
1913 |
|
1914 |
# Remove all previously setup handlers
|
1915 |
for handler in root_logger.handlers: |
1916 |
handler.close() |
1917 |
root_logger.removeHandler(handler) |
1918 |
|
1919 |
if stderr_logging:
|
1920 |
stderr_handler = logging.StreamHandler() |
1921 |
stderr_handler.setFormatter(formatter) |
1922 |
if debug:
|
1923 |
stderr_handler.setLevel(logging.NOTSET) |
1924 |
else:
|
1925 |
stderr_handler.setLevel(logging.CRITICAL) |
1926 |
root_logger.addHandler(stderr_handler) |
1927 |
|
1928 |
if syslog in (constants.SYSLOG_YES, constants.SYSLOG_ONLY): |
1929 |
facility = logging.handlers.SysLogHandler.LOG_DAEMON |
1930 |
syslog_handler = logging.handlers.SysLogHandler(constants.SYSLOG_SOCKET, |
1931 |
facility) |
1932 |
syslog_handler.setFormatter(sys_fmt) |
1933 |
# Never enable debug over syslog
|
1934 |
syslog_handler.setLevel(logging.INFO) |
1935 |
root_logger.addHandler(syslog_handler) |
1936 |
|
1937 |
if syslog != constants.SYSLOG_ONLY:
|
1938 |
# this can fail, if the logging directories are not setup or we have
|
1939 |
# a permisssion problem; in this case, it's best to log but ignore
|
1940 |
# the error if stderr_logging is True, and if false we re-raise the
|
1941 |
# exception since otherwise we could run but without any logs at all
|
1942 |
try:
|
1943 |
logfile_handler = logging.FileHandler(logfile) |
1944 |
logfile_handler.setFormatter(formatter) |
1945 |
if debug:
|
1946 |
logfile_handler.setLevel(logging.DEBUG) |
1947 |
else:
|
1948 |
logfile_handler.setLevel(logging.INFO) |
1949 |
root_logger.addHandler(logfile_handler) |
1950 |
except EnvironmentError: |
1951 |
if stderr_logging or syslog == constants.SYSLOG_YES: |
1952 |
logging.exception("Failed to enable logging to file '%s'", logfile)
|
1953 |
else:
|
1954 |
# we need to re-raise the exception
|
1955 |
raise
|
1956 |
|
1957 |
|
1958 |
def IsNormAbsPath(path): |
1959 |
"""Check whether a path is absolute and also normalized
|
1960 |
|
1961 |
This avoids things like /dir/../../other/path to be valid.
|
1962 |
|
1963 |
"""
|
1964 |
return os.path.normpath(path) == path and os.path.isabs(path) |
1965 |
|
1966 |
|
1967 |
def PathJoin(*args): |
1968 |
"""Safe-join a list of path components.
|
1969 |
|
1970 |
Requirements:
|
1971 |
- the first argument must be an absolute path
|
1972 |
- no component in the path must have backtracking (e.g. /../),
|
1973 |
since we check for normalization at the end
|
1974 |
|
1975 |
@param args: the path components to be joined
|
1976 |
@raise ValueError: for invalid paths
|
1977 |
|
1978 |
"""
|
1979 |
# ensure we're having at least one path passed in
|
1980 |
assert args
|
1981 |
# ensure the first component is an absolute and normalized path name
|
1982 |
root = args[0]
|
1983 |
if not IsNormAbsPath(root): |
1984 |
raise ValueError("Invalid parameter to PathJoin: '%s'" % str(args[0])) |
1985 |
result = os.path.join(*args) |
1986 |
# ensure that the whole path is normalized
|
1987 |
if not IsNormAbsPath(result): |
1988 |
raise ValueError("Invalid parameters to PathJoin: '%s'" % str(args)) |
1989 |
# check that we're still under the original prefix
|
1990 |
prefix = os.path.commonprefix([root, result]) |
1991 |
if prefix != root:
|
1992 |
raise ValueError("Error: path joining resulted in different prefix" |
1993 |
" (%s != %s)" % (prefix, root))
|
1994 |
return result
|
1995 |
|
1996 |
|
1997 |
def TailFile(fname, lines=20): |
1998 |
"""Return the last lines from a file.
|
1999 |
|
2000 |
@note: this function will only read and parse the last 4KB of
|
2001 |
the file; if the lines are very long, it could be that less
|
2002 |
than the requested number of lines are returned
|
2003 |
|
2004 |
@param fname: the file name
|
2005 |
@type lines: int
|
2006 |
@param lines: the (maximum) number of lines to return
|
2007 |
|
2008 |
"""
|
2009 |
fd = open(fname, "r") |
2010 |
try:
|
2011 |
fd.seek(0, 2) |
2012 |
pos = fd.tell() |
2013 |
pos = max(0, pos-4096) |
2014 |
fd.seek(pos, 0)
|
2015 |
raw_data = fd.read() |
2016 |
finally:
|
2017 |
fd.close() |
2018 |
|
2019 |
rows = raw_data.splitlines() |
2020 |
return rows[-lines:]
|
2021 |
|
2022 |
|
2023 |
def SafeEncode(text): |
2024 |
"""Return a 'safe' version of a source string.
|
2025 |
|
2026 |
This function mangles the input string and returns a version that
|
2027 |
should be safe to display/encode as ASCII. To this end, we first
|
2028 |
convert it to ASCII using the 'backslashreplace' encoding which
|
2029 |
should get rid of any non-ASCII chars, and then we process it
|
2030 |
through a loop copied from the string repr sources in the python; we
|
2031 |
don't use string_escape anymore since that escape single quotes and
|
2032 |
backslashes too, and that is too much; and that escaping is not
|
2033 |
stable, i.e. string_escape(string_escape(x)) != string_escape(x).
|
2034 |
|
2035 |
@type text: str or unicode
|
2036 |
@param text: input data
|
2037 |
@rtype: str
|
2038 |
@return: a safe version of text
|
2039 |
|
2040 |
"""
|
2041 |
if isinstance(text, unicode): |
2042 |
# only if unicode; if str already, we handle it below
|
2043 |
text = text.encode('ascii', 'backslashreplace') |
2044 |
resu = ""
|
2045 |
for char in text: |
2046 |
c = ord(char)
|
2047 |
if char == '\t': |
2048 |
resu += r'\t'
|
2049 |
elif char == '\n': |
2050 |
resu += r'\n'
|
2051 |
elif char == '\r': |
2052 |
resu += r'\'r'
|
2053 |
elif c < 32 or c >= 127: # non-printable |
2054 |
resu += "\\x%02x" % (c & 0xff) |
2055 |
else:
|
2056 |
resu += char |
2057 |
return resu
|
2058 |
|
2059 |
|
2060 |
def UnescapeAndSplit(text, sep=","): |
2061 |
"""Split and unescape a string based on a given separator.
|
2062 |
|
2063 |
This function splits a string based on a separator where the
|
2064 |
separator itself can be escape in order to be an element of the
|
2065 |
elements. The escaping rules are (assuming coma being the
|
2066 |
separator):
|
2067 |
- a plain , separates the elements
|
2068 |
- a sequence \\\\, (double backslash plus comma) is handled as a
|
2069 |
backslash plus a separator comma
|
2070 |
- a sequence \, (backslash plus comma) is handled as a
|
2071 |
non-separator comma
|
2072 |
|
2073 |
@type text: string
|
2074 |
@param text: the string to split
|
2075 |
@type sep: string
|
2076 |
@param text: the separator
|
2077 |
@rtype: string
|
2078 |
@return: a list of strings
|
2079 |
|
2080 |
"""
|
2081 |
# we split the list by sep (with no escaping at this stage)
|
2082 |
slist = text.split(sep) |
2083 |
# next, we revisit the elements and if any of them ended with an odd
|
2084 |
# number of backslashes, then we join it with the next
|
2085 |
rlist = [] |
2086 |
while slist:
|
2087 |
e1 = slist.pop(0)
|
2088 |
if e1.endswith("\\"): |
2089 |
num_b = len(e1) - len(e1.rstrip("\\")) |
2090 |
if num_b % 2 == 1: |
2091 |
e2 = slist.pop(0)
|
2092 |
# here the backslashes remain (all), and will be reduced in
|
2093 |
# the next step
|
2094 |
rlist.append(e1 + sep + e2) |
2095 |
continue
|
2096 |
rlist.append(e1) |
2097 |
# finally, replace backslash-something with something
|
2098 |
rlist = [re.sub(r"\\(.)", r"\1", v) for v in rlist] |
2099 |
return rlist
|
2100 |
|
2101 |
|
2102 |
def CommaJoin(names): |
2103 |
"""Nicely join a set of identifiers.
|
2104 |
|
2105 |
@param names: set, list or tuple
|
2106 |
@return: a string with the formatted results
|
2107 |
|
2108 |
"""
|
2109 |
return ", ".join([str(val) for val in names]) |
2110 |
|
2111 |
|
2112 |
def BytesToMebibyte(value): |
2113 |
"""Converts bytes to mebibytes.
|
2114 |
|
2115 |
@type value: int
|
2116 |
@param value: Value in bytes
|
2117 |
@rtype: int
|
2118 |
@return: Value in mebibytes
|
2119 |
|
2120 |
"""
|
2121 |
return int(round(value / (1024.0 * 1024.0), 0)) |
2122 |
|
2123 |
|
2124 |
def CalculateDirectorySize(path): |
2125 |
"""Calculates the size of a directory recursively.
|
2126 |
|
2127 |
@type path: string
|
2128 |
@param path: Path to directory
|
2129 |
@rtype: int
|
2130 |
@return: Size in mebibytes
|
2131 |
|
2132 |
"""
|
2133 |
size = 0
|
2134 |
|
2135 |
for (curpath, _, files) in os.walk(path): |
2136 |
for filename in files: |
2137 |
st = os.lstat(PathJoin(curpath, filename)) |
2138 |
size += st.st_size |
2139 |
|
2140 |
return BytesToMebibyte(size)
|
2141 |
|
2142 |
|
2143 |
def GetFilesystemStats(path): |
2144 |
"""Returns the total and free space on a filesystem.
|
2145 |
|
2146 |
@type path: string
|
2147 |
@param path: Path on filesystem to be examined
|
2148 |
@rtype: int
|
2149 |
@return: tuple of (Total space, Free space) in mebibytes
|
2150 |
|
2151 |
"""
|
2152 |
st = os.statvfs(path) |
2153 |
|
2154 |
fsize = BytesToMebibyte(st.f_bavail * st.f_frsize) |
2155 |
tsize = BytesToMebibyte(st.f_blocks * st.f_frsize) |
2156 |
return (tsize, fsize)
|
2157 |
|
2158 |
|
2159 |
def RunInSeparateProcess(fn, *args): |
2160 |
"""Runs a function in a separate process.
|
2161 |
|
2162 |
Note: Only boolean return values are supported.
|
2163 |
|
2164 |
@type fn: callable
|
2165 |
@param fn: Function to be called
|
2166 |
@rtype: bool
|
2167 |
@return: Function's result
|
2168 |
|
2169 |
"""
|
2170 |
pid = os.fork() |
2171 |
if pid == 0: |
2172 |
# Child process
|
2173 |
try:
|
2174 |
# In case the function uses temporary files
|
2175 |
ResetTempfileModule() |
2176 |
|
2177 |
# Call function
|
2178 |
result = int(bool(fn(*args))) |
2179 |
assert result in (0, 1) |
2180 |
except: # pylint: disable-msg=W0702 |
2181 |
logging.exception("Error while calling function in separate process")
|
2182 |
# 0 and 1 are reserved for the return value
|
2183 |
result = 33
|
2184 |
|
2185 |
os._exit(result) # pylint: disable-msg=W0212
|
2186 |
|
2187 |
# Parent process
|
2188 |
|
2189 |
# Avoid zombies and check exit code
|
2190 |
(_, status) = os.waitpid(pid, 0)
|
2191 |
|
2192 |
if os.WIFSIGNALED(status):
|
2193 |
exitcode = None
|
2194 |
signum = os.WTERMSIG(status) |
2195 |
else:
|
2196 |
exitcode = os.WEXITSTATUS(status) |
2197 |
signum = None
|
2198 |
|
2199 |
if not (exitcode in (0, 1) and signum is None): |
2200 |
raise errors.GenericError("Child program failed (code=%s, signal=%s)" % |
2201 |
(exitcode, signum)) |
2202 |
|
2203 |
return bool(exitcode) |
2204 |
|
2205 |
|
2206 |
def LockedMethod(fn): |
2207 |
"""Synchronized object access decorator.
|
2208 |
|
2209 |
This decorator is intended to protect access to an object using the
|
2210 |
object's own lock which is hardcoded to '_lock'.
|
2211 |
|
2212 |
"""
|
2213 |
def _LockDebug(*args, **kwargs): |
2214 |
if debug_locks:
|
2215 |
logging.debug(*args, **kwargs) |
2216 |
|
2217 |
def wrapper(self, *args, **kwargs): |
2218 |
# pylint: disable-msg=W0212
|
2219 |
assert hasattr(self, '_lock') |
2220 |
lock = self._lock
|
2221 |
_LockDebug("Waiting for %s", lock)
|
2222 |
lock.acquire() |
2223 |
try:
|
2224 |
_LockDebug("Acquired %s", lock)
|
2225 |
result = fn(self, *args, **kwargs)
|
2226 |
finally:
|
2227 |
_LockDebug("Releasing %s", lock)
|
2228 |
lock.release() |
2229 |
_LockDebug("Released %s", lock)
|
2230 |
return result
|
2231 |
return wrapper
|
2232 |
|
2233 |
|
2234 |
def LockFile(fd): |
2235 |
"""Locks a file using POSIX locks.
|
2236 |
|
2237 |
@type fd: int
|
2238 |
@param fd: the file descriptor we need to lock
|
2239 |
|
2240 |
"""
|
2241 |
try:
|
2242 |
fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB) |
2243 |
except IOError, err: |
2244 |
if err.errno == errno.EAGAIN:
|
2245 |
raise errors.LockError("File already locked") |
2246 |
raise
|
2247 |
|
2248 |
|
2249 |
def FormatTime(val): |
2250 |
"""Formats a time value.
|
2251 |
|
2252 |
@type val: float or None
|
2253 |
@param val: the timestamp as returned by time.time()
|
2254 |
@return: a string value or N/A if we don't have a valid timestamp
|
2255 |
|
2256 |
"""
|
2257 |
if val is None or not isinstance(val, (int, float)): |
2258 |
return "N/A" |
2259 |
# these two codes works on Linux, but they are not guaranteed on all
|
2260 |
# platforms
|
2261 |
return time.strftime("%F %T", time.localtime(val)) |
2262 |
|
2263 |
|
2264 |
def ReadWatcherPauseFile(filename, now=None, remove_after=3600): |
2265 |
"""Reads the watcher pause file.
|
2266 |
|
2267 |
@type filename: string
|
2268 |
@param filename: Path to watcher pause file
|
2269 |
@type now: None, float or int
|
2270 |
@param now: Current time as Unix timestamp
|
2271 |
@type remove_after: int
|
2272 |
@param remove_after: Remove watcher pause file after specified amount of
|
2273 |
seconds past the pause end time
|
2274 |
|
2275 |
"""
|
2276 |
if now is None: |
2277 |
now = time.time() |
2278 |
|
2279 |
try:
|
2280 |
value = ReadFile(filename) |
2281 |
except IOError, err: |
2282 |
if err.errno != errno.ENOENT:
|
2283 |
raise
|
2284 |
value = None
|
2285 |
|
2286 |
if value is not None: |
2287 |
try:
|
2288 |
value = int(value)
|
2289 |
except ValueError: |
2290 |
logging.warning(("Watcher pause file (%s) contains invalid value,"
|
2291 |
" removing it"), filename)
|
2292 |
RemoveFile(filename) |
2293 |
value = None
|
2294 |
|
2295 |
if value is not None: |
2296 |
# Remove file if it's outdated
|
2297 |
if now > (value + remove_after):
|
2298 |
RemoveFile(filename) |
2299 |
value = None
|
2300 |
|
2301 |
elif now > value:
|
2302 |
value = None
|
2303 |
|
2304 |
return value
|
2305 |
|
2306 |
|
2307 |
class RetryTimeout(Exception): |
2308 |
"""Retry loop timed out.
|
2309 |
|
2310 |
"""
|
2311 |
|
2312 |
|
2313 |
class RetryAgain(Exception): |
2314 |
"""Retry again.
|
2315 |
|
2316 |
"""
|
2317 |
|
2318 |
|
2319 |
class _RetryDelayCalculator(object): |
2320 |
"""Calculator for increasing delays.
|
2321 |
|
2322 |
"""
|
2323 |
__slots__ = [ |
2324 |
"_factor",
|
2325 |
"_limit",
|
2326 |
"_next",
|
2327 |
"_start",
|
2328 |
] |
2329 |
|
2330 |
def __init__(self, start, factor, limit): |
2331 |
"""Initializes this class.
|
2332 |
|
2333 |
@type start: float
|
2334 |
@param start: Initial delay
|
2335 |
@type factor: float
|
2336 |
@param factor: Factor for delay increase
|
2337 |
@type limit: float or None
|
2338 |
@param limit: Upper limit for delay or None for no limit
|
2339 |
|
2340 |
"""
|
2341 |
assert start > 0.0 |
2342 |
assert factor >= 1.0 |
2343 |
assert limit is None or limit >= 0.0 |
2344 |
|
2345 |
self._start = start
|
2346 |
self._factor = factor
|
2347 |
self._limit = limit
|
2348 |
|
2349 |
self._next = start
|
2350 |
|
2351 |
def __call__(self): |
2352 |
"""Returns current delay and calculates the next one.
|
2353 |
|
2354 |
"""
|
2355 |
current = self._next
|
2356 |
|
2357 |
# Update for next run
|
2358 |
if self._limit is None or self._next < self._limit: |
2359 |
self._next = min(self._limit, self._next * self._factor) |
2360 |
|
2361 |
return current
|
2362 |
|
2363 |
|
2364 |
#: Special delay to specify whole remaining timeout
|
2365 |
RETRY_REMAINING_TIME = object()
|
2366 |
|
2367 |
|
2368 |
def Retry(fn, delay, timeout, args=None, wait_fn=time.sleep, |
2369 |
_time_fn=time.time): |
2370 |
"""Call a function repeatedly until it succeeds.
|
2371 |
|
2372 |
The function C{fn} is called repeatedly until it doesn't throw L{RetryAgain}
|
2373 |
anymore. Between calls a delay, specified by C{delay}, is inserted. After a
|
2374 |
total of C{timeout} seconds, this function throws L{RetryTimeout}.
|
2375 |
|
2376 |
C{delay} can be one of the following:
|
2377 |
- callable returning the delay length as a float
|
2378 |
- Tuple of (start, factor, limit)
|
2379 |
- L{RETRY_REMAINING_TIME} to sleep until the timeout expires (this is
|
2380 |
useful when overriding L{wait_fn} to wait for an external event)
|
2381 |
- A static delay as a number (int or float)
|
2382 |
|
2383 |
@type fn: callable
|
2384 |
@param fn: Function to be called
|
2385 |
@param delay: Either a callable (returning the delay), a tuple of (start,
|
2386 |
factor, limit) (see L{_RetryDelayCalculator}),
|
2387 |
L{RETRY_REMAINING_TIME} or a number (int or float)
|
2388 |
@type timeout: float
|
2389 |
@param timeout: Total timeout
|
2390 |
@type wait_fn: callable
|
2391 |
@param wait_fn: Waiting function
|
2392 |
@return: Return value of function
|
2393 |
|
2394 |
"""
|
2395 |
assert callable(fn) |
2396 |
assert callable(wait_fn) |
2397 |
assert callable(_time_fn) |
2398 |
|
2399 |
if args is None: |
2400 |
args = [] |
2401 |
|
2402 |
end_time = _time_fn() + timeout |
2403 |
|
2404 |
if callable(delay): |
2405 |
# External function to calculate delay
|
2406 |
calc_delay = delay |
2407 |
|
2408 |
elif isinstance(delay, (tuple, list)): |
2409 |
# Increasing delay with optional upper boundary
|
2410 |
(start, factor, limit) = delay |
2411 |
calc_delay = _RetryDelayCalculator(start, factor, limit) |
2412 |
|
2413 |
elif delay is RETRY_REMAINING_TIME: |
2414 |
# Always use the remaining time
|
2415 |
calc_delay = None
|
2416 |
|
2417 |
else:
|
2418 |
# Static delay
|
2419 |
calc_delay = lambda: delay
|
2420 |
|
2421 |
assert calc_delay is None or callable(calc_delay) |
2422 |
|
2423 |
while True: |
2424 |
try:
|
2425 |
# pylint: disable-msg=W0142
|
2426 |
return fn(*args)
|
2427 |
except RetryAgain:
|
2428 |
pass
|
2429 |
|
2430 |
remaining_time = end_time - _time_fn() |
2431 |
|
2432 |
if remaining_time < 0.0: |
2433 |
raise RetryTimeout()
|
2434 |
|
2435 |
assert remaining_time >= 0.0 |
2436 |
|
2437 |
if calc_delay is None: |
2438 |
wait_fn(remaining_time) |
2439 |
else:
|
2440 |
current_delay = calc_delay() |
2441 |
if current_delay > 0.0: |
2442 |
wait_fn(current_delay) |
2443 |
|
2444 |
|
2445 |
class FileLock(object): |
2446 |
"""Utility class for file locks.
|
2447 |
|
2448 |
"""
|
2449 |
def __init__(self, filename): |
2450 |
"""Constructor for FileLock.
|
2451 |
|
2452 |
This will open the file denoted by the I{filename} argument.
|
2453 |
|
2454 |
@type filename: str
|
2455 |
@param filename: path to the file to be locked
|
2456 |
|
2457 |
"""
|
2458 |
self.filename = filename
|
2459 |
self.fd = open(self.filename, "w") |
2460 |
|
2461 |
def __del__(self): |
2462 |
self.Close()
|
2463 |
|
2464 |
def Close(self): |
2465 |
"""Close the file and release the lock.
|
2466 |
|
2467 |
"""
|
2468 |
if hasattr(self, "fd") and self.fd: |
2469 |
self.fd.close()
|
2470 |
self.fd = None |
2471 |
|
2472 |
def _flock(self, flag, blocking, timeout, errmsg): |
2473 |
"""Wrapper for fcntl.flock.
|
2474 |
|
2475 |
@type flag: int
|
2476 |
@param flag: operation flag
|
2477 |
@type blocking: bool
|
2478 |
@param blocking: whether the operation should be done in blocking mode.
|
2479 |
@type timeout: None or float
|
2480 |
@param timeout: for how long the operation should be retried (implies
|
2481 |
non-blocking mode).
|
2482 |
@type errmsg: string
|
2483 |
@param errmsg: error message in case operation fails.
|
2484 |
|
2485 |
"""
|
2486 |
assert self.fd, "Lock was closed" |
2487 |
assert timeout is None or timeout >= 0, \ |
2488 |
"If specified, timeout must be positive"
|
2489 |
assert not (flag & fcntl.LOCK_NB), "LOCK_NB must not be set" |
2490 |
|
2491 |
# When a timeout is used, LOCK_NB must always be set
|
2492 |
if not (timeout is None and blocking): |
2493 |
flag |= fcntl.LOCK_NB |
2494 |
|
2495 |
if timeout is None: |
2496 |
self._Lock(self.fd, flag, timeout) |
2497 |
else:
|
2498 |
try:
|
2499 |
Retry(self._Lock, (0.1, 1.2, 1.0), timeout, |
2500 |
args=(self.fd, flag, timeout))
|
2501 |
except RetryTimeout:
|
2502 |
raise errors.LockError(errmsg)
|
2503 |
|
2504 |
@staticmethod
|
2505 |
def _Lock(fd, flag, timeout): |
2506 |
try:
|
2507 |
fcntl.flock(fd, flag) |
2508 |
except IOError, err: |
2509 |
if timeout is not None and err.errno == errno.EAGAIN: |
2510 |
raise RetryAgain()
|
2511 |
|
2512 |
logging.exception("fcntl.flock failed")
|
2513 |
raise
|
2514 |
|
2515 |
def Exclusive(self, blocking=False, timeout=None): |
2516 |
"""Locks the file in exclusive mode.
|
2517 |
|
2518 |
@type blocking: boolean
|
2519 |
@param blocking: whether to block and wait until we
|
2520 |
can lock the file or return immediately
|
2521 |
@type timeout: int or None
|
2522 |
@param timeout: if not None, the duration to wait for the lock
|
2523 |
(in blocking mode)
|
2524 |
|
2525 |
"""
|
2526 |
self._flock(fcntl.LOCK_EX, blocking, timeout,
|
2527 |
"Failed to lock %s in exclusive mode" % self.filename) |
2528 |
|
2529 |
def Shared(self, blocking=False, timeout=None): |
2530 |
"""Locks the file in shared mode.
|
2531 |
|
2532 |
@type blocking: boolean
|
2533 |
@param blocking: whether to block and wait until we
|
2534 |
can lock the file or return immediately
|
2535 |
@type timeout: int or None
|
2536 |
@param timeout: if not None, the duration to wait for the lock
|
2537 |
(in blocking mode)
|
2538 |
|
2539 |
"""
|
2540 |
self._flock(fcntl.LOCK_SH, blocking, timeout,
|
2541 |
"Failed to lock %s in shared mode" % self.filename) |
2542 |
|
2543 |
def Unlock(self, blocking=True, timeout=None): |
2544 |
"""Unlocks the file.
|
2545 |
|
2546 |
According to C{flock(2)}, unlocking can also be a nonblocking
|
2547 |
operation::
|
2548 |
|
2549 |
To make a non-blocking request, include LOCK_NB with any of the above
|
2550 |
operations.
|
2551 |
|
2552 |
@type blocking: boolean
|
2553 |
@param blocking: whether to block and wait until we
|
2554 |
can lock the file or return immediately
|
2555 |
@type timeout: int or None
|
2556 |
@param timeout: if not None, the duration to wait for the lock
|
2557 |
(in blocking mode)
|
2558 |
|
2559 |
"""
|
2560 |
self._flock(fcntl.LOCK_UN, blocking, timeout,
|
2561 |
"Failed to unlock %s" % self.filename) |
2562 |
|
2563 |
|
2564 |
def SignalHandled(signums): |
2565 |
"""Signal Handled decoration.
|
2566 |
|
2567 |
This special decorator installs a signal handler and then calls the target
|
2568 |
function. The function must accept a 'signal_handlers' keyword argument,
|
2569 |
which will contain a dict indexed by signal number, with SignalHandler
|
2570 |
objects as values.
|
2571 |
|
2572 |
The decorator can be safely stacked with iself, to handle multiple signals
|
2573 |
with different handlers.
|
2574 |
|
2575 |
@type signums: list
|
2576 |
@param signums: signals to intercept
|
2577 |
|
2578 |
"""
|
2579 |
def wrap(fn): |
2580 |
def sig_function(*args, **kwargs): |
2581 |
assert 'signal_handlers' not in kwargs or \ |
2582 |
kwargs['signal_handlers'] is None or \ |
2583 |
isinstance(kwargs['signal_handlers'], dict), \ |
2584 |
"Wrong signal_handlers parameter in original function call"
|
2585 |
if 'signal_handlers' in kwargs and kwargs['signal_handlers'] is not None: |
2586 |
signal_handlers = kwargs['signal_handlers']
|
2587 |
else:
|
2588 |
signal_handlers = {} |
2589 |
kwargs['signal_handlers'] = signal_handlers
|
2590 |
sighandler = SignalHandler(signums) |
2591 |
try:
|
2592 |
for sig in signums: |
2593 |
signal_handlers[sig] = sighandler |
2594 |
return fn(*args, **kwargs)
|
2595 |
finally:
|
2596 |
sighandler.Reset() |
2597 |
return sig_function
|
2598 |
return wrap
|
2599 |
|
2600 |
|
2601 |
class SignalHandler(object): |
2602 |
"""Generic signal handler class.
|
2603 |
|
2604 |
It automatically restores the original handler when deconstructed or
|
2605 |
when L{Reset} is called. You can either pass your own handler
|
2606 |
function in or query the L{called} attribute to detect whether the
|
2607 |
signal was sent.
|
2608 |
|
2609 |
@type signum: list
|
2610 |
@ivar signum: the signals we handle
|
2611 |
@type called: boolean
|
2612 |
@ivar called: tracks whether any of the signals have been raised
|
2613 |
|
2614 |
"""
|
2615 |
def __init__(self, signum): |
2616 |
"""Constructs a new SignalHandler instance.
|
2617 |
|
2618 |
@type signum: int or list of ints
|
2619 |
@param signum: Single signal number or set of signal numbers
|
2620 |
|
2621 |
"""
|
2622 |
self.signum = set(signum) |
2623 |
self.called = False |
2624 |
|
2625 |
self._previous = {}
|
2626 |
try:
|
2627 |
for signum in self.signum: |
2628 |
# Setup handler
|
2629 |
prev_handler = signal.signal(signum, self._HandleSignal)
|
2630 |
try:
|
2631 |
self._previous[signum] = prev_handler
|
2632 |
except:
|
2633 |
# Restore previous handler
|
2634 |
signal.signal(signum, prev_handler) |
2635 |
raise
|
2636 |
except:
|
2637 |
# Reset all handlers
|
2638 |
self.Reset()
|
2639 |
# Here we have a race condition: a handler may have already been called,
|
2640 |
# but there's not much we can do about it at this point.
|
2641 |
raise
|
2642 |
|
2643 |
def __del__(self): |
2644 |
self.Reset()
|
2645 |
|
2646 |
def Reset(self): |
2647 |
"""Restore previous handler.
|
2648 |
|
2649 |
This will reset all the signals to their previous handlers.
|
2650 |
|
2651 |
"""
|
2652 |
for signum, prev_handler in self._previous.items(): |
2653 |
signal.signal(signum, prev_handler) |
2654 |
# If successful, remove from dict
|
2655 |
del self._previous[signum] |
2656 |
|
2657 |
def Clear(self): |
2658 |
"""Unsets the L{called} flag.
|
2659 |
|
2660 |
This function can be used in case a signal may arrive several times.
|
2661 |
|
2662 |
"""
|
2663 |
self.called = False |
2664 |
|
2665 |
# we don't care about arguments, but we leave them named for the future
|
2666 |
def _HandleSignal(self, signum, frame): # pylint: disable-msg=W0613 |
2667 |
"""Actual signal handling function.
|
2668 |
|
2669 |
"""
|
2670 |
# This is not nice and not absolutely atomic, but it appears to be the only
|
2671 |
# solution in Python -- there are no atomic types.
|
2672 |
self.called = True |
2673 |
|
2674 |
|
2675 |
class FieldSet(object): |
2676 |
"""A simple field set.
|
2677 |
|
2678 |
Among the features are:
|
2679 |
- checking if a string is among a list of static string or regex objects
|
2680 |
- checking if a whole list of string matches
|
2681 |
- returning the matching groups from a regex match
|
2682 |
|
2683 |
Internally, all fields are held as regular expression objects.
|
2684 |
|
2685 |
"""
|
2686 |
def __init__(self, *items): |
2687 |
self.items = [re.compile("^%s$" % value) for value in items] |
2688 |
|
2689 |
def Extend(self, other_set): |
2690 |
"""Extend the field set with the items from another one"""
|
2691 |
self.items.extend(other_set.items)
|
2692 |
|
2693 |
def Matches(self, field): |
2694 |
"""Checks if a field matches the current set
|
2695 |
|
2696 |
@type field: str
|
2697 |
@param field: the string to match
|
2698 |
@return: either None or a regular expression match object
|
2699 |
|
2700 |
"""
|
2701 |
for m in itertools.ifilter(None, (val.match(field) for val in self.items)): |
2702 |
return m
|
2703 |
return None |
2704 |
|
2705 |
def NonMatching(self, items): |
2706 |
"""Returns the list of fields not matching the current set
|
2707 |
|
2708 |
@type items: list
|
2709 |
@param items: the list of fields to check
|
2710 |
@rtype: list
|
2711 |
@return: list of non-matching fields
|
2712 |
|
2713 |
"""
|
2714 |
return [val for val in items if not self.Matches(val)] |