4 # Copyright (C) 2006, 2007 Google Inc.
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful, but
12 # WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 # General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program; if not, write to the Free Software
18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 """Ganeti utility module.
24 This module holds functions that can be used in both daemons (all) and
25 the command line scripts.
46 from cStringIO import StringIO
49 from hashlib import sha1
54 from ganeti import errors
55 from ganeti import constants
59 _re_shell_unquoted = re.compile('^[-.,=:/_+@A-Za-z0-9]+$')
63 #: when set to True, L{RunCmd} is disabled
66 _RANDOM_UUID_FILE = "/proc/sys/kernel/random/uuid"
69 class RunResult(object):
70 """Holds the result of running external programs.
73 @ivar exit_code: the exit code of the program, or None (if the program
75 @type signal: int or None
76 @ivar signal: the signal that caused the program to finish, or None
77 (if the program wasn't terminated by a signal)
79 @ivar stdout: the standard output of the program
81 @ivar stderr: the standard error of the program
83 @ivar failed: True in case the program was
84 terminated by a signal or exited with a non-zero exit code
85 @ivar fail_reason: a string detailing the termination reason
88 __slots__ = ["exit_code", "signal", "stdout", "stderr",
89 "failed", "fail_reason", "cmd"]
92 def __init__(self, exit_code, signal_, stdout, stderr, cmd):
94 self.exit_code = exit_code
98 self.failed = (signal_ is not None or exit_code != 0)
100 if self.signal is not None:
101 self.fail_reason = "terminated by signal %s" % self.signal
102 elif self.exit_code is not None:
103 self.fail_reason = "exited with exit code %s" % self.exit_code
105 self.fail_reason = "unable to determine termination reason"
108 logging.debug("Command '%s' failed (%s); output: %s",
109 self.cmd, self.fail_reason, self.output)
111 def _GetOutput(self):
112 """Returns the combined stdout and stderr for easier usage.
115 return self.stdout + self.stderr
117 output = property(_GetOutput, None, None, "Return full output")
120 def RunCmd(cmd, env=None, output=None, cwd='/'):
121 """Execute a (shell) command.
123 The command should not read from its standard input, as it will be
126 @type cmd: string or list
127 @param cmd: Command to run
129 @param env: Additional environment
131 @param output: if desired, the output of the command can be
132 saved in a file instead of the RunResult instance; this
133 parameter denotes the file name (if not None)
135 @param cwd: if specified, will be used as the working
136 directory for the command; the default will be /
138 @return: RunResult instance
139 @raise errors.ProgrammerError: if we call this when forks are disabled
143 raise errors.ProgrammerError("utils.RunCmd() called with fork() disabled")
145 if isinstance(cmd, list):
146 cmd = [str(val) for val in cmd]
147 strcmd = " ".join(cmd)
152 logging.debug("RunCmd '%s'", strcmd)
154 cmd_env = os.environ.copy()
155 cmd_env["LC_ALL"] = "C"
161 out, err, status = _RunCmdPipe(cmd, cmd_env, shell, cwd)
163 status = _RunCmdFile(cmd, cmd_env, shell, output, cwd)
166 if err.errno == errno.ENOENT:
167 raise errors.OpExecError("Can't execute '%s': not found (%s)" %
179 return RunResult(exitcode, signal_, out, err, strcmd)
182 def _RunCmdPipe(cmd, env, via_shell, cwd):
183 """Run a command and return its output.
185 @type cmd: string or list
186 @param cmd: Command to run
188 @param env: The environment to use
189 @type via_shell: bool
190 @param via_shell: if we should run via the shell
192 @param cwd: the working directory for the program
194 @return: (out, err, status)
197 poller = select.poll()
198 child = subprocess.Popen(cmd, shell=via_shell,
199 stderr=subprocess.PIPE,
200 stdout=subprocess.PIPE,
201 stdin=subprocess.PIPE,
202 close_fds=True, env=env,
206 poller.register(child.stdout, select.POLLIN)
207 poller.register(child.stderr, select.POLLIN)
211 child.stdout.fileno(): (out, child.stdout),
212 child.stderr.fileno(): (err, child.stderr),
215 status = fcntl.fcntl(fd, fcntl.F_GETFL)
216 fcntl.fcntl(fd, fcntl.F_SETFL, status | os.O_NONBLOCK)
220 pollresult = poller.poll()
221 except EnvironmentError, eerr:
222 if eerr.errno == errno.EINTR:
225 except select.error, serr:
226 if serr[0] == errno.EINTR:
230 for fd, event in pollresult:
231 if event & select.POLLIN or event & select.POLLPRI:
232 data = fdmap[fd][1].read()
233 # no data from read signifies EOF (the same as POLLHUP)
235 poller.unregister(fd)
238 fdmap[fd][0].write(data)
239 if (event & select.POLLNVAL or event & select.POLLHUP or
240 event & select.POLLERR):
241 poller.unregister(fd)
247 status = child.wait()
248 return out, err, status
251 def _RunCmdFile(cmd, env, via_shell, output, cwd):
252 """Run a command and save its output to a file.
254 @type cmd: string or list
255 @param cmd: Command to run
257 @param env: The environment to use
258 @type via_shell: bool
259 @param via_shell: if we should run via the shell
261 @param output: the filename in which to save the output
263 @param cwd: the working directory for the program
265 @return: the exit status
268 fh = open(output, "a")
270 child = subprocess.Popen(cmd, shell=via_shell,
271 stderr=subprocess.STDOUT,
273 stdin=subprocess.PIPE,
274 close_fds=True, env=env,
278 status = child.wait()
284 def RemoveFile(filename):
285 """Remove a file ignoring some errors.
287 Remove a file, ignoring non-existing ones or directories. Other
291 @param filename: the file to be removed
297 if err.errno not in (errno.ENOENT, errno.EISDIR):
301 def RenameFile(old, new, mkdir=False, mkdir_mode=0750):
305 @param old: Original path
309 @param mkdir: Whether to create target directory if it doesn't exist
310 @type mkdir_mode: int
311 @param mkdir_mode: Mode for newly created directories
315 return os.rename(old, new)
317 # In at least one use case of this function, the job queue, directory
318 # creation is very rare. Checking for the directory before renaming is not
320 if mkdir and err.errno == errno.ENOENT:
321 # Create directory and try again
322 os.makedirs(os.path.dirname(new), mkdir_mode)
323 return os.rename(old, new)
327 def _FingerprintFile(filename):
328 """Compute the fingerprint of a file.
330 If the file does not exist, a None will be returned
334 @param filename: the filename to checksum
336 @return: the hex digest of the sha checksum of the contents
340 if not (os.path.exists(filename) and os.path.isfile(filename)):
353 return fp.hexdigest()
356 def FingerprintFiles(files):
357 """Compute fingerprints for a list of files.
360 @param files: the list of filename to fingerprint
362 @return: a dictionary filename: fingerprint, holding only
368 for filename in files:
369 cksum = _FingerprintFile(filename)
371 ret[filename] = cksum
376 def ForceDictType(target, key_types, allowed_values=None):
377 """Force the values of a dict to have certain types.
380 @param target: the dict to update
381 @type key_types: dict
382 @param key_types: dict mapping target dict keys to types
383 in constants.ENFORCEABLE_TYPES
384 @type allowed_values: list
385 @keyword allowed_values: list of specially allowed values
388 if allowed_values is None:
391 if not isinstance(target, dict):
392 msg = "Expected dictionary, got '%s'" % target
393 raise errors.TypeEnforcementError(msg)
396 if key not in key_types:
397 msg = "Unknown key '%s'" % key
398 raise errors.TypeEnforcementError(msg)
400 if target[key] in allowed_values:
403 ktype = key_types[key]
404 if ktype not in constants.ENFORCEABLE_TYPES:
405 msg = "'%s' has non-enforceable type %s" % (key, ktype)
406 raise errors.ProgrammerError(msg)
408 if ktype == constants.VTYPE_STRING:
409 if not isinstance(target[key], basestring):
410 if isinstance(target[key], bool) and not target[key]:
413 msg = "'%s' (value %s) is not a valid string" % (key, target[key])
414 raise errors.TypeEnforcementError(msg)
415 elif ktype == constants.VTYPE_BOOL:
416 if isinstance(target[key], basestring) and target[key]:
417 if target[key].lower() == constants.VALUE_FALSE:
419 elif target[key].lower() == constants.VALUE_TRUE:
422 msg = "'%s' (value %s) is not a valid boolean" % (key, target[key])
423 raise errors.TypeEnforcementError(msg)
428 elif ktype == constants.VTYPE_SIZE:
430 target[key] = ParseUnit(target[key])
431 except errors.UnitParseError, err:
432 msg = "'%s' (value %s) is not a valid size. error: %s" % \
433 (key, target[key], err)
434 raise errors.TypeEnforcementError(msg)
435 elif ktype == constants.VTYPE_INT:
437 target[key] = int(target[key])
438 except (ValueError, TypeError):
439 msg = "'%s' (value %s) is not a valid integer" % (key, target[key])
440 raise errors.TypeEnforcementError(msg)
443 def IsProcessAlive(pid):
444 """Check if a given pid exists on the system.
446 @note: zombie status is not handled, so zombie processes
447 will be returned as alive
449 @param pid: the process ID to check
451 @return: True if the process exists
458 os.stat("/proc/%d/status" % pid)
460 except EnvironmentError, err:
461 if err.errno in (errno.ENOENT, errno.ENOTDIR):
466 def ReadPidFile(pidfile):
467 """Read a pid from a file.
469 @type pidfile: string
470 @param pidfile: path to the file containing the pid
472 @return: The process id, if the file exists and contains a valid PID,
477 raw_data = ReadFile(pidfile)
478 except EnvironmentError, err:
479 if err.errno != errno.ENOENT:
480 logging.exception("Can't read pid file")
485 except ValueError, err:
486 logging.info("Can't parse pid file contents", exc_info=True)
492 def MatchNameComponent(key, name_list, case_sensitive=True):
493 """Try to match a name against a list.
495 This function will try to match a name like test1 against a list
496 like C{['test1.example.com', 'test2.example.com', ...]}. Against
497 this list, I{'test1'} as well as I{'test1.example'} will match, but
498 not I{'test1.ex'}. A multiple match will be considered as no match
499 at all (e.g. I{'test1'} against C{['test1.example.com',
500 'test1.example.org']}), except when the key fully matches an entry
501 (e.g. I{'test1'} against C{['test1', 'test1.example.com']}).
504 @param key: the name to be searched
505 @type name_list: list
506 @param name_list: the list of strings against which to search the key
507 @type case_sensitive: boolean
508 @param case_sensitive: whether to provide a case-sensitive match
511 @return: None if there is no match I{or} if there are multiple matches,
512 otherwise the element from the list which matches
519 if not case_sensitive:
520 re_flags |= re.IGNORECASE
522 mo = re.compile("^%s(\..*)?$" % re.escape(key), re_flags)
525 for name in name_list:
526 if mo.match(name) is not None:
527 names_filtered.append(name)
528 if not case_sensitive and key == name.upper():
529 string_matches.append(name)
531 if len(string_matches) == 1:
532 return string_matches[0]
533 if len(names_filtered) == 1:
534 return names_filtered[0]
539 """Class implementing resolver and hostname functionality
542 def __init__(self, name=None):
543 """Initialize the host name object.
545 If the name argument is not passed, it will use this system's
550 name = self.SysName()
553 self.name, self.aliases, self.ipaddrs = self.LookupHostname(name)
554 self.ip = self.ipaddrs[0]
557 """Returns the hostname without domain.
560 return self.name.split('.')[0]
564 """Return the current system's name.
566 This is simply a wrapper over C{socket.gethostname()}.
569 return socket.gethostname()
572 def LookupHostname(hostname):
576 @param hostname: hostname to look up
579 @return: a tuple (name, aliases, ipaddrs) as returned by
580 C{socket.gethostbyname_ex}
581 @raise errors.ResolverError: in case of errors in resolving
585 result = socket.gethostbyname_ex(hostname)
586 except socket.gaierror, err:
587 # hostname not found in DNS
588 raise errors.ResolverError(hostname, err.args[0], err.args[1])
593 def ListVolumeGroups():
594 """List volume groups and their size
598 Dictionary with keys volume name and values
599 the size of the volume
602 command = "vgs --noheadings --units m --nosuffix -o name,size"
603 result = RunCmd(command)
608 for line in result.stdout.splitlines():
610 name, size = line.split()
611 size = int(float(size))
612 except (IndexError, ValueError), err:
613 logging.error("Invalid output from vgs (%s): %s", err, line)
621 def BridgeExists(bridge):
622 """Check whether the given bridge exists in the system
625 @param bridge: the bridge name to check
627 @return: True if it does
630 return os.path.isdir("/sys/class/net/%s/bridge" % bridge)
633 def NiceSort(name_list):
634 """Sort a list of strings based on digit and non-digit groupings.
636 Given a list of names C{['a1', 'a10', 'a11', 'a2']} this function
637 will sort the list in the logical order C{['a1', 'a2', 'a10',
640 The sort algorithm breaks each name in groups of either only-digits
641 or no-digits. Only the first eight such groups are considered, and
642 after that we just use what's left of the string.
644 @type name_list: list
645 @param name_list: the names to be sorted
647 @return: a copy of the name list sorted with our algorithm
650 _SORTER_BASE = "(\D+|\d+)"
651 _SORTER_FULL = "^%s%s?%s?%s?%s?%s?%s?%s?.*$" % (_SORTER_BASE, _SORTER_BASE,
652 _SORTER_BASE, _SORTER_BASE,
653 _SORTER_BASE, _SORTER_BASE,
654 _SORTER_BASE, _SORTER_BASE)
655 _SORTER_RE = re.compile(_SORTER_FULL)
656 _SORTER_NODIGIT = re.compile("^\D*$")
658 """Attempts to convert a variable to integer."""
659 if val is None or _SORTER_NODIGIT.match(val):
664 to_sort = [([_TryInt(grp) for grp in _SORTER_RE.match(name).groups()], name)
665 for name in name_list]
667 return [tup[1] for tup in to_sort]
670 def TryConvert(fn, val):
671 """Try to convert a value ignoring errors.
673 This function tries to apply function I{fn} to I{val}. If no
674 C{ValueError} or C{TypeError} exceptions are raised, it will return
675 the result, else it will return the original value. Any other
676 exceptions are propagated to the caller.
679 @param fn: function to apply to the value
680 @param val: the value to be converted
681 @return: The converted value if the conversion was successful,
682 otherwise the original value.
687 except (ValueError, TypeError):
693 """Verifies the syntax of an IPv4 address.
695 This function checks if the IPv4 address passes is valid or not based
696 on syntax (not IP range, class calculations, etc.).
699 @param ip: the address to be checked
700 @rtype: a regular expression match object
701 @return: a regular expression match object, or None if the
705 unit = "(0|[1-9]\d{0,2})"
706 #TODO: convert and return only boolean
707 return re.match("^%s\.%s\.%s\.%s$" % (unit, unit, unit, unit), ip)
710 def IsValidShellParam(word):
711 """Verifies is the given word is safe from the shell's p.o.v.
713 This means that we can pass this to a command via the shell and be
714 sure that it doesn't alter the command line and is passed as such to
717 Note that we are overly restrictive here, in order to be on the safe
721 @param word: the word to check
723 @return: True if the word is 'safe'
726 return bool(re.match("^[-a-zA-Z0-9._+/:%@]+$", word))
729 def BuildShellCmd(template, *args):
730 """Build a safe shell command line from the given arguments.
732 This function will check all arguments in the args list so that they
733 are valid shell parameters (i.e. they don't contain shell
734 metacharacters). If everything is ok, it will return the result of
738 @param template: the string holding the template for the
741 @return: the expanded command line
745 if not IsValidShellParam(word):
746 raise errors.ProgrammerError("Shell argument '%s' contains"
747 " invalid characters" % word)
748 return template % args
751 def FormatUnit(value, units):
752 """Formats an incoming number of MiB with the appropriate unit.
755 @param value: integer representing the value in MiB (1048576)
757 @param units: the type of formatting we should do:
758 - 'h' for automatic scaling
763 @return: the formatted value (with suffix)
766 if units not in ('m', 'g', 't', 'h'):
767 raise errors.ProgrammerError("Invalid unit specified '%s'" % str(units))
771 if units == 'm' or (units == 'h' and value < 1024):
774 return "%d%s" % (round(value, 0), suffix)
776 elif units == 'g' or (units == 'h' and value < (1024 * 1024)):
779 return "%0.1f%s" % (round(float(value) / 1024, 1), suffix)
784 return "%0.1f%s" % (round(float(value) / 1024 / 1024, 1), suffix)
787 def ParseUnit(input_string):
788 """Tries to extract number and scale from the given string.
790 Input must be in the format C{NUMBER+ [DOT NUMBER+] SPACE*
791 [UNIT]}. If no unit is specified, it defaults to MiB. Return value
792 is always an int in MiB.
795 m = re.match('^([.\d]+)\s*([a-zA-Z]+)?$', str(input_string))
797 raise errors.UnitParseError("Invalid format")
799 value = float(m.groups()[0])
803 lcunit = unit.lower()
807 if lcunit in ('m', 'mb', 'mib'):
808 # Value already in MiB
811 elif lcunit in ('g', 'gb', 'gib'):
814 elif lcunit in ('t', 'tb', 'tib'):
818 raise errors.UnitParseError("Unknown unit: %s" % unit)
820 # Make sure we round up
821 if int(value) < value:
824 # Round up to the next multiple of 4
827 value += 4 - value % 4
832 def AddAuthorizedKey(file_name, key):
833 """Adds an SSH public key to an authorized_keys file.
836 @param file_name: path to authorized_keys file
838 @param key: string containing key
841 key_fields = key.split()
843 f = open(file_name, 'a+')
847 # Ignore whitespace changes
848 if line.split() == key_fields:
850 nl = line.endswith('\n')
854 f.write(key.rstrip('\r\n'))
861 def RemoveAuthorizedKey(file_name, key):
862 """Removes an SSH public key from an authorized_keys file.
865 @param file_name: path to authorized_keys file
867 @param key: string containing key
870 key_fields = key.split()
872 fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name))
874 out = os.fdopen(fd, 'w')
876 f = open(file_name, 'r')
879 # Ignore whitespace changes while comparing lines
880 if line.split() != key_fields:
884 os.rename(tmpname, file_name)
894 def SetEtcHostsEntry(file_name, ip, hostname, aliases):
895 """Sets the name of an IP address and hostname in /etc/hosts.
898 @param file_name: path to the file to modify (usually C{/etc/hosts})
900 @param ip: the IP address
902 @param hostname: the hostname to be added
904 @param aliases: the list of aliases to add for the hostname
907 # FIXME: use WriteFile + fn rather than duplicating its efforts
908 # Ensure aliases are unique
909 aliases = UniqueSequence([hostname] + aliases)[1:]
911 fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name))
913 out = os.fdopen(fd, 'w')
915 f = open(file_name, 'r')
918 fields = line.split()
919 if fields and not fields[0].startswith('#') and ip == fields[0]:
923 out.write("%s\t%s" % (ip, hostname))
925 out.write(" %s" % ' '.join(aliases))
930 os.chmod(tmpname, 0644)
931 os.rename(tmpname, file_name)
941 def AddHostToEtcHosts(hostname):
942 """Wrapper around SetEtcHostsEntry.
945 @param hostname: a hostname that will be resolved and added to
946 L{constants.ETC_HOSTS}
949 hi = HostInfo(name=hostname)
950 SetEtcHostsEntry(constants.ETC_HOSTS, hi.ip, hi.name, [hi.ShortName()])
953 def RemoveEtcHostsEntry(file_name, hostname):
954 """Removes a hostname from /etc/hosts.
956 IP addresses without names are removed from the file.
959 @param file_name: path to the file to modify (usually C{/etc/hosts})
961 @param hostname: the hostname to be removed
964 # FIXME: use WriteFile + fn rather than duplicating its efforts
965 fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name))
967 out = os.fdopen(fd, 'w')
969 f = open(file_name, 'r')
972 fields = line.split()
973 if len(fields) > 1 and not fields[0].startswith('#'):
975 if hostname in names:
976 while hostname in names:
977 names.remove(hostname)
979 out.write("%s %s\n" % (fields[0], ' '.join(names)))
986 os.chmod(tmpname, 0644)
987 os.rename(tmpname, file_name)
997 def RemoveHostFromEtcHosts(hostname):
998 """Wrapper around RemoveEtcHostsEntry.
1001 @param hostname: hostname that will be resolved and its
1002 full and shot name will be removed from
1003 L{constants.ETC_HOSTS}
1006 hi = HostInfo(name=hostname)
1007 RemoveEtcHostsEntry(constants.ETC_HOSTS, hi.name)
1008 RemoveEtcHostsEntry(constants.ETC_HOSTS, hi.ShortName())
1011 def CreateBackup(file_name):
1012 """Creates a backup of a file.
1014 @type file_name: str
1015 @param file_name: file to be backed up
1017 @return: the path to the newly created backup
1018 @raise errors.ProgrammerError: for invalid file names
1021 if not os.path.isfile(file_name):
1022 raise errors.ProgrammerError("Can't make a backup of a non-file '%s'" %
1025 prefix = '%s.backup-%d.' % (os.path.basename(file_name), int(time.time()))
1026 dir_name = os.path.dirname(file_name)
1028 fsrc = open(file_name, 'rb')
1030 (fd, backup_name) = tempfile.mkstemp(prefix=prefix, dir=dir_name)
1031 fdst = os.fdopen(fd, 'wb')
1033 shutil.copyfileobj(fsrc, fdst)
1042 def ShellQuote(value):
1043 """Quotes shell argument according to POSIX.
1046 @param value: the argument to be quoted
1048 @return: the quoted value
1051 if _re_shell_unquoted.match(value):
1054 return "'%s'" % value.replace("'", "'\\''")
1057 def ShellQuoteArgs(args):
1058 """Quotes a list of shell arguments.
1061 @param args: list of arguments to be quoted
1063 @return: the quoted arguments concatenated with spaces
1066 return ' '.join([ShellQuote(i) for i in args])
1069 def TcpPing(target, port, timeout=10, live_port_needed=False, source=None):
1070 """Simple ping implementation using TCP connect(2).
1072 Check if the given IP is reachable by doing attempting a TCP connect
1076 @param target: the IP or hostname to ping
1078 @param port: the port to connect to
1080 @param timeout: the timeout on the connection attempt
1081 @type live_port_needed: boolean
1082 @param live_port_needed: whether a closed port will cause the
1083 function to return failure, as if there was a timeout
1084 @type source: str or None
1085 @param source: if specified, will cause the connect to be made
1086 from this specific source address; failures to bind other
1087 than C{EADDRNOTAVAIL} will be ignored
1090 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
1094 if source is not None:
1096 sock.bind((source, 0))
1097 except socket.error, (errcode, _):
1098 if errcode == errno.EADDRNOTAVAIL:
1101 sock.settimeout(timeout)
1104 sock.connect((target, port))
1107 except socket.timeout:
1109 except socket.error, (errcode, _):
1110 success = (not live_port_needed) and (errcode == errno.ECONNREFUSED)
1115 def OwnIpAddress(address):
1116 """Check if the current host has the the given IP address.
1118 Currently this is done by TCP-pinging the address from the loopback
1121 @type address: string
1122 @param address: the address to check
1124 @return: True if we own the address
1127 return TcpPing(address, constants.DEFAULT_NODED_PORT,
1128 source=constants.LOCALHOST_IP_ADDRESS)
1131 def ListVisibleFiles(path):
1132 """Returns a list of visible files in a directory.
1135 @param path: the directory to enumerate
1137 @return: the list of all files not starting with a dot
1140 files = [i for i in os.listdir(path) if not i.startswith(".")]
1145 def GetHomeDir(user, default=None):
1146 """Try to get the homedir of the given user.
1148 The user can be passed either as a string (denoting the name) or as
1149 an integer (denoting the user id). If the user is not found, the
1150 'default' argument is returned, which defaults to None.
1154 if isinstance(user, basestring):
1155 result = pwd.getpwnam(user)
1156 elif isinstance(user, (int, long)):
1157 result = pwd.getpwuid(user)
1159 raise errors.ProgrammerError("Invalid type passed to GetHomeDir (%s)" %
1163 return result.pw_dir
1167 """Returns a random UUID.
1169 @note: This is a Linux-specific method as it uses the /proc
1174 return ReadFile(_RANDOM_UUID_FILE, size=128).rstrip("\n")
1177 def GenerateSecret(numbytes=20):
1178 """Generates a random secret.
1180 This will generate a pseudo-random secret returning an hex string
1181 (so that it can be used where an ASCII string is needed).
1183 @param numbytes: the number of bytes which will be represented by the returned
1184 string (defaulting to 20, the length of a SHA1 hash)
1186 @return: an hex representation of the pseudo-random sequence
1189 return os.urandom(numbytes).encode('hex')
1192 def EnsureDirs(dirs):
1193 """Make required directories, if they don't exist.
1195 @param dirs: list of tuples (dir_name, dir_mode)
1196 @type dirs: list of (string, integer)
1199 for dir_name, dir_mode in dirs:
1201 os.mkdir(dir_name, dir_mode)
1202 except EnvironmentError, err:
1203 if err.errno != errno.EEXIST:
1204 raise errors.GenericError("Cannot create needed directory"
1205 " '%s': %s" % (dir_name, err))
1206 if not os.path.isdir(dir_name):
1207 raise errors.GenericError("%s is not a directory" % dir_name)
1210 def ReadFile(file_name, size=None):
1213 @type size: None or int
1214 @param size: Read at most size bytes
1216 @return: the (possibly partial) content of the file
1219 f = open(file_name, "r")
1229 def WriteFile(file_name, fn=None, data=None,
1230 mode=None, uid=-1, gid=-1,
1231 atime=None, mtime=None, close=True,
1232 dry_run=False, backup=False,
1233 prewrite=None, postwrite=None):
1234 """(Over)write a file atomically.
1236 The file_name and either fn (a function taking one argument, the
1237 file descriptor, and which should write the data to it) or data (the
1238 contents of the file) must be passed. The other arguments are
1239 optional and allow setting the file mode, owner and group, and the
1240 mtime/atime of the file.
1242 If the function doesn't raise an exception, it has succeeded and the
1243 target file has the new contents. If the function has raised an
1244 exception, an existing target file should be unmodified and the
1245 temporary file should be removed.
1247 @type file_name: str
1248 @param file_name: the target filename
1250 @param fn: content writing function, called with
1251 file descriptor as parameter
1253 @param data: contents of the file
1255 @param mode: file mode
1257 @param uid: the owner of the file
1259 @param gid: the group of the file
1261 @param atime: a custom access time to be set on the file
1263 @param mtime: a custom modification time to be set on the file
1264 @type close: boolean
1265 @param close: whether to close file after writing it
1266 @type prewrite: callable
1267 @param prewrite: function to be called before writing content
1268 @type postwrite: callable
1269 @param postwrite: function to be called after writing content
1272 @return: None if the 'close' parameter evaluates to True,
1273 otherwise the file descriptor
1275 @raise errors.ProgrammerError: if any of the arguments are not valid
1278 if not os.path.isabs(file_name):
1279 raise errors.ProgrammerError("Path passed to WriteFile is not"
1280 " absolute: '%s'" % file_name)
1282 if [fn, data].count(None) != 1:
1283 raise errors.ProgrammerError("fn or data required")
1285 if [atime, mtime].count(None) == 1:
1286 raise errors.ProgrammerError("Both atime and mtime must be either"
1289 if backup and not dry_run and os.path.isfile(file_name):
1290 CreateBackup(file_name)
1292 dir_name, base_name = os.path.split(file_name)
1293 fd, new_name = tempfile.mkstemp('.new', base_name, dir_name)
1295 # here we need to make sure we remove the temp file, if any error
1296 # leaves it in place
1298 if uid != -1 or gid != -1:
1299 os.chown(new_name, uid, gid)
1301 os.chmod(new_name, mode)
1302 if callable(prewrite):
1304 if data is not None:
1308 if callable(postwrite):
1311 if atime is not None and mtime is not None:
1312 os.utime(new_name, (atime, mtime))
1314 os.rename(new_name, file_name)
1323 RemoveFile(new_name)
1328 def FirstFree(seq, base=0):
1329 """Returns the first non-existing integer from seq.
1331 The seq argument should be a sorted list of positive integers. The
1332 first time the index of an element is smaller than the element
1333 value, the index will be returned.
1335 The base argument is used to start at a different offset,
1336 i.e. C{[3, 4, 6]} with I{offset=3} will return 5.
1338 Example: C{[0, 1, 3]} will return I{2}.
1341 @param seq: the sequence to be analyzed.
1343 @param base: use this value as the base index of the sequence
1345 @return: the first non-used index in the sequence
1348 for idx, elem in enumerate(seq):
1349 assert elem >= base, "Passed element is higher than base offset"
1350 if elem > idx + base:
1356 def all(seq, pred=bool):
1357 "Returns True if pred(x) is True for every element in the iterable"
1358 for _ in itertools.ifilterfalse(pred, seq):
1363 def any(seq, pred=bool):
1364 "Returns True if pred(x) is True for at least one element in the iterable"
1365 for _ in itertools.ifilter(pred, seq):
1370 def UniqueSequence(seq):
1371 """Returns a list with unique elements.
1373 Element order is preserved.
1376 @param seq: the sequence with the source elements
1378 @return: list of unique elements from seq
1382 return [i for i in seq if i not in seen and not seen.add(i)]
1385 def IsValidMac(mac):
1386 """Predicate to check if a MAC address is valid.
1388 Checks whether the supplied MAC address is formally correct, only
1389 accepts colon separated format.
1392 @param mac: the MAC to be validated
1394 @return: True is the MAC seems valid
1397 mac_check = re.compile("^([0-9a-f]{2}(:|$)){6}$")
1398 return mac_check.match(mac) is not None
1401 def TestDelay(duration):
1402 """Sleep for a fixed amount of time.
1404 @type duration: float
1405 @param duration: the sleep duration
1407 @return: False for negative value, True otherwise
1411 return False, "Invalid sleep duration"
1412 time.sleep(duration)
1416 def _CloseFDNoErr(fd, retries=5):
1417 """Close a file descriptor ignoring errors.
1420 @param fd: the file descriptor
1422 @param retries: how many retries to make, in case we get any
1423 other error than EBADF
1428 except OSError, err:
1429 if err.errno != errno.EBADF:
1431 _CloseFDNoErr(fd, retries - 1)
1432 # else either it's closed already or we're out of retries, so we
1433 # ignore this and go on
1436 def CloseFDs(noclose_fds=None):
1437 """Close file descriptors.
1439 This closes all file descriptors above 2 (i.e. except
1442 @type noclose_fds: list or None
1443 @param noclose_fds: if given, it denotes a list of file descriptor
1444 that should not be closed
1447 # Default maximum for the number of available file descriptors.
1448 if 'SC_OPEN_MAX' in os.sysconf_names:
1450 MAXFD = os.sysconf('SC_OPEN_MAX')
1457 maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
1458 if (maxfd == resource.RLIM_INFINITY):
1461 # Iterate through and close all file descriptors (except the standard ones)
1462 for fd in range(3, maxfd):
1463 if noclose_fds and fd in noclose_fds:
1468 def Daemonize(logfile):
1469 """Daemonize the current process.
1471 This detaches the current process from the controlling terminal and
1472 runs it in the background as a daemon.
1475 @param logfile: the logfile to which we should redirect stdout/stderr
1477 @return: the value zero
1485 if (pid == 0): # The first child.
1488 pid = os.fork() # Fork a second child.
1489 if (pid == 0): # The second child.
1493 # exit() or _exit()? See below.
1494 os._exit(0) # Exit parent (the first child) of the second child.
1496 os._exit(0) # Exit parent of the first child.
1500 i = os.open("/dev/null", os.O_RDONLY) # stdin
1501 assert i == 0, "Can't close/reopen stdin"
1502 i = os.open(logfile, os.O_WRONLY|os.O_CREAT|os.O_APPEND, 0600) # stdout
1503 assert i == 1, "Can't close/reopen stdout"
1504 # Duplicate standard output to standard error.
1509 def DaemonPidFileName(name):
1510 """Compute a ganeti pid file absolute path
1513 @param name: the daemon name
1515 @return: the full path to the pidfile corresponding to the given
1519 return os.path.join(constants.RUN_GANETI_DIR, "%s.pid" % name)
1522 def WritePidFile(name):
1523 """Write the current process pidfile.
1525 The file will be written to L{constants.RUN_GANETI_DIR}I{/name.pid}
1528 @param name: the daemon name to use
1529 @raise errors.GenericError: if the pid file already exists and
1530 points to a live process
1534 pidfilename = DaemonPidFileName(name)
1535 if IsProcessAlive(ReadPidFile(pidfilename)):
1536 raise errors.GenericError("%s contains a live process" % pidfilename)
1538 WriteFile(pidfilename, data="%d\n" % pid)
1541 def RemovePidFile(name):
1542 """Remove the current process pidfile.
1544 Any errors are ignored.
1547 @param name: the daemon name used to derive the pidfile name
1550 pidfilename = DaemonPidFileName(name)
1551 # TODO: we could check here that the file contains our pid
1553 RemoveFile(pidfilename)
1558 def KillProcess(pid, signal_=signal.SIGTERM, timeout=30,
1560 """Kill a process given by its pid.
1563 @param pid: The PID to terminate.
1565 @param signal_: The signal to send, by default SIGTERM
1567 @param timeout: The timeout after which, if the process is still alive,
1568 a SIGKILL will be sent. If not positive, no such checking
1570 @type waitpid: boolean
1571 @param waitpid: If true, we should waitpid on this process after
1572 sending signals, since it's our own child and otherwise it
1573 would remain as zombie
1576 def _helper(pid, signal_, wait):
1577 """Simple helper to encapsulate the kill/waitpid sequence"""
1578 os.kill(pid, signal_)
1581 os.waitpid(pid, os.WNOHANG)
1586 # kill with pid=0 == suicide
1587 raise errors.ProgrammerError("Invalid pid given '%s'" % pid)
1589 if not IsProcessAlive(pid):
1592 _helper(pid, signal_, waitpid)
1597 def _CheckProcess():
1598 if not IsProcessAlive(pid):
1602 (result_pid, _) = os.waitpid(pid, os.WNOHANG)
1612 # Wait up to $timeout seconds
1613 Retry(_CheckProcess, (0.01, 1.5, 0.1), timeout)
1614 except RetryTimeout:
1617 if IsProcessAlive(pid):
1618 # Kill process if it's still alive
1619 _helper(pid, signal.SIGKILL, waitpid)
1622 def FindFile(name, search_path, test=os.path.exists):
1623 """Look for a filesystem object in a given path.
1625 This is an abstract method to search for filesystem object (files,
1626 dirs) under a given search path.
1629 @param name: the name to look for
1630 @type search_path: str
1631 @param search_path: location to start at
1632 @type test: callable
1633 @param test: a function taking one argument that should return True
1634 if the a given object is valid; the default value is
1635 os.path.exists, causing only existing files to be returned
1637 @return: full path to the object if found, None otherwise
1640 for dir_name in search_path:
1641 item_name = os.path.sep.join([dir_name, name])
1647 def CheckVolumeGroupSize(vglist, vgname, minsize):
1648 """Checks if the volume group list is valid.
1650 The function will check if a given volume group is in the list of
1651 volume groups and has a minimum size.
1654 @param vglist: dictionary of volume group names and their size
1656 @param vgname: the volume group we should check
1658 @param minsize: the minimum size we accept
1660 @return: None for success, otherwise the error message
1663 vgsize = vglist.get(vgname, None)
1665 return "volume group '%s' missing" % vgname
1666 elif vgsize < minsize:
1667 return ("volume group '%s' too small (%s MiB required, %d MiB found)" %
1668 (vgname, minsize, vgsize))
1672 def SplitTime(value):
1673 """Splits time as floating point number into a tuple.
1675 @param value: Time in seconds
1676 @type value: int or float
1677 @return: Tuple containing (seconds, microseconds)
1680 (seconds, microseconds) = divmod(int(value * 1000000), 1000000)
1682 assert 0 <= seconds, \
1683 "Seconds must be larger than or equal to 0, but are %s" % seconds
1684 assert 0 <= microseconds <= 999999, \
1685 "Microseconds must be 0-999999, but are %s" % microseconds
1687 return (int(seconds), int(microseconds))
1690 def MergeTime(timetuple):
1691 """Merges a tuple into time as a floating point number.
1693 @param timetuple: Time as tuple, (seconds, microseconds)
1694 @type timetuple: tuple
1695 @return: Time as a floating point number expressed in seconds
1698 (seconds, microseconds) = timetuple
1700 assert 0 <= seconds, \
1701 "Seconds must be larger than or equal to 0, but are %s" % seconds
1702 assert 0 <= microseconds <= 999999, \
1703 "Microseconds must be 0-999999, but are %s" % microseconds
1705 return float(seconds) + (float(microseconds) * 0.000001)
1708 def GetDaemonPort(daemon_name):
1709 """Get the daemon port for this cluster.
1711 Note that this routine does not read a ganeti-specific file, but
1712 instead uses C{socket.getservbyname} to allow pre-customization of
1713 this parameter outside of Ganeti.
1715 @type daemon_name: string
1716 @param daemon_name: daemon name (in constants.DAEMONS_PORTS)
1720 if daemon_name not in constants.DAEMONS_PORTS:
1721 raise errors.ProgrammerError("Unknown daemon: %s" % daemon_name)
1723 (proto, default_port) = constants.DAEMONS_PORTS[daemon_name]
1725 port = socket.getservbyname(daemon_name, proto)
1726 except socket.error:
1732 def SetupLogging(logfile, debug=False, stderr_logging=False, program="",
1733 multithreaded=False):
1734 """Configures the logging module.
1737 @param logfile: the filename to which we should log
1738 @type debug: boolean
1739 @param debug: whether to enable debug messages too or
1740 only those at C{INFO} and above level
1741 @type stderr_logging: boolean
1742 @param stderr_logging: whether we should also log to the standard error
1744 @param program: the name under which we should log messages
1745 @type multithreaded: boolean
1746 @param multithreaded: if True, will add the thread name to the log file
1747 @raise EnvironmentError: if we can't open the log file and
1748 stderr logging is disabled
1751 fmt = "%(asctime)s: " + program + " pid=%(process)d"
1753 fmt += "/%(threadName)s"
1755 fmt += " %(module)s:%(lineno)s"
1756 fmt += " %(levelname)s %(message)s"
1757 formatter = logging.Formatter(fmt)
1759 root_logger = logging.getLogger("")
1760 root_logger.setLevel(logging.NOTSET)
1762 # Remove all previously setup handlers
1763 for handler in root_logger.handlers:
1765 root_logger.removeHandler(handler)
1768 stderr_handler = logging.StreamHandler()
1769 stderr_handler.setFormatter(formatter)
1771 stderr_handler.setLevel(logging.NOTSET)
1773 stderr_handler.setLevel(logging.CRITICAL)
1774 root_logger.addHandler(stderr_handler)
1776 # this can fail, if the logging directories are not setup or we have
1777 # a permisssion problem; in this case, it's best to log but ignore
1778 # the error if stderr_logging is True, and if false we re-raise the
1779 # exception since otherwise we could run but without any logs at all
1781 logfile_handler = logging.FileHandler(logfile)
1782 logfile_handler.setFormatter(formatter)
1784 logfile_handler.setLevel(logging.DEBUG)
1786 logfile_handler.setLevel(logging.INFO)
1787 root_logger.addHandler(logfile_handler)
1788 except EnvironmentError:
1790 logging.exception("Failed to enable logging to file '%s'", logfile)
1792 # we need to re-raise the exception
1796 def IsNormAbsPath(path):
1797 """Check whether a path is absolute and also normalized
1799 This avoids things like /dir/../../other/path to be valid.
1802 return os.path.normpath(path) == path and os.path.isabs(path)
1805 def TailFile(fname, lines=20):
1806 """Return the last lines from a file.
1808 @note: this function will only read and parse the last 4KB of
1809 the file; if the lines are very long, it could be that less
1810 than the requested number of lines are returned
1812 @param fname: the file name
1814 @param lines: the (maximum) number of lines to return
1817 fd = open(fname, "r")
1821 pos = max(0, pos-4096)
1823 raw_data = fd.read()
1827 rows = raw_data.splitlines()
1828 return rows[-lines:]
1831 def SafeEncode(text):
1832 """Return a 'safe' version of a source string.
1834 This function mangles the input string and returns a version that
1835 should be safe to display/encode as ASCII. To this end, we first
1836 convert it to ASCII using the 'backslashreplace' encoding which
1837 should get rid of any non-ASCII chars, and then we process it
1838 through a loop copied from the string repr sources in the python; we
1839 don't use string_escape anymore since that escape single quotes and
1840 backslashes too, and that is too much; and that escaping is not
1841 stable, i.e. string_escape(string_escape(x)) != string_escape(x).
1843 @type text: str or unicode
1844 @param text: input data
1846 @return: a safe version of text
1849 if isinstance(text, unicode):
1850 # only if unicode; if str already, we handle it below
1851 text = text.encode('ascii', 'backslashreplace')
1861 elif c < 32 or c >= 127: # non-printable
1862 resu += "\\x%02x" % (c & 0xff)
1868 def BytesToMebibyte(value):
1869 """Converts bytes to mebibytes.
1872 @param value: Value in bytes
1874 @return: Value in mebibytes
1877 return int(round(value / (1024.0 * 1024.0), 0))
1880 def CalculateDirectorySize(path):
1881 """Calculates the size of a directory recursively.
1884 @param path: Path to directory
1886 @return: Size in mebibytes
1891 for (curpath, _, files) in os.walk(path):
1892 for filename in files:
1893 st = os.lstat(os.path.join(curpath, filename))
1896 return BytesToMebibyte(size)
1899 def GetFilesystemStats(path):
1900 """Returns the total and free space on a filesystem.
1903 @param path: Path on filesystem to be examined
1905 @return: tuple of (Total space, Free space) in mebibytes
1908 st = os.statvfs(path)
1910 fsize = BytesToMebibyte(st.f_bavail * st.f_frsize)
1911 tsize = BytesToMebibyte(st.f_blocks * st.f_frsize)
1912 return (tsize, fsize)
1915 def LockedMethod(fn):
1916 """Synchronized object access decorator.
1918 This decorator is intended to protect access to an object using the
1919 object's own lock which is hardcoded to '_lock'.
1922 def _LockDebug(*args, **kwargs):
1924 logging.debug(*args, **kwargs)
1926 def wrapper(self, *args, **kwargs):
1927 assert hasattr(self, '_lock')
1929 _LockDebug("Waiting for %s", lock)
1932 _LockDebug("Acquired %s", lock)
1933 result = fn(self, *args, **kwargs)
1935 _LockDebug("Releasing %s", lock)
1937 _LockDebug("Released %s", lock)
1943 """Locks a file using POSIX locks.
1946 @param fd: the file descriptor we need to lock
1950 fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
1951 except IOError, err:
1952 if err.errno == errno.EAGAIN:
1953 raise errors.LockError("File already locked")
1957 def FormatTime(val):
1958 """Formats a time value.
1960 @type val: float or None
1961 @param val: the timestamp as returned by time.time()
1962 @return: a string value or N/A if we don't have a valid timestamp
1965 if val is None or not isinstance(val, (int, float)):
1967 # these two codes works on Linux, but they are not guaranteed on all
1969 return time.strftime("%F %T", time.localtime(val))
1972 def ReadWatcherPauseFile(filename, now=None, remove_after=3600):
1973 """Reads the watcher pause file.
1975 @type filename: string
1976 @param filename: Path to watcher pause file
1977 @type now: None, float or int
1978 @param now: Current time as Unix timestamp
1979 @type remove_after: int
1980 @param remove_after: Remove watcher pause file after specified amount of
1981 seconds past the pause end time
1988 value = ReadFile(filename)
1989 except IOError, err:
1990 if err.errno != errno.ENOENT:
1994 if value is not None:
1998 logging.warning(("Watcher pause file (%s) contains invalid value,"
1999 " removing it"), filename)
2000 RemoveFile(filename)
2003 if value is not None:
2004 # Remove file if it's outdated
2005 if now > (value + remove_after):
2006 RemoveFile(filename)
2015 class RetryTimeout(Exception):
2016 """Retry loop timed out.
2021 class RetryAgain(Exception):
2027 class _RetryDelayCalculator(object):
2028 """Calculator for increasing delays.
2038 def __init__(self, start, factor, limit):
2039 """Initializes this class.
2042 @param start: Initial delay
2044 @param factor: Factor for delay increase
2045 @type limit: float or None
2046 @param limit: Upper limit for delay or None for no limit
2050 assert factor >= 1.0
2051 assert limit is None or limit >= 0.0
2054 self._factor = factor
2060 """Returns current delay and calculates the next one.
2063 current = self._next
2065 # Update for next run
2066 if self._limit is None or self._next < self._limit:
2067 self._next = max(self._limit, self._next * self._factor)
2072 #: Special delay to specify whole remaining timeout
2073 RETRY_REMAINING_TIME = object()
2076 def Retry(fn, delay, timeout, args=None, wait_fn=time.sleep,
2077 _time_fn=time.time):
2078 """Call a function repeatedly until it succeeds.
2080 The function C{fn} is called repeatedly until it doesn't throw L{RetryAgain}
2081 anymore. Between calls a delay, specified by C{delay}, is inserted. After a
2082 total of C{timeout} seconds, this function throws L{RetryTimeout}.
2084 C{delay} can be one of the following:
2085 - callable returning the delay length as a float
2086 - Tuple of (start, factor, limit)
2087 - L{RETRY_REMAINING_TIME} to sleep until the timeout expires (this is
2088 useful when overriding L{wait_fn} to wait for an external event)
2089 - A static delay as a number (int or float)
2092 @param fn: Function to be called
2093 @param delay: Either a callable (returning the delay), a tuple of (start,
2094 factor, limit) (see L{_RetryDelayCalculator}),
2095 L{RETRY_REMAINING_TIME} or a number (int or float)
2096 @type timeout: float
2097 @param timeout: Total timeout
2098 @type wait_fn: callable
2099 @param wait_fn: Waiting function
2100 @return: Return value of function
2104 assert callable(wait_fn)
2105 assert callable(_time_fn)
2110 end_time = _time_fn() + timeout
2113 # External function to calculate delay
2116 elif isinstance(delay, (tuple, list)):
2117 # Increasing delay with optional upper boundary
2118 (start, factor, limit) = delay
2119 calc_delay = _RetryDelayCalculator(start, factor, limit)
2121 elif delay is RETRY_REMAINING_TIME:
2122 # Always use the remaining time
2127 calc_delay = lambda: delay
2129 assert calc_delay is None or callable(calc_delay)
2137 remaining_time = end_time - _time_fn()
2139 if remaining_time < 0.0:
2140 raise RetryTimeout()
2142 assert remaining_time >= 0.0
2144 if calc_delay is None:
2145 wait_fn(remaining_time)
2147 current_delay = calc_delay()
2148 if current_delay > 0.0:
2149 wait_fn(current_delay)
2152 class FileLock(object):
2153 """Utility class for file locks.
2156 def __init__(self, filename):
2157 """Constructor for FileLock.
2159 This will open the file denoted by the I{filename} argument.
2162 @param filename: path to the file to be locked
2165 self.filename = filename
2166 self.fd = open(self.filename, "w")
2172 """Close the file and release the lock.
2179 def _flock(self, flag, blocking, timeout, errmsg):
2180 """Wrapper for fcntl.flock.
2183 @param flag: operation flag
2184 @type blocking: bool
2185 @param blocking: whether the operation should be done in blocking mode.
2186 @type timeout: None or float
2187 @param timeout: for how long the operation should be retried (implies
2189 @type errmsg: string
2190 @param errmsg: error message in case operation fails.
2193 assert self.fd, "Lock was closed"
2194 assert timeout is None or timeout >= 0, \
2195 "If specified, timeout must be positive"
2197 if timeout is not None:
2198 flag |= fcntl.LOCK_NB
2199 timeout_end = time.time() + timeout
2201 # Blocking doesn't have effect with timeout
2203 flag |= fcntl.LOCK_NB
2206 # TODO: Convert to utils.Retry
2211 fcntl.flock(self.fd, flag)
2213 except IOError, err:
2214 if err.errno in (errno.EAGAIN, ):
2215 if timeout_end is not None and time.time() < timeout_end:
2216 # Wait before trying again
2217 time.sleep(max(0.1, min(1.0, timeout)))
2219 raise errors.LockError(errmsg)
2221 logging.exception("fcntl.flock failed")
2224 def Exclusive(self, blocking=False, timeout=None):
2225 """Locks the file in exclusive mode.
2227 @type blocking: boolean
2228 @param blocking: whether to block and wait until we
2229 can lock the file or return immediately
2230 @type timeout: int or None
2231 @param timeout: if not None, the duration to wait for the lock
2235 self._flock(fcntl.LOCK_EX, blocking, timeout,
2236 "Failed to lock %s in exclusive mode" % self.filename)
2238 def Shared(self, blocking=False, timeout=None):
2239 """Locks the file in shared mode.
2241 @type blocking: boolean
2242 @param blocking: whether to block and wait until we
2243 can lock the file or return immediately
2244 @type timeout: int or None
2245 @param timeout: if not None, the duration to wait for the lock
2249 self._flock(fcntl.LOCK_SH, blocking, timeout,
2250 "Failed to lock %s in shared mode" % self.filename)
2252 def Unlock(self, blocking=True, timeout=None):
2253 """Unlocks the file.
2255 According to C{flock(2)}, unlocking can also be a nonblocking
2258 To make a non-blocking request, include LOCK_NB with any of the above
2261 @type blocking: boolean
2262 @param blocking: whether to block and wait until we
2263 can lock the file or return immediately
2264 @type timeout: int or None
2265 @param timeout: if not None, the duration to wait for the lock
2269 self._flock(fcntl.LOCK_UN, blocking, timeout,
2270 "Failed to unlock %s" % self.filename)
2273 def SignalHandled(signums):
2274 """Signal Handled decoration.
2276 This special decorator installs a signal handler and then calls the target
2277 function. The function must accept a 'signal_handlers' keyword argument,
2278 which will contain a dict indexed by signal number, with SignalHandler
2281 The decorator can be safely stacked with iself, to handle multiple signals
2282 with different handlers.
2285 @param signums: signals to intercept
2289 def sig_function(*args, **kwargs):
2290 assert 'signal_handlers' not in kwargs or \
2291 kwargs['signal_handlers'] is None or \
2292 isinstance(kwargs['signal_handlers'], dict), \
2293 "Wrong signal_handlers parameter in original function call"
2294 if 'signal_handlers' in kwargs and kwargs['signal_handlers'] is not None:
2295 signal_handlers = kwargs['signal_handlers']
2297 signal_handlers = {}
2298 kwargs['signal_handlers'] = signal_handlers
2299 sighandler = SignalHandler(signums)
2302 signal_handlers[sig] = sighandler
2303 return fn(*args, **kwargs)
2310 class SignalHandler(object):
2311 """Generic signal handler class.
2313 It automatically restores the original handler when deconstructed or
2314 when L{Reset} is called. You can either pass your own handler
2315 function in or query the L{called} attribute to detect whether the
2319 @ivar signum: the signals we handle
2320 @type called: boolean
2321 @ivar called: tracks whether any of the signals have been raised
2324 def __init__(self, signum):
2325 """Constructs a new SignalHandler instance.
2327 @type signum: int or list of ints
2328 @param signum: Single signal number or set of signal numbers
2331 self.signum = set(signum)
2336 for signum in self.signum:
2338 prev_handler = signal.signal(signum, self._HandleSignal)
2340 self._previous[signum] = prev_handler
2342 # Restore previous handler
2343 signal.signal(signum, prev_handler)
2346 # Reset all handlers
2348 # Here we have a race condition: a handler may have already been called,
2349 # but there's not much we can do about it at this point.
2356 """Restore previous handler.
2358 This will reset all the signals to their previous handlers.
2361 for signum, prev_handler in self._previous.items():
2362 signal.signal(signum, prev_handler)
2363 # If successful, remove from dict
2364 del self._previous[signum]
2367 """Unsets the L{called} flag.
2369 This function can be used in case a signal may arrive several times.
2374 def _HandleSignal(self, signum, frame):
2375 """Actual signal handling function.
2378 # This is not nice and not absolutely atomic, but it appears to be the only
2379 # solution in Python -- there are no atomic types.
2383 class FieldSet(object):
2384 """A simple field set.
2386 Among the features are:
2387 - checking if a string is among a list of static string or regex objects
2388 - checking if a whole list of string matches
2389 - returning the matching groups from a regex match
2391 Internally, all fields are held as regular expression objects.
2394 def __init__(self, *items):
2395 self.items = [re.compile("^%s$" % value) for value in items]
2397 def Extend(self, other_set):
2398 """Extend the field set with the items from another one"""
2399 self.items.extend(other_set.items)
2401 def Matches(self, field):
2402 """Checks if a field matches the current set
2405 @param field: the string to match
2406 @return: either False or a regular expression match object
2409 for m in itertools.ifilter(None, (val.match(field) for val in self.items)):
2413 def NonMatching(self, items):
2414 """Returns the list of fields not matching the current set
2417 @param items: the list of fields to check
2419 @return: list of non-matching fields
2422 return [val for val in items if not self.Matches(val)]