#
#
# Copyright (C) 2006, 2007 Google Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
"""Ganeti small utilities
"""
import sys
import os
import sha
import time
import subprocess
import re
import socket
import tempfile
import shutil
import errno
import pwd
import itertools
from ganeti import logger
from ganeti import errors
_locksheld = []
_re_shell_unquoted = re.compile('^[-.,=:/_+@A-Za-z0-9]+$')
class RunResult(object):
"""Simple class for holding the result of running external programs.
Instance variables:
exit_code: the exit code of the program, or None (if the program
didn't exit())
signal: numeric signal that caused the program to finish, or None
(if the program wasn't terminated by a signal)
stdout: the standard output of the program
stderr: the standard error of the program
failed: a Boolean value which is True in case the program was
terminated by a signal or exited with a non-zero exit code
fail_reason: a string detailing the termination reason
"""
__slots__ = ["exit_code", "signal", "stdout", "stderr",
"failed", "fail_reason", "cmd"]
def __init__(self, exit_code, signal, stdout, stderr, cmd):
self.cmd = cmd
self.exit_code = exit_code
self.signal = signal
self.stdout = stdout
self.stderr = stderr
self.failed = (signal is not None or exit_code != 0)
if self.signal is not None:
self.fail_reason = "terminated by signal %s" % self.signal
elif self.exit_code is not None:
self.fail_reason = "exited with exit code %s" % self.exit_code
else:
self.fail_reason = "unable to determine termination reason"
def _GetOutput(self):
"""Returns the combined stdout and stderr for easier usage.
"""
return self.stdout + self.stderr
output = property(_GetOutput, None, None, "Return full output")
def _GetLockFile(subsystem):
"""Compute the file name for a given lock name."""
return "/var/lock/ganeti_lock_%s" % subsystem
def Lock(name, max_retries=None, debug=False):
"""Lock a given subsystem.
In case the lock is already held by an alive process, the function
will sleep indefintely and poll with a one second interval.
When the optional integer argument 'max_retries' is passed with a
non-zero value, the function will sleep only for this number of
times, and then it will will raise a LockError if the lock can't be
acquired. Passing in a negative number will cause only one try to
get the lock. Passing a positive number will make the function retry
for approximately that number of seconds.
"""
lockfile = _GetLockFile(name)
if name in _locksheld:
raise errors.LockError('Lock "%s" already held!' % (name,))
errcount = 0
retries = 0
while True:
try:
fd = os.open(lockfile, os.O_CREAT | os.O_EXCL | os.O_RDWR | os.O_SYNC)
break
except OSError, creat_err:
if creat_err.errno != errno.EEXIST:
raise errors.LockError("Can't create the lock file. Error '%s'." %
str(creat_err))
try:
pf = open(lockfile, 'r')
except IOError, open_err:
errcount += 1
if errcount >= 5:
raise errors.LockError("Lock file exists but cannot be opened."
" Error: '%s'." % str(open_err))
time.sleep(1)
continue
try:
pid = int(pf.read())
except ValueError:
raise errors.LockError("Invalid pid string in %s" %
(lockfile,))
if not IsProcessAlive(pid):
raise errors.LockError("Stale lockfile %s for pid %d?" %
(lockfile, pid))
if max_retries and max_retries <= retries:
raise errors.LockError("Can't acquire lock during the specified"
" time, aborting.")
if retries == 5 and (debug or sys.stdin.isatty()):
logger.ToStderr("Waiting for '%s' lock from pid %d..." % (name, pid))
time.sleep(1)
retries += 1
continue
os.write(fd, '%d\n' % (os.getpid(),))
os.close(fd)
_locksheld.append(name)
def Unlock(name):
"""Unlock a given subsystem.
"""
lockfile = _GetLockFile(name)
try:
fd = os.open(lockfile, os.O_RDONLY)
except OSError:
raise errors.LockError('Lock "%s" not held.' % (name,))
f = os.fdopen(fd, 'r')
pid_str = f.read()
try:
pid = int(pid_str)
except ValueError:
raise errors.LockError('Unable to determine PID of locking process.')
if pid != os.getpid():
raise errors.LockError('Lock not held by me (%d != %d)' %
(os.getpid(), pid,))
os.unlink(lockfile)
_locksheld.remove(name)
def LockCleanup():
"""Remove all locks.
"""
for lock in _locksheld:
Unlock(lock)
def RunCmd(cmd):
"""Execute a (shell) command.
The command should not read from its standard input, as it will be
closed.
Args:
cmd: command to run. (str)
Returns: `RunResult` instance
"""
if isinstance(cmd, list):
cmd = [str(val) for val in cmd]
strcmd = " ".join(cmd)
shell = False
else:
strcmd = cmd
shell = True
env = os.environ.copy()
env["LC_ALL"] = "C"
child = subprocess.Popen(cmd, shell=shell,
stderr=subprocess.PIPE,
stdout=subprocess.PIPE,
stdin=subprocess.PIPE,
close_fds=True, env=env)
child.stdin.close()
out = child.stdout.read()
err = child.stderr.read()
status = child.wait()
if status >= 0:
exitcode = status
signal = None
else:
exitcode = None
signal = -status
return RunResult(exitcode, signal, out, err, strcmd)
def RunCmdUnlocked(cmd):
"""Execute a shell command without the 'cmd' lock.
This variant of `RunCmd()` drops the 'cmd' lock before running the
command and re-aquires it afterwards, thus it can be used to call
other ganeti commands.
The argument and return values are the same as for the `RunCmd()`
function.
Args:
cmd - command to run. (str)
Returns:
`RunResult`
"""
Unlock('cmd')
ret = RunCmd(cmd)
Lock('cmd')
return ret
def RemoveFile(filename):
"""Remove a file ignoring some errors.
Remove a file, ignoring non-existing ones or directories. Other
errors are passed.
"""
try:
os.unlink(filename)
except OSError, err:
if err.errno not in (errno.ENOENT, errno.EISDIR):
raise
def _FingerprintFile(filename):
"""Compute the fingerprint of a file.
If the file does not exist, a None will be returned
instead.
Args:
filename - Filename (str)
"""
if not (os.path.exists(filename) and os.path.isfile(filename)):
return None
f = open(filename)
fp = sha.sha()
while True:
data = f.read(4096)
if not data:
break
fp.update(data)
return fp.hexdigest()
def FingerprintFiles(files):
"""Compute fingerprints for a list of files.
Args:
files - array of filenames. ( [str, ...] )
Return value:
dictionary of filename: fingerprint for the files that exist
"""
ret = {}
for filename in files:
cksum = _FingerprintFile(filename)
if cksum:
ret[filename] = cksum
return ret
def CheckDict(target, template, logname=None):
"""Ensure a dictionary has a required set of keys.
For the given dictionaries `target` and `template`, ensure target
has all the keys from template. Missing keys are added with values
from template.
Args:
target - the dictionary to check
template - template dictionary
logname - a caller-chosen string to identify the debug log
entry; if None, no logging will be done
Returns value:
None
"""
missing = []
for k in template:
if k not in target:
missing.append(k)
target[k] = template[k]
if missing and logname:
logger.Debug('%s missing keys %s' %
(logname, ', '.join(missing)))
def IsProcessAlive(pid):
"""Check if a given pid exists on the system.
Returns: true or false, depending on if the pid exists or not
Remarks: zombie processes treated as not alive
"""
try:
f = open("/proc/%d/status" % pid)
except IOError, err:
if err.errno in (errno.ENOENT, errno.ENOTDIR):
return False
alive = True
try:
data = f.readlines()
if len(data) > 1:
state = data[1].split()
if len(state) > 1 and state[1] == "Z":
alive = False
finally:
f.close()
return alive
def MatchNameComponent(key, name_list):
"""Try to match a name against a list.
This function will try to match a name like test1 against a list
like ['test1.example.com', 'test2.example.com', ...]. Against this
list, 'test1' as well as 'test1.example' will match, but not
'test1.ex'. A multiple match will be considered as no match at all
(e.g. 'test1' against ['test1.example.com', 'test1.example.org']).
Args:
key: the name to be searched
name_list: the list of strings against which to search the key
Returns:
None if there is no match *or* if there are multiple matches
otherwise the element from the list which matches
"""
mo = re.compile("^%s(\..*)?$" % re.escape(key))
names_filtered = [name for name in name_list if mo.match(name) is not None]
if len(names_filtered) != 1:
return None
return names_filtered[0]
class HostInfo:
"""Class implementing resolver and hostname functionality
"""
def __init__(self, name=None):
"""Initialize the host name object.
If the name argument is not passed, it will use this system's
name.
"""
if name is None:
name = self.SysName()
self.query = name
self.name, self.aliases, self.ipaddrs = self.LookupHostname(name)
self.ip = self.ipaddrs[0]
def ShortName(self):
"""Returns the hostname without domain.
"""
return self.name.split('.')[0]
@staticmethod
def SysName():
"""Return the current system's name.
This is simply a wrapper over socket.gethostname()
"""
return socket.gethostname()
@staticmethod
def LookupHostname(hostname):
"""Look up hostname
Args:
hostname: hostname to look up
Returns:
a tuple (name, aliases, ipaddrs) as returned by socket.gethostbyname_ex
in case of errors in resolving, we raise a ResolverError
"""
try:
result = socket.gethostbyname_ex(hostname)
except socket.gaierror, err:
# hostname not found in DNS
raise errors.ResolverError(hostname, err.args[0], err.args[1])
return result
def ListVolumeGroups():
"""List volume groups and their size
Returns:
Dictionary with keys volume name and values the size of the volume
"""
command = "vgs --noheadings --units m --nosuffix -o name,size"
result = RunCmd(command)
retval = {}
if result.failed:
return retval
for line in result.stdout.splitlines():
try:
name, size = line.split()
size = int(float(size))
except (IndexError, ValueError), err:
logger.Error("Invalid output from vgs (%s): %s" % (err, line))
continue
retval[name] = size
return retval
def BridgeExists(bridge):
"""Check whether the given bridge exists in the system
Returns:
True if it does, false otherwise.
"""
return os.path.isdir("/sys/class/net/%s/bridge" % bridge)
def NiceSort(name_list):
"""Sort a list of strings based on digit and non-digit groupings.
Given a list of names ['a1', 'a10', 'a11', 'a2'] this function will
sort the list in the logical order ['a1', 'a2', 'a10', 'a11'].
The sort algorithm breaks each name in groups of either only-digits
or no-digits. Only the first eight such groups are considered, and
after that we just use what's left of the string.
Return value
- a copy of the list sorted according to our algorithm
"""
_SORTER_BASE = "(\D+|\d+)"
_SORTER_FULL = "^%s%s?%s?%s?%s?%s?%s?%s?.*$" % (_SORTER_BASE, _SORTER_BASE,
_SORTER_BASE, _SORTER_BASE,
_SORTER_BASE, _SORTER_BASE,
_SORTER_BASE, _SORTER_BASE)
_SORTER_RE = re.compile(_SORTER_FULL)
_SORTER_NODIGIT = re.compile("^\D*$")
def _TryInt(val):
"""Attempts to convert a variable to integer."""
if val is None or _SORTER_NODIGIT.match(val):
return val
rval = int(val)
return rval
to_sort = [([_TryInt(grp) for grp in _SORTER_RE.match(name).groups()], name)
for name in name_list]
to_sort.sort()
return [tup[1] for tup in to_sort]
def CheckDaemonAlive(pid_file, process_string):
"""Check wether the specified daemon is alive.
Args:
- pid_file: file to read the daemon pid from, the file is
expected to contain only a single line containing
only the PID
- process_string: a substring that we expect to find in
the command line of the daemon process
Returns:
- True if the daemon is judged to be alive (that is:
- the PID file exists, is readable and contains a number
- a process of the specified PID is running
- that process contains the specified string in its
command line
- the process is not in state Z (zombie))
- False otherwise
"""
try:
pid_file = file(pid_file, 'r')
try:
pid = int(pid_file.readline())
finally:
pid_file.close()
cmdline_file_path = "/proc/%s/cmdline" % (pid)
cmdline_file = open(cmdline_file_path, 'r')
try:
cmdline = cmdline_file.readline()
finally:
cmdline_file.close()
if not process_string in cmdline:
return False
stat_file_path = "/proc/%s/stat" % (pid)
stat_file = open(stat_file_path, 'r')
try:
process_state = stat_file.readline().split()[2]
finally:
stat_file.close()
if process_state == 'Z':
return False
except (IndexError, IOError, ValueError):
return False
return True
def TryConvert(fn, val):
"""Try to convert a value ignoring errors.
This function tries to apply function `fn` to `val`. If no
ValueError or TypeError exceptions are raised, it will return the
result, else it will return the original value. Any other exceptions
are propagated to the caller.
"""
try:
nv = fn(val)
except (ValueError, TypeError), err:
nv = val
return nv
def IsValidIP(ip):
"""Verifies the syntax of an IP address.
This function checks if the ip address passes is valid or not based
on syntax (not ip range, class calculations or anything).
"""
unit = "(0|[1-9]\d{0,2})"
return re.match("^%s\.%s\.%s\.%s$" % (unit, unit, unit, unit), ip)
def IsValidShellParam(word):
"""Verifies is the given word is safe from the shell's p.o.v.
This means that we can pass this to a command via the shell and be
sure that it doesn't alter the command line and is passed as such to
the actual command.
Note that we are overly restrictive here, in order to be on the safe
side.
"""
return bool(re.match("^[-a-zA-Z0-9._+/:%@]+$", word))
def BuildShellCmd(template, *args):
"""Build a safe shell command line from the given arguments.
This function will check all arguments in the args list so that they
are valid shell parameters (i.e. they don't contain shell
metacharaters). If everything is ok, it will return the result of
template % args.
"""
for word in args:
if not IsValidShellParam(word):
raise errors.ProgrammerError("Shell argument '%s' contains"
" invalid characters" % word)
return template % args
def FormatUnit(value):
"""Formats an incoming number of MiB with the appropriate unit.
Value needs to be passed as a numeric type. Return value is always a string.
"""
if value < 1024:
return "%dM" % round(value, 0)
elif value < (1024 * 1024):
return "%0.1fG" % round(float(value) / 1024, 1)
else:
return "%0.1fT" % round(float(value) / 1024 / 1024, 1)
def ParseUnit(input_string):
"""Tries to extract number and scale from the given string.
Input must be in the format NUMBER+ [DOT NUMBER+] SPACE* [UNIT]. If no unit
is specified, it defaults to MiB. Return value is always an int in MiB.
"""
m = re.match('^([.\d]+)\s*([a-zA-Z]+)?$', input_string)
if not m:
raise errors.UnitParseError("Invalid format")
value = float(m.groups()[0])
unit = m.groups()[1]
if unit:
lcunit = unit.lower()
else:
lcunit = 'm'
if lcunit in ('m', 'mb', 'mib'):
# Value already in MiB
pass
elif lcunit in ('g', 'gb', 'gib'):
value *= 1024
elif lcunit in ('t', 'tb', 'tib'):
value *= 1024 * 1024
else:
raise errors.UnitParseError("Unknown unit: %s" % unit)
# Make sure we round up
if int(value) < value:
value += 1
# Round up to the next multiple of 4
value = int(value)
if value % 4:
value += 4 - value % 4
return value
def AddAuthorizedKey(file_name, key):
"""Adds an SSH public key to an authorized_keys file.
Args:
file_name: Path to authorized_keys file
key: String containing key
"""
key_fields = key.split()
f = open(file_name, 'a+')
try:
nl = True
for line in f:
# Ignore whitespace changes
if line.split() == key_fields:
break
nl = line.endswith('\n')
else:
if not nl:
f.write("\n")
f.write(key.rstrip('\r\n'))
f.write("\n")
f.flush()
finally:
f.close()
def RemoveAuthorizedKey(file_name, key):
"""Removes an SSH public key from an authorized_keys file.
Args:
file_name: Path to authorized_keys file
key: String containing key
"""
key_fields = key.split()
fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name))
try:
out = os.fdopen(fd, 'w')
try:
f = open(file_name, 'r')
try:
for line in f:
# Ignore whitespace changes while comparing lines
if line.split() != key_fields:
out.write(line)
out.flush()
os.rename(tmpname, file_name)
finally:
f.close()
finally:
out.close()
except:
RemoveFile(tmpname)
raise
def SetEtcHostsEntry(file_name, ip, hostname, aliases):
"""Sets the name of an IP address and hostname in /etc/hosts.
"""
# Ensure aliases are unique
aliases = UniqueSequence([hostname] + aliases)[1:]
fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name))
try:
out = os.fdopen(fd, 'w')
try:
f = open(file_name, 'r')
try:
written = False
for line in f:
fields = line.split()
if fields and not fields[0].startswith('#') and ip == fields[0]:
continue
out.write(line)
out.write("%s\t%s" % (ip, hostname))
if aliases:
out.write(" %s" % ' '.join(aliases))
out.write('\n')
out.flush()
os.fsync(out)
os.rename(tmpname, file_name)
finally:
f.close()
finally:
out.close()
except:
RemoveFile(tmpname)
raise
def RemoveEtcHostsEntry(file_name, hostname):
"""Removes a hostname from /etc/hosts.
IP addresses without names are removed from the file.
"""
fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name))
try:
out = os.fdopen(fd, 'w')
try:
f = open(file_name, 'r')
try:
for line in f:
fields = line.split()
if len(fields) > 1 and not fields[0].startswith('#'):
names = fields[1:]
if hostname in names:
while hostname in names:
names.remove(hostname)
if names:
out.write("%s %s\n" % (fields[0], ' '.join(names)))
continue
out.write(line)
out.flush()
os.fsync(out)
os.rename(tmpname, file_name)
finally:
f.close()
finally:
out.close()
except:
RemoveFile(tmpname)
raise
def CreateBackup(file_name):
"""Creates a backup of a file.
Returns: the path to the newly created backup file.
"""
if not os.path.isfile(file_name):
raise errors.ProgrammerError("Can't make a backup of a non-file '%s'" %
file_name)
prefix = '%s.backup-%d.' % (os.path.basename(file_name), int(time.time()))
dir_name = os.path.dirname(file_name)
fsrc = open(file_name, 'rb')
try:
(fd, backup_name) = tempfile.mkstemp(prefix=prefix, dir=dir_name)
fdst = os.fdopen(fd, 'wb')
try:
shutil.copyfileobj(fsrc, fdst)
finally:
fdst.close()
finally:
fsrc.close()
return backup_name
def ShellQuote(value):
"""Quotes shell argument according to POSIX.
"""
if _re_shell_unquoted.match(value):
return value
else:
return "'%s'" % value.replace("'", "'\\''")
def ShellQuoteArgs(args):
"""Quotes all given shell arguments and concatenates using spaces.
"""
return ' '.join([ShellQuote(i) for i in args])
def TcpPing(source, target, port, timeout=10, live_port_needed=False):
"""Simple ping implementation using TCP connect(2).
Try to do a TCP connect(2) from the specified source IP to the specified
target IP and the specified target port. If live_port_needed is set to true,
requires the remote end to accept the connection. The timeout is specified
in seconds and defaults to 10 seconds
"""
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sucess = False
try:
sock.bind((source, 0))
except socket.error, (errcode, errstring):
if errcode == errno.EADDRNOTAVAIL:
success = False
sock.settimeout(timeout)
try:
sock.connect((target, port))
sock.close()
success = True
except socket.timeout:
success = False
except socket.error, (errcode, errstring):
success = (not live_port_needed) and (errcode == errno.ECONNREFUSED)
return success
def ListVisibleFiles(path):
"""Returns a list of all visible files in a directory.
"""
files = [i for i in os.listdir(path) if not i.startswith(".")]
files.sort()
return files
def GetHomeDir(user, default=None):
"""Try to get the homedir of the given user.
The user can be passed either as a string (denoting the name) or as
an integer (denoting the user id). If the user is not found, the
'default' argument is returned, which defaults to None.
"""
try:
if isinstance(user, basestring):
result = pwd.getpwnam(user)
elif isinstance(user, (int, long)):
result = pwd.getpwuid(user)
else:
raise errors.ProgrammerError("Invalid type passed to GetHomeDir (%s)" %
type(user))
except KeyError:
return default
return result.pw_dir
def NewUUID():
"""Returns a random UUID.
"""
f = open("/proc/sys/kernel/random/uuid", "r")
try:
return f.read(128).rstrip("\n")
finally:
f.close()
def WriteFile(file_name, fn=None, data=None,
mode=None, uid=-1, gid=-1,
atime=None, mtime=None):
"""(Over)write a file atomically.
The file_name and either fn (a function taking one argument, the
file descriptor, and which should write the data to it) or data (the
contents of the file) must be passed. The other arguments are
optional and allow setting the file mode, owner and group, and the
mtime/atime of the file.
If the function doesn't raise an exception, it has succeeded and the
target file has the new contents. If the file has raised an
exception, an existing target file should be unmodified and the
temporary file should be removed.
"""
if not os.path.isabs(file_name):
raise errors.ProgrammerError("Path passed to WriteFile is not"
" absolute: '%s'" % file_name)
if [fn, data].count(None) != 1:
raise errors.ProgrammerError("fn or data required")
if [atime, mtime].count(None) == 1:
raise errors.ProgrammerError("Both atime and mtime must be either"
" set or None")
dir_name, base_name = os.path.split(file_name)
fd, new_name = tempfile.mkstemp('.new', base_name, dir_name)
# here we need to make sure we remove the temp file, if any error
# leaves it in place
try:
if uid != -1 or gid != -1:
os.chown(new_name, uid, gid)
if mode:
os.chmod(new_name, mode)
if data is not None:
os.write(fd, data)
else:
fn(fd)
os.fsync(fd)
if atime is not None and mtime is not None:
os.utime(new_name, (atime, mtime))
os.rename(new_name, file_name)
finally:
os.close(fd)
RemoveFile(new_name)
def all(seq, pred=bool):
"Returns True if pred(x) is True for every element in the iterable"
for elem in itertools.ifilterfalse(pred, seq):
return False
return True
def any(seq, pred=bool):
"Returns True if pred(x) is True for at least one element in the iterable"
for elem in itertools.ifilter(pred, seq):
return True
return False
def UniqueSequence(seq):
"""Returns a list with unique elements.
Element order is preserved.
"""
seen = set()
return [i for i in seq if i not in seen and not seen.add(i)]