def _dumpPartitionTable(targetDir, backupUser, backupGroup, compress=True):
"""
Dumps information about the partition table via ``fdisk``.
Args:
targetDir: Directory to write output file into
backupUser: User which should own the resulting file
backupGroup: Group which should own the resulting file
compress: Indicates whether to compress the output file
Raises:
IOError: If the dump fails for some reason
"""
if not os.path.exists(FDISK_PATH):
logger.info(
"Not executing partition table dump since %s doesn't seem to exist.",
FDISK_PATH)
elif not os.access(FDISK_PATH, os.X_OK):
logger.info(
"Not executing partition table dump since %s cannot be executed.",
FDISK_PATH)
else:
(outputFile, filename) = _getOutputFile(targetDir, "fdisk-l", compress)
with outputFile:
command = resolveCommand(FDISK_COMMAND)
result = executeCommand(command, [],
returnOutput=False,
ignoreStderr=True,
outputFile=outputFile)[0]
if result != 0:
raise IOError("Error [%d] executing partition table dump." %
result)
if not os.path.exists(filename):
raise IOError(
"File [%s] does not seem to exist after partition table dump finished."
% filename)
changeOwnership(filename, backupUser, backupGroup)
def _encryptFileWithGpg(sourcePath, recipient):
"""
Encrypts the indicated source file using GPG.
The encrypted file will be in GPG's binary output format and will have the
same name as the source file plus a ``".gpg"`` extension. The source file
will not be modified or removed by this function call.
Args:
sourcePath: Absolute path of file to be encrypted
recipient: Recipient name to be passed to GPG's ``"-r"`` option
Returns:
Path to the newly-created encrypted file
Raises:
IOError: If there is a problem encrypting the file
"""
encryptedPath = "%s.gpg" % sourcePath
command = resolveCommand(GPG_COMMAND)
args = ["--batch", "--yes", "-e", "-r", recipient, "-o", encryptedPath, sourcePath]
result = executeCommand(command, args)[0]
if result != 0:
raise IOError("Error [%d] calling gpg to encrypt [%s]." % (result, sourcePath))
if not os.path.exists(encryptedPath):
raise IOError("After call to [%s], encrypted file [%s] does not exist." % (command, encryptedPath))
logger.debug("Completed encrypting file [%s] to [%s].", sourcePath, encryptedPath)
return encryptedPath
def _dumpFilesystemContents(targetDir, backupUser, backupGroup, compress=True):
"""
Dumps complete listing of filesystem contents via ``ls -laR``.
Args:
targetDir: Directory to write output file into
backupUser: User which should own the resulting file
backupGroup: Group which should own the resulting file
compress: Indicates whether to compress the output file
Raises:
IOError: If the dump fails for some reason
"""
(outputFile, filename) = _getOutputFile(targetDir, "ls-laR", compress)
with outputFile:
# Note: can't count on return status from 'ls', so we don't check it.
command = resolveCommand(LS_COMMAND)
executeCommand(command, [],
returnOutput=False,
ignoreStderr=True,
doNotLog=True,
outputFile=outputFile)
if not os.path.exists(filename):
raise IOError(
"File [%s] does not seem to exist after filesystem contents dump finished."
% filename)
changeOwnership(filename, backupUser, backupGroup)
def _getEstimatedSize(self, entries):
"""
Returns the estimated size (in bytes) for the passed-in entries dictionary.
Returns:
Estimated size of the image, in bytes
Raises:
IOError: If there is a problem calling ``mkisofs``
"""
args = self._buildSizeArgs(entries)
command = resolveCommand(MKISOFS_COMMAND)
(result, output) = executeCommand(command,
args,
returnOutput=True,
ignoreStderr=True)
if result != 0:
raise IOError(
"Error (%d) executing mkisofs command to estimate size." %
result)
if len(output) != 1:
raise IOError("Unable to parse mkisofs output.")
try:
sectors = float(output[0])
size = convertSize(sectors, UNIT_SECTORS, UNIT_BYTES)
return size
except:
raise IOError("Unable to parse mkisofs output.")
def _writeImage(self, newDisc, imagePath, entries, mediaLabel=None):
"""
Writes an image to disc using either an entries list or an ISO image on
disk.
Callers are assumed to have done validation on paths, etc. before calling
this method.
Args:
newDisc: Indicates whether the disc should be re-initialized
imagePath: Path to an ISO image on disk, or c{None} to use ``entries``
entries: Mapping from path to graft point, or ``None`` to use ``imagePath``
Raises:
IOError: If the media could not be written to for some reason
"""
command = resolveCommand(GROWISOFS_COMMAND)
args = DvdWriter._buildWriteArgs(newDisc,
self.hardwareId,
self._driveSpeed,
imagePath,
entries,
mediaLabel,
dryRun=False)
(result, output) = executeCommand(command, args, returnOutput=True)
if result != 0:
DvdWriter._searchForOverburn(
output) # throws own exception if overburn condition is found
raise IOError("Error (%d) executing command to write disc." %
result)
self.refreshMedia()
def backupDatabase(user, backupFile, database=None):
"""
Backs up an individual PostgreSQL database, or all databases.
This function backs up either a named local PostgreSQL database or all local
PostgreSQL databases, using the passed in user for connectivity.
This is *always* a full backup. There is no facility for incremental
backups.
The backup data will be written into the passed-in back file. Normally,
this would be an object as returned from ``open``, but it is possible to
use something like a ``GzipFile`` to write compressed output. The caller is
responsible for closing the passed-in backup file.
*Note:* Typically, you would use the ``root`` user to back up all databases.
Args:
user (String representing PostgreSQL username): User to use for connecting to the database
backupFile (Python file object as from ``open`` or ``file``): File use for writing backup
database (String representing database name, or ``None`` for all databases): Name of the database to be backed up
Raises:
ValueError: If some value is missing or invalid
IOError: If there is a problem executing the PostgreSQL dump
"""
args = []
if user is not None:
args.append("-U")
args.append(user)
if database is None:
command = resolveCommand(POSTGRESQLDUMPALL_COMMAND)
else:
command = resolveCommand(POSTGRESQLDUMP_COMMAND)
args.append(database)
result = executeCommand(command, args, returnOutput=False, ignoreStderr=True, doNotLog=True, outputFile=backupFile)[0]
if result != 0:
if database is None:
raise IOError("Error [%d] executing PostgreSQL database dump for all databases." % result)
else:
raise IOError("Error [%d] executing PostgreSQL database dump for database [%s]." % (result, database))
def unlockTray(self):
"""
Unlocks the device's tray via 'eject -i off'.
Raises:
IOError: If there is an error talking to the device
"""
command = resolveCommand(EJECT_COMMAND)
args = ["-i", "off", self.device]
result = executeCommand(command, args)[0]
if result != 0:
raise IOError(
"Error (%d) executing eject command to unlock tray." % result)
def _confirmGpgRecipient(recipient):
"""
Confirms that a recipient's public key is known to GPG.
Throws an exception if there is a problem, or returns normally otherwise.
Args:
recipient: Recipient name
Raises:
IOError: If the recipient's public key is not known to GPG
"""
command = resolveCommand(GPG_COMMAND)
args = ["--batch", "-k", recipient] # should use --with-colons if the output will be parsed
result = executeCommand(command, args)[0]
if result != 0:
raise IOError("GPG unable to find public key for [%s]." % recipient)
def openTray(self):
"""
Opens the device's tray and leaves it open.
This only works if the device has a tray and supports ejecting its media.
We have no way to know if the tray is currently open or closed, so we
just send the appropriate command and hope for the best. If the device
does not have a tray or does not support ejecting its media, then we do
nothing.
Starting with Debian wheezy on my backup hardware, I started seeing
consistent problems with the eject command. I couldn't tell whether
these problems were due to the device management system or to the new
kernel (3.2.0). Initially, I saw simple eject failures, possibly because
I was opening and closing the tray too quickly. I worked around that
behavior with the new ejectDelay flag.
Later, I sometimes ran into issues after writing an image to a disc:
eject would give errors like "unable to eject, last error: Inappropriate
ioctl for device". Various sources online (like Ubuntu bug #875543)
suggested that the drive was being locked somehow, and that the
workaround was to run 'eject -i off' to unlock it. Sure enough, that
fixed the problem for me, so now it's a normal error-handling strategy.
Raises:
IOError: If there is an error talking to the device
"""
if self._deviceHasTray and self._deviceCanEject:
command = resolveCommand(EJECT_COMMAND)
args = [self.device]
result = executeCommand(command, args)[0]
if result != 0:
logger.debug(
"Eject failed; attempting kludge of unlocking the tray before retrying."
)
self.unlockTray()
result = executeCommand(command, args)[0]
if result != 0:
raise IOError(
"Error (%d) executing eject command to open tray (failed even after unlocking tray)."
% result)
logger.debug("Kludge was apparently successful.")
if self.ejectDelay is not None:
logger.debug(
"Per configuration, sleeping %d seconds after opening tray.",
self.ejectDelay)
time.sleep(self.ejectDelay)
def _retrieveSectorsUsed(self):
"""
Retrieves the number of sectors used on the current media.
This is a little ugly. We need to call growisofs in "dry-run" mode and
parse some information from its output. However, to do that, we need to
create a dummy file that we can pass to the command -- and we have to
make sure to remove it later.
Once growisofs has been run, then we call ``_parseSectorsUsed`` to parse
the output and calculate the number of sectors used on the media.
Returns:
Number of sectors used on the media
"""
tempdir = tempfile.mkdtemp()
try:
entries = {tempdir: None}
args = DvdWriter._buildWriteArgs(False,
self.hardwareId,
self.driveSpeed,
None,
entries,
None,
dryRun=True)
command = resolveCommand(GROWISOFS_COMMAND)
(result, output) = executeCommand(command, args, returnOutput=True)
if result != 0:
logger.debug(
"Error (%d) calling growisofs to read sectors used.",
result)
logger.warning(
"Unable to read disc (might not be initialized); returning zero sectors used."
)
return 0.0
sectorsUsed = DvdWriter._parseSectorsUsed(output)
logger.debug("Determined sectors used as %s", sectorsUsed)
return sectorsUsed
finally:
if os.path.exists(tempdir):
try:
os.rmdir(tempdir)
except:
pass
def readMediaLabel(devicePath):
"""
Reads the media label (volume name) from the indicated device.
The volume name is read using the ``volname`` command.
Args:
devicePath: Device path to read from
Returns:
Media label as a string, or None if there is no name or it could not be read
"""
args = [devicePath]
command = resolveCommand(VOLNAME_COMMAND)
(result, output) = executeCommand(command,
args,
returnOutput=True,
ignoreStderr=True)
if result != 0:
return None
if output is None or len(output) < 1:
return None
return output[0].rstrip()
def closeTray(self):
"""
Closes the device's tray.
This only works if the device has a tray and supports ejecting its media.
We have no way to know if the tray is currently open or closed, so we
just send the appropriate command and hope for the best. If the device
does not have a tray or does not support ejecting its media, then we do
nothing.
Raises:
IOError: If there is an error talking to the device
"""
if self._deviceHasTray and self._deviceCanEject:
command = resolveCommand(EJECT_COMMAND)
args = ["-t", self.device]
result = executeCommand(command, args)[0]
if result != 0:
raise IOError(
"Error (%d) executing eject command to close tray." %
result)
def writeImage(self, imagePath):
"""
Writes this image to disk using the image path.
Args:
imagePath (String representing a path on disk): Path to write image out as
Raises:
IOError: If there is an error writing the image to disk
ValueError: If there are no filesystem entries in the image
ValueError: If a path cannot be encoded properly
"""
imagePath = encodePath(imagePath)
if len(list(self.entries.keys())) == 0:
raise ValueError("Image does not contain any entries.")
args = self._buildWriteArgs(self.entries, imagePath)
command = resolveCommand(MKISOFS_COMMAND)
(result, output) = executeCommand(command, args, returnOutput=False)
if result != 0:
raise IOError(
"Error (%d) executing mkisofs command to build image." %
result)
def _dumpDebianPackages(targetDir, backupUser, backupGroup, compress=True):
"""
Dumps a list of currently installed Debian packages via ``dpkg``.
Args:
targetDir: Directory to write output file into
backupUser: User which should own the resulting file
backupGroup: Group which should own the resulting file
compress: Indicates whether to compress the output file
Raises:
IOError: If the dump fails for some reason
"""
if not os.path.exists(DPKG_PATH):
logger.info(
"Not executing Debian package dump since %s doesn't seem to exist.",
DPKG_PATH)
elif not os.access(DPKG_PATH, os.X_OK):
logger.info(
"Not executing Debian package dump since %s cannot be executed.",
DPKG_PATH)
else:
(outputFile, filename) = _getOutputFile(targetDir, "dpkg-selections",
compress)
with outputFile:
command = resolveCommand(DPKG_COMMAND)
result = executeCommand(command, [],
returnOutput=False,
ignoreStderr=True,
doNotLog=True,
outputFile=outputFile)[0]
if result != 0:
raise IOError("Error [%d] executing Debian package dump." %
result)
if not os.path.exists(filename):
raise IOError(
"File [%s] does not seem to exist after Debian package dump finished."
% filename)
changeOwnership(filename, backupUser, backupGroup)
def _splitFile(sourcePath,
splitSize,
backupUser,
backupGroup,
removeSource=False):
"""
Splits the source file into chunks of the indicated size.
The split files will be owned by the indicated backup user and group. If
``removeSource`` is ``True``, then the source file will be removed after it is
successfully split.
Args:
sourcePath: Absolute path of the source file to split
splitSize: Encryption mode (only "gpg" is allowed)
backupUser: User that target files should be owned by
backupGroup: Group that target files should be owned by
removeSource: Indicates whether to remove the source file
Raises:
IOError: If there is a problem accessing, splitting or removing the source file
"""
cwd = os.getcwd()
try:
if not os.path.exists(sourcePath):
raise ValueError("Source path [%s] does not exist." % sourcePath)
dirname = os.path.dirname(sourcePath)
filename = os.path.basename(sourcePath)
prefix = "%s_" % filename
bytes = int(splitSize.bytes) # pylint: disable=W0622
os.chdir(
dirname
) # need to operate from directory that we want files written to
command = resolveCommand(SPLIT_COMMAND)
args = [
"--verbose", "--numeric-suffixes", "--suffix-length=5",
"--bytes=%d" % bytes, filename, prefix
]
(result, output) = executeCommand(command,
args,
returnOutput=True,
ignoreStderr=False)
if result != 0:
raise IOError("Error [%d] calling split for [%s]." %
(result, sourcePath))
pattern = re.compile(r"(creating file [`'])(%s)(.*)(')" % prefix)
match = pattern.search(output[-1:][0])
if match is None:
raise IOError("Unable to parse output from split command.")
value = int(match.group(3).strip())
for index in range(0, value):
path = "%s%05d" % (prefix, index)
if not os.path.exists(path):
raise IOError(
"After call to split, expected file [%s] does not exist." %
path)
changeOwnership(path, backupUser, backupGroup)
if removeSource:
if os.path.exists(sourcePath):
try:
os.remove(sourcePath)
logger.debug("Completed removing old file [%s].",
sourcePath)
except:
raise IOError(
"Failed to remove file [%s] after splitting it." %
(sourcePath))
finally:
os.chdir(cwd)
def backupDatabase(user, password, backupFile, database=None):
"""
Backs up an individual MySQL database, or all databases.
This function backs up either a named local MySQL database or all local
MySQL databases, using the passed-in user and password (if provided) for
connectivity. This function call *always* results a full backup. There is
no facility for incremental backups.
The backup data will be written into the passed-in backup file. Normally,
this would be an object as returned from ``open``, but it is possible to
use something like a ``GzipFile`` to write compressed output. The caller is
responsible for closing the passed-in backup file.
Often, the "root" database user will be used when backing up all databases.
An alternative is to create a separate MySQL "backup" user and grant that
user rights to read (but not write) all of the databases that will be backed
up.
This function accepts a username and password. However, you probably do not
want to pass those values in. This is because they will be provided to
``mysqldump`` via the command-line ``--user`` and ``--password`` switches,
which will be visible to other users in the process listing.
Instead, you should configure the username and password in one of MySQL's
configuration files. Typically, this would be done by putting a stanza like
this in ``/root/.my.cnf``, to provide ``mysqldump`` with the root database
username and its password::
[mysqldump]
user = root
password = <secret>
If you are executing this function as some system user other than root, then
the ``.my.cnf`` file would be placed in the home directory of that user. In
either case, make sure to set restrictive permissions (typically, mode
``0600``) on ``.my.cnf`` to make sure that other users cannot read the file.
Args:
user (String representing MySQL username, or ``None``): User to use for connecting to the database (if any)
password (String representing MySQL password, or ``None``): Password associated with user (if any)
backupFile (Python file object as from ``open`` or ``file``): File use for writing backup
database (String representing database name, or ``None`` for all databases): Name of the database to be backed up
Raises:
ValueError: If some value is missing or invalid
IOError: If there is a problem executing the MySQL dump
"""
args = ["-all", "--flush-logs", "--opt"]
if user is not None:
logger.warning(
"Warning: MySQL username will be visible in process listing (consider using ~/.my.cnf)."
)
args.append("--user=%s" % user)
if password is not None:
logger.warning(
"Warning: MySQL password will be visible in process listing (consider using ~/.my.cnf)."
)
args.append("--password=%s" % password)
if database is None:
args.insert(0, "--all-databases")
else:
args.insert(0, "--databases")
args.append(database)
command = resolveCommand(MYSQLDUMP_COMMAND)
result = executeCommand(command,
args,
returnOutput=False,
ignoreStderr=True,
doNotLog=True,
outputFile=backupFile)[0]
if result != 0:
if database is None:
raise IOError(
"Error [%d] executing MySQL database dump for all databases." %
result)
else:
raise IOError(
"Error [%d] executing MySQL database dump for database [%s]." %
(result, database))
