Package rtslib :: Module utils

Module utils


Provides various utility functions.

This file is part of RTSLib.
Copyright (c) 2011-2013 by Datera, Inc

Licensed under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations
under the License.

Classes

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RTSLibError
Generic rtslib error.

RTSLibBrokenLink
Broken link in configfs, i.e.

RTSLibNotInCFS
The underlying configfs object does not exist.

Functions

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fwrite(path, string)
This function writes a string to a file, and takes care of opening it and closing it.

source code

fread(path)
This function reads the contents of a file.

source code

is_dev_in_use(path)
This function will check if the device or file referenced by path is already mounted or used as a storage object backend.

source code

get_blockdev_size(path)
Returns the size in logical blocks of a disk-type block device.

source code

get_block_size(path)
Returns the size in logical blocks of a disk-type block device.

source code

get_blockdev_type(path)
This function returns a block device's type.

source code

get_block_type(path)
This function returns a block device's type.

source code

convert_scsi_path_to_hctl(path)
This function returns the SCSI ID in H:C:T:L form for the block device being mapped to the udev path specified.

source code

convert_scsi_hctl_to_path(host, controller, target, lun)
This function returns a udev path pointing to the block device being mapped to the SCSI device that has the provided H:C:T:L.

source code

generate_wwn(wwn_type)
Generates a random WWN of the specified type:

source code

colonize(str)
helper function to add colons every 2 chars

source code

_cleanse_wwn(wwn_type, wwn)
Some wwns may have alternate text representations.

source code

normalize_wwn(wwn_types, wwn)
Take a WWN as given by the user and convert it to a standard text representation.

source code

list_loaded_kernel_modules()
List all currently loaded kernel modules

source code

modprobe(module)
Load the specified kernel module if needed.

source code

mount_configfs()

source code

dict_remove(d, items)

source code

ignored(*args, **kwds)

source code

_get_auth_attr(self, attribute, ignore=False)

source code

_set_auth_attr(self, value, attribute, ignore=False)

source code

set_attributes(obj, attr_dict, err_func)

source code

set_parameters(obj, param_dict, err_func)

source code

_test()
Run the doctests

source code

Variables

[hide private]

__package__ = 'rtslib'

Function Details

[hide private]

fwrite(path, string)

source code

This function writes a string to a file, and takes care of opening it and closing it. If the file does not exist, it will be created.

>>> from rtslib.utils import *
>>> fwrite("/tmp/test", "hello")
>>> fread("/tmp/test")
'hello'

Parameters:

path (string) - The file to write to.
string (string) - The string to write to the file.

fread(path)

source code

This function reads the contents of a file. It takes care of opening and closing it.

>>> from rtslib.utils import *
>>> fwrite("/tmp/test", "hello")
>>> fread("/tmp/test")
'hello'
>>> fread("/tmp/notexistingfile") # doctest: +ELLIPSIS
Traceback (most recent call last):
    ...
IOError: [Errno 2] No such file or directory: '/tmp/notexistingfile'

Parameters:

path (string) - The path to the file to read from.

Returns:

A string containing the file's contents.

is_dev_in_use(path)

source code

This function will check if the device or file referenced by path is already mounted or used as a storage object backend. It works by trying to open the path with O_EXCL flag, which will fail if someone else already did. Note that the file is closed before the function returns, so this does not guaranteed the device will still be available after the check.

Parameters:

path (string) - path to the file of device to check

Returns:

A boolean, True is we cannot get exclusive descriptor on the path, False if we can.

get_blockdev_type(path)

source code

This function returns a block device's type. Example: 0 is TYPE_DISK If no match is found, None is returned.

>>> from rtslib.utils import *
>>> get_blockdev_type("/dev/sda")
0
>>> get_blockdev_type("/dev/sr0")
5
>>> get_blockdev_type("/dev/scd0")
5
>>> get_blockdev_type("/dev/nodevicehere") is None
True

Parameters:

path (string) - path to the block device

Returns:

An int for the block device type, or None if not a block device.

get_block_type(path)

source code

This function returns a block device's type. Example: 0 is TYPE_DISK If no match is found, None is returned.

>>> from rtslib.utils import *
>>> get_blockdev_type("/dev/sda")
0
>>> get_blockdev_type("/dev/sr0")
5
>>> get_blockdev_type("/dev/scd0")
5
>>> get_blockdev_type("/dev/nodevicehere") is None
True

Parameters:

path (string) - path to the block device

Returns:

An int for the block device type, or None if not a block device.

convert_scsi_path_to_hctl(path)

source code

This function returns the SCSI ID in H:C:T:L form for the block device being mapped to the udev path specified. If no match is found, None is returned.

>>> import rtslib.utils as utils
>>> utils.convert_scsi_path_to_hctl('/dev/scd0')
(2, 0, 0, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sr0')
(2, 0, 0, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sda')
(3, 0, 0, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sda1')
>>> utils.convert_scsi_path_to_hctl('/dev/sdb')
(3, 0, 1, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sdc')
(3, 0, 2, 0)

Parameters:

path (string) - The udev path to the SCSI block device.

Returns:

An (host, controller, target, lun) tuple of integer values representing the SCSI ID of the device, or None if no match is found.

convert_scsi_hctl_to_path(host, controller, target, lun)

source code

This function returns a udev path pointing to the block device being mapped to the SCSI device that has the provided H:C:T:L.

>>> import rtslib.utils as utils
>>> utils.convert_scsi_hctl_to_path(0,0,0,0)
''
>>> utils.convert_scsi_hctl_to_path(2,0,0,0) # doctest: +ELLIPSIS
'/dev/s...0'
>>> utils.convert_scsi_hctl_to_path(3,0,2,0)
'/dev/sdc'

Parameters:

host (int) - The SCSI host id.
controller (int) - The SCSI controller id.
target (int) - The SCSI target id.
lun (int) - The SCSI Logical Unit Number.

Returns:

A string for the canonical path to the device, or empty string.

generate_wwn(wwn_type)

source code

Generates a random WWN of the specified type:

unit_serial: T10 WWN Unit Serial.
iqn: iSCSI IQN
naa: SAS NAA address

Parameters:

wwn_type (str) - The WWN address type.

Returns:

A string containing the WWN.

_cleanse_wwn(wwn_type, wwn)

source code

Some wwns may have alternate text representations. Adjust to our preferred representation.

normalize_wwn(wwn_types, wwn)

source code

Take a WWN as given by the user and convert it to a standard text representation. If possible_wwns is not None, verify that the given WWN is on that list.

Returns (normalized_wwn, wwn_type), or exception if invalid wwn.

modprobe(module)

source code

Load the specified kernel module if needed.

Parameters:

module (str) - The name of the kernel module to be loaded.

ignored(*args, **kwds)

source code

Decorators:

@contextmanager