COT.ovf module

Module for handling OVF and OVA virtual machine description files.

Functions

byte_count	Convert an OVF-style value + multiplier into decimal byte count.
byte_string	Pretty-print the given bytes value.
factor_bytes	Convert a byte count into OVF-style bytes + multiplier.

Classes and Exceptions

OVF	Representation of the contents of an OVF or OVA.
OVFNameHelper	Helper class for OVF.
OVFHardware	Helper class for OVF.
OVFHardwareDataError	The input data used to construct an OVFHardware is not sane.
OVFItem	Helper class for OVF.
OVFItemDataError	Data to be added to an OVFItem conflicts with existing data.

byte_count(base_val, multiplier)

Convert an OVF-style value + multiplier into decimal byte count.

Inverse operation of factor_bytes().

>>> byte_count("128", "byte * 2^20")
134217728

Parameters:

• base_val (str) – Base value string (value of ovf:capacity, etc.)
• multiplier (str) – Multiplier string (value of ovf:capacityAllocationUnits, etc.)

Returns:

Number of bytes

Return type:

int

byte_string(byte_count, base_shift=0)

Pretty-print the given bytes value.

Parameters:

• byte_count (float) – Value
• base_shift (int) – Base value of byte_count (0 = bytes, 1 = kB, 2 = MB, etc.)

Returns:

Pretty-printed byte string such as “1.00 GB”

factor_bytes(byte_count)

Convert a byte count into OVF-style bytes + multiplier.

Inverse operation of byte_count()

>>> factor_bytes(134217728)
('128', 'byte * 2^20')
>>> factor_bytes(134217729)
('134217729', 'byte')

Parameters:byte_count (int) – Number of bytes Returns:(base_val, multiplier)

class OVF(input_file, output_file)

Bases: COT.vm_description.VMDescription, COT.xml_file.XML

Representation of the contents of an OVF or OVA.

Variables:ovf_version – Float representing the OVF specification version in use. Supported values at present are 0.9, 1.0, and 2.0.

Properties

input_file	Data file to read in.
output_file	OVF or OVA file that will be created or updated by write().
platform	The platform type, as determined from the OVF descriptor.
config_profiles	The list of supported configuration profiles.
default_config_profile	The name of the default configuration profile.
environment_properties	The array of environment properties.
networks	The list of network names currently defined in this VM.
system_types	List of virtual system type(s) supported by this virtual machine.
version_short	Short descriptive version string (XML Version element).
version_long	Long descriptive version string (XML FullVersion element).

add_controller_device(type, subtype, address, ctrl_item=None)

Create a new IDE or SCSI controller, or update existing one.

Parameters:

• type (str) – 'ide' or 'scsi'
• subtype (str) – Subtype such as 'virtio' (optional)
• address (int) – Controller address such as 0 or 1 (optional)
• ctrl_item – Existing controller device to update (optional)

Returns:

New or updated controller device object

add_disk(file_path, file_id, disk_type, disk=None)

Add a new disk object to the VM or overwrite the provided one.

Parameters:

• file_path (str) – Path to disk image file
• file_id (str) – Identifier string for the file/disk mapping
• disk_type (str) – ‘harddisk’ or ‘cdrom’
• disk – Existing disk object to overwrite

Returns:

New or updated disk object

add_disk_device(type, address, name, description, disk, file, ctrl_item, disk_item=None)

Create a new disk hardware device or overwrite an existing one.

Parameters:

• type (str) – 'harddisk' or 'cdrom'
• address (str) – Address on controller, such as “1:0” (optional)
• name (str) – Device name string (optional)
• description (str) – Description string (optional)
• disk – Disk object to map to this device
• file – File object to map to this device
• ctrl_item – Controller object to serve as parent
• disk_item – Existing disk device to update instead of making a new device.

Returns:

New or updated disk device object.

add_file(file_path, file_id, file=None, disk=None)

Add a new file object to the VM or overwrite the provided one.

Parameters:

• file_path (str) – Path to file to add
• file_id (str) – Identifier string for the file in the VM
• file – Existing file object to overwrite
• disk – Existing disk object referencing file.

Returns:

New or updated file object

check_sanity_of_disk_device(disk, file, disk_item, ctrl_item)

Check if the given disk is linked properly to the other objects.

Parameters:

• disk – Disk object to validate
• file – File object which this disk should be linked to (optional)
• disk_item – Disk device object which should link to this disk (optional)
• ctrl_item – Controller device object which should link to the disk_item

Raises:

• ValueMismatchError – if the given items are not linked properly.
• ValueUnsupportedError – if the disk_item has a HostResource value in an unrecognized or invalid format.

config_file_to_properties(file)

Import each line of a text file into a configuration property.

Raises NotImplementedError:  if the platform for this OVF does not define LITERAL_CLI_STRING Parameters:file (str) – File name to import.

convert_disk_if_needed(file_path, kind)

Convert the disk to a more appropriate format if needed.

• All hard disk files are converted to stream-optimized VMDK as it is the only format that VMware supports in OVA packages.
• CD-ROM iso images are accepted without change.

Parameters:

• file_path (str) – Image to inspect and possibly convert
• kind (str) – Image type (harddisk/cdrom)

Returns:

• file_path, if no conversion was required
• or a file path in output_dir containing the converted image

create_configuration_profile(id, label, description)

Create or update a configuration profile with the given ID.

Parameters:

• id – Profile identifier
• label (str) – Brief descriptive label for the profile
• description (str) – Verbose description of the profile

create_envelope_section_if_absent(section_tag, info_string, attrib={})

If the OVF doesn’t already have the given Section, create it.

Parameters:

• section_tag (str) – XML tag of the desired section.
• info_string (str) – Info string to set if a new Section is created.
• attrib (dict) – Attributes to filter by when looking for any existing section.

Returns:

Section element that was found or created

create_network(label, description)

Define a new network with the given label and description.

Parameters:

• label (str) – Brief label for the network
• description (str) – Verbose description of the network

delete_configuration_profile(profile)

Delete the profile with the given ID.

classmethod detect_type_from_name(filename)

Check the given filename to see if it looks like a type we support.

For our purposes, the file needs to match ”.ov[af]” to appear to be an OVF/OVA file. We also support names like “foo.ovf.20150101” as those have been seen in the wild.

Does not check file contents, as the given filename may not yet exist.

Returns:‘.ovf’ or ‘.ova’ Raises ValueUnsupportedError:  if filename doesn’t match ovf/ova

device_info_str(device_item)

Get a one-line summary of a hardware device.

Parameters:device_item (OVFItem) – Device to summarize Returns:Descriptive string such as “harddisk @ IDE 1:0”

find_device_location(device)

Find the controller type and address of a given device object.

Parameters:device – Hardware device object. Returns:(type, address), such as ("ide", "1:0").

find_disk_from_file_id(file_id)

Find the Disk that uses the given file_id for backing.

Parameters:file_id (str) – File identifier string Returns:Disk element matching the file, or None

find_empty_drive(type)

Find a disk device that exists but contains no data.

Parameters:type (str) – Either ‘cdrom’ or ‘harddisk’ Returns:Hardware device object, or None.

find_item_from_disk(disk)

Find the disk Item that references the given Disk.

Parameters:disk (xml.etree.ElementTree.Element) – Disk element Returns:OVFItem instance, or None

find_item_from_file(file)

Find the disk Item that references the given File.

Parameters:file (xml.etree.ElementTree.Element) – File element Returns:OVFItem instance, or None.

find_open_controller(type)

Find the first open slot on a controller of the given type.

Parameters:type (str) – 'ide' or 'scsi' Returns:(ctrl_item, address_string) or (None, None)

find_parent_from_item(item)

Find the parent Item of the given Item.

Parameters:item (OVFItem) – Item whose parent is desired Returns:OVFItem representing the parent device, or None

generate_manifest(ovf_file)

Construct the manifest file for this package, if possible.

Parameters:ovf_file (str) – OVF descriptor file path Returns:True if the manifest was successfully generated, False if not successful (such as if checksum helper tools are unavailable).

get_capacity_from_disk(disk)

Get the capacity of the given Disk in bytes.

Parameters:disk (xml.etree.ElementTree.Element) – Disk element Return type:int

get_common_subtype(type)

Get the sub-type common to all devices of the given type.

Parameters:type (str) – Device type such as 'ide' or 'memory'. Returns:None, if multiple such devices exist and they do not all have the same sub-type. Returns:Subtype string common to all devices of the type.

get_file_ref_from_disk(disk)

Get the file reference from the given opaque disk object.

Parameters:disk (xml.etree.ElementTree.Element) – ‘Disk’ element Returns:‘fileRef’ attribute value of this element

get_id_from_file(file)

Get the file ID from the given opaque file object.

Parameters:file (xml.etree.ElementTree.Element) – ‘File’ element Returns:‘id’ attribute value of this element

get_nic_count(profile_list)

Get the number of NICs under the given profile(s).

Parameters:profile_list (list) – Profile(s) of interest. Return type:dict Returns:{ profile_name : nic_count }

get_path_from_file(file)

Get the file path from the given opaque file object.

Parameters:file (xml.etree.ElementTree.Element) – ‘File’ element Returns:‘href’ attribute value of this element

get_property_value(key)

Get the value of the given property.

Parameters:key (str) – Property identifier Returns:Value of this property, or None

get_serial_connectivity(profile)

Get the serial port connectivity strings under the given profile.

Parameters:profile (str) – Profile of interest. Returns:List of connectivity strings

get_serial_count(profile_list)

Get the number of serial ports under the given profile(s).

Return type:dict Returns:{ profile_name : serial_count }

get_subtype_from_device(device)

Get the sub-type of the given opaque device object.

Parameters:device – Device object to query Returns:None, or string such as ‘virtio’ or ‘lsilogic’

get_type_from_device(device)

Get the type of the given device.

Parameters:device (OVFItem) – Device object to query Returns:string such as ‘ide’ or ‘memory’

info_string(TEXT_WIDTH=79, verbosity_option=None)

Get a descriptive string summarizing the contents of this OVF.

Parameters:

• TEXT_WIDTH (int) – Line length to wrap to where possible.
• verbosity_option (str) – 'brief', None (default), or 'verbose'

Returns:

Wrapped, appropriately verbose string.

profile_info_list(TEXT_WIDTH=79, verbose=False)

Get a list describing available configuration profiles.

Parameters:

• TEXT_WIDTH (int) – Line length to wrap to if possible
• verbose (str) – if True, generate multiple lines per profile

Returns:

(header, list)

profile_info_string(TEXT_WIDTH=79, verbosity_option=None)

Get a string summarizing available configuration profiles.

Parameters:

• TEXT_WIDTH (int) – Line length to wrap to if possible
• verbosity_option (str) – 'brief', None (default), or 'verbose'

Returns:

Appropriately formatted and verbose string.

search_from_controller(controller, address)

From the controller type and device address, look for existing disk.

This implementation uses the parameters to find matching controller and disk Item elements, then using the disk Item to find matching File and/or Disk.

Parameters:

• controller (str) – 'ide' or 'scsi'
• address (str) – Device address such as '1:0'

Returns:

(file, disk, ctrl_item, disk_item), any or all of which may be None

search_from_file_id(file_id)

From the given file ID, try to find any existing objects.

This implementation uses the given file_id to find a matching File in the OVF, then using that to find a matching Disk and Item entries.

Parameters:file_id (str) – Filename to search from Returns:(file, disk, ctrl_item, disk_item), any or all of which may be None

search_from_filename(filename)

From the given filename, try to find any existing objects.

This implementation uses the given filename to find a matching File in the OVF, then using that to find a matching Disk and Item entries.

Parameters:filename (str) – Filename to search from Returns:(file, disk, ctrl_item, disk_item), any or all of which may be None

set_capacity_of_disk(disk, capacity_bytes)

Set the storage capacity of the given Disk.

Tries to use the most human-readable form possible (i.e., 8 GB instead of 8589934592 bytes).

Parameters:

• disk (xml.etree.ElementTree.Element) – Disk to update
• capacity_bytes (int) – Disk capacity, in bytes

set_cpu_count(cpus, profile_list)

Set the number of CPUs.

Parameters:

• cpus (int) – Number of CPUs
• profile_list (list) – Change only the given profiles

set_ide_subtype(type, profile_list)

Set the device subtype for the IDE controller(s).

Parameters:

• type (str) – IDE subtype string
• profile_list (list) – Change only the given profiles

set_memory(megabytes, profile_list)

Set the amount of RAM, in megabytes.

Parameters:

• megabytes (int) – Memory value, in megabytes
• profile_list (list) – Change only the given profiles

set_nic_count(count, profile_list)

Set the given profile(s) to have the given number of NICs.

Parameters:

• count (int) – number of NICs
• profile_list (list) – Change only the given profiles

set_nic_mac_addresses(mac_list, profile_list)

Set the MAC addresses for NICs under the given profile(s).

Note

If the length of mac_list is less than the number of NICs, will use the last entry in the list for all remaining NICs.

Parameters:

• mac_list (list) – List of MAC addresses to assign to NICs
• profile_list (list) – Change only the given profiles

set_nic_names(name_list, profile_list)

Set the device names for NICs under the given profile(s).

Parameters:

• name_list (list) – List of names to assign.
• profile_list (list) – Change only the given profiles

set_nic_networks(network_list, profile_list)

Set the NIC to network mapping for NICs under the given profile(s).

Note

If the length of network_list is less than the number of NICs, will use the last entry in the list for all remaining NICs.

Parameters:

• network_list (list) – List of networks to map NICs to
• profile_list (list) – Change only the given profiles

set_nic_type(type, profile_list)

Set the hardware type for NICs.

Parameters:

• type (str) – NIC hardware type
• profile_list (list) – Change only the given profiles.

set_product_section_child(child_tag, child_text)

If the OVF doesn’t already have the given Section, create it.

Parameters:

• child_tag (str) – XML tag of the product section child element.
• child_text (str) – Text to set for the child element.

Returns:

The product section element that was updated or created

set_property_value(key, value)

Set the value of the given property (converting value if needed).

Parameters:

• key (str) – Property identifier
• value – Value to set for this property

Returns:

the (converted) value that was set.

set_scsi_subtype(type, profile_list)

Set the device subtype for the SCSI controller(s).

Parameters:

• type (str) – SCSI subtype string
• profile_list (list) – Change only the given profiles

set_serial_connectivity(conn_list, profile_list)

Set the serial port connectivity under the given profile(s).

Parameters:

• conn_list (list) – List of connectivity strings
• profile_list (list) – Change only the given profiles

set_serial_count(count, profile_list)

Set the given profile(s) to have the given number of serial ports.

Parameters:

• count (int) – Number of serial ports
• profile_list (list) – Change only the given profiles

tar(ovf_descriptor, tar_file)

Create a .ova tar file based on the given OVF descriptor.

Parameters:

• ovf_descriptor (str) – File path for an OVF descriptor
• tar_file (str) – File path for the desired OVA archive.

untar(file)

Untar the OVF descriptor from an .ova to the working directory.

Parameters:file (str) – OVA file path Raises VMInitError:  if the given file does not represent a valid OVA archive. Returns:Path to extracted OVF descriptor

validate_and_update_file_references()

Check all File entries to make sure they are valid and up to date.

Helper method for write().

validate_and_update_networks()

Make sure all defined networks are actually used by NICs.

Delete any networks that are unused and warn the user. Helper method for write().

write()

Write OVF or OVA to output_file, if set.

application_url

Application URL string (XML AppUrl element).

config_profiles

The list of supported configuration profiles.

If this OVF has no defined profiles, returns an empty list. If there is a default profile, it will be first in the list.

environment_properties

The array of environment properties.

Returns:Array of dicts (one per property) with the keys "key", "value", "qualifiers", "type", "label", and "description".

networks

The list of network names currently defined in this VM.

Return type:list[str]

output_file

OVF or OVA file that will be created or updated by write().

Raises ValueUnsupportedError:  if detect_type_from_name() fails

platform

The platform type, as determined from the OVF descriptor.

Type:Class object - GenericPlatform or a more-specific subclass if recognized as such.

product

Short descriptive product string (XML Product element).

product_url

Product URL string (XML ProductUrl element).

system_types

List of virtual system type(s) supported by this virtual machine.

For an OVF, this corresponds to the VirtualSystemType element.

vendor

Short descriptive vendor string (XML Vendor element).

vendor_url

Vendor URL string (XML VendorUrl element).

version_long

Long descriptive version string (XML FullVersion element).

version_short

Short descriptive version string (XML Version element).

class OVFNameHelper(version)

Bases: object

Helper class for OVF.

Provides string constants for easier lookup of various OVF XML elements and attributes.

class OVFHardware(ovf)

Helper class for OVF.

Represents all hardware items defined by this OVF; i.e., the contents of all Items in the VirtualHardwareSection.

Fundamentally it’s just a dict of OVFItem objects with a bunch of helper methods.

clone_item(parent_item, profile_list)

Clone an OVFItem to create a new instance.

Parameters:

• parent_item (OVFItem) – Instance to clone from
• profile_list (list) – List of profiles to clone into

Returns:

(instance, ovfitem)

find_all_items(resource_type=None, properties=None, profile_list=None)

Find all items matching the given type, properties, and profiles.

Parameters:

• resource_type – Resource type string like ‘scsi’ or ‘serial’
• value] properties (dict[property,) – Property values to match
• profile_list (list) – List of profiles to filter on

Returns:

list of OVFItem instances

find_item(resource_type=None, properties=None, profile=None)

Find the only OVFItem of the given resource_type.

Parameters:

• resource_type –
• properties –
• profile – Single profile ID to search within

Return type:

OVFItem or None

Raises LookupError:  

if more than one such Item exists.

find_unused_instance_id()

Find the first available InstanceID number.

Return type:string

get_item_count(resource_type, profile)

Wrapper for get_item_count_per_profile().

Parameters:

• resource_type (str) –
• profile (str) – Single profile identifier string to look up.

Returns:

Number of items of this type in this profile.

get_item_count_per_profile(resource_type, profile_list)

Get the number of Items of the given type per profile.

Items present under “no profile” will be counted against the total for each profile.

Parameters:

• resource_type (str) –
• profile_list (list) – List of profiles to filter on (default: apply across all profiles)

Return type:

dict[profile, count]

new_item(resource_type, profile_list=None)

Create a new OVFItem of the given type.

Parameters:

• resource_type (str) –
• profile_list (list) – Profiles the new item should belong to

Returns:

(instance, ovfitem)

set_item_count_per_profile(resource_type, count, profile_list)

Set the number of items of a given type under the given profile(s).

If the new count is greater than the current count under this profile, then additional instances that already exist under another profile will be added to this profile, starting with the lowest-sequence instance not already present, and only as a last resort will new instances be created.

If the new count is less than the current count under this profile, then the highest-numbered instances will be removed preferentially.

Parameters:

• resource_type (str) – ‘cpu’, ‘harddisk’, etc.
• count (int) – Desired number of items
• profile_list (list) – List of profiles to filter on (default: apply across all profiles)

set_item_values_per_profile(resource_type, property, value_list, profile_list, default=None)

Set value(s) for a property of multiple items of a type.

Parameters:

• resource_type (str) – Device type such as ‘harddisk’ or ‘cpu’
• property (str) – Property name to update
• value_list (list) – List of values to set (one value per item of the given resource_type)
• profile_list (list) – List of profiles to filter on (default: apply across all profiles)
• default – If there are more matching items than entries in value_list, set extra items to this value

set_value_for_all_items(resource_type, property, new_value, profile_list, create_new=False)

Set a property to the given value for all items of the given type.

If no items of the given type exist, will create a new Item if create_new is set to True; otherwise will log a warning and do nothing.

Parameters:

• resource_type (str) – Resource type such as ‘cpu’ or ‘harddisk’
• property (str) – Property name to update
• new_value – New value to set the property to
• profile_list (list) – List of profiles to filter on (default: apply across all profiles)
• create_new (boolean) – Whether to create a new entry if no items of this resource_type presently exist.

update_xml()

Regenerate all Items under the VirtualHardwareSection, if needed.

Will do nothing if no Items have been changed.

class OVFHardwareDataError

Bases: exceptions.Exception

The input data used to construct an OVFHardware is not sane.

class OVFItem(ovf, item=None)

Helper class for OVF.

Represents all variations of a given hardware Item amongst different hardware configuration profiles.

In essence, it is:

• a dict of Item properties (indexed by element name)
• each of which is a dict of sets of profiles (indexed by element value)

add_item(item)

Add the given Item element to this OVFItem.

Parameters:item – XML Item element Raises OVFItemDataError:  if the new Item conflicts with existing data already in the OVFItem.

add_profile(new_profile, from_item=None)

Add a new profile to this item.

Parameters:

• new_profile (str) – Profile name to add
• from_item (OVFItem) – Item to inherit properties from. If unset, this defaults to self.

generate_items()

Get a list of Item XML elements derived from this object’s data.

Return type:list[xml.etree.ElementTree.Element]

get(tag)

Get the dict associated with the given XML tag, if any.

Parameters:tag (str) – XML tag to look up Return type:dict Returns:Dictionary of values associated with this tag (TODO?)

get_all_values(tag)

Get the set of all value strings for the given tag.

Parameters:tag – Return type:set

get_value(tag, profiles=None)

Get the value for the given tag under the given profiles.

If the tag does not exist under these profiles, or the tag values differ across the profiles, returns None.

Parameters:

• tag (str) – Tag that the value is associated with
• profiles – set of profile names, or None

Returns:

Value string or None

has_profile(profile)

Check if this Item exists under the given profile.

Parameters:profile (str) – Profile name Return type:boolean

remove_profile(profile, split_default=True)

Remove all trace of the given profile from this item.

Parameters:

• profile – Profile name to remove
• split_default – If false, do not split out ‘default’ profile items to specifically exclude this profile. Used when the profile being removed will no longer exist anywhere and so ‘default’ will continue to exclude this profile.

set_property(key, value, profiles=None, overwrite=True)

Store the value and profiles associated with it for the given key.

Parameters:

• key (str) – Property key
• value – Value associated with key
• profiles (list[str]) – If None, set for all profiles currently known to this item, else set only for the given list of profiles.
• overwrite (boolean) – Whether to permit overwriting of existing value set in this item.

Raises OVFItemDataError:  

if a value is already defined and would be overwritten, unless overwrite is True

validate()

Verify that the OVFItem describes a valid set of items.

Raises RuntimeError:  if validation fails and self-repair is impossible.

ATTRIB_KEY_SUFFIX = ' {Item attribute}'

ELEMENT_KEY_SUFFIX = ' {custom element}'

class OVFItemDataError

Bases: exceptions.Exception

Data to be added to an OVFItem conflicts with existing data.