Operator Libs Linux

By Jon Seager

Architecture:

Channel	Revision	Published	Runs on
latest/stable	2	09 Mar 2023	Ubuntu 22.04

Platform:

22.04

charms.operator_libs_linux.v0.apt

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  Download apt.py
- 03 Jan 2024
- Library version 0.13

Abstractions for the system's Debian/Ubuntu package information and repositories.

This module contains abstractions and wrappers around Debian/Ubuntu-style repositories and packages, in order to easily provide an idiomatic and Pythonic mechanism for adding packages and/or repositories to systems for use in machine charms.

A sane default configuration is attainable through nothing more than instantiation of the appropriate classes. DebianPackage objects provide information about the architecture, version, name, and status of a package.

DebianPackage will try to look up a package either from dpkg -L or from apt-cache when provided with a string indicating the package name. If it cannot be located, PackageNotFoundError will be returned, as apt and dpkg otherwise return 100 for all errors, and a meaningful error message if the package is not known is desirable.

To install packages with convenience methods:

try:
    # Run `apt-get update`
    apt.update()
    apt.add_package("zsh")
    apt.add_package(["vim", "htop", "wget"])
except PackageNotFoundError:
    logger.error("a specified package not found in package cache or on system")
except PackageError as e:
    logger.error("could not install package. Reason: %s", e.message)

To find details of a specific package:

try:
    vim = apt.DebianPackage.from_system("vim")

    # To find from the apt cache only
    # apt.DebianPackage.from_apt_cache("vim")

    # To find from installed packages only
    # apt.DebianPackage.from_installed_package("vim")

    vim.ensure(PackageState.Latest)
    logger.info("updated vim to version: %s", vim.fullversion)
except PackageNotFoundError:
    logger.error("a specified package not found in package cache or on system")
except PackageError as e:
    logger.error("could not install package. Reason: %s", e.message)

RepositoryMapping will return a dict-like object containing enabled system repositories and their properties (available groups, baseuri. gpg key). This class can add, disable, or manipulate repositories. Items can be retrieved as DebianRepository objects.

In order add a new repository with explicit details for fields, a new DebianRepository can be added to RepositoryMapping

RepositoryMapping provides an abstraction around the existing repositories on the system, and can be accessed and iterated over like any Mapping object, to retrieve values by key, iterate, or perform other operations.

Keys are constructed as {repo_type}-{}-{release} in order to uniquely identify a repository.

Repositories can be added with explicit values through a Python constructor.

Example:

repositories = apt.RepositoryMapping()

if "deb-example.com-focal" not in repositories:
    repositories.add(DebianRepository(enabled=True, repotype="deb",
                     uri="https://example.com", release="focal", groups=["universe"]))

Alternatively, any valid sources.list line may be used to construct a new DebianRepository.

Example:

repositories = apt.RepositoryMapping()

if "deb-us.archive.ubuntu.com-xenial" not in repositories:
    line = "deb http://us.archive.ubuntu.com/ubuntu xenial main restricted"
    repo = DebianRepository.from_repo_line(line)
    repositories.add(repo)

Index

class Error
- def __repr__( self)
- def name( self)
- def message( self)
class PackageError
class PackageNotFoundError
class PackageState
class DebianPackage
- def __init__( self, name, version, epoch, arch, state)
- def __eq__( self, other)
- def __hash__( self)
- def __repr__( self)
- def __str__( self)
- def name( self)
- def ensure( self, state)
- def present( self)
- def latest( self)
- def state( self)
- def state( self, state)
- def version( self)
- def epoch( self)
- def arch( self)
- def fullversion( self)
- def from_system( cls, package, version, arch)
- def from_installed_package( cls, package, version, arch)
- def from_apt_cache( cls, package, version, arch)
class Version
- def __init__( self, version, epoch)
- def __repr__( self)
- def __str__( self)
- def epoch( self)
- def number( self)
- def __lt__( self, other)
- def __eq__( self, other)
- def __gt__( self, other)
- def __le__( self, other)
- def __ge__( self, other)
- def __ne__( self, other)
def add_package( package_names, version, arch, update_cache )
def remove_package( package_names )
def update( )
def import_key( key )
class InvalidSourceError
class GPGKeyError
class DebianRepository
- def __init__( self, enabled, repotype, uri, release, groups, filename, gpg_key_filename, options)
- def enabled( self)
- def repotype( self)
- def uri( self)
- def release( self)
- def groups( self)
- def filename( self)
- def filename( self, fname)
- def gpg_key( self)
- def options( self)
- def make_options_string( self)
- def prefix_from_uri( uri)
- def from_repo_line( repo_line, write_file)
- def disable( self)
- def import_key( self, key)
class RepositoryMapping
- def __init__( self)
- def __contains__( self, key)
- def __len__( self)
- def __iter__( self)
- def __getitem__( self, repository_uri)
- def __setitem__( self, repository_uri, repository)
- def load( self, filename)
- def add( self, repo, default_filename)
- def disable( self, repo)

Description

Base class of most errors raised by this library. None

Methods

Error. __repr__( self )

Description

Represent the Error. None

Error. name( self )

Description

Return a string representation of the model plus class. None

Error. message( self )

Description

Return the message passed as an argument. None

Description

Raised when there's an error installing or removing a package. None

Description

Raised when a requested package is not known to the system. None

Description

A class to represent possible package states. None

Description

DebianPackage wraps information and functionality around a known package, whether installed or available. The version, epoch, name, and architecture can be easily queried and compared against other DebianPackage objects to determine the latest version or to install a specific version.

The representation of this object as a string mimics the output from dpkg for familiarity.

Installation and removal of packages is handled through the state property or ensure method, with the following options:

apt.PackageState.Absent
apt.PackageState.Available
apt.PackageState.Present
apt.PackageState.Latest

When DebianPackage is initialized, the state of a given DebianPackage object will be set to Available, Present, or Latest, with Absent implemented as a convenience for removal (though it operates essentially the same as Available).

Methods

DebianPackage. __init__( self , name: str , version: str , epoch: str , arch: str , state: PackageState )

DebianPackage. __eq__( self , other )

Equality for comparison.

Arguments

other

a DebianPackage object for comparison

Returns

A boolean reflecting equality

DebianPackage. __hash__( self )

Description

Return a hash of this package. None

DebianPackage. __repr__( self )

Description

Represent the package. None

DebianPackage. __str__( self )

Description

Return a human-readable representation of the package. None

DebianPackage. name( self )

Description

Returns the name of the package. None

DebianPackage. ensure( self , state: PackageState )

Ensure that a package is in a given state.

Description

Args: state: a PackageState to reconcile the package to

Raises: PackageError from the underlying call to apt

DebianPackage. present( self )

Description

Returns whether or not a package is present. None

DebianPackage. latest( self )

Description

Returns whether the package is the most recent version. None

DebianPackage. state( self )

Description

Returns the current package state. None

DebianPackage. state( self , state: PackageState )

Set the package state to a given value.

Description

Args: state: a PackageState to reconcile the package to

Raises: PackageError from the underlying call to apt

DebianPackage. version( self )

Description

Returns the version for a package. None

DebianPackage. epoch( self )

Description

Returns the epoch for a package. May be unset. None

DebianPackage. arch( self )

Description

Returns the architecture for a package. None

DebianPackage. fullversion( self )

Description

Returns the name+epoch for a package. None

DebianPackage. from_system( cls , package: str , version , arch )

Locates a package, either on the system or known to apt, and serializes the information.

Arguments

package

a string representing the package

version

an optional string if a specific version is requested

arch

an optional architecture, defaulting to dpkg --print-architecture. If an architecture is not specified, this will be used for selection.

DebianPackage. from_installed_package( cls , package: str , version , arch )

Check whether the package is already installed and return an instance.

Arguments

package

a string representing the package

version

an optional string if a specific version is requested

arch

an optional architecture, defaulting to dpkg --print-architecture. If an architecture is not specified, this will be used for selection.

DebianPackage. from_apt_cache( cls , package: str , version , arch )

Check whether the package is already installed and return an instance.

Arguments

package

a string representing the package

version

an optional string if a specific version is requested

arch

an optional architecture, defaulting to dpkg --print-architecture. If an architecture is not specified, this will be used for selection.

Description

This seems like it should be strictly unnecessary, except that apt_pkg is not usable inside a venv, and wedging version comparisons into DebianPackage would overcomplicate it.

This class implements the algorithm found here: https://www.debian.org/doc/debian-policy/ch-controlfields.html#version

Methods

Version. __init__( self , version: str , epoch: str )

Version. __repr__( self )

Description

Represent the package. None

Version. __str__( self )

Description

Return human-readable representation of the package. None

Version. epoch( self )

Description

Returns the epoch for a package. May be empty. None

Version. number( self )

Description

Returns the version number for a package. None

Version. __lt__( self , other )

Description

Less than magic method impl. None

Version. __eq__( self , other )

Description

Equality magic method impl. None

Version. __gt__( self , other )

Description

Greater than magic method impl. None

Version. __le__( self , other )

Description

Less than or equal to magic method impl. None

Version. __ge__( self , other )

Description

Greater than or equal to magic method impl. None

Version. __ne__( self , other )

Description

Not equal to magic method impl. None

Description

Args: package_names: single package name, or list of package names name: the name(s) of the package(s) version: an (Optional) version as a string. Defaults to the latest known arch: an optional architecture for the package update_cache: whether or not to run apt-get update prior to operating

Raises: TypeError if no package name is given, or explicit version is set for multiple packages PackageNotFoundError if the package is not in the cache. PackageError if packages fail to install

Description

Args: package_names: the name of a package

Raises: PackageNotFoundError if the package is not found.

Description

Update the apt cache via apt-get update. None

Description

A Radix64 format keyid is also supported for backwards compatibility. In this case Ubuntu keyserver will be queried for a key via HTTPS by its keyid. This method is less preferable because https proxy servers may require traffic decryption which is equivalent to a man-in-the-middle attack (a proxy server impersonates keyserver TLS certificates and has to be explicitly trusted by the system).

Args: key: A GPG key in ASCII armor format, including BEGIN and END markers or a keyid.

Returns: The GPG key filename written.

Raises: GPGKeyError if the key could not be imported

Description

Exceptions for invalid source entries. None

Description

Exceptions for GPG keys. None

Description

An abstraction to represent a repository. None

Methods

DebianRepository. __init__( self , enabled: bool , repotype: str , uri: str , release: str , groups , filename , gpg_key_filename , options )

DebianRepository. enabled( self )

Description

Return whether or not the repository is enabled. None

DebianRepository. repotype( self )

Description

Return whether it is binary or source. None

DebianRepository. uri( self )

Description

Return the URI. None

DebianRepository. release( self )

Description

Return which Debian/Ubuntu releases it is valid for. None

DebianRepository. groups( self )

Description

Return the enabled package groups. None

DebianRepository. filename( self )

Description

Returns the filename for a repository. None

DebianRepository. filename( self , fname: str )

Set the filename used when a repo is written back to disk.

Arguments

fname

a filename to write the repository information to.

DebianRepository. gpg_key( self )

Description

Returns the path to the GPG key for this repository. None

DebianRepository. options( self )

Description

Returns any additional repo options which are set. None

DebianRepository. make_options_string( self )

Generate the complete options string for a a repository.

Description

Combining gpg_key, if set, and the rest of the options to find a complex repo string.

DebianRepository. prefix_from_uri( uri: str )

Description

Get a repo list prefix from the uri, depending on whether a path is set. None

DebianRepository. from_repo_line( repo_line: str , write_file )

Instantiate a new DebianRepository a sources.list entry line.

Arguments

repo_line

a string representing a repository entry

write_file

boolean to enable writing the new repo to disk

DebianRepository. disable( self )

Remove this repository from consideration.

Description

Disable it instead of removing from the repository file.

DebianRepository. import_key( self , key: str )

Import an ASCII Armor key.

Description

Args: key: A GPG key in ASCII armor format, including BEGIN and END markers or a keyid.

Raises: GPGKeyError if the key could not be imported

Description

Instantiation of RepositoryMapping will iterate through the filesystem, parse out repository files in /etc/apt/..., and create DebianRepository objects in this list.

Typical usage:

repositories = apt.RepositoryMapping()
repositories.add(DebianRepository(
    enabled=True, repotype="deb", uri="https://example.com", release="focal",
    groups=["universe"]
))

Methods

RepositoryMapping. __init__( self )

RepositoryMapping. __contains__( self , key: str )

Description

Magic method for checking presence of repo in mapping. None

RepositoryMapping. __len__( self )

Description

Return number of repositories in map. None

RepositoryMapping. __iter__( self )

Description

Return iterator for RepositoryMapping. None

RepositoryMapping. __getitem__( self , repository_uri: str )

Description

Return a given DebianRepository. None

RepositoryMapping. __setitem__( self , repository_uri: str , repository: DebianRepository )

Description

Add a DebianRepository to the cache. None

RepositoryMapping. load( self , filename: str )

Load a repository source file into the cache.

Arguments

filename

the path to the repository file

RepositoryMapping. add( self , repo: DebianRepository , default_filename )

Add a new repository to the system.

Arguments

repo

a DebianRepository object

default_filename

an (Optional) filename if the default is not desirable

RepositoryMapping. disable( self , repo: DebianRepository )

Remove a repository. Disable by default.

Arguments

repo

a DebianRepository to disable

Operator Libs Linux

charms.operator_libs_linux.v0.apt

class Error

class PackageError

class PackageNotFoundError

class PackageState

class DebianPackage

class Version

def add_package(
    package_names,
    version,
    arch,
    update_cache
)

def remove_package(package_names)

def update()

def import_key(key: str)

class InvalidSourceError

class GPGKeyError

class DebianRepository

class RepositoryMapping

Operator Libs Linux

charms.operator_libs_linux.v0.apt

class Error

class PackageError

class PackageNotFoundError

class PackageState

class DebianPackage

class Version

def add_package( package_names, version, arch, update_cache )

def remove_package(package_names)

def update()

def import_key(key: str)

class InvalidSourceError

class GPGKeyError

class DebianRepository

class RepositoryMapping

def add_package(
package_names,
version,
arch,
update_cache
)