Version 1 (modified by skvidal, 9 years ago)


Yum has a simple but powerful plugin architecture which allows external modules to add new features and/or modify Yum's behaviour. Yum plugins are Python modules (.py files) which are loaded when Yum starts.

Plugins were created partially as a place to put functionality that was seen as either less common or undesirable for the main yum package. Functionality in plugins will generally not be moved or included in the core yum package.

This document explains how to create plugins for Yum. See the yum(8) and yum.conf(5) man pages for information on how to install and configure pre-existing plugins.

A Basic Plugin

The following example shows a minimal Yum plugin:: {{{#!python numbering=off from yum.plugins import PluginYumExit?, TYPE_CORE, TYPE_INTERACTIVE

requires_api_version = '2.3' plugin_type = (TYPE_CORE, TYPE_INTERACTIVE)

def init_hook(conduit):, 'Hello world')

def postreposetup_hook(conduit):

raise PluginYumExit?('Goodbye')


This plugin will display "Hello world" as it loads and then will cause Yum to quit with a "Goodbye" message once it has finished initialising its repositories.

Slots and Hooks

Plugins integrate with Yum by registering a 'hook' function that corresponds to a given 'slot'. A slot is simply a point in Yum's execution. All plugin hook functions for a given slot are called as Yum reaches that slot.

Registration of hook functions is automatic. The plugin module is inspected for functions named <slotname>_hook. If a function matching a valid slot name is found then that function is automatically registered as a hook function.

Hook functions all take one argument, for a conduit instance. Conduits are explained below.

The following slots exist:

    Called first as plugins are initialised. Plugins that need to extend Yum's
    configuration files or command line options should do so during this slot.

    Called immediately after Yum's config object is initialised. Useful for 
    extending variables or modifying items in the config, for example the 
    $ variables that are used in repo configuration. 
    Note: Only available in yum 3.1.7 or later

    Called early in Yum's initialisation. May be used for general plugin
    related initialisation.

    Called just before Yum starts downloads of packages. Plugins may access
    information about the packages to be downloaded here.

    Called just after Yum finishes package downloads. Plugins may access
    error information about the packages just downloaded.

    Called just before Yum initialises its repository information.

    Called just after Yum initialises its repository information.

    Called after package inclusion and exclusions are processed. Plugins
    may modify package exclusions here.

    Called before Yum begins package resolution.

    Called just after Yum finishes package resolution.

    Called before Yum begins the RPM update transation.

    Called just after Yum has finished the RPM update transation.

    Called as Yum is performing a normal exit. Plugins may wish to
    perform cleanup functions here.

    Called during Yum's cleanup.  This slot will be executed when Yum 
    is run with the parameters 'clean all' or 'clean plugins'.


An object known as a conduit is passed into hook functions when they are called. This object provides methods and attributes that should be used for all interaction that the plugin has with the rest of Yum.

The conduit varies depending on the plugin slot. Different methods and attributes are available as appropriate for the slot. See the yum.plugins.SLOT_TO_CONDUIT dictionary for details on the conduit class used for a particular slot. All conduits are subclassed from the PluginConduit class.

API Dependencies

The plugin API and general Yum API are subject to change. For this reason, plugins must state which API they were written for via the requires_api_version attribute. Yum will exit with a useful error if it tries to load the plugin which is not compatible with its API version.

In general, a plugin author should set requires_api_version to the API version at the time that the plugin is written. The current API version can be found at yum.plugins.API_VERSION.

The yum.plugins module documents how the API version is incremented and the rules for compatibility tests.

Plugin Types

Plugins must advertise what type of plugin they are via the plugin_type tuple. The advertised type(s) can be used by software using the Yum libraries to control the types of plugins that will be loaded. Yum itself will always load all types of plugins.

A plugin may have more than one type. Two plugin types currently exist.

    A core plugin modifies Yum's base functionality. For example, a core plugin might modify 
    package exclusions, dependency resolving or repository loading.

    An interative plugin may modify Yum's user interface flow. For example, a TYPE_INTERACTIVE 
    plugin might terminate Yum early in some conditions or output extra information to the user.

    In Yum versions 2.6.x and earlier (plugin API version < 2.3) this constant was called 
    but the meaning of the old name wasn't clear and so it has been deprecated. 

Stopping Yum

A plugin may stop Yum's execution at any point by raising the yum.plugins.PluginYumExit exception. The argument of the exception will be displayed to the user as Yum terminates.

Reading Private Plugin Options

Each plugin has its own configuration file in /etc/yum/pluginconf.d/. These configuration files follow standard INI file conventions like Yum's own configuration files. Arbitrary options can be read from a plugin's configuration file at any time by using the following methods. These are available on any conduit instance:

{{{#!python numbering=off

def confString(self, section, opt, default=None)

def confInt(self, section, opt, default=None)

def confFloat(self, section, opt, default=None)

def confBool(self, section, opt, default=None)


If the option is missing from the configuration file then the default value passed to method will be returned. See yum.plugins for more documentation on these methods and see the yum(8) and yum.conf(5) man pages for general information on plugin configuration files.

Extending Yum's Configuration Options

In addition to having their own configuration file, plugins may modify the options available in Yum's own configuration files. A plugin can add new options or modify the existing options by modifying the YumConf and RepoConf classes defined in yum.config.

The YumConf class defines options that are available in the [main] section of yum.conf. The RepoConf class defines options that are available in each repository sections of Yum's configuration file(s). Modifications to YumConf and RepoConf should occur in the config slot.

Here is a simple example of how options can be added to Yum's configuration files.

{{{#!python numbering=off from yum import config from yum.plugins import TYPE_INTERACTIVE

requires_api_version = '2.4' plugin_type = (TYPE_INTERACTIVE,)

def config_hook(conduit):

# Add a boolean option to the [main] section config.YumConf?.enable_foo = config.BoolOption?(False)

# Add a URL option to repository sections config.RepoConf?.foo_url = config.UrlOption?()

# Add an option to to [main] and the repository sections. The # repository options will inherit the properties of the [main] option # and will use the value from [main] if the option is not specified in # the repo section. config.YumConf?.max_foo = config.IntOption?(10) config.RepoConf?.max_foo = config.Inherit(config.YumConf?.max_foo)

def init_hook(conduit):

conf = conduit.getConf()

# Display the options from the [main] section, "enable_foo = %r" % conf.enable_foo), "max_foo = %r" % conf.max_foo)

# Display the options from the repository sections for repo in conduit.getRepos().listEnabled():, "%s.foo_url = %r" % (, repo.foo_url)), "%s.max_foo = %r" % (, repo.max_foo))


Note how different types of options are defined (IntOption, UrlOption, BoolOption). A wide variety of option types are available in yum.config. It is even possible for plugins to define their own option types by subclassing Option if the existing types aren't sufficient. See the source code for the yum.config module for further details.

Extending Yum's Configuration Options (pre Yum 2.9.x, deprecated)

In addition to having their own configuration file, plugins may add extra options to Yum's main configuration files. A plugin must register new options in the config slot using the registerOpt() conduit method: {{{#!python numbering=off

registerOpt(name, valuetype, where, default)

}}} where the arguments are...

    The name of the new option.

    The type of the option. Valid values are PLUG_OPT_STRING, PLUG_OPT_INT,
    PLUG_OPT_FLOAT and PLUG_OPT_BOOL (defined in yum.constants). The value
    returned for the option will be automatically parsed according to the type.

    Defines where the option should be available in configuration files. Valid
    values are: 
        - PLUG_OPT_WHERE_MAIN: the option only exists in the [main] section
        - PLUG_OPT_WHERE_REPO: the option only exists in repository sections
        - PLUG_OPT_WHERE_ALL: the option exists in both [main] and repository

    The default value returned for the option if it isn't present.

The option values defined in the [main] section may be read by calling the getConf() repository method. The options will be available as attributes of the returned object.

New repository options will be available as attributes of the repository objects returned via the getRepos() conduit method.

The following example plugin shows how a custom option may be defined and read: {{{#!python numbering=off

from yum.constants import * from yum.plugins import TYPE_INTERACTIVE

requires_api_version = '2.3' plugin_type = (TYPE_INTERACTIVE,)

def config_hook(conduit):

conduit.registerOpt('foo', PLUG_OPT_BOOL, PLUG_OPT_WHERE_ALL, False)

def init_hook(conduit):, "[main] foo=%r" % conduit.getConf().foo)

def exclude_hook(conduit):

for repo in conduit.getRepos().listEnabled():, "[%s] foo=%r" % (,


Extending Yum's Command Line Options

A plugin may add extra command line options to Yum. To do this the plugin should call the getOptParser() conduit method during the config or init slot. This will return an OptionParser instance which the plugin may modify. See the Python standard library optparse module documentation for information on how to manipulate this object.

The parsed command line options may be read in any slot after the init slot. The values returned are as for OptionParser.parse_args().

Options added by plugins will show up in Yum's command line help output (ie. yum --help)

The following plugin demonstrates the addition of new command line options by adding a --downloadonly option: {{{#!python numbering=off

from yum.plugins import PluginYumExit?, TYPE_INTERACTIVE

requires_api_version = '2.3' plugin_type = (TYPE_INTERACTIVE,)

def config_hook(conduit):

parser = conduit.getOptParser() parser.add_option(, '--downloadonly', dest='dlonly',

action='store_true', default=False, help="don't update, just download")

def postdownload_hook(conduit):

opts, commands = conduit.getCmdLine() if opts.dlonly:

raise PluginYumExit?('exiting because --downloadonly specified ')


More Examples

The easiest way to get started writing Yum plugins is to look at some examples. The yum-utils package contains a number of useful plugins which will act as a useful starting point. The yum-utils git tree can be viewed here:;a=tree