MkDocs Plugins

A Guide to installing, using and creating MkDocs Plugins

Installing Plugins

Before a plugin can be used, it must be installed on the system. If you are using a plugin which comes with MkDocs, then it was installed when you installed MkDocs. However, to install third party plugins, you need to determine the appropriate package name and install it using pip:

pip install mkdocs-foo-plugin

Warning

Installing an MkDocs plugin means installing a Python package and executing any code that the author has put in there. So, exercise the usual caution; there's no attempt at sandboxing.

Once a plugin has been successfully installed, it is ready to use. It just needs to be enabled in the configuration file. The Catalog repository has a large ranked list of plugins that you can install and use.

Using Plugins

The plugins configuration option should contain a list of plugins to use when building the site. Each "plugin" must be a string name assigned to the plugin (see the documentation for a given plugin to determine its "name"). A plugin listed here must already be installed.

plugins:
  - search

Some plugins may provide configuration options of their own. If you would like to set any configuration options, then you can nest a key/value mapping (option_name: option value) of any options that a given plugin supports. Note that a colon (:) must follow the plugin name and then on a new line the option name and value must be indented and separated by a colon. If you would like to define multiple options for a single plugin, each option must be defined on a separate line.

plugins:
  - search:
      lang: en
      foo: bar

For information regarding the configuration options available for a given plugin, see that plugin's documentation.

For a list of default plugins and how to override them, see the configuration documentation.

Developing Plugins

Like MkDocs, plugins must be written in Python. It is generally expected that each plugin would be distributed as a separate Python module, although it is possible to define multiple plugins in the same module. At a minimum, a MkDocs Plugin must consist of a BasePlugin subclass and an entry point which points to it.

BasePlugin

A subclass of mkdocs.plugins.BasePlugin should define the behavior of the plugin. The class generally consists of actions to perform on specific events in the build process as well as a configuration scheme for the plugin.

All BasePlugin subclasses contain the following attributes:

config_scheme

A tuple of configuration validation instances. Each item must consist of a two item tuple in which the first item is the string name of the configuration option and the second item is an instance of mkdocs.config.config_options.BaseConfigOption or any of its subclasses.

For example, the following config_scheme defines three configuration options: foo, which accepts a string; bar, which accepts an integer; and baz, which accepts a boolean value.

class MyPlugin(mkdocs.plugins.BasePlugin):
    config_scheme = (
        ('foo', mkdocs.config.config_options.Type(str, default='a default value')),
        ('bar', mkdocs.config.config_options.Type(int, default=0)),
        ('baz', mkdocs.config.config_options.Type(bool, default=True))
    )

New in version 1.4

Subclassing `Config` to specify the config schema

To get type safety benefits, if you're targeting only MkDocs 1.4+, define the config schema as a class instead:

class MyPluginConfig(mkdocs.config.base.Config):
    foo = mkdocs.config.config_options.Type(str, default='a default value')
    bar = mkdocs.config.config_options.Type(int, default=0)
    baz = mkdocs.config.config_options.Type(bool, default=True)

class MyPlugin(mkdocs.plugins.BasePlugin[MyPluginConfig]):
    ...

Examples of config definitions

! EXAMPLE:
from mkdocs.config import base, config_options as c

class _ValidationOptions(base.Config):
    enabled = c.Type(bool, default=True)
    verbose = c.Type(bool, default=False)
    skip_checks = c.ListOfItems(c.Choice(('foo', 'bar', 'baz')), default=[])

class MyPluginConfig(base.Config):
    definition_file = c.File(exists=True)  # required
    checksum_file = c.Optional(c.File(exists=True))  # can be None but must exist if specified
    validation = c.SubConfig(_ValidationOptions)
From the user's point of view SubConfig is similar to Type(dict), it's just that it also retains full ability for validation: you define all valid keys and what each value should adhere to.

And ListOfItems is similar to Type(list), but again, we define the constraint that each value must adhere to.

This accepts a config as follows:
my_plugin:
  definition_file: configs/test.ini  # relative to mkdocs.yml
  validation:
    enabled: !ENV [CI, false]
    verbose: true
    skip_checks:
      - foo
      - baz

? EXAMPLE:

import numbers
from mkdocs.config import base, config_options as c

class _Rectangle(base.Config):
    width = c.Type(numbers.Real)  # required
    height = c.Type(numbers.Real)  # required

class MyPluginConfig(base.Config):
    add_rectangles = c.ListOfItems(c.SubConfig(_Rectangle))  # required

In this example we define a list of complex items, and that's achieved by passing a concrete SubConfig to ListOfItems.

This accepts a config as follows:

my_plugin:
  add_rectangles:
    - width: 5
      height: 7
    - width: 12
      height: 2

When the user's configuration is loaded, the above scheme will be used to validate the configuration and fill in any defaults for settings not provided by the user. The validation classes may be any of the classes provided in mkdocs.config.config_options or a third party subclass defined in the plugin.

Any settings provided by the user which fail validation or are not defined in the config_scheme will raise a mkdocs.config.base.ValidationError.

config

A dictionary of configuration options for the plugin, which is populated by the load_config method after configuration validation has completed. Use this attribute to access options provided by the user.

def on_pre_build(self, config, **kwargs):
    if self.config['baz']:
        # implement "baz" functionality here...

New in version 1.4

Safe attribute-based access

To get type safety benefits, if you're targeting only MkDocs 1.4+, access options as attributes instead:

def on_pre_build(self, config, **kwargs):
    if self.config.baz:
        print(self.config.bar ** 2)  # OK, `int ** 2` is valid.

All BasePlugin subclasses contain the following method(s):

load_config(options)

Loads configuration from a dictionary of options. Returns a tuple of (errors, warnings). This method is called by MkDocs during configuration validation and should not need to be called by the plugin.

on_<event_name>()

Optional methods which define the behavior for specific events. The plugin should define its behavior within these methods. Replace <event_name> with the actual name of the event. For example, the pre_build event would be defined in the on_pre_build method.

Most events accept one positional argument and various keyword arguments. It is generally expected that the positional argument would be modified (or replaced) by the plugin and returned. If nothing is returned (the method returns None), then the original, unmodified object is used. The keyword arguments are simply provided to give context and/or supply data which may be used to determine how the positional argument should be modified. It is good practice to accept keyword arguments as **kwargs. In the event that additional keywords are provided to an event in a future version of MkDocs, there will be no need to alter your plugin.

For example, the following event would add an additional static_template to the theme config:

class MyPlugin(BasePlugin):
    def on_config(self, config, **kwargs):
        config['theme'].static_templates.add('my_template.html')
        return config

New in version 1.4

To get type safety benefits, if you're targeting only MkDocs 1.4+, access config options as attributes instead:

def on_config(self, config: MkDocsConfig):
    config.theme.static_templates.add('my_template.html')
    return config

Events

There are three kinds of events: Global Events, Page Events and Template Events.

See a diagram with relations between all the plugin events

The events themselves are shown in yellow, with their parameters.
Arrows show the flow of arguments and outputs of each event. Sometimes they're omitted.
The events are chronologically ordered from top to bottom.
Dotted lines appear at splits from global events to per-page events.
Click the events' titles to jump to their description.

One-time Events

One-time events run once per mkdocs invocation. The only case where these tangibly differ from global events is for mkdocs serve: global events, unlike these, will run multiple times -- once per build.

on_startup

The startup event runs once at the very beginning of an mkdocs invocation.

New in MkDocs 1.4.

The presence of an on_startup method (even if empty) migrates the plugin to the new system where the plugin object is kept across builds within one mkdocs serve.

Note that for initializing variables, the __init__ method is still preferred. For initializing per-build variables (and whenever in doubt), use the on_config event.

Parameters:

command (Literal['build', 'gh-deploy', 'serve']) –

the command that MkDocs was invoked with, e.g. "serve" for mkdocs serve.
dirty (bool) –

whether --dirty flag was passed.

on_shutdown

The shutdown event runs once at the very end of an mkdocs invocation, before exiting.

This event is relevant only for support of mkdocs serve, otherwise within a single build it's undistinguishable from on_post_build.

New in MkDocs 1.4.

The presence of an on_shutdown method (even if empty) migrates the plugin to the new system where the plugin object is kept across builds within one mkdocs serve.

Note the on_post_build method is still preferred for cleanups, when possible, as it has a much higher chance of actually triggering. on_shutdown is "best effort" because it relies on detecting a graceful shutdown of MkDocs.

on_serve

The serve event is only called when the serve command is used during development. It runs only once, after the first build finishes. It is passed the Server instance which can be modified before it is activated. For example, additional files or directories could be added to the list of "watched" files for auto-reloading.

Parameters:

server (LiveReloadServer) –

livereload.Server instance
config (MkDocsConfig) –

global configuration object
builder (Callable) –

a callable which gets passed to each call to server.watch

Returns:

LiveReloadServer | None –

livereload.Server instance

Global Events

Global events are called once per build at either the beginning or end of the build process. Any changes made in these events will have a global effect on the entire site.

on_config

The config event is the first event called on build and is run immediately after the user configuration is loaded and validated. Any alterations to the config should be made here.

Parameters:

config (MkDocsConfig) –

global configuration object

Returns:

MkDocsConfig | None –

global configuration object

on_pre_build

The pre_build event does not alter any variables. Use this event to call pre-build scripts.

Parameters:

config (MkDocsConfig) –

global configuration object

on_files

The files event is called after the files collection is populated from the docs_dir. Use this event to add, remove, or alter files in the collection. Note that Page objects have not yet been associated with the file objects in the collection. Use Page Events to manipulate page specific data.

Parameters:

files (Files) –

global files collection
config (MkDocsConfig) –

global configuration object

Returns:

Files | None –

global files collection

on_nav

The nav event is called after the site navigation is created and can be used to alter the site navigation.

Parameters:

nav (Navigation) –

global navigation object
config (MkDocsConfig) –

global configuration object
files (Files) –

global files collection

Returns:

Navigation | None –

global navigation object

on_env

The env event is called after the Jinja template environment is created and can be used to alter the Jinja environment.

Parameters:

env (Environment) –

global Jinja environment
config (MkDocsConfig) –

global configuration object
files (Files) –

global files collection

Returns:

Environment | None –

global Jinja Environment

on_post_build

The post_build event does not alter any variables. Use this event to call post-build scripts.

Parameters:

config (MkDocsConfig) –

global configuration object

on_build_error

The build_error event is called after an exception of any kind is caught by MkDocs during the build process. Use this event to clean things up before MkDocs terminates. Note that any other events which were scheduled to run after the error will have been skipped. See Handling Errors for more details.

Parameters:

error (Exception) –

exception raised

Template Events

Template events are called once for each non-page template. Each template event will be called for each template defined in the extra_templates config setting as well as any static_templates defined in the theme. All template events are called after the env event and before any page events.

on_pre_template

The pre_template event is called immediately after the subject template is loaded and can be used to alter the template.

Parameters:

template (Template) –

a Jinja2 Template object
template_name (str) –

string filename of template
config (MkDocsConfig) –

global configuration object

Returns:

Template | None –

a Jinja2 Template object

on_template_context

The template_context event is called immediately after the context is created for the subject template and can be used to alter the context for that specific template only.

Parameters:

context (TemplateContext) –

dict of template context variables
template_name (str) –

string filename of template
config (MkDocsConfig) –

global configuration object

Returns:

TemplateContext | None –

dict of template context variables

on_post_template

The post_template event is called after the template is rendered, but before it is written to disc and can be used to alter the output of the template. If an empty string is returned, the template is skipped and nothing is is written to disc.

Parameters:

output_content (str) –

output of rendered template as string
template_name (str) –

string filename of template
config (MkDocsConfig) –

global configuration object

Returns:

str | None –

output of rendered template as string

Page Events

Page events are called once for each Markdown page included in the site. All page events are called after the post_template event and before the post_build event.

on_pre_page

The pre_page event is called before any actions are taken on the subject page and can be used to alter the Page instance.

Parameters:

page (Page) –

mkdocs.structure.pages.Page instance
config (MkDocsConfig) –

global configuration object
files (Files) –

global files collection

Returns:

Page | None –

mkdocs.structure.pages.Page instance

on_page_read_source

Deprecated

Instead of this event, prefer one of these alternatives:

Since MkDocs 1.6, instead set content_bytes/content_string of a File inside on_files.
Usually (although it's not an exact alternative), on_page_markdown can serve the same purpose.

The on_page_read_source event can replace the default mechanism to read the contents of a page's source from the filesystem.

Parameters:

page (Page) –

mkdocs.structure.pages.Page instance
config (MkDocsConfig) –

global configuration object

Returns:

str | None –

The raw source for a page as unicode string. If None is returned, the default loading from a file will be performed.

on_page_markdown

The page_markdown event is called after the page's markdown is loaded from file and can be used to alter the Markdown source text. The meta- data has been stripped off and is available as page.meta at this point.

Parameters:

markdown (str) –

Markdown source text of page as string
page (Page) –

mkdocs.structure.pages.Page instance
config (MkDocsConfig) –

global configuration object
files (Files) –

global files collection

Returns:

str | None –

Markdown source text of page as string

on_page_content

The page_content event is called after the Markdown text is rendered to HTML (but before being passed to a template) and can be used to alter the HTML body of the page.

Parameters:

html (str) –

HTML rendered from Markdown source as string
page (Page) –

mkdocs.structure.pages.Page instance
config (MkDocsConfig) –

global configuration object
files (Files) –

global files collection

Returns:

str | None –

HTML rendered from Markdown source as string

on_page_context

The page_context event is called after the context for a page is created and can be used to alter the context for that specific page only.

Parameters:

context (TemplateContext) –

dict of template context variables
page (Page) –

mkdocs.structure.pages.Page instance
config (MkDocsConfig) –

global configuration object
nav (Navigation) –

global navigation object

Returns:

TemplateContext | None –

dict of template context variables

on_post_page

The post_page event is called after the template is rendered, but before it is written to disc and can be used to alter the output of the page. If an empty string is returned, the page is skipped and nothing is written to disc.

Parameters:

output (str) –

output of rendered template as string
page (Page) –

mkdocs.structure.pages.Page instance
config (MkDocsConfig) –

global configuration object

Returns:

str | None –

output of rendered template as string

Event Priorities

For each event type, corresponding methods of plugins are called in the order that the plugins appear in the plugins config.

Since MkDocs 1.4, plugins can choose to set a priority value for their events. Events with higher priority are called first. Events without a chosen priority get a default of 0. Events that have the same priority are ordered as they appear in the config.

`mkdocs.plugins.event_priority(priority: float) -> Callable[[T], T]` 

A decorator to set an event priority for an event handler method.

Recommended priority values: 100 "first", 50 "early", 0 "default", -50 "late", -100 "last". As different plugins discover more precise relations to each other, the values should be further tweaked.

Usage example:

@plugins.event_priority(-100)  # Wishing to run this after all other plugins' `on_files` events.
def on_files(self, files, config, **kwargs):
    ...

New in MkDocs 1.4. Recommended shim for backwards compatibility:

try:
    from mkdocs.plugins import event_priority
except ImportError:
    event_priority = lambda priority: lambda f: f  # No-op fallback

New in version 1.6

There may also arise a need to register a handler for the same event at multiple different priorities.

CombinedEvent makes this possible.

`mkdocs.plugins.CombinedEvent` 

Bases: Generic[P, T]

A descriptor that allows defining multiple event handlers and declaring them under one event's name.

Usage example:

@plugins.event_priority(100)
def _on_page_markdown_1(self, markdown: str, **kwargs):
    ...

@plugins.event_priority(-50)
def _on_page_markdown_2(self, markdown: str, **kwargs):
    ...

on_page_markdown = plugins.CombinedEvent(_on_page_markdown_1, _on_page_markdown_2)

Note

The names of the sub-methods can't start with on_; instead they can start with _on_ like in the the above example, or anything else.

Handling Errors

MkDocs defines four error types:

`mkdocs.exceptions.MkDocsException` 

Bases: ClickException

The base class which all MkDocs exceptions inherit from. This should not be raised directly. One of the subclasses should be raised instead.

`mkdocs.exceptions.ConfigurationError` 

Bases: MkDocsException

This error is raised by configuration validation when a validation error is encountered. This error should be raised by any configuration options defined in a plugin's config_scheme.

`mkdocs.exceptions.BuildError` 

Bases: MkDocsException

This error may be raised by MkDocs during the build process. Plugins should not raise this error.

`mkdocs.exceptions.PluginError` 

Bases: BuildError

A subclass of mkdocs.exceptions.BuildError which can be raised by plugin events.

Unexpected and uncaught exceptions will interrupt the build process and produce typical Python tracebacks, which are useful for debugging your code. However, users generally find tracebacks overwhelming and often miss the helpful error message. Therefore, MkDocs will catch any of the errors listed above, retrieve the error message, and exit immediately with only the helpful message displayed to the user.

Therefore, you might want to catch any exceptions within your plugin and raise a PluginError, passing in your own custom-crafted message, so that the build process is aborted with a helpful message.

The on_build_error event will be triggered for any exception.

For example:

from mkdocs.exceptions import PluginError
from mkdocs.plugins import BasePlugin


class MyPlugin(BasePlugin):
    def on_post_page(self, output, page, config, **kwargs):
        try:
            # some code that could throw a KeyError
            ...
        except KeyError as error:
            raise PluginError(f"Failed to find the item by key: '{error}'")

    def on_build_error(self, error, **kwargs):
        # some code to clean things up
        ...

Logging in plugins

To ensure that your plugins' log messages adhere with MkDocs' formatting and --verbose/--debug flags, please write the logs to a logger under the mkdocs.plugins. namespace.

Example

import logging

log = logging.getLogger(f"mkdocs.plugins.{__name__}")

log.warning("File '%s' not found. Breaks the build if --strict is passed", my_file_name)
log.info("Shown normally")
log.debug("Shown only with `--verbose`")

if log.getEffectiveLevel() <= logging.DEBUG:
    log.debug("Very expensive calculation only for debugging: %s", get_my_diagnostics())

log.error() is another logging level that is differentiated by its look, but in all other ways it functions the same as warning, so it's strange to use it. If your plugin encounters an actual error, it is best to just interrupt the build by raising mkdocs.exceptions.PluginError (which will also log an ERROR message).

New in version 1.5

MkDocs now provides a get_plugin_logger() convenience function that returns a logger like the above that is also prefixed with the plugin's name.

`mkdocs.plugins.get_plugin_logger(name: str) -> PrefixedLogger` 

Return a logger for plugins.

Parameters:

name (str) –

The name to use with logging.getLogger.

Returns:

PrefixedLogger –

A logger configured to work well in MkDocs, prefixing each message with the plugin package name.

Example

from mkdocs.plugins import get_plugin_logger

log = get_plugin_logger(__name__)
log.info("My plugin message")

Entry Point

Plugins need to be packaged as Python libraries (distributed on PyPI separate from MkDocs) and each must register as a Plugin via a setuptools entry_points. Add the following to your setup.py script:

entry_points={
    'mkdocs.plugins': [
        'pluginname = path.to.some_plugin:SomePluginClass',
    ]
}

The pluginname would be the name used by users (in the config file) and path.to.some_plugin:SomePluginClass would be the importable plugin itself (from path.to.some_plugin import SomePluginClass) where SomePluginClass is a subclass of BasePlugin which defines the plugin behavior. Naturally, multiple Plugin classes could exist in the same module. Simply define each as a separate entry point.

entry_points={
    'mkdocs.plugins': [
        'featureA = path.to.my_plugins:PluginA',
        'featureB = path.to.my_plugins:PluginB'
    ]
}

Note that registering a plugin does not activate it. The user still needs to tell MkDocs to use it via the config.

Publishing a Plugin

You should publish a package on PyPI, then add it to the Catalog for discoverability. Plugins are strongly recommended to have a unique plugin name (entry point name) according to the catalog.

Keys	Action
`?`	Open this help
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MkDocs Plugins

Installing Plugins

Using Plugins

Developing Plugins

BasePlugin

config_scheme

Subclassing Config to specify the config schema

Examples of config definitions

config

Safe attribute-based access

load_config(options)

on_<event_name>()

Events

One-time Events

on_startup

on_shutdown

on_serve

Global Events

on_config

on_pre_build

on_files

on_nav

on_env

on_post_build

on_build_error

Template Events

on_pre_template

on_template_context

on_post_template

Page Events

on_pre_page

on_page_read_source

on_page_markdown

on_page_content

on_page_context

on_post_page

Event Priorities

mkdocs.plugins.event_priority(priority: float) -> Callable[[T], T] 

mkdocs.plugins.CombinedEvent 

Handling Errors

mkdocs.exceptions.MkDocsException 

mkdocs.exceptions.ConfigurationError 

mkdocs.exceptions.BuildError 

mkdocs.exceptions.PluginError 

Logging in plugins

mkdocs.plugins.get_plugin_logger(name: str) -> PrefixedLogger 

Entry Point

Publishing a Plugin

Subclassing `Config` to specify the config schema

`mkdocs.plugins.event_priority(priority: float) -> Callable[[T], T]` 

`mkdocs.plugins.CombinedEvent` 

`mkdocs.exceptions.MkDocsException` 

`mkdocs.exceptions.ConfigurationError` 

`mkdocs.exceptions.BuildError` 

`mkdocs.exceptions.PluginError` 

`mkdocs.plugins.get_plugin_logger(name: str) -> PrefixedLogger` 