zephyr/doc/develop/west/basics.rst

209 lines
7.5 KiB
ReStructuredText

.. _west-basics:
Basics
######
This page introduces west's basic concepts and provides references to further
reading.
West's built-in commands allow you to work with :term:`projects <west project>`
(Git repositories) under a common :term:`workspace <west workspace>` directory.
West works in the following manner: the ``west init`` command creates the
:term:`west workspace`, and clones the :term:`manifest repo <west manifest
repository>`, while the ``west update`` command initially clones, and later updates, the
:term:`projects <west project>` listed in the manifest in the workspace.
Example workspace
*****************
If you've followed the :ref:`getting_started`, your local
:term:`west workspace`, which in this case is the folder named
:file:`zephyrproject` as well as all its subfolders, looks like this:
.. code-block:: none
zephyrproject/ # west topdir
├── .west/ # marks the location of the topdir
│ └── config # per-workspace local configuration file
│ # The manifest repository, never modified by west after creation:
├── zephyr/ # .git/ repo
│ ├── west.yml # manifest file
│ └── [... other files ...]
│ # Projects managed by west:
├── modules/
│ └── lib/
│ └── zcbor/ # .git/ project
├── tools/
│ └── net-tools/ # .git/ project
└── [ ... other projects ...]
.. _west-workspace:
Workspace concepts
******************
Here are the basic concepts you should understand about this structure.
Additional details are in :ref:`west-workspaces`.
topdir
Above, :file:`zephyrproject` is the name of the workspace's top level
directory, or *topdir*. (The name :file:`zephyrproject` is just an example
-- it could be anything, like ``z``, ``my-zephyr-workspace``, etc.)
You'll typically create the topdir and a few other files and directories
using :ref:`west init <west-init-basics>`.
.west directory
The topdir contains the :file:`.west` directory. When west needs to find
the topdir, it searches for :file:`.west`, and uses its parent directory.
The search starts from the current working directory (and starts again from
the location in the :envvar:`ZEPHYR_BASE` environment variable as a
fallback if that fails).
configuration file
The file :file:`.west/config` is the workspace's :ref:`local configuration
file <west-config>`.
manifest repository
Every west workspace contains exactly one *manifest repository*, which is a
Git repository containing a *manifest file*. The location of the manifest
repository is given by the :ref:`manifest.path configuration option
<west-config-index>` in the local configuration file.
For upstream Zephyr, :file:`zephyr` is the manifest repository, but you can
configure west to use any Git repository in the workspace as the manifest
repository. The only requirement is that it contains a valid manifest file.
See :ref:`west-topologies` for information on other options, and
:ref:`west-manifests` for details on the manifest file format.
manifest file
The manifest file is a YAML file that defines *projects*, which are the
additional Git repositories in the workspace managed by west. The manifest
file is named :file:`west.yml` by default; this can be overridden using the
``manifest.file`` local configuration option.
You use the :ref:`west update <west-update-basics>` command to update the
workspace's projects based on the contents of the manifest file.
projects
Projects are Git repositories managed by west. Projects are defined in the
manifest file and can be located anywhere inside the workspace. In the above
example workspace, ``zcbor`` and ``net-tools`` are projects.
By default, the Zephyr :ref:`build system <build_overview>` uses west to get
the locations of all the projects in the workspace, so any code they contain
can be used as :ref:`modules`. Note however that modules and projects
:ref:`are conceptually different <modules-vs-projects>`.
extensions
Any repository known to west (either the manifest repository or any project
repository) can define :ref:`west-extensions`. Extensions are extra west
commands you can run when using that workspace.
The zephyr repository uses this feature to provide Zephyr-specific commands
like :ref:`west build <west-building>`. Defining these as extensions keeps
west's core agnostic to the specifics of any workspace's Zephyr version,
etc.
ignored files
A workspace can contain additional Git repositories or other files and
directories not managed by west. West basically ignores anything in the
workspace except :file:`.west`, the manifest repository, and the projects
specified in the manifest file.
west init and west update
*************************
The two most important workspace-related commands are ``west init`` and ``west
update``.
.. _west-init-basics:
``west init`` basics
--------------------
This command creates a west workspace.
.. important::
West doesn't change your manifest repository contents after ``west init`` is
run. Use ordinary Git commands to pull new versions, etc.
You will typically run it once, like this:
.. code-block:: shell
west init -m https://github.com/zephyrproject-rtos/zephyr --mr v2.5.0 zephyrproject
This will:
#. Create the topdir, :file:`zephyrproject`, along with
:file:`.west` and :file:`.west/config` inside it
#. Clone the manifest repository from
https://github.com/zephyrproject-rtos/zephyr, placing it into
:file:`zephyrproject/zephyr`
#. Check out the ``v2.5.0`` git tag in your local zephyr clone
#. Set ``manifest.path`` to ``zephyr`` in :file:`.west/config`
#. Set ``manifest.file`` to ``west.yml``
Your workspace is now almost ready to use; you just need to run ``west update``
to clone the rest of the projects into the workspace to finish.
For more details, see :ref:`west-init`.
.. _west-update-basics:
``west update`` basics
----------------------
This command makes sure your workspace contains Git repositories matching the
projects in the manifest file.
.. important::
Whenever you check out a different revision in your manifest repository, you
should run ``west update`` to make sure your workspace contains the
project repositories the new revision expects.
The ``west update`` command reads the manifest file's contents by:
#. Finding the topdir. In the ``west init`` example above, that
means finding :file:`zephyrproject`.
#. Loading :file:`.west/config` in the topdir to read the ``manifest.path``
(e.g. ``zephyr``) and ``manifest.file`` (e.g. ``west.yml``) options.
#. Loading the manifest file given by these options (e.g.
:file:`zephyrproject/zephyr/west.yml`).
It then uses the manifest file to decide where missing projects should be
placed within the workspace, what URLs to clone them from, and what Git
revisions should be checked out locally. Project repositories which already
exist are updated in place by fetching and checking out their respective Git
revisions in the manifest file.
For more details, see :ref:`west-update`.
Other built-in commands
***********************
See :ref:`west-built-in-cmds`.
.. _west-zephyr-extensions:
Zephyr Extensions
*****************
See the following pages for information on Zephyr's extension commands:
- :ref:`west-build-flash-debug`
- :ref:`west-sign`
- :ref:`west-zephyr-ext-cmds`
- :ref:`west-shell-completion`
Troubleshooting
***************
See :ref:`west-troubleshooting`.