Basics

.. _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.

west init basics

west update basics

`west init` basics

`west update` basics