zephyr/doc/services/serialization/nanopb.rst

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.. _nanopb_reference:
Nanopb
######
`Nanopb <https://jpa.kapsi.fi/nanopb/>`_ is a C implementation of Google's
`Protocol Buffers <https://protobuf.dev/>`_.
Requirements
************
Nanopb uses the protocol buffer compiler to generate source and header files,
make sure the ``protoc`` executable is installed and available.
.. tabs::
.. group-tab:: Ubuntu
Use ``apt`` to install dependency:
.. code-block:: shell
sudo apt install protobuf-compiler
.. group-tab:: macOS
Use ``brew`` to install dependency:
.. code-block:: shell
brew install protobuf
.. group-tab:: Windows
Use ``choco`` to install dependency:
.. code-block:: shell
choco install protoc
Additionally, Nanopb is an optional module and needs to be added explicitly to the workspace:
.. code-block:: shell
west config manifest.project-filter -- +nanopb
west update
Configuration
*************
Make sure to include ``nanopb`` within your ``CMakeLists.txt`` file as follows:
.. code-block:: cmake
list(APPEND CMAKE_MODULE_PATH ${ZEPHYR_BASE}/modules/nanopb)
include(nanopb)
Adding ``proto`` files can be done with the ``zephyr_nanopb_sources()`` CMake function which
ensures the generated header and source files are created before building the specified target.
Nanopb has `generator options <https://jpa.kapsi.fi/nanopb/docs/reference.html#generator-options>`_
that can be used to configure messages or fields. This allows to set fixed sizes or skip fields
entirely.
The internal CMake generator has an extension to configure ``*.options.in`` files automatically
with CMake variables.
See :zephyr_file:`samples/modules/nanopb/src/simple.options.in` and
:zephyr_file:`samples/modules/nanopb/CMakeLists.txt` for usage example.