Building Matter

Matter supports configuring the build with GN, a fast and scalable meta-build system that generates inputs to ninja.

Tested Operating Systems

The build system has been tested on the following Operating Systems:

macOS 10.15
Debian 11 (64 bit required)
Ubuntu 22.04 LTS

Build system features

The Matter build system has the following features:

Very fast and small footprint
Cross-platform handling: Linux, Darwin, Embedded Arm, among others
Multiple toolchains & cross toolchain dependencies
Integrates automated testing framework: ninja check
Introspection: gn desc
Automatic formatting: gn format

Checking out the Matter code

To check out the Matter repository, run the following command:

git clone --recurse-submodules git@github.com:project-chip/connectedhomeip.git

Synchronizing submodules

If you already have the Matter code checked out, run the following command to synchronize submodules:

git submodule update --init

Prerequisites

Before building, you must install a few OS specific dependencies.

Installing prerequisites on Linux

On Debian-based Linux distributions such as Ubuntu, these dependencies can be satisfied with the following command:

sudo apt-get install git gcc g++ pkg-config libssl-dev libdbus-1-dev \
     libglib2.0-dev libavahi-client-dev ninja-build python3-venv python3-dev \
     python3-pip unzip libgirepository1.0-dev libcairo2-dev libreadline-dev

UI builds

If building -with-ui variant, also install SDL2:

sudo apt-get install libsdl2-dev

Installing prerequisites on macOS

On macOS, install Xcode from the Mac App Store.

UI builds

If building -with-ui variant, also install SDL2:

brew install sdl2

Installing prerequisites on Raspberry Pi 4

Complete the following steps:

Using rpi-imager, install the Ubuntu 22.04 64-bit server OS for arm64 architectures on a micro SD card.
Boot the SD card.
Log in with the default user account “ubuntu” and password “ubuntu”
Proceed with Installing prerequisites on Linux.

Install some Raspberry Pi specific dependencies:

sudo apt-get install pi-bluetooth avahi-utils

Reboot your Raspberry Pi after installing pi-bluetooth.

Configuring wpa_supplicant for storing permanent changes

By default, wpa_supplicant is not allowed to update (overwrite) configuration. If you want the Matter application to be able to store the configuration changes permanently, you need to make the following changes:

Edit the dbus-fi.w1.wpa_supplicant1.service file to use configuration file instead by running the following command:
```
sudo nano /etc/systemd/system/dbus-fi.w1.wpa_supplicant1.service
```

Run the following command to change the wpa_supplicant start parameters to the provided values:

ExecStart=/sbin/wpa_supplicant -u -s -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf

Add the wpa-supplicant configuration file by running the following command:
```
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
```

Add the following content to the wpa-supplicant file:

ctrl_interface=DIR=/run/wpa_supplicant
update_config=1

Reboot your Raspberry Pi.

Installing ZAP tool

bootstrap.sh will download a compatible ZAP tool version and set it up in $PATH. If you want to install or use a different version of the tool, you may download one from the ZAP project’s Releases page.

Linux ARM

Zap does not provide binary releases for arm. Rosetta solves this for Darwin, however for linux arm you will have to use a local ZAP, generally through setting $ZAP_DEVELOPMENT_PATH (see the section Which zap to use below).

The file scripts/setup/zap.json contains the version that CIPD would download, so you can download a compatible version from the zap project Releases. To checkout as source code the corresponding tag should exist in the zap repository tags list.

Example commands:

RUN set -x \
    && mkdir -p /opt/zap-${ZAP_VERSION} \
    && git clone https://github.com/project-chip/zap.git /opt/zap-${ZAP_VERSION} \
    && cd /opt/zap-${ZAP_VERSION} \
    && git checkout ${ZAP_VERSION} \
    && npm config set user 0 \
    && npm ci
ENV ZAP_DEVELOPMENT_PATH=/opt/zap-${ZAP_VERSION}

Which ZAP to use

The ZAP tool scripting uses the following detection, in order of importance:

$ZAP_DEVELOPMENT_PATH to point to a ZAP checkout.
- Use this if you are developing ZAP locally and would like to run ZAP with your changes.
$ZAP_INSTALL_PATH to point to where zap-linux.zip or zap-mac.zip was unpacked.
- This allows you to not need to place zap or zap-cli (or both) in $PATH.
Otherwise, the scripts assume zap-cli or zap is available in $PATH.

Prepare for building

Before running any other build command, the scripts/activate.sh environment setup script should be sourced at the top level. This script takes care of downloading GN, ninja, and setting up a Python environment with libraries used to build and test.

Run the following command:

source scripts/activate.sh

Updating the environment

If the script says the environment is out of date, you can update it by running the following command:

source scripts/bootstrap.sh

The scripts/bootstrap.sh script re-creates the environment from scratch, which is expensive, so avoid running it unless the environment is out of date.

Build for the host OS (Linux or macOS)

Run the following commands to build all sources, libraries, and tests for the host platform:

source scripts/activate.sh

gn gen out/host

ninja -C out/host

These commands generate a configuration suitable for debugging. To configure an optimized build, specify is_debug=false:

gn gen out/host --args='is_debug=false'

ninja -C out/host

Note: The directory name out/host can be any directory, although it’s conventional to build within the out directory. This example uses host to emphasize building for the host system. Different build directories can be used for different configurations, or a single directory can be used and reconfigured as necessary via gn args.

To run all tests, run the following command:

ninja -C out/host check

To run only the tests in src/inet/tests, you can run the following command:

ninja -C out/host src/inet/tests:tests_run

Note: The build system caches passing tests, so you may see the following message:
ninja: no work to do
This means that the tests passed in a previous build.

Build custom configuration

The build is configured by setting build arguments. These you can set in one of the following manners:

Passing the --args option to gn gen.
Running gn args on the output directory.
Editing args.gn in the output directory.

To configure a new build or edit the arguments to existing build, run the following command:

source scripts/activate.sh

gn args out/custom

ninja -C out/custom

Two key built-in build arguments are target_os and target_cpu, which control the OS and CPU of the build, respectively.

To see help for all available build arguments, run the following command:

gn gen out/custom
gn args --list out/custom

Build examples

You can build examples in two ways.

Build examples as separate projects

To build examples as separate projects that add Matter in the third_party directory, run the following command with the correct path to the example (here, chip-shell):

cd examples/shell
gn gen out/debug
ninja -C out/debug

Build examples at the top level

You can build examples at the top level of the Matter project. See the following “Unified builds” section for details.

Unified builds

To build a unified configuration that approximates the set of continuous builds, run the following commands:

source scripts/activate.sh

gn gen out/unified --args='is_debug=true target_os="all"'

ninja -C out/unified all

You can use this set of commands before changing a submission to configure, build, and test the GCC, Clang, MbedTLS, and examples configurations all together in one parallel build. Each configuration has a separate subdirectory in the output directory.

This unified build can be used for day-to-day development, although it’s more expensive to build everything for every edit. To save time, you can name the configuration to build:

ninja -C out/unified host_gcc
ninja -C out/unified check_host_gcc

Replace host_gcc with the name of the configuration, which is found in the root BUILD.gn.

You can also fine tune the configurations generated with arguments. For example:

gn gen out/unified --args='is_debug=true target_os="all" enable_host_clang_build=false'

For a full list, see the root BUILD.gn.

In the unified build, targets have multiple instances and need to be disambiguated by adding a (toolchain) suffix. Use gn ls out/debug to list all of the target instances. For example:

gn desc out/unified '//src/controller(//build/toolchain/host:linux_x64_clang)'

Note: Some platforms that can be built as part of the unified build require downloading additional tools. To add these to the build, the location must be provided as a build argument. For example, to add the Simplelink cc13x2_26x2 examples to the unified build, install SysConfig and add the following build arguments:
gn gen out/unified --args="target_os=\"all\" enable_ti_simplelink_builds=true > ti_sysconfig_root=\"/path/to/sysconfig\""

Getting help

GN has integrated help that you can access with the gn help command.

Make sure to check the following recommended topics:

gn help execution
gn help grammar
gn help toolchain

Also see the quick start guide.

Introspection

GN has various introspection tools to help you examine the build configuration. The following examples use the out/host output directory as example:

Show all of the targets in an output directory:
```
gn ls out/host
```
Show all of the files that will be built:
```
gn outputs out/host '*'
```
Show the GN representation of a configured target:
```
gn desc out/host //src/inet --all
```
Dump the GN representation of the entire build as JSON:
```
gn desc out/host/ '*' --all --format=json
```

Show the dependency tree:

gn desc out/host //:all deps --tree --all

Find dependency paths:

gn path out/host //src/transport/tests:tests //src/system

List useful information for linking against libCHIP:

gn desc out/host //src/lib include_dirs
gn desc out/host //src/lib defines
gn desc out/host //src/lib outputs

# everything as JSON
gn desc out/host //src/lib --format=json

Coverage

The code coverage script generates a report that details how much of the Matter SDK source code has been executed. It also provides information on how often the Matter SDK executes segments of the code and produces a copy of the source file, annotated with execution frequencies.

Run the following command to initiate the script:

./scripts/build_coverage.sh

By default, the code coverage script is performed at the unit testing level. Unit tests are created by developers, thus giving them the best overview of what tests to include in unit testing. You can extend the coverage test by scope and ways of execution with the following parameters:

  -c, --code                Specify which scope to collect coverage data.
                            'core': collect coverage data from core stack in Matter SDK. --default
                            'clusters': collect coverage data from clusters implementation in Matter SDK.
                            'all': collect coverage data from Matter SDK.
  -t, --tests               Specify which tools to run the coverage check.
                            'unit': Run unit test to drive the coverage check. --default
                            'yaml': Run yaml test to drive the coverage check.
                            'all': Run unit & yaml test to drive the coverage check.

Also, see the up-to-date unit testing coverage report of the Matter SDK (collected daily) at: matter coverage.

Maintaining Matter

If you make any change to the GN build system, the next build will regenerate the ninja files automatically. No need to do anything.