AGL CMake template

Files used to build an application, or binding, project with the AGL Application Framework.

To build your AGL project using these templates, you have to install them within your project and adjust compilation option in config.cmake. For technical reasons, you also have to specify cmake target in sub CMakeLists.txt installed. Make a globbing search to find source files isn’t recommended now to handle project build especially in a multiuser project because CMake will not be aware of new or removed source files.

You’ll find usage samples here:

Quickstart

Initialization

To use these templates files on your project just install the reference files using git submodule then use config.cmake file to configure your project specificities :

git submodule add https://gerrit.automotivelinux.org/gerrit/p/apps/app-templates.git conf.d/app-templates
mkdir conf.d/cmake
cp conf.d/app-templates/samples.d/config.cmake.sample conf.d/cmake/config.cmake

Edit the copied config.cmake file to fit your needs.

Now, create your top CMakeLists.txt file which include config.cmake file.

An example is available in app-templates submodule that you can copy and use:

cp conf.d/app-templates/samples.d/CMakeLists.txt.sample CMakeLists.txt

Create your CMake targets

For each target part of your project, you need to use PROJECT_TARGET_ADD to include this target to your project.

Using it, make available the cmake variable TARGET_NAME until the next PROJECT_TARGET_ADD is invoked with a new target name.

So, typical usage defining a target is:

PROJECT_TARGET_ADD(SuperExampleName) --> Adding target to your project

add_executable/add_library(${TARGET_NAME}.... --> defining your target sources

SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES.... --> fit target properties
for macros usage

Targets PROPERTIES

You should set properties on your targets that will be used to package your apps in a widget file that could be installed on an AGL system.

Specify what is the type of your targets that you want to be included in the widget package with the property LABELS:

Choose between:

  • BINDING: Shared library that be loaded by the AGL Application Framework
  • BINDINGV2: Shared library that be loaded by the AGL Application Framework This has to be accompagnied with a JSON file named like the ${OUTPUT_NAME}-apidef of the target that describe the API with OpenAPI syntax (e.g: mybinding-apidef). Or you can choose the name, without the extension, by setting the CACHE cmake variable OPENAPI_DEF (CAUTION: setting a CACHE variable is needed, or set a normal variable with the PARENT_SCOPE option to make it visible for the parent scope where the target is defined) JSON file will be used to generate header file using afb-genskel tool.
  • PLUGIN: Shared library meant to be used as a binding plugin. Binding would load it as a plugin to extend its functionnalities. It should be named with a special extension that you choose with SUFFIX cmake target property or it’d be .ctlso by default.
  • HTDOCS: Root directory of a web app. This target has to build its directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
  • DATA: Resources used by your application. This target has to build its directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
  • EXECUTABLE: Entry point of your application executed by the AGL Application Framework
  • LIBRARY: An external 3rd party library bundled with the binding for its own purpose because platform doesn’t provide it.

TIP you should use the prefix afb- with your BINDING* targets which stand for **Application Framework Binding.

SET_TARGET_PROPERTIES(${TARGET_NAME}
	PREFIX "afb-"
	LABELS "BINDING"
	OUTPUT_NAME "file_output_name"
)

NOTE: You doesn’t need to specify an INSTALL command for these targets. This is already handle by template and will be installed in the following path : ${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}

More details: Typical project architecture

A typical project architecture would be :

<project-root-path>
│
├── conf.d/
│   ├── autobuild/
│   │   ├── agl
│   │   │   └── autobuild
│   │   ├── linux
│   │   │   └── autobuild
│   │   └── windows
│   │       └── autobuild
│   ├── app-templates/
│   │   ├── README.md
│   │   ├── cmake/
│   │   │   ├── export.map
│   │   │   └── macros.cmake
│   │   ├── samples.d/
│   │   │   ├── CMakeLists.txt.sample
│   │   │   ├── config.cmake.sample
│   │   │   ├── config.xml.in.sample
│   │   │   └── xds-config.env.sample
│   │   ├── template.d/
│   │   │   ├── autobuild/
│   │   │   │   ├── agl
│   │   │   │   │   └── autobuild.in
│   │   │   │   ├── linux
│   │   │   │   │   └── autobuild.in
│   │   │   │   └── windows
│   │   │   │       └── autobuild.in
│   │   │   ├── config.xml.in
│   │   │   ├── deb-config.dsc.in
│   │   │   ├── deb-config.install.in
│   │   │   ├── debian.changelog.in
│   │   │   ├── debian.compat.in
│   │   │   ├── debian.rules.in
│   │   │   ├── gdb-on-target.ini.in
│   │   │   ├── install-wgt-on-target.sh.in
│   │   │   ├── start-on-target.sh.in
│   │   │   ├── rpm-config.spec.in
│   │   │   └── xds-project-target.conf.in
│   │   └── wgt/
│   │       ├── icon-default.png
│   │       ├── icon-html5.png
│   │       ├── icon-native.png
│   │       ├── icon-qml.png
│   │       └── icon-service.png
│   ├── packaging/
│   │   ├── config.spec
│   │   └── config.deb
│   ├── cmake
│   │   └── config.cmake
│   └── wgt
│      └── config.xml.in
├── <libs>
├── <target>
│   └── <files>
├── <target>
│   └── <file>
└── <target>
    └── <files>
# Parent Description  
<root-path> - Path to your project. Hold master CMakeLists.txt and general files of your projects.  
conf.d <root-path> Holds needed files to build, install, debug, package an AGL app project  
app-templates conf.d Git submodule to app-templates AGL repository which provides CMake helpers macros library, and build scripts. config.cmake is a copy of config.cmake.sample configured for the projects. SHOULD NOT BE MODIFIED MANUALLY !  
autobuild conf.d Scripts generated from app-templates to build packages the same way for differents platforms.  
cmake conf.d Contains at least config.cmake file modified from the sample provided in app-templates submodule.  
wgt conf.d Contains at least config.xml.in template file modified from the sample provided in app-templates submodule for the needs of project (See config.xml.in.sample file for more details).  
packaging conf.d Contains output files used to build packages.  
<libs> <root-path> External dependencies libraries. This isn’t to be used to include header file but build and link statically specifics libraries. Library sources files. Can be a decompressed library archive file or project fork.
<target> <root-path> A target to build, typically library, executable, etc.  

Update app-templates submodule

You may have some news bug fixes or features available from app-templates repository that you want. To update your submodule proceed like the following:

git submodule update --remote
git commit -s conf.d/app-templates

This will update the submodule to the HEAD of master branch repository.

You could just want to update at a specified repository tag or branch or commit , here are the method to do so:

cd conf.d/app-templates
# Choose one of the following depending what you want
git checkout <tag_name>
git checkout --detach <branch_name>
git checkout --detach <commit_id>
# Then commit
cd ../..
git commit -s conf.d/app-templates

Build a widget

config.xml.in file

To build a widget you need a config.xml file describing what is your apps and how Application Framework would launch it. This repo provide a simple default file config.xml.in that should work for simple application without interactions with others bindings.

It is recommanded that you use the sample one which is more complete. You can find it at the same location under the name config.xml.in.sample (stunning isn’t it). Just copy the sample file to your conf.d/wgt directory and name it config.xml.in, then edit it to fit your needs.

CAUTION : The default file is only meant to be use for a simple widget app, more complicated ones which needed to export their api, or ship several app in one widget need to use the provided config.xml.in.sample which had all new Application Framework features explained and examples.

Using cmake template macros

To leverage all cmake templates features, you have to specify properties on your targets. Some macros will not works without specifying which is the target type.

As the type is not always specified for some custom targets, like an HTML5 application, macros make the difference using LABELS property.

Choose between:

  • BINDING: Shared library that be loaded by the AGL Application Framework
  • BINDINGV2: Shared library that be loaded by the AGL Application Framework This has to be accompagnied with a JSON file named like the ${OUTPUT_NAME}-apidef of the target that describe the API with OpenAPI syntax (e.g: mybinding-apidef). Or you can choose the name, without the extension, by setting the CACHE cmake variable OPENAPI_DEF (CAUTION: setting a CACHE variable is needed, or set a normal variable with the PARENT_SCOPE option to make it visible for the parent scope where the target is defined) JSON file will be used to generate header file using afb-genskel tool.
  • PLUGIN: Shared library meant to be used as a binding plugin. Binding would load it as a plugin to extend its functionnalities. It should be named with a special extension that you choose with SUFFIX cmake target property or it’d be .ctlso by default.
  • HTDOCS: Root directory of a web app. This target has to build its directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
  • DATA: Resources used by your application. This target has to build its directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
  • EXECUTABLE: Entry point of your application executed by the AGL Application Framework
  • LIBRARY: An external 3rd party library bundled with the binding for its own purpose because platform doesn’t provide it.

TIP you should use the prefix afb- with your BINDING* targets which stand for **Application Framework Binding.

Example:

SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
		LABELS "HTDOCS"
		OUTPUT_NAME dist.prod
	)

NOTE: You doesn’t need to specify an INSTALL command for these targets. This is already handle by template and will be installed in the following path : ${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}

NOTE: if you want to set and use rpath with your target you should use and set the target property INSTALL_RPATH.

Add external 3rd party library

You could need to include an external library that isn’t shipped in the platform. Then you have to bundle the required library in the lib widget directory.

Templates includes some facilities to help you to do so. Classic way to do so is to declare as many CMake ExternalProject as library you need.

An ExternalProject is a special CMake module that let you define how to: download, update, patch, configure, build and install an external project. It doesn’t have to be a CMake project and custom step could be added for special needs using ExternalProject step. More informations on CMake ExternalProject documentation site.

Example to include mxml library for unicens2-binding project:

set(MXML external-mxml)
set(MXML_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/mxml)
ExternalProject_Add(${MXML}
    GIT_REPOSITORY https://github.com/michaelrsweet/mxml.git
    GIT_TAG release-2.10
    SOURCE_DIR ${MXML_SOURCE_DIR}
    CONFIGURE_COMMAND ./configure --build x86_64 --host aarch64
    BUILD_COMMAND make libmxml.so.1.5
    BUILD_IN_SOURCE 1
    INSTALL_COMMAND ""
)

PROJECT_TARGET_ADD(mxml)

add_library(${TARGET_NAME} SHARED IMPORTED GLOBAL)

SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
    LABELS LIBRARY
    IMPORTED_LOCATION ${MXML_SOURCE_DIR}/libmxml.so.1
    INTERFACE_INCLUDE_DIRECTORIES ${MXML_SOURCE_DIR}
)

add_dependencies(${TARGET_NAME} ${MXML})

Here we define an external project that drive the build of the library then we define new CMake target of type IMPORTED. Meaning that this target hasn’t been built using CMake but is available at the location defined in the target property IMPORTED_LOCATION.

You could want to build the library as SHARED or STATIC depending on your needs and goals. Then you only have to modify the external project configure step and change filename used by IMPORTED library target defined after external project.

Then target LABELS property is set to LIBRARY to ship it in the widget.

Unicens project also need some header from this library, so we use the target property INTERFACE_INCLUDE_DIRECTORIES. Setting that when another target link to that imported target, it can access to the include directories.

We bound the target to the external project using a CMake dependency at last.

Then this target could be use like any other CMake target and be linked etc.

If you already have a binary version of the library that you want to use and you can’t or don’t want to build the library then you only have to add an IMPORTED library target.

So, taking the above example, mxml library inclusion would be:

PROJECT_TARGET_ADD(mxml)

add_library(${TARGET_NAME} SHARED IMPORTED GLOBAL)

SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
    LABELS LIBRARY
    IMPORTED_LOCATION /path/to/library/libmxml.so.1
    INTERFACE_INCLUDE_DIRECTORIES /path/to/mxml/include/dir
)

Finally, you can link any other lib or executable target with this imported library like any other target.

Macro reference

PROJECT_TARGET_ADD

Typical usage would be to add the target to your project using macro PROJECT_TARGET_ADD with the name of your target as parameter.

Example:

PROJECT_TARGET_ADD(low-can-demo)

NOTE: This will make available the variable ${TARGET_NAME} set with the specificied name. This variable will change at the next call to this macros.

project_subdirs_add

This macro will search in all subfolder any CMakeLists.txt file. If found then it will be added to your project. This could be use in an hybrid application by example where the binding lay in a sub directory.

Usage :

project_subdirs_add()

You also can specify a globbing pattern as argument to filter which folders will be looked for.

To filter all directories that begin with a number followed by a dash the anything:

project_subdirs_add("[0-9]-*")

Advanced build customization

Including additionnals cmake files

Machine and system custom cmake files

Advanced tuning is possible using addionnals cmake files that are included automatically from some specifics locations. They are included in that order:

  • Project CMake files normaly located in _/conf.d/app-templates/cmake/cmake.d_
  • Home CMake files located in $HOME/.config/app-templates/cmake.d
  • System CMake files located in /etc/app-templates/cmake.d

CMake files has to be named using the following convention: XX-common*.cmake or XX-${PROJECT_NAME}*.cmake, where XX are numbers, * file name (ie. 99-common-my_customs.cmake).

NOTE You need to specify after numbers that indicate include order, to which project that file applies, if it applies to all project then use keyword common.

So, saying that you should be aware that every normal cmake variables used at project level could be overwrited by home or system located cmake files if variables got the same name. Exceptions are cached variables set using CACHE keyword:

Example:

set(VARIABLE_NAME 'value string random' CACHE STRING 'docstring')

OS custom cmake files

This is meant to personalize the project depending on the OS your are using. At the end of config.cmake, common.cmake will include lot of cmake file to customize project build depending on your plateform. It will detect your OS deducing it from file /etc/os-release now as default in almost all Linux distribution.

So you can use the value of field ID_LIKE or ID if the first one doesn’t exists and add a cmake file for that distribution in your conf.d/cmake/ directory or relatively to your app-templates submodule path app-templates/../cmake/

Those files has to be named use the following scheme XX-${OSRELEASE}*.cmake where XX are numbers, ${OSRELEASE} the ID_LIKE or ID field from /etc/os-release file. You can also define default OS configuration file to use as fallback is none specific OS configuration is available using the scheme XX-default*.cmake. Then is you need by example a module that isn’t named the same in one distro only, you only has to define a specific file to handle that case then for all the other case put the configuration in the default file.

Include customs templated scripts

As well as for additionnals cmake files you can include your own templated scripts that will be passed to cmake command configure_file.

Just create your own script to the following directories:

  • Home location in $HOME/.config/app-templates/scripts
  • System location in /etc/app-templates/scripts

Scripts only needs to use the extension .in to be parsed and configured by CMake command.

Autobuild script usage

Generation

To be integrated in the Yocto build workflow you have to generate autobuild scripts using autobuild target.

To generate those scripts proceeds:

mkdir -p build
cd build
cmake .. && make autobuild

You should see conf.d/autobuild/agl/autobuild file now.

Available targets

Here are the available targets available from autobuild scripts:

  • clean : clean build directory from object file and targets results.
  • distclean : delete build directory
  • configure : generate project Makefile from CMakeLists.txt files.
  • build : compile all project targets.
  • package : build and output a wgt package.

You can specify variables that modify the behavior of compilation using the following variables:

  • CONFIGURE_ARGS : Variable used at configure time.
  • BUILD_ARGS : Variable used at build time.
  • DEST : Directory where to output wgt file.

Variable as to be in CMake format. (ie: BUILD_ARGS=”-DC_FLAGS=’-g -O2’”)

Usage example:

./conf.d/autobuild/wgt/autobuild package DEST=/tmp