Bus Agnostic C API

[[TOC]]

Introduction

The goal of this library is to provide an API that makes it possible to connect to different kinds of software buses and perform actions on it.

This library acts as a mediator between the application using the API and the real bus.

The real implementation (communication with a specific bus) is in the back-ends.

The differences (in functionality and semantics) should be hidden by this library. This will make it easier to write services, applications on top of this API and run it on any bus.

Supported bus features:

• method invocation (synchronous and asynchronous implementation)
• get data model objects/parameters
• set data model parameters
• add data model object instances
• del data model object instances
• describe data model objects (full introspection)
• get_supported data model
• subscribe for events/notifications
• publish events/notifications
• register objects/methods

Back-end implementations:

• ubus (openwrt)
• pcb (sah sop)
• rbus (RDK-B) (work in progress)

Building, installing and testing

Docker container

You could install all tools needed for testing and developing on your local machine, but it is easier to just use a pre-configured environment. Such an environment is already prepared for you as a docker container.

1. Install docker

   Docker must be installed on your system.

   If you have no clue how to do this here are some links that could help you:

   • Get Docker Engine - Community for Ubuntu
   • Get Docker Engine - Community for Debian
   • Get Docker Engine - Community for Fedora
   • Get Docker Engine - Community for CentOS
     
     

   Make sure you user id is added to the docker group:

   ``` sudo usermod -aG docker $USER ```

1. Fetch the container image

   To get access to the pre-configured environment, all you need to do is pull the image and launch a container.

   Pull the image:

   ```bash docker pull registry.gitlab.com/soft.at.home/docker/oss-dbg:latest ```

   Before launching the container, you should create a directory which will be shared between your local machine and the container.

   ```bash mkdir -p ~/amx_project/libraries/ ```

   Launch the container:

   ```bash docker run -ti -d –name oss-dbg –restart always –cap-add=SYS_PTRACE –sysctl net.ipv6.conf.all.disable_ipv6=1 -e "USER=$USER" -e "UID=$(id -u)" -e "GID=$(id -g)" -v ~/amx_project/:/home/$USER/amx_project/ registry.gitlab.com/soft.at.home/docker/oss-dbg:latest ```

   If you are using vpn, you need to add --dns 192.168.16.10 --dns 192.168.16.11 to the docker run command.

   The -v option bind mounts the local directory for the ambiorix project in the container, at the exact same place. The -e options create environment variables in the container. These variables are used to create a user name with exactly the same user id and group id in the container as on your local host (user mapping).

   You can open as many terminals/consoles as you like:

   ```bash docker exec -ti –user $USER oss-dbg /bin/bash ```

Building

Prerequisites

• libamxc - Generic C api for common data containers
• libamxp - common patterns implementation
• libamxd - Data model C API
• liburiparser - RFC 3986 compliant URI parsing and handling

---

Dependency graph - libraries needed by libamxb. For graph simplicity direct dependencies which are also an indirect dependency are not shown.

@code{mermaid}

graph TD; libamxb-->libamxd-->libamxp-->libamxc libamxb-->liburiparser libamxb-->libdl

Build libamxb

1. Clone the git repository

   To be able to build it, you need the source code. So open the directory just created for the ambiorix project and clone this library in it (on your local machine).

   ```bash cd ~/amx_project/libraries/ git clone git@g.nosp@m.itla.nosp@m.b.com:prpl-foundation/components/ambiorix/libraries/libamxb.git ```

1. Install dependencies

   Although the container will contain all tools needed for building, it does not contain the libraries needed for building libamxb. To be able to build libamxb you need libamxc, libamxp and libamxd. These libraries can be installed in the container.

   ```bash sudo apt update sudo apt install libamxd ```

   Note that you do not need to install all components explicitly. Some components will be installed automatically because the other components depend on them. Some of the components are allready preinstalled in the container.

1. Build it

   When using the internal gitlab, you must define an environment variable VERSION_PREFIX before building.

   ```bash export VERSION_PREFIX="master_" ```

   After the variable is set, you can build the package.

   ```bash cd ~/amx_project/libraries/libamxb make ```

Installing

Using make target install

You can install your own compiled version easily in the container by running the install target.

cd ~/amx_project/libraries/libamxb
sudo -E make install

Using package

From within the container you can create packages.

cd ~/amx_project/libraries/libamxb
make package

The packages generated are:

~/amx_project/libraries/libamxb/libamxb-<VERSION>.tar.gz
~/amx_project/libraries/libamxb/libamxb-<VERSION>.deb

You can copy these packages and extract/install them.

For ubuntu or debian distributions use dpkg:

sudo dpkg -i ~/amx_project/libraries/libamxb/libamxb-<VERSION>.deb

Testing

Prerequisites

• libamxo - The ODL compiler library

Run tests

1. Install dependencies

   Most of the packages needed for testing are allready preinstalled in the container. To be able to test libamxb you need to extra install libamxo.

   ```bash sudo apt update sudo apt install libamxo ```

1. Run tests

   You can run the tests by executing the following command.

   ```bash cd ~/amx_project/libraries/libamxb/tests make ```

   Or this command if you also want the coverage tests to run:

   ```bash cd ~/amx_project/libraries/libamxb/tests make run coverage ```

Coverage reports

The coverage target will generate coverage reports using gcov and gcovr.

A summary for each file (*.c files) is printed in your console after the tests are run. A HTML version of the coverage reports is also generated. These reports are available in the output directory of the compiler used. Example: using native gcc When the output of gcc -dumpmachine is x86_64-linux-gnu, the HTML coverage reports can be found at ~/amx_project/libraries/libamxb/output/x86_64-linux-gnu/coverage/report.

You can easily access the reports in your browser. In the container start a python3 http server in background.

cd ~/amx_project/
python3 -m http.server 8080 &

Use the following url to access the reports http://<IP ADDRESS OF YOUR CONTAINER>:8080/libraries/libamxb/output/<MACHINE>/coverage/report You can find the ip address of your container by using the ip command in the container.

Example:

USER@<CID>:~/amx_project/libraries/libamxb$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
173: eth0@if174: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:11:00:07 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.0.7/16 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 2001:db8:1::242:ac11:7/64 scope global nodad 
       valid_lft forever preferred_lft forever
    inet6 fe80::42:acff:fe11:7/64 scope link 
       valid_lft forever preferred_lft forever

in this case the ip address of the container is 172.17.0.7. So the uri you should use is: http://172.17.0.7:8080/libraries/libamxb/output/x86_64-linux-gnu/coverage/report/