helloworld binding

A binding example, implemented in a redpesk context

Pre-requisites

To follow this tutorial without inconvenience, you have to get the following tools ready to use:

wget
xz
ssh
qemu (more details at a later stage)

Moreover, in order to use redpesk services, you must register on the redpesk Community signup page ! You can either use a GitHub or a GitLab account.

Project configuration

Refer to the documentation for detailed guidance on creating and configuring your redpesk project and application setup.

⚠️ Key consideration

Ensure that the application name specified in your spec file matches the name used during the application's creation.

Deploy on a board

Now that a helloworld-binding package has been generated using redpesk, let's see how to install it on a board. Since redpesk supports cross-compilation, we will use an emulated x86_64 board (qemu-x86_64) for this purpose.

Refer to the documentation for detailed instructions on installing QEMU.

Getting a redpesk image

Download the latest redpesk image according to your board architecture.

For more details, please refer to the UP Board documentation.

mkdir ~/redpeskimage

cd ~/redpeskimage

wget -r -nd -nc --no-parent --accept-regex='redpesk.*smack.*\.(bmap|xz|sha256)' --reject-regex '(image\.raw|ova|index)' 'https://download.redpesk.bzh/redpesk-lts/batz-2.1-update/images/smack/minimal/x86_64/generic/'

tar xJf redpesk*.tar.xz

Running a redpesk image

Here we are, you are about to run the redpesk image.

$ ls
redpesk-lts-batz-2.1-update-smack-minimal-x86_64-generic-2025_04_10_0641.bmap           Redpesk-OS.img
redpesk-lts-batz-2.1-update-smack-minimal-x86_64-generic-2025_04_10_0641.tar            Redpesk-OS.img.bmap
redpesk-lts-batz-2.1-update-smack-minimal-x86_64-generic-2025_04_10_0641.tar.xz.sha256

The image you have just downloaded has the following configuration:

login: root
password: root

Then, simply run the redpesk image by doing:

export TCP_PORT=3333
qemu-system-x86_64 \
  -hda Redpesk-OS.img \
  -enable-kvm \
  -drive if=pflash,format=raw,readonly=on,file=/usr/share/OVMF/OVMF_CODE.fd \
  -drive if=pflash,format=raw,file=/usr/share/OVMF/OVMF_VARS.fd \
  -machine q35 \
  -m 2048 \
  -cpu kvm64 \
  -cpu qemu64,+ssse3,+sse4.1,+sse4.2,+popcnt \
  -net nic \
  -net user,hostfwd=tcp::${TCP_PORT}-:22 \
  -nographic \
  -snapshot

You may have noticed that in the previous command we allow the user to connect to the emulated board by establishing a ssh connection through the port ${TCP_PORT}.

You can access your emulated board with the following command:

ssh root@localhost -p ${TCP_PORT}

Installing your package

After building your package, refer to the deployment documentation, specifically section 4: "Install your package," to proceed with the installation.

If you correctly set your project name and version as explained in the Build part, you should have the following output during the package installation

[root@localhost ~]# dnf install helloworld-binding --nogpgcheck
Updating Subscription Management repositories.
Unable to read consumer identity

This system is not registered with an entitlement server. You can use subscription-manager to register.

hello-2_f098e52f--redpesk-lts-batz-2.1-update-build                                  4.8 kB/s | 2.1 kB     00:00
redpesk-lts-batz-2.1-update-build                                                    2.0 MB/s | 6.3 MB     00:03
redpesk-lts-batz-2.1-update-middleware-build                                         608 kB/s | 324 kB     00:00
redpesk-config-build                                                                 3.5 kB/s | 1.6 kB     00:00
RedPesk Middleware batz-2.1 Update - x86_64                                          658 kB/s | 323 kB     00:00
RedPesk Baseos batz-2.1 Update - x86_64                                              9.0 MB/s | 7.9 MB     00:00
RedPesk Config                                                                       2.8 kB/s | 903  B     00:00
Dependencies resolved.
=====================================================================================================================
 Package            Arch   Version                         Repository                                           Size
=====================================================================================================================
Installing:
 helloworld-binding x86_64 1.1.1+20240722+30+ga9c2297-1.hello.2_f098e52f.rpbatz_1_1
                                                           hello-2_f098e52f--redpesk-lts-batz-2.1-update-build  13 k

Transaction Summary
=====================================================================================================================
Install  1 Package

Total download size: 13 k
Installed size: 16 k
Is this ok [y/N]: y
Downloading Packages:
helloworld-binding-1.1.1+20240722+30+ga9c2297-1.hello.2_f098e52f.rpbatz_1_1.x86_64.r  64 kB/s |  13 kB     00:00
---------------------------------------------------------------------------------------------------------------------
Total                                                                                 60 kB/s |  13 kB     00:00
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                             1/1
  Installing       : helloworld-binding-1.1.1+20240722+30+ga9c2297-1.hello.2_f098e52f.rpbatz_1_1.x86_64          1/1
  Running scriptlet: helloworld-binding-1.1.1+20240722+30+ga9c2297-1.hello.2_f098e52f.rpbatz_1_1.x86_64          1/1
  Verifying        : helloworld-binding-1.1.1+20240722+30+ga9c2297-1.hello.2_f098e52f.rpbatz_1_1.x86_64          1/1
Installed products updated.

Installed:
  helloworld-binding-1.1.1+20240722+30+ga9c2297-1.hello.2_f098e52f.rpbatz_1_1.x86_64

Complete!

This implies that your widget has been installed correctly.

Verify if your package is properly installed :

[root@localhost ~]# rpm -ql helloworld-binding
/usr/lib/.build-id
/usr/lib/.build-id/12
/usr/lib/.build-id/12/87c1ceb24a017dc7318252044c04533873f330
/usr/redpesk
/usr/redpesk/helloworld-binding
/usr/redpesk/helloworld-binding/.rpconfig
/usr/redpesk/helloworld-binding/.rpconfig/manifest.yml
/usr/redpesk/helloworld-binding/lib
/usr/redpesk/helloworld-binding/lib/helloworld-binding.so

You can then start the binding by running:

[root@localhost ~]# afb-binder -v -b /usr/redpesk/helloworld-binding/lib/helloworld-binding.so

The binder has started successfully.

   NOTICE: Browser URL= http://localhost:1234
   NOTICE: Serving rootdir=. uploaddir=.
   NOTICE: API helloworld starting...
   NOTICE: API monitor starting...
   NOTICE: Listening interface *:1234
   NOTICE: [REQ/API helloworld] context initialized for new client

In another terminal on the same machine (you can open one terminal with SSH and another terminal with QEMU for the same machine), you can query the verb hello, for example:

[root@localhost ~]# afb-client -H localhost:1234/api helloworld hello

and the response with success

implicit null in arguments is deprecated and will be removed soon.
ON-EVENT helloworld/verb_called:
{
  "jtype":"afb-event",
  "event":"helloworld/verb_called",
  "data":"hello"
}
ON-REPLY 1:helloworld/hello: OK
{
  "jtype":"afb-reply",
  "request":{
    "status":"success",
    "code":0
  },
  "response":"Hello world!"
}

Automated testing in a non-embedded environment

Since this helloworld binding is not connected to real hardware, it can be run and tested on a Linux workstation.

In order to run the tests you need afb-libpython. It is available in redpesk SDK.

If you haven't already, please follow the quick installation guide to ensure your platform is supported and properly set up.

Install then Python bindings on your platform thanks to your distribution's tools:

sudo dnf install afb-binder afb-client afb-binding-devel afb-libpython

Build the project

To build the helloworld-binding binding, follow these steps after cloning the repository onto your host machine:

cd helloworld-binding # this repo

# Create a build directory
mkdir build
cd build

# Configure the build system
/helloworld-binding/build$ cmake ..
-- The C compiler identification is GNU 14.2.1
-- The CXX compiler identification is GNU 14.2.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found PkgConfig: /usr/bin/pkg-config (found version "2.3.0")
-- Checking for modules 'json-c;afb-binding>=4.1.0'
--   Found json-c, version 0.17
--   Found afb-binding, version 4.1.11
-- Configuring done (0.9s)
-- Generating done (0.0s)
-- Build files have been written to: /home/iheb/orig/helloworld-binding/build

# Build the project
/helloworld-binding/build$ make
[ 25%] Generating info_verb.c
[ 50%] Building C object CMakeFiles/helloworld-binding.dir/src/helloworld.c.o
[ 75%] Building C object CMakeFiles/helloworld-binding.dir/info_verb.c.o
[100%] Linking C shared library helloworld-binding.so
[100%] Built target helloworld-binding

You can see that the build process has successfully generated the helloworld-binding.so file for the binding.

/helloworld-binding/build$ ls
CMakeCache.txt  CMakeFiles  cmake_install.cmake  helloworld-binding.so  info_verb.c  Makefile

Test binding

Now you can test either manually, as demonstrated earlier on QEMU using afb-binder and afb-client, or automatically using the script ./tests/tests.py.

LD_LIBRARY_PATH=./build python  ./tests/tests.py --tap

Then a prompt appears in TAP format, describing which test is currently running and whether it succeed or failed.

$ LD_LIBRARY_PATH=./build python  ./tests/tests.py
Entering Python module initialization function PyInit_libafb
     INFO: API py-binder added
     INFO: API monitor added
     INFO: binding [helloworld-binding.so] looks like an AFB binding V4
     INFO: API helloworld added
   NOTICE: Entering binder mainloop
   NOTICE: API helloworld starting...
     INFO: API helloworld started
   NOTICE: API py-binder starting...
     INFO: API py-binder started
   NOTICE: API monitor starting...
     INFO: API monitor started
   NOTICE: [REQ/API helloworld] context initialized for new client
.   NOTICE: Entering binder mainloop
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[0]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[1]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[2]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[3]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[4]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[5]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[6]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[7]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[8]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[9]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[10]
.   NOTICE: Entering binder mainloop
.   NOTICE: Entering binder mainloop
.   NOTICE: Entering binder mainloop
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[11]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[12]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[13]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[14]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[15]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[16]
    ERROR: [API helloworld] parameter should be a JSON array of integers [/home/iheb/orig/helloworld-binding/src/helloworld.c:165,sum_verb]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[17]
    ERROR: [API helloworld] parameter should be a JSON array of integers [/home/iheb/orig/helloworld-binding/src/helloworld.c:165,sum_verb]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[18]
    ERROR: [API helloworld] parameter should be a JSON array of integers [/home/iheb/orig/helloworld-binding/src/helloworld.c:165,sum_verb]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[19]
    ERROR: [API helloworld] parameter should be a JSON array of integers [/home/iheb/orig/helloworld-binding/src/helloworld.c:165,sum_verb]
     INFO: [API py-binder] orphan event=[helloworld/verb_called] count=[20]

.
----------------------------------------------------------------------
Ran 5 tests in 0.012s

OK

Name		Name	Last commit message	Last commit date
Latest commit History 126 Commits
docs		docs
redtest		redtest
rpconfig		rpconfig
src		src
tests		tests
.gitignore		.gitignore
.gitlab-ci.yml		.gitlab-ci.yml
CHANGELOG		CHANGELOG
CMakeLists.txt		CMakeLists.txt
LICENSE		LICENSE
MAINTAINERS		MAINTAINERS
README.md		README.md
helloworld.spec		helloworld.spec

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helloworld binding

Pre-requisites

Project configuration

⚠️ Key consideration

Deploy on a board

Getting a redpesk image

Running a redpesk image

Installing your package

Automated testing in a non-embedded environment

Build the project

Test binding

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helloworld binding

Pre-requisites

Project configuration

⚠️ Key consideration

Deploy on a board

Getting a redpesk image

Running a redpesk image

Installing your package

Automated testing in a non-embedded environment

Build the project

Test binding

About

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