Building as Flatpak

Constellation can be built and distributed as Flatpak. The advantage is that this only requires an installation of Meson and Flatpak to build and makes it easy to distribute Constellation to the users.

Setting up Flatpak

The installation instruction for Flatpak can be found on the Flatpak website. To build the Flatpak, some additional steps have to be taken.

First, Flathub needs to be added as a repository user-wide:

flatpak remote-add --if-not-exists --user flathub https://dl.flathub.org/repo/flathub.flatpakrepo

Then the Flatpak Builder needs to be installed:

flatpak install -y --user flathub org.flatpak.Builder

Preparing the Flatpak

To build the Flatpak, a MetaInfo file for Constellation needs to be created. The file should be named de.desy.constellation.metainfo.xml and located in a folder named flatpak within a clone of the Constellation repository with the following contents:

<?xml version="1.0" encoding="UTF-8" ?>
<component type="desktop-application">
  <id>de.desy.constellation</id>
  <metadata_license>CC0-1.0</metadata_license>

  <name>Constellation</name>
  <developer id="de.desy"><name>Deutsches Elektronen-Synchrotron DESY</name></developer>
  <summary>Control and Data Acquisition System</summary>
  <project_license>EUPL-1.2</project_license>
  <url type="homepage">https://constellation.pages.desy.de/</url>
  <url type="vcs-browser">https://gitlab.desy.de/constellation/constellation</url>

  <description>
    <p>
      Constellation is an autonomous control and data acquisition system for small-scale experiments and experimental setup with volatile and dynamic constituents such as testbeam environments or laboratory test stands. Constellation aims to provide a flexible framework that requires minimal effort for the integration of new devices, that is based on widely adopted open-source network communication libraries and that keeps the required maintenance as low as possible.
    </p>
    <p>
      This Flatpak contains the graphical MissionControl interface for controlling and many C++ satellites. They can be started with <code>flatpak run de.desy.constellation -t TYPE</code>. The following satellites are included:
    </p>
    <ul>
      <li>DevNullReceiver</li>
      <li>EudaqNativeWriter</li>
      <li>RandomTransmitter</li>
      <li>Sputnik</li>
    </ul>
    <p>
      Please note that file permissions for file writing have to be given explicitly e.g. with Flatseal.
    </p>
  </description>
  <screenshots>
    <screenshot type="default">
      <image>https://constellation.pages.desy.de/_images/missioncontrol_run.png</image>
      <caption>MissionControl main window</caption>
    </screenshot>
  </screenshots>
  <keywords>
    <keyword translate="no">DAQ</keyword>
    <keyword>testbeam</keyword>
  </keywords>
  <branding>
    <color type="primary" scheme_preference="light">#b5e2f4</color>
    <color type="primary" scheme_preference="dark">#623030</color>
  </branding>

  <content_rating type="oars-1.1" />
  <requires>
    <display_length compare="ge">768</display_length>
  </requires>
  <recommends>
    <control>keyboard</control>
    <control>pointing</control>
  </recommends>
  <supports>
    <control>touch</control>
  </supports>

  <launchable type="desktop-id">de.desy.constellation.missioncontrol.desktop</launchable>

  <releases>
      <release version="0.2" date="2024-12-09">
        <url type="details">https://constellation.pages.desy.de/news/2024-12-09-Constellation-Release-0.2.html</url>
      </release>
      <release version="0.1" date="2024-11-05">
        <url type="details">https://constellation.pages.desy.de/news/2024-11-05-Constellation-Release-0.1.html</url>
      </release>
  </releases>
</component>

Next, the manifest for the Flatpak can be created. It should be named de.desy.constellation.yml and located within the same flatpak folder:

id: de.desy.constellation
runtime: org.kde.Platform
runtime-version: "6.8"
sdk: org.kde.Sdk
command: Satellite
finish-args:
  - --share=network
  - --filesystem=host
  - --share=ipc
  - --socket=fallback-x11
  - --socket=wayland
  - --device=dri
cleanup:
  - /include
  - /lib/pkgconfig
  - /share/pkgconfig
modules:
  - name: Constellation
    buildsystem: meson
    config-opts:
      - -Dbuildtype=release
      - -Dimpl_py=disabled
      - -Dcxx_tools=false
      - -Dcxx_tests=disabled
      - -Dsatellite_dev_null_receiver=true
      - -Dsatellite_eudaq_native_writer=true
      - -Dsatellite_random_transmitter=true
      - -Dsatellite_sputnik=true
    sources:
      - type: dir
        path: ..
  - name: Constellation-metainfo
    buildsystem: simple
    build-commands:
      - install -D de.desy.constellation.metainfo.xml /app/share/metainfo/de.desy.constellation.metainfo.xml
    sources:
      - type: file
        path: de.desy.constellation.metainfo.xml

Building the Flatpak

Since internet access is not available during the Flatpak build, all dependencies need to be downloaded beforehand. This can be easily done with Meson:

meson subprojects download

Finally the Flatpak can be built by running the following command in the flatpak folder:

flatpak run --user org.flatpak.Builder --force-clean --user --install --install-deps-from=flathub --ccache --repo=repo builddir de.desy.constellation.yml

The Flatpak should now be installed for the current user.

Running the Flatpak

Currently, the Flatpak only contains the C++ side of Constellation. It includes the hardware-independent satellites and the MissionControl GUI. The GUIs can be started like any other desktop application.

Satellites can be started using the following command:

flatpak run de.desy.constellation -t Sputnik -n Flatpak -g edda

Attention

Satellite that require access to the file system might require additional file system permissions for special data folder like e.g. /data. These path can be added using e.g. Flatseal.