Flatpak

Flatpak (former xdg-app) is a package management system to distribute desktop applications for Linux. It is based on OSTree. Flatpak is RedHat initiative.

Unlike AppImage, usually applications are distributed via flathub store, and require a special runtime to install applications on target machines.

The major advantage of Flatpak is sandboxing: each application runs in its own isolated environment. Flatpak provides fine-grained control to system resources (e.g. network, bluetooth, host filesystem, etc.). Flatpak also offers a set of runtimes for various Linux desktop applications, e.g. Freedesktop, GNOME and KDE.

The packaging process is:

• Install the flatpak runtime, flatpak-builder and SDK.
• Create a manifest <app-id>.json
• Run the flatpak-builder in order to produce the application
• Publish the application for further distribution

With help of conan’s json generator, the manifest creation could be easily automated. For example, the custom script could generate build-commands and sources entries within the manifest file:

app_id = "org.flatpak.%s" % self._name
manifest = {
    "app-id": app_id,
    "runtime": "org.freedesktop.Platform",
    "runtime-version": "18.08",
    "sdk": "org.freedesktop.Sdk",
    "command": "conan-entrypoint.sh",
    "modules": [
        {
            "name": self._name,
            "buildsystem": "simple",
            "build-commands": ["install -D conan-entrypoint.sh /app/bin/conan-entrypoint.sh"],
            "sources": [
                {
                    "type": "file",
                    "path": "conan-entrypoint.sh"
                }
            ]
        }
    ]
}
sources = []
build_commands = []
for root, _, filenames in os.walk(temp_folder):
    for filename in filenames:
        filepath = os.path.join(root, filename)
        unique_name = str(uuid.uuid4())
        source = {
            "type": "file",
            "path": filepath,
            "dest-filename": unique_name
        }
        build_command = "install -D %s /app/%s" % (unique_name, os.path.relpath(filepath, temp_folder))
        sources.append(source)
        build_commands.append(build_command)

manifest["modules"][0]["sources"].extend(sources)
manifest["modules"][0]["build-commands"].extend(build_commands)

Alternatively, flatpak allows distributing the single-file package. Such package, however, cannot be run or installed on its own, it’s needed to be imported to the local repository on another machine.