Redistribute on Linux

Bundle the SmartSpectra Linux C++ SDK tarball into your own .deb so end users install your app on stock Ubuntu without a Presage apt source.

Validated path for a developer to take the published SmartSpectra Linux C++ SDK release tarball, build their own application against it, and ship a self-contained .deb that installs on a stock Ubuntu / Mint / Debian host without configuring a Presage apt source.

This is the only Linux redistribution shape currently supported. Other shapes are not currently validated.

When to use this path

You're a developer who:

Ships a desktop app to enterprise Linux end-users
Wants the end-user install to be one sudo apt install ./your-app.deb step
Cannot ask end-users to configure a Presage apt source
Targets Debian-family distros — currently Ubuntu 22.04 / 24.04 (Mint 21 / 22), with Debian 11+ as a documented equivalent. arm64 redistribution remains a follow-up

If your end-users run a non-Debian-family distro (Fedora, RHEL, openSUSE, Arch), you're in territory we don't currently validate.

The example app

The public GitHub mirror ships the example as cpp/samples/debian-app-example/README.md with its packaging logic in cpp/samples/debian-app-example/CMakeLists.txt. It demonstrates every choice this page documents and is a suitable starting point to copy into your own repository when integrating the SDK into a redistributable .deb.

Build it standalone against an extracted SDK release tarball:

# 1. Extract the published SDK release tarball
#    Use the codename-qualified asset name:
#    - Ubuntu 22.04 / Mint 21 / Debian 11+: linux-jammy-amd64
#    - Ubuntu 24.04 / Mint 22: linux-noble-amd64
mkdir -p /tmp/sdk
tar -xzf smartspectra-sdk-<version>-linux-<codename>-amd64.tar.gz -C /tmp/sdk

# 2. Choose the example source path for your checkout:
#    - Public GitHub mirror: cpp/samples/debian-app-example
cmake -S <example-source-dir> -B /tmp/dae-build \
      -DCMAKE_PREFIX_PATH=/tmp/sdk \
      -DCMAKE_BUILD_TYPE=Release
cmake --build /tmp/dae-build -j$(nproc)

# 3. Produce the .deb (per-codename revision suffix)
cd /tmp/dae-build
cpack -G DEB
# Produces e.g. debian-app-example_0.1.0-noble1_amd64.deb on Ubuntu 24.04
# or debian-app-example_0.1.0-jammy1_amd64.deb on Ubuntu 22.04 — the
# revision suffix tracks the build-host codename so the same .deb stream
# never serves a mismatched stock-archive Depends set.

# 4. Install on a clean Debian-family container
sudo apt install -y ./debian-app-example_*.deb

Read the example CMakeLists.txt end-to-end — it's the canonical source for the install layout, CPack DEB config, Depends manifest reading, and maintainer-script wiring.

Install layout

The .deb installs entirely under /opt/debian-app-example/ (an app-private prefix per FHS 3.0 §3.12). Replace debian-app-example with your own app name when you adapt the example.

/opt/<app-name>/
├── bin/
│   └── <app-name>                          (the executable)
├── lib/
│   ├── libsmartspectra.so                  (bundled from SDK tarball)
│   └── smartspectra_manifest.json          (written at install time)
└── share/
    └── smartspectra/
        └── graph/
            ├── models/                     (bundled from SDK tarball)
            └── ...

Plus one file outside the app's prefix, written by postinst:

# /etc/ld.so.conf.d/<app-name>.conf
/opt/<app-name>/lib

postrm removes that fragment on remove / purge.

RPATH and per-app ldconfig

Two mechanisms place the bundled libsmartspectra.so on the loader's path when the end-user launches the binary.

RPATH on the binary. The example binary is linked with INSTALL_RPATH=$ORIGIN/../lib and INSTALL_RPATH_USE_LINK_PATH=FALSE so the resulting DT_RUNPATH is exactly $ORIGIN/../lib. From /opt/<app-name>/bin/<app> this walks to /opt/<app-name>/lib/, where libsmartspectra.so lives.

ldconfig fragment for libsmartspectra.so. The SDK's shared library has no embedded DT_RUNPATH / DT_RPATH, and /opt/<app-name>/lib is not on the loader's default search path, so postinst also registers it with the system loader cache:

# /etc/ld.so.conf.d/<app-name>.conf
/opt/<app-name>/lib

and runs ldconfig, so libsmartspectra.so resolves at load time.

postrm removes the ldconfig fragment on remove / purge so the cache no longer maps libraries to the now-removed prefix.

Model-path resolution

At runtime the SDK locates its own shared-library directory and reads smartspectra_manifest.json from that directory. The manifest contains a single absolute path:

{
  "resource_root_dir": "/opt/<app-name>/share/smartspectra"
}

The SDK joins resource_root_dir with the relative model paths it ships internally, so model lookups land under /opt/<app-name>/share/smartspectra/... at runtime.

The example's CMake writes this manifest at install time (not build time) so the recorded prefix matches the actual install location, not the build prefix.

Depends: from SmartSpectraPackageManifest.json

The example does not hard-code its Depends: list. Drift between the SDK's own apt-resolved dependencies and the example's list would silently produce a .deb that installs but fails to load the SDK on a stock container.

Instead, the example reads <sdk>/share/smartspectra/package/SmartSpectraPackageManifest.json at CMake-configure time and feeds its debian_depends field straight into CPACK_DEBIAN_PACKAGE_DEPENDS. The manifest is per-codename, so each codename produces its own Depends set from the same example source.

A FATAL_ERROR guard in the example's CMake refuses to package if the manifest is missing or its debian_depends field is empty.

The end-user therefore needs no Presage apt source — every transitive dependency resolves from the codename's stock archive at apt install ./<app>.deb time on both jammy and noble. arm64 remains a follow-up.