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

cpp/samples/debian-app-example/ on the public mirror is a working reference implementation. 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. Configure + build the example out-of-tree
cmake -S cpp/samples/debian-app-example -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 cpp/samples/debian-app-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)
│   └── smartspectra/
│       └── libopencv_*.so.*                (bundled private OpenCV runtime)
└── 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
/opt/<app-name>/lib/smartspectra

postrm removes that fragment on remove / purge.

RPATH and per-app ldconfig

Two mechanisms together resolve the bundled-library chain 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. The binary's DT_RUNPATH resolves only that one direct dependency — under --enable-new-dtags (the linker default since ~2008) DT_RUNPATH does not propagate to transitive dependencies, so it plays no role in finding the bundled OpenCV runtime that libsmartspectra.so itself depends on.

ldconfig fragment for the SDK's transitive chain. The SDK's shared library has no embedded DT_RUNPATH / DT_RPATH, so its DT_NEEDED entries for the bundled OpenCV runtime can be resolved only via the system loader cache. To populate the cache, postinst writes:

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

and runs ldconfig. The system cache then maps the bundled OpenCV runtime to /opt/<app-name>/lib/smartspectra/, so the SDK's DT_NEEDED chain resolves at load time. The redistributed layout keeps the OpenCV runtime in the same lib/smartspectra/ subdir the SDK uses when installed via apt, so the installed tree mirrors the SDK's own install shape.

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.