Hands-On: Persistent Application State

ara::per::OpenKeyValueStorage(
    ara::core::InstanceSpecifier{"OdoApp/OdometerKVS"})
.then([](auto kvsResult) {
    auto& kvs = kvsResult.Value();

    // Restore previous value on startup
    auto odo = kvs.GetValue<uint64_t>("odometer_km").ValueOr(0);
    ara::log::LogInfo() << "Restored odometer: " << odo << " km";

    // Increment on each km pulse from wheel speed
    wheelSpeedProxy.KmPulse.SetReceiveHandler([&] {
        wheelSpeedProxy.KmPulse.GetNewSamples([&](auto) {
            ++odo;
            kvs.SetValue("odometer_km", odo);
            kvs.SyncToStorage(); // flush immediately for safety
        }, 1);
    });
    wheelSpeedProxy.KmPulse.Subscribe(1);
});

# Simulate KVS corruption for testing
# (on development target — never in production!)
dd if=/dev/urandom of=/var/per/OdometerKVS/odometer_km.bin bs=1 count=8

# Restart OdoApp — expect RecoveryHandler callback
journalctl -f -t OdoApp
# Expected: "KVS corrupt: reset to defaults"
# Expected: odometer starts from 0 (default value from manifest)

# Build updated OdoApp binary
cmake --build build/OdoApp -- -j8

# Package as Software Package
autosar-packager \
  --manifest manifests/OdoApp_v2/ \
  --binary build/OdoApp/bin/OdoApp \
  --output OdoApp_v2.0.0.swcl \
  --sign keys/oem_private_key.pem

# Transfer to UCM via OTA client
./ota_client --package OdoApp_v2.0.0.swcl --ucm 192.168.0.1:50100

// After UCM.Activate():
// 1. Verify new binary version
assert(GetSWVersion() == "2.0.0");

// 2. Verify KVS persisted data survives OTA
auto odo = kvs.GetValue<uint64_t>("odometer_km").Value();
assert(odo == pre_update_odometer); // KVS must survive OTA

// 3. Trigger rollback
ucmProxy.Rollback().get();

// 4. Verify rollback restored previous binary
assert(GetSWVersion() == "1.0.0");

// 5. Verify KVS still intact after rollback
odo = kvs.GetValue<uint64_t>("odometer_km").Value();
assert(odo == pre_update_odometer); // data must be unchanged