Feat/238 implement native c grpc reader in qt

[melaniereis]

Pull Request

Related issue(s): closes #24

Type of change

• feat: A new feature
• fix: A bug fix
• docs: Documentation only changes
• style: Formatting, missing semicolons, etc (no code change)
• refactor: Code change that neither fixes a bug nor adds a feature
• perf: A code change that improves performance
• test: Adding or updating tests
• ci: CI configuration changes
• chore: Maintenance tasks
• spike: Investigation / research

Summary

This PR implements a hybrid data ingestion architecture for the Qt Dashboard, allowing it to consume vehicle speed data from either the direct CAN bus (via SocketCAN) or the KUKSA Databroker (via gRPC).

Key Changes:

• CMake Build System: Updated CMakeLists.txt to find and link native gRPC, Protobuf, and absl libraries. Added custom commands to auto-generate C++ sources from val.proto and types.proto.
• KuksaReader Class: Implemented a new KUKSAReader class inheriting from QObject. It manages the gRPC channel and subscription loop.
• Worker Threading: The gRPC Subscribe loop is blocking, so KUKSAReader is moved to a dedicated QThread in main.cpp to prevent freezing the UI.
• Runtime Switching: Implemented QCommandLineParser in main.cpp. Users can now switch modes at runtime using the --kuksa or -k flag.
• Wiring: Signals from either CANReader or KUKSAReader are dynamically connected to VehicleData slots based on the startup arguments.

How to test / Validation

1. Setup (Virtual CAN)
If running locally, ensure vcan0 is up:

sudo modprobe vcan
sudo ip link add dev vcan0 type vcan
sudo ip link set up vcan0

2. Test Default Mode (CAN)
Run the application without arguments. It should attempt to open vcan0:

./myqtapp
# Expected output: "Starting in CAN mode" ... "CAN device opened on interface vcan0"

Send CAN frames (e.g., using cangen vcan0) and verify the dashboard updates.

3. Test KUKSA Mode (gRPC)
Run the application with the flag. Ensure a Databroker instance is running on localhost:55555.

./myqtapp --kuksa
# Expected output: "Starting in KUKSA mode" ... "KuksaReader: Connected and Subscribed"

Publish speed updates to the broker and verify the dashboard updates.

Checklist

• I have run the project tests locally and they pass
• CI checks are green for this branch (or I will fix any failures)
• I have added or updated tests where applicable
• I have updated documentation (if applicable)
• I have added/updated any migration notes (if database or protocol changes)
• I have requested appropriate reviewers and added labels if needed
• This PR contains no secrets or sensitive data

Risks and backward compatibility

• Linker Issues: This PR introduces dependencies on grpc, protobuf, and abseil-cpp. The Yocto recipe must be updated to include these packages (DEPENDS and RDEPENDS) to avoid "Symbol Lookup Errors" on the target hardware.
• Backward Compatibility: Fully compatible. The default behavior remains CAN mode, so existing startup scripts will continue to work unchanged.

Related / dependent PRs

• Requires the corresponding update to the Yocto recipe qt-app_git.bb to add grpc dependencies.

---

Approval: Requires a minimum of 2 approvals.

Action: The feature branch MUST be deleted upon successful merge.

[github-actions]

✅ STM32 CI: Threadx.elf was built successfully.

[github-actions]

🔍 TSF Validation Results

Check	Status
trudag lint	✅ PASSED
trudag score	✅ PASSED
trudag publish	✅ PASSED

📋 Lint Output (first 500 chars)

[Zahhask45]

Everything looks great! I don't see any issues.

[Hugofslopes]

Looks ok, a lot of comments that help to understand the new code added. Good job Melanie!