ROS and ROS2 Rules

Package Structure

• Keep packages focused on one robot capability or integration boundary.
• Use package.xml and CMakeLists.txt or setup.py consistently with the package type.
• Keep launch files under launch/, configs under config/, messages under msg/, services under srv/, and actions under action/.
• Use namespaces and remapping instead of hardcoded topic names when nodes may be reused.

Nodes and Interfaces

• Keep nodes small and composable.
• Use parameters for tunable behavior; declare ROS2 parameters explicitly.
• Prefer messages for state streams, services for quick request/response operations, and actions for long-running goals with feedback.
• Use standard message types before creating custom interfaces.
• Document topic, service, action, frame, and parameter contracts.

Timing and Frames

• Use ROS time when simulation or bag replay matters.
• Use tf2 for frame transforms and document frame names.
• Avoid blocking callbacks; move long work to timers, worker threads, or actions.
• Set QoS profiles intentionally for sensor data, latched-like config, and reliable command paths.

Build and Test

• Use colcon build and keep package dependencies explicit.
• Run linters and formatters used by the workspace.
• Add launch tests or integration tests for multi-node behavior.
• Use simulation, bags, or recorded fixtures for repeatable sensor scenarios.
• Test failure cases such as missing transforms, stale sensor data, and unavailable services.

Common Mistakes

• Do not hardcode absolute paths; use package share directories.
• Do not publish commands without validating frame, units, and timestamp assumptions.
• Do not create custom messages when a standard message fits.
• Do not ignore QoS mismatches between publishers and subscribers.