Sprint 17 - lifecore_state architecture RFC¶

Track. State Architecture / Research.

Branch. sprint/17-lifecore-state-rfc.

Priority. P2 - separate future architecture.

Objective. Decide the future lifecore_state architecture before coding runtime or message packages.

Context¶

The future model should be treated as a distributed typed state space or semantic synchronized state model, not as a generic industrial I/O bus hidden inside lifecore_ros2.

Concepts to evaluate include StateField, StateRegistry, StateDescriptor, StateQuality, StateSnapshot, StateDelta, StateProjection, StateMirror, StatePublisher, StateSubscriber, and StateBridge.

Questions to decide¶

Public name: lifecore_state or lifecore_io.
Package split: lifecore_state_msgs, lifecore_state_core, and lifecore_state_ros.
Separation between description, state, and command.
Required quality, sequence, and description_version fields.
Timestamp strategy: source timestamp per value and/or publication timestamp per batch.
Identity strategy: id, uuid, key, path-derived deterministic identity, future config_uuid or external id.
Projection model: registry-scoped synchronization or state-space projection.
Policies for unknown signals, missing signals, type mismatches, and stale data.
Relationship with lifecycle core, EventBus ideas, lightweight ECS ideas, and structured fast-access memory.

Explicit limits¶

No hard real-time loop.
No full ECS framework.
No replacement for ROS 2 topics or services.
No state-store concepts hidden inside lifecore_ros2.

Acceptance criteria¶

[ ] An RFC document exists.
[ ] Boundaries between lifecore_ros2 and lifecore_state are clear.
[ ] Go/no-go for implementation is explicit.
[ ] Architectural risks are listed.
[ ] Public names are provisionally stabilized.