odometer system

[patrickelectric]

Summary by Sourcery

Introduce a new Zenoh-powered odometer microservice and expose it through the HTTP/API gateway.

New Features:

• Add an odometer FastAPI service that tracks cumulative distance from MAVLink GLOBAL_POSITION_INT messages via Zenoh and persists state to disk.
• Expose odometer state retrieval and reset endpoints under a versioned /odometer API path via the existing HTTP gateway and frontend dev proxy.

Build:

• Define a dedicated pyproject configuration for the odometer service with its Python dependencies.

[sourcery-ai]

Reviewer's Guide

Introduces a new Zenoh-powered "odometer" microservice (with HTTP API, persistence, and FastAPI versioning) and wires it into BlueOS via nginx, frontend dev proxy, and helper port configuration.

Sequence diagram for odometer HTTP state retrieval

sequenceDiagram
    actor User
    participant Browser
    participant Nginx
    participant OdometerAPI as Odometer_FastAPI
    participant OdometerService

    User->>Browser: Request_/odometer/
    Browser->>Nginx: HTTP_GET_/odometer/
    Nginx->>OdometerAPI: Proxy_GET_/odometer/
    OdometerAPI->>OdometerService: get_state()
    OdometerService-->>OdometerAPI: OdometerState
    OdometerAPI-->>Nginx: 200_OK_JSON_OdometerState
    Nginx-->>Browser: 200_OK_JSON_OdometerState
    Browser-->>User: Render_total_distance_and_metadata

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Sequence diagram for odometer Zenoh sample processing

sequenceDiagram
    participant ArduPilot
    participant ZenohRouter as Zenoh_router
    participant OdometerSession as zenoh_Session
    participant OdometerService
    participant StateFile as odometer_json_state

    ArduPilot->>ZenohRouter: Publish_GLOBAL_POSITION_INT
    ZenohRouter->>OdometerSession: Forward_SAMPLE_for_key_expr
    OdometerSession->>OdometerService: _on_sample(sample)
    OdometerService->>OdometerService: Parse_payload_to_Position
    OdometerService->>OdometerService: update_position(position)
    Note over OdometerService: Update_total_distance_m_last_position_sample_count
    loop Periodic_persistence
        OdometerService->>StateFile: persist_state()
    end

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Class diagram for the new odometer service domain model

classDiagram
    class Position {
        float lat_deg
        float lon_deg
        float alt_m
        int time_boot_ms
    }

    class OdometerState {
        float total_distance_m
        Position last_position
        int sample_count
        datetime updated_at
    }

    class _RawState {
        float total_distance_m
        dict~string_Any~ last_position
        int sample_count
        string updated_at
    }

    class ResetResponse {
        string status
        OdometerState state
    }

    class OdometerService {
        +Path state_path
        +string key_expr
        +Path zenoh_config_path
        +float persist_interval_seconds
        -OdometerState _state
        -Lock _lock
        -zenoh_Session _session
        -zenoh_Subscriber _subscriber
        -Task _persist_task
        -AbstractEventLoop _loop
        +OdometerService(state_path, key_expr, zenoh_config_path, persist_interval_seconds)
        +start()
        +stop()
        -_open_session() zenoh_Session
        -_load_state() OdometerState
        -_on_sample(sample)
        +update_position(position) OdometerState
        +get_state() OdometerState
        +reset() OdometerState
        -_serialize_state() _RawState
        +persist_state()
        -_write_state(serialized)
        -_persist_state_periodically()
    }

    Position <.. OdometerState : uses
    Position <.. OdometerService : uses
    OdometerState <.. OdometerService : manages
    _RawState <.. OdometerService : serialization
    OdometerState <.. ResetResponse : contains
    OdometerService <.. get_odometer_service : provided_by

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File-Level Changes

Change	Details	Files
Expose the odometer HTTP API through nginx and the frontend dev proxy so it is reachable via /odometer.	Add /odometer/ location block in nginx that proxies to the odometer service on port 9127 with CORS enabled. Add a Vite dev-server proxy rule mapping ^/odometer to the backend SERVER_ADDRESS.	core/tools/nginx/nginx.conf core/frontend/vite.config.js
Register the odometer service port in the helper service so it is considered an expected/managed core service.	Include port 9127 in the Helper service’s known core service ports list.	core/services/helper/main.py
Implement the odometer microservice that accumulates traveled distance from MAVLink GLOBAL_POSITION_INT messages received via Zenoh and exposes a REST API to read/reset the state.	Define configuration via argparse and environment variables for HTTP port, state file path, Zenoh config, key expression, and persistence interval. Implement OdometerState and Position Pydantic models plus internal _RawState dataclass for JSON serialization. Implement haversine-based distance calculation between subsequent positions to update total_distance_m and sample_count with thread-safe access via an asyncio.Lock. Open a Zenoh session (optionally from config file) and declare a subscriber on the configured key expression, parsing MAVLink GLOBAL_POSITION_INT-style messages into Position objects. Persist state periodically and on shutdown to a JSON file under an appdirs-based data directory, with robust load/parse and error handling. Expose FastAPI endpoints /odometer/ (GET) to fetch state and /odometer/reset (POST) to reset state, wrapped with fastapi-versioning and GenericErrorHandlingRoute, and add a simple HTML root handler. Wire service lifecycle into FastAPI startup/shutdown events and run it via uvicorn in an asyncio main().	core/services/odometer/main.py
Declare the odometer service as a standalone Python project with its dependencies for packaging/running.	Add pyproject.toml specifying project metadata, Python version, runtime dependencies (zenoh, FastAPI, commonwealth, etc.), and uv configuration with commonwealth sourced from the workspace.	core/services/odometer/pyproject.toml

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