Data Flow Patterns

Understanding the flow of data through the SDV-Runtime architecture is essential for effective development. This page explains the key data flows and control patterns.

Reading Guide

  1. First, make sure you’ve read the Architecture Overview and Component Details
  2. On this page, learn how data flows between components
  3. After understanding the architecture, proceed to the Getting Started Guide to begin using SDV-Runtime

Main Component Interactions

The following describes the main data flows between components:

1. Signal Publishing Flow

Pattern: Mock Provider → KUKSA Databroker → Subscribed Applications

Description:

  1. The Mock Provider generates simulated vehicle signals (e.g., Vehicle.Speed = 50 km/h)
  2. These signals are published to the KUKSA Databroker based on the VSS specification
  3. Applications that have subscribed to these signals receive updates when values change

2. Management Flow

Pattern: Kit Manager ↔ Kuksa Syncer ↔ playground.digital.auto

Description:

  1. The Kit Manager initializes and manages the runtime environment
  2. The Kuksa Syncer establishes connection with playground.digital.auto
  3. Configuration, status, and commands are exchanged bidirectionally
  4. The playground can send commands and configuration updates back to the runtime

3. Application Data Access Flow

Pattern: Application → Velocitas SDK → KUKSA Databroker → VSS Data

Description:

  1. Vehicle applications use the Velocitas SDK’s object-oriented API
  2. The SDK translates these requests to Databroker API calls
  3. The Databroker retrieves or updates the requested data
  4. Results are returned through the SDK to the application

4. Python Runtime Connections

Pattern: Python Runtime → All Components

Description:

  • The Python runtime environment supports all components
  • It provides direct access to the Mock Provider, Velocitas SDK, KUKSA Databroker, and Kuksa Syncer
  • It enables communication between various services through standard Python interfaces

Detailed Data Flow Examples

Example 1: Reading a Vehicle Signal

  1. An application requests the current vehicle speed via the Velocitas SDK:

    speed = await vehicle.Speed.get()

  2. The Velocitas SDK translates this to a gRPC request to the Databroker:

    GetRequest(path="Vehicle.Speed")

  3. The Databroker looks up the current value and returns it:

    GetResponse(value=50, timestamp=...)

  4. The SDK processes the response and returns the value to the application:

    # speed now contains 50

Example 2: Subscribing to Signal Changes

  1. An application subscribes to speed changes:

    vehicle.Speed.subscribe(on_speed_change)

  2. The SDK registers this subscription with the Databroker:

    SubscribeRequest(path="Vehicle.Speed")

  3. When the Mock Provider updates the speed value:

    SetRequest(path="Vehicle.Speed", value=55)

  4. The Databroker sends an update to all subscribers:

    SubscriptionUpdate(path="Vehicle.Speed", value=55)

  5. The SDK receives this update and calls the application’s callback function:

    on_speed_change(SpeedData(value=55, timestamp=...))

Flow Categories

The data flows in SDV-Runtime can be categorized as:

  • Signal Flow: Related to vehicle signal data generation and distribution
  • Management Flow: Handling runtime configuration and external communication
  • Application Flow: Supporting application development and interaction

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