Developing a Worker

This guide walks through creating a new MOSAIC worker from scratch. A complete worker has two sides:

        graph LR
    subgraph "Backend (3rd_party/)"
        CFG["Config<br/>config.py"]
        RT["Runtime<br/>runtime.py"]
        CLI["CLI<br/>cli.py"]
        EP["Entry Point<br/>pyproject.toml"]
    end

    subgraph "Frontend (gym_gui/ui/)"
        FORM["Train Form<br/>widgets/"]
        FAC["Form Factory<br/>forms/"]
        CAT["Worker Catalog<br/>worker_catalog/"]
        PRES["Presenter<br/>presenters/"]
    end

    subgraph "Bridge"
        HANDLER["TrainingFormHandler"]
        CLIENT["TrainerClient (gRPC)"]
    end

    FORM -->|"get_config()"| HANDLER
    HANDLER -->|"submit_run()"| CLIENT
    CLIENT -->|"gRPC"| RT
    EP -.->|"discovery"| CFG
    FAC -.->|"creates"| FORM
    CAT -.->|"metadata"| FAC

    style CFG fill:#ff7f50,stroke:#cc5500,color:#fff
    style RT fill:#ff7f50,stroke:#cc5500,color:#fff
    style CLI fill:#ff7f50,stroke:#cc5500,color:#fff
    style EP fill:#ff7f50,stroke:#cc5500,color:#fff
    style FORM fill:#4a90d9,stroke:#2e5a87,color:#fff
    style FAC fill:#4a90d9,stroke:#2e5a87,color:#fff
    style CAT fill:#4a90d9,stroke:#2e5a87,color:#fff
    style PRES fill:#4a90d9,stroke:#2e5a87,color:#fff
    style HANDLER fill:#50c878,stroke:#2e8b57,color:#fff
    style CLIENT fill:#50c878,stroke:#2e8b57,color:#fff
    

• Backend: the worker package under 3rd_party/. Handles training logic, telemetry, and the CLI entry point that the Daemon spawns.

• Frontend: the Qt6 UI integration under gym_gui/ui/. Handles the training form dialog, worker catalog entry, presenter, and how user configuration reaches the backend via gRPC.