Client | App Orchestrator

The client_app is the central executable for the BetaTrader client suite. It acts as the composition root: owning the ASIO networking context, instantiating UI and exchange modules, and driving the 60 FPS ImGui render loop.

Overview

This application bridges the gap between raw trading data (maintained by pure C++ micro-modules) and a human-readable interface. It coordinates the lifecycle of the embedded local exchange, the FIX client session, and the Dear ImGui rendering context.

Key Responsibilities

• Initialize the GLFW/OpenGL3 window and ImGui context (via client_ui::UIManager).
• Own the asio::io_context and run it on a dedicated network thread.
• Instantiate and wire the ExchangeManager (local exchange), ConnectionPanel (FIX session UI), and ExchangePanel (exchange monitor).
• Drive the main render loop until window close.
• Handle graceful shutdown (stop io_context → join network thread → destroy UI).

Architecture

graph TD
    classDef ui fill:#2b303a,stroke:#4caf50,stroke-width:2px,color:white;
    classDef net fill:#1f2833,stroke:#66fcf1,stroke-width:2px,color:white;
    classDef logic fill:#0b0c10,stroke:#c5c6c7,stroke-width:2px,color:white;
 
    subgraph "client_app Process"
        MAIN(Main Thread<br/>ImGui Render Loop):::ui
        UI[UIManager + Dockspace]:::ui
        
        subgraph "Panels"
            CONN[ConnectionPanel]:::ui
            EXCH[ExchangePanel]:::ui
        end
        
        subgraph "Network Thread"
            IO_CTX(asio::io_context):::net
        end
        
        subgraph "Embedded Exchange"
            ADMIN[ExchangeManager]:::logic
            CORE[TradingCore]:::logic
            FIX_SRV[FixServer]:::net
        end
    end
 
    MAIN --> UI
    UI --> CONN
    UI --> EXCH
    CONN -->|Manages| FIX_SESSION[FixClientSession]
    FIX_SESSION -.->|Runs on| IO_CTX
    EXCH -->|Controls| ADMIN
    ADMIN -->|Owns| CORE
    ADMIN -->|Owns| FIX_SRV
    FIX_SRV -.->|Runs on| IO_CTX

Class Diagram

classDiagram
    class App {
        +App()
        +~App()
        +run() : int
        -mUI: UIManager
        -mConnPanel: ConnectionPanel
        -mExchMgr: ExchangeManager
        -mExchPanel: ExchangePanel
        -mIoCtx: asio::io_context
        -mWork: executor_work_guard
        -mNetworkThread: std::thread
        -mFixSession: shared_ptr~FixClientSession~
    }
 
    App *--> UIManager : Owns
    App *--> ConnectionPanel : Owns
    App *--> ExchangeManager : Owns
    App *--> ExchangePanel : Owns

Component Responsibilities

Component	Description
**App**	The composition root. Constructs all modules, starts the network thread in the constructor, and enters the render loop in run().
**UIManager**	Manages GLFW window and ImGui context lifecycle (from client_ui).
**ConnectionPanel**	ImGui panel for FIX session management — connect, logon, logout, message log (from client_ui).
**ExchangeManager**	Manages the lifecycle of an embedded local TradingCore + FixServer (from client_admin).
**ExchangePanel**	ImGui panel for monitoring and controlling the local exchange (from client_admin).

Critical Design Conventions

• Composition Root: App is the only class that wires dependencies together. Panels receive references, not owned pointers.
• Two-Thread Model: The main thread runs the ImGui render loop; a dedicated background thread runs io_context::run() for all async networking.
• Work Guard: asio::make_work_guard keeps the network thread alive even when no async operations are pending.
• Shutdown Order: Stop work guard → stop io_context → join network thread → destroy UI context.