PrimeLoader System Architecture

Multi-Tenant Hydrology Sensor SaaS Platform

Delphi Spring4D XData OAuth2 Linux Daemon

Overview

PrimeLoader is a Linux daemon-based multi-tenant application server built with Delphi. It manages multiple tenant databases, dynamic plugin loading, and OAuth2 authentication.

Key Patterns:

Dependency Injection — Spring4D container for IoC
Multi-Tenancy — Separate database per tenant with connection pooling
Plugin Architecture — Dynamic .so library loading at runtime
Factory Pattern — Tenant and Plugin factories
Thread-Safe Pooling — Critical sections protecting shared resources

Class Diagram

%%{init: {'theme': 'dark'}}%%
classDiagram
    direction TB
    class PrimeLoader_Apache {
        -SID: Integer
        -ControllerModule: TMainServer
        +RunDaemon()
        +Daemonize()
        +StartServer()
    }
    class IServer {
        +HttpServer
        +TenantFactory
        +PluginFactory
        +CreateServer()
        +StartServer()
    }
    class TServer {
        -FHTTPServer
        -FTenantFactory
        +CreateServer()
    }
    class TMainServer {
        +AdminServer: TXDataServer
        +InitialiseServer()
        +LoadPlugins()
    }
    class TTenantPoolManager {
        -FPools: TDictionary
        -FLock: TCriticalSection
        +GetPool()
        +Shutdown()
    }
    class TTenantConnectionPool {
        -FPool: TList
        -FInUse: TList
        +Acquire()
        +Release()
    }
    class IPluginFactory {
        +ManagePluginLibraries()
        +FindPlugin()
    }
    PrimeLoader_Apache --> IServer
    PrimeLoader_Apache --> TMainServer
    IServer <|.. TServer
    TServer --> TTenantPoolManager
    TMainServer --> TTenantPoolManager
    TTenantPoolManager o-- TTenantConnectionPool
    TServer --> IPluginFactory

Startup Sequence

%%{init: {'theme': 'dark'}}%%
sequenceDiagram
    participant OS as Linux
    participant D as PrimeLoader
    participant IC as DI Container
    participant S as IServer
    participant MS as TMainServer
    participant TPM as PoolManager

    OS->>D: Start
    D->>D: Daemonize()
    D->>IC: Register interfaces
    D->>IC: Resolve IServer
    IC-->>S: TServer
    D->>MS: Create TMainServer
    MS->>MS: LoadConfigs()
    D->>S: CreateServer()
    D->>MS: InitialiseServer()
    MS->>TPM: Initialize pools
    MS->>MS: LoadPlugins()
    D->>S: StartServer()

HTTP Request Flow

%%{init: {'theme': 'dark'}}%%
sequenceDiagram
    participant C as Client
    participant H as HTTP Server
    participant JWT as JWT Middleware
    participant TPM as PoolManager
    participant Pool as ConnectionPool
    participant Svc as Service

    C->>H: Request
    H->>JWT: Validate Token
    JWT->>TPM: GetPool(tenant)
    TPM-->>JWT: Pool
    JWT->>Pool: Acquire()
    Pool-->>JWT: Connection
    JWT->>Svc: Execute
    Svc-->>JWT: Response
    JWT->>Pool: Release()
    JWT-->>C: Response

Component Reference

Core

PrimeLoader_Apache

Main daemon entry point.

PRIMELOADER/PrimeLoader_Apache.dpr

TServer

HTTP server, factories, modules.

COMMON/SERVER/OBJECTS/Obj.Server.pas

TMainServer

Primary DataModule controller.

COMMON/DATAMODULES/BackOffice.Data.Main.pas

Multi-Tenancy

TTenantPoolManager

Singleton managing all pools.

COMMON/USERS/OBJECTS/Obj.Tenant.PoolManager.pas

TTenantConnectionPool

Per-tenant thread-safe pool.

COMMON/USERS/OBJECTS/Obj.Tenant.ConnectionPool.pas

TTenantFactory

Creates/manages tenants.

COMMON/FACTORIES/OBJECTS/Obj.Factory.Tenant.pas

Interface Summary

Interface	Implementation	Purpose
IServer	TServer	Application server
ITenant	TTenant	Tenant entity
ITenantFactory	TTenantFactory	Tenant creation
IPlugin	TPlugin	Plugin entity
IPluginFactory	TPluginFactory	Plugin management