Application Bootstrap

Bootstrapping Pipeline

Every Lemmego application starts with a builder pattern in cmd/app/main.go:

func main() {
    webApp := app.Configure()

    webApp.
        WithRoutes(bootstrap.LoadRoutes()).
        WithHTTPMiddlewares(bootstrap.LoadHTTPMiddlewares()).
        WithMiddlewares(bootstrap.LoadMiddlewares()).
        WithCommands(bootstrap.LoadCommands()).
        WithProviders(bootstrap.LoadProviders()).
        WithErrMap(bootstrap.LoadErrMap()).
    Run()
}

The app.Configure() function creates a new AppEngine instance using functional options:

app.Configure(
    app.WithConfig(config.M{...}),
    app.WithRoutes([]RouteCallback{...}),
    app.WithProviders([]Provider{...}),
)

Boot Order

When Run() is called, the framework initializes in this order:

Configuration — Config map is set up from internal/configs/
Commands — CLI commands are registered
Events — Middleware, routes, commands, and services events fire
HTTP Middleware — Global net/http middleware wraps the router
Providers — All service providers run their Provide() methods
App Middleware — Application-level middleware is registered
Routes — Route callbacks register all endpoints
ErrMap — Error-to-handler mappings are applied
Server Start — The HTTP server begins listening (or CLI executes)

Run Modes

The application detects whether it’s running as a web server or CLI command:

// Returns true if command-line arguments were provided
a.RunningInConsole()

// Check the environment
a.InProduction()
a.Env("development")

If CLI arguments are provided, Run() executes the matching command instead of starting the web server.

Lifecycle Events

The framework fires events at each stage of bootstrapping:

app.ServerStarted            // Fired when the HTTP server starts
app.MiddlewareRegistering    // Before middleware is registered
app.MiddlewareRegistered     // After middleware is registered
app.RoutesRegistering        // Before routes are registered
app.RoutesRegistered         // After routes are registered
app.CommandsRegistering      // Before commands are registered
app.CommandsRegistered       // After commands are registered
app.ServicesRegistering      // Before services are registered
app.ServicesRegistered       // After services are registered

Listen to these events to hook into the application lifecycle (see Event System).

Core Concepts Service Container