Better server manager

pkg/server/interfaces.go

@@ -3,6 +3,7 @@ package server
 import (
 	"context"
 	"net/http"
+	"time"
 )
 
 // Config holds the configuration for a single web server instance.
@@ -11,11 +12,52 @@ type Config struct {
 	Host        string
 	Port        int
 	Description string
-	SSLCert     string
-	SSLKey      string
-	GZIP        bool
+
 	// Handler is the http.Handler (e.g., a router) to be served.
 	Handler http.Handler
+
+	// GZIP compression support
+	GZIP bool
+
+	// TLS/HTTPS configuration options (mutually exclusive)
+	// Option 1: Provide certificate and key files directly
+	SSLCert string
+	SSLKey  string
+
+	// Option 2: Use self-signed certificate (for development/testing)
+	// Generates a self-signed certificate automatically if no SSLCert/SSLKey provided
+	SelfSignedSSL bool
+
+	// Option 3: Use Let's Encrypt / Certbot for automatic TLS
+	// AutoTLS enables automatic certificate management via Let's Encrypt
+	AutoTLS bool
+	// AutoTLSDomains specifies the domains for Let's Encrypt certificates
+	AutoTLSDomains []string
+	// AutoTLSCacheDir specifies where to cache certificates (default: "./certs-cache")
+	AutoTLSCacheDir string
+	// AutoTLSEmail is the email for Let's Encrypt registration (optional but recommended)
+	AutoTLSEmail string
+
+	// Graceful shutdown configuration
+	// ShutdownTimeout is the maximum time to wait for graceful shutdown
+	// Default: 30 seconds
+	ShutdownTimeout time.Duration
+
+	// DrainTimeout is the time to wait for in-flight requests to complete
+	// before forcing shutdown. Default: 25 seconds
+	DrainTimeout time.Duration
+
+	// ReadTimeout is the maximum duration for reading the entire request
+	// Default: 15 seconds
+	ReadTimeout time.Duration
+
+	// WriteTimeout is the maximum duration before timing out writes of the response
+	// Default: 15 seconds
+	WriteTimeout time.Duration
+
+	// IdleTimeout is the maximum amount of time to wait for the next request
+	// Default: 60 seconds
+	IdleTimeout time.Duration
 }
 
 // Instance defines the interface for a single server instance.
@@ -24,11 +66,33 @@ type Instance interface {
 	// Start begins serving requests. This method should be non-blocking and
 	// run the server in a separate goroutine.
 	Start() error
+
 	// Stop gracefully shuts down the server without interrupting any active connections.
 	// It accepts a context to allow for a timeout.
 	Stop(ctx context.Context) error
+
 	// Addr returns the network address the server is listening on.
 	Addr() string
+
+	// Name returns the server instance name.
+	Name() string
+
+	// HealthCheckHandler returns a handler that responds to health checks.
+	// Returns 200 OK when healthy, 503 Service Unavailable when shutting down.
+	HealthCheckHandler() http.HandlerFunc
+
+	// ReadinessHandler returns a handler for readiness checks.
+	// Includes in-flight request count.
+	ReadinessHandler() http.HandlerFunc
+
+	// InFlightRequests returns the current number of in-flight requests.
+	InFlightRequests() int64
+
+	// IsShuttingDown returns true if the server is shutting down.
+	IsShuttingDown() bool
+
+	// Wait blocks until shutdown is complete.
+	Wait()
 }
 
 // Manager defines the interface for a server manager.
@@ -37,16 +101,37 @@ type Manager interface {
 	// Add registers a new server instance based on the provided configuration.
 	// The server is not started until StartAll or Start is called on the instance.
 	Add(cfg Config) (Instance, error)
+
 	// Get returns a server instance by its name.
 	Get(name string) (Instance, error)
+
 	// Remove stops and removes a server instance by its name.
 	Remove(name string) error
+
 	// StartAll starts all registered server instances that are not already running.
 	StartAll() error
+
 	// StopAll gracefully shuts down all running server instances.
+	// Executes shutdown callbacks and drains in-flight requests.
 	StopAll() error
+
+	// StopAllWithContext gracefully shuts down all running server instances with a context.
+	StopAllWithContext(ctx context.Context) error
+
 	// RestartAll gracefully restarts all running server instances.
 	RestartAll() error
+
 	// List returns all registered server instances.
 	List() []Instance
+
+	// ServeWithGracefulShutdown starts all servers and blocks until a shutdown signal is received.
+	// It handles SIGINT and SIGTERM signals and performs graceful shutdown with callbacks.
+	ServeWithGracefulShutdown() error
+
+	// RegisterShutdownCallback registers a callback to be called during shutdown.
+	// Useful for cleanup tasks like closing database connections, flushing metrics, etc.
+	RegisterShutdownCallback(cb ShutdownCallback)
 }
+
+// ShutdownCallback is a function called during graceful shutdown.
+type ShutdownCallback func(context.Context) error