Refactor database interface to use *sql.DB directly

Simplified the database layer by removing custom interface wrappers
and using standard library *sql.DB and *sql.Tx types directly.

Changes:
- Removed DBConnection and DBTransaction interfaces from database.go
- Removed NewDBConnection() wrapper function
- Updated TokenGenerator to use *sql.DB instead of DBConnection
- Updated all validation and revocation methods to accept *sql.Tx
- Updated TableManager to work with *sql.DB directly
- Updated all tests to use db.Begin() instead of custom wrappers
- Fixed GeneratorConfig.DB field (was DBConn)
- Updated documentation in doc.go with correct API usage

Benefits:
- Simpler API with fewer abstractions
- Works directly with database/sql standard library
- Compatible with GORM (via gormDB.DB()) and Bun (share same *sql.DB)
- Easier to understand and maintain
- No unnecessary wrapper layers

Breaking changes:
- GeneratorConfig.DBConn renamed to GeneratorConfig.DB
- Removed NewDBConnection() function - pass *sql.DB directly
- ValidateAccess/ValidateRefresh now accept *sql.Tx instead of DBTransaction
- Token.Revoke/CheckNotRevoked now accept *sql.Tx instead of DBTransaction

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

hws/server.go

@@ -3,48 +3,98 @@ package hws
 import (
 	"context"
 	"fmt"
-	"net"
 	"net/http"
+	"sync"
 	"time"
 
+	"k8s.io/apimachinery/pkg/util/validation"
+
 	"github.com/pkg/errors"
 )
 
 type Server struct {
+	GZIP       bool
 	server     *http.Server
 	logger     *logger
 	routes     bool
 	middleware bool
-	gzip       bool
-	errorPage  ErrorPage
+	errorPage  ErrorPageFunc
+	ready      chan struct{}
 }
 
-// NewServer returns a new hws.Server with the specified parameters.
-// The timeout options are specified in seconds
-func NewServer(
-	host string,
-	port string,
-	readHeaderTimeout time.Duration,
-	writeTimeout time.Duration,
-	idleTimeout time.Duration,
-	gzip bool,
-) (*Server, error) {
-	// TODO: test that host and port are valid values
-	httpServer := &http.Server{
-		Addr:              net.JoinHostPort(host, port),
-		ReadHeaderTimeout: readHeaderTimeout * time.Second,
-		WriteTimeout:      writeTimeout * time.Second,
-		IdleTimeout:       idleTimeout * time.Second,
+// Ready returns a channel that is closed when the server is started
+func (server *Server) Ready() <-chan struct{} {
+	return server.ready
+}
+
+// IsReady checks if the server is running
+func (server *Server) IsReady() bool {
+	select {
+	case <-server.ready:
+		return true
+	default:
+		return false
 	}
+}
+
+// Addr returns the server's network address
+func (server *Server) Addr() string {
+	return server.server.Addr
+}
+
+// Handler returns the server's HTTP handler for testing purposes
+func (server *Server) Handler() http.Handler {
+	return server.server.Handler
+}
+
+// NewServer returns a new hws.Server with the specified configuration.
+func NewServer(config *Config) (*Server, error) {
+	if config == nil {
+		return nil, errors.New("Config cannot be nil")
+	}
+
+	// Apply defaults for undefined fields
+	if config.Host == "" {
+		config.Host = "127.0.0.1"
+	}
+	if config.Port == 0 {
+		config.Port = 3000
+	}
+	if config.ReadHeaderTimeout == 0 {
+		config.ReadHeaderTimeout = 2 * time.Second
+	}
+	if config.WriteTimeout == 0 {
+		config.WriteTimeout = 10 * time.Second
+	}
+	if config.IdleTimeout == 0 {
+		config.IdleTimeout = 120 * time.Second
+	}
+
+	valid := isValidHostname(config.Host)
+	if !valid {
+		return nil, fmt.Errorf("Hostname '%s' is not valid", config.Host)
+	}
+
+	httpServer := &http.Server{
+		Addr:              fmt.Sprintf("%s:%v", config.Host, config.Port),
+		ReadHeaderTimeout: config.ReadHeaderTimeout,
+		WriteTimeout:      config.WriteTimeout,
+		IdleTimeout:       config.IdleTimeout,
+	}
+
 	server := &Server{
 		server: httpServer,
 		routes: false,
-		gzip:   gzip,
+		GZIP:   config.GZIP,
+		ready:  make(chan struct{}),
 	}
 	return server, nil
 }
 
-func (server *Server) Start() error {
+func (server *Server) Start(ctx context.Context) error {
+	if ctx == nil {
+		return errors.New("Context cannot be nil")
+	}
 	if !server.routes {
 		return errors.New("Server.AddRoutes must be run before starting the server")
 	}
@@ -65,20 +115,67 @@ func (server *Server) Start() error {
 			if server.logger == nil {
 				fmt.Printf("Server encountered a fatal error: %s", err.Error())
 			} else {
-				server.logger.logger.Error().Err(err).Msg("Server encountered a fatal error")
+				server.LogError(HWSError{Error: err, Message: "Server encountered a fatal error"})
 			}
 		}
 	}()
 
+	server.waitUntilReady(ctx)
+
 	return nil
 }
 
-func (server *Server) Shutdown(ctx context.Context) {
-	if err := server.server.Shutdown(ctx); err != nil {
-		if server.logger == nil {
-			fmt.Printf("Failed to gracefully shutdown the server: %s", err.Error())
-		} else {
-			server.logger.logger.Error().Err(err).Msg("Failed to gracefully shutdown the server")
+func (server *Server) Shutdown(ctx context.Context) error {
+	if !server.IsReady() {
+		return errors.New("Server isn't running")
+	}
+	if ctx == nil {
+		return errors.New("Context cannot be nil")
+	}
+	err := server.server.Shutdown(ctx)
+	if err != nil {
+		return errors.Wrap(err, "Failed to shutdown the server gracefully")
+	}
+	server.ready = make(chan struct{})
+	return nil
+}
+
+func isValidHostname(host string) bool {
+	// Validate as IP or hostname
+	if errs := validation.IsDNS1123Subdomain(host); len(errs) == 0 {
+		return true
+	}
+
+	// Check IPv4 / IPv6
+	if errs := validation.IsValidIP(nil, host); len(errs) == 0 {
+		return true
+	}
+
+	return false
+}
+
+func (server *Server) waitUntilReady(ctx context.Context) error {
+	ticker := time.NewTicker(50 * time.Millisecond)
+	defer ticker.Stop()
+
+	closeOnce := sync.Once{}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+
+		case <-ticker.C:
+			resp, err := http.Get("http://" + server.server.Addr + "/healthz")
+			if err != nil {
+				continue // not accepting yet
+			}
+			resp.Body.Close()
+
+			if resp.StatusCode == http.StatusOK {
+				closeOnce.Do(func() { close(server.ready) })
+				return nil
+			}
 		}
 	}
 }