Implement SQLite database persistence for instance management

pkg/database/migrations.go

@@ -0,0 +1,78 @@
+package database
+
+import (
+	"embed"
+	"fmt"
+	"log"
+
+	"github.com/golang-migrate/migrate/v4"
+	"github.com/golang-migrate/migrate/v4/database/sqlite3"
+	"github.com/golang-migrate/migrate/v4/source/iofs"
+)
+
+//go:embed migrations/*.sql
+var migrationFiles embed.FS
+
+// RunMigrations applies all pending database migrations
+func RunMigrations(db *DB) error {
+	if db == nil || db.DB == nil {
+		return fmt.Errorf("database connection is nil")
+	}
+
+	// Create migration source from embedded files
+	sourceDriver, err := iofs.New(migrationFiles, "migrations")
+	if err != nil {
+		return fmt.Errorf("failed to create migration source: %w", err)
+	}
+
+	// Create database driver for migrations
+	dbDriver, err := sqlite3.WithInstance(db.DB, &sqlite3.Config{})
+	if err != nil {
+		return fmt.Errorf("failed to create database driver: %w", err)
+	}
+
+	// Create migrator
+	migrator, err := migrate.NewWithInstance("iofs", sourceDriver, "sqlite3", dbDriver)
+	if err != nil {
+		return fmt.Errorf("failed to create migrator: %w", err)
+	}
+
+	// Get current version
+	currentVersion, dirty, err := migrator.Version()
+	if err != nil && err != migrate.ErrNilVersion {
+		return fmt.Errorf("failed to get current migration version: %w", err)
+	}
+
+	if dirty {
+		return fmt.Errorf("database is in dirty state at version %d - manual intervention required", currentVersion)
+	}
+
+	// Run migrations
+	log.Printf("Running database migrations (current version: %v)", currentVersionString(currentVersion, err))
+
+	if err := migrator.Up(); err != nil {
+		if err == migrate.ErrNoChange {
+			log.Println("Database schema is up to date")
+			return nil
+		}
+		return fmt.Errorf("failed to run migrations: %w", err)
+	}
+
+	// Get new version
+	newVersion, _, err := migrator.Version()
+	if err != nil {
+		log.Printf("Migrations completed (unable to determine new version: %v)", err)
+	} else {
+		log.Printf("Migrations completed successfully (new version: %d)", newVersion)
+	}
+
+	return nil
+}
+
+// currentVersionString returns a string representation of the current version
+func currentVersionString(version uint, err error) string {
+	if err == migrate.ErrNilVersion {
+		return "none"
+	}
+	return fmt.Sprintf("%d", version)
+}