feat: add sqlite database for storing sessions (#326)

* feat: add sqlite database for storing sessions

* refactor: use db instance instead of service in auth service

* fix: coderabbit suggestions

internal/service/database_service.go

@@ -0,0 +1,78 @@
+package service
+
+import (
+	"database/sql"
+	"tinyauth/internal/assets"
+
+	"github.com/glebarez/sqlite"
+	"github.com/golang-migrate/migrate/v4"
+	sqliteMigrate "github.com/golang-migrate/migrate/v4/database/sqlite3"
+	"github.com/golang-migrate/migrate/v4/source/iofs"
+	"gorm.io/gorm"
+)
+
+type DatabaseServiceConfig struct {
+	DatabasePath string
+}
+
+type DatabaseService struct {
+	Config   DatabaseServiceConfig
+	Database *gorm.DB
+}
+
+func NewDatabaseService(config DatabaseServiceConfig) *DatabaseService {
+	return &DatabaseService{
+		Config: config,
+	}
+}
+
+func (ds *DatabaseService) Init() error {
+	gormDB, err := gorm.Open(sqlite.Open(ds.Config.DatabasePath), &gorm.Config{})
+
+	if err != nil {
+		return err
+	}
+
+	sqlDB, err := gormDB.DB()
+
+	if err != nil {
+		return err
+	}
+
+	sqlDB.SetMaxOpenConns(1)
+
+	err = ds.migrateDatabase(sqlDB)
+
+	if err != nil && err != migrate.ErrNoChange {
+		return err
+	}
+
+	ds.Database = gormDB
+	return nil
+}
+
+func (ds *DatabaseService) migrateDatabase(sqlDB *sql.DB) error {
+	data, err := iofs.New(assets.Migrations, "migrations")
+
+	if err != nil {
+		return err
+	}
+
+	target, err := sqliteMigrate.WithInstance(sqlDB, &sqliteMigrate.Config{})
+
+	if err != nil {
+		return err
+	}
+
+	migrator, err := migrate.NewWithInstance("iofs", data, "tinyauth", target)
+
+	if err != nil {
+		return err
+	}
+
+	return migrator.Up()
+}
+
+func (ds *DatabaseService) GetDatabase() *gorm.DB {
+	return ds.Database
+}