add support for integrated database schema migrations

added the "initprovider" command to initialize the database structure.
If we change the database schema the required changes will be checked
at startup and automatically applyed.

dataprovider/mysql.go

@@ -3,11 +3,24 @@ package dataprovider
 import (
 	"database/sql"
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/drakkan/sftpgo/logger"
 )
 
+const (
+	mysqlUsersTableSQL = "CREATE TABLE `{{users}}` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, " +
+		"`username` varchar(255) NOT NULL UNIQUE, `password` varchar(255) NULL, `public_keys` longtext NULL, " +
+		"`home_dir` varchar(255) NOT NULL, `uid` integer NOT NULL, `gid` integer NOT NULL, `max_sessions` integer NOT NULL, " +
+		" `quota_size` bigint NOT NULL, `quota_files` integer NOT NULL, `permissions` longtext NOT NULL, " +
+		"`used_quota_size` bigint NOT NULL, `used_quota_files` integer NOT NULL, `last_quota_update` bigint NOT NULL, " +
+		"`upload_bandwidth` integer NOT NULL, `download_bandwidth` integer NOT NULL, `expiration_date` bigint(20) NOT NULL, " +
+		"`last_login` bigint(20) NOT NULL, `status` int(11) NOT NULL, `filters` longtext DEFAULT NULL, " +
+		"`filesystem` longtext DEFAULT NULL);"
+	mysqlSchemaTableSQL = "CREATE TABLE `schema_version` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `version` integer NOT NULL);"
+)
+
 // MySQLProvider auth provider for MySQL/MariaDB database
 type MySQLProvider struct {
 	dbHandle *sql.DB
@@ -103,3 +116,32 @@ func (p MySQLProvider) close() error {
 func (p MySQLProvider) reloadConfig() error {
 	return nil
 }
+
+// initializeDatabase creates the initial database structure
+func (p MySQLProvider) initializeDatabase() error {
+	sqlUsers := strings.Replace(mysqlUsersTableSQL, "{{users}}", config.UsersTable, 1)
+	tx, err := p.dbHandle.Begin()
+	if err != nil {
+		return err
+	}
+	_, err = tx.Exec(sqlUsers)
+	if err != nil {
+		tx.Rollback()
+		return err
+	}
+	_, err = tx.Exec(mysqlSchemaTableSQL)
+	if err != nil {
+		tx.Rollback()
+		return err
+	}
+	_, err = tx.Exec(initialDBVersionSQL)
+	if err != nil {
+		tx.Rollback()
+		return err
+	}
+	return tx.Commit()
+}
+
+func (p MySQLProvider) migrateDatabase() error {
+	return sqlCommonMigrateDatabase(p.dbHandle)
+}