Scert/backend/internal/cli/mysql_backup.go
xuans c4051c9166 保存MySQL例程备份整改检查点(验证未完成)
保留存储过程与函数导出、权限检查、编码处理、共享存储对象逻辑及正式测试,同步两份任务进度文档。

已知阻塞:已有MySQL 5.7实库记录中,两种恢复入口均存在Latin-1例程注释乱码;已有8.0编码与权限专项通过,但不能代替最终双版本全量复测。本次仅重新运行例程单元测试及相关包静态检查,均通过。

这是未完成整改的保存检查点,不是发布版本,不表示P0-05完成或生产验收通过。未纳入运行数据、构建产物、原始实库日志或凭据。
2026-09-27 22:16:23 +08:00

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package cli
import (
"context"
"database/sql"
"encoding/hex"
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
"time"
"git.pcux.cn/xuans/Scert/backend/internal/config"
"git.pcux.cn/xuans/Scert/backend/internal/database"
)
// backupMySQL 将 MySQL 的基础表、数据、例程和触发器导出为可在 MySQL 5.7/8.0 导入的 SQL 文件。
func backupMySQL(ctx context.Context, cfg config.Config, output string) error {
resolved, err := resolveMaintenanceDatabase(ctx, cfg.Database, cfg.Paths.Config)
if err != nil {
return err
}
return backupMySQLDatabase(ctx, resolved, output)
}
func backupMySQLDatabase(ctx context.Context, cfg config.DatabaseConfig, output string) error {
db, err := database.Open(ctx, cfg)
if err != nil {
return fmt.Errorf("打开 MySQL 备份连接失败:%w", err)
}
defer db.Close()
temporaryPath := output + ".tmp"
file, err := os.OpenFile(temporaryPath, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0o600)
if err != nil {
return fmt.Errorf("创建 MySQL 备份文件失败:%w", err)
}
removeTemporary := true
defer func() {
_ = file.Close()
if removeTemporary {
_ = os.Remove(temporaryPath)
}
}()
// 所有表的数据必须来自同一个可重复读事务,不能按表从连接池独立读取。
// 元数据变更不属于 MVCC 快照,运维期间仍需禁止外部并发 DDL。
tx, err := db.DB.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelRepeatableRead, ReadOnly: true})
if err != nil {
return fmt.Errorf("创建 MySQL 一致性备份事务失败:%w", err)
}
defer tx.Rollback()
// 客户端取消会关闭连接,但服务端等待元数据锁时未必立即感知断开。
// 仅限制本次备份会话的单次锁等待;不限制总导出时间,也不修改全局配置。
if _, err := tx.ExecContext(ctx, "SET SESSION lock_wait_timeout = 5"); err != nil {
return fmt.Errorf("设置 MySQL 备份元数据锁等待上限失败:%w", err)
}
if _, err := fmt.Fprintf(file, "-- Scert MySQL 数据备份\n-- 生成时间:%s\n\nSET FOREIGN_KEY_CHECKS=0;\n\n", time.Now().UTC().Format(time.RFC3339)); err != nil {
return fmt.Errorf("写入 MySQL 备份头失败:%w", err)
}
rows, err := tx.QueryContext(ctx, "SELECT TABLE_NAME, ENGINE, TABLE_TYPE FROM information_schema.TABLES WHERE TABLE_SCHEMA = DATABASE() ORDER BY TABLE_NAME")
if err != nil {
return fmt.Errorf("读取 MySQL 表列表失败:%w", err)
}
var tableNames []string
for rows.Next() {
var tableName, tableType string
var engine sql.NullString
if err := rows.Scan(&tableName, &engine, &tableType); err != nil {
_ = rows.Close()
return fmt.Errorf("读取 MySQL 表名失败:%w", err)
}
if tableType != "BASE TABLE" || !engine.Valid || !strings.EqualFold(engine.String, "InnoDB") {
_ = rows.Close()
return fmt.Errorf("MySQL 一致性备份当前仅支持 InnoDB 基础表,不能静默导出其他对象:%s", tableName)
}
tableNames = append(tableNames, tableName)
}
if err := rows.Err(); err != nil {
_ = rows.Close()
return fmt.Errorf("遍历 MySQL 表列表失败:%w", err)
}
if err := rows.Close(); err != nil {
return fmt.Errorf("关闭 MySQL 表列表失败:%w", err)
}
if err := requireMySQLTriggerVisibility(ctx, tx, tableNames); err != nil {
return err
}
routines, err := listMySQLRoutines(ctx, tx)
if err != nil {
return err
}
for _, tableName := range tableNames {
if err := dumpMySQLTable(ctx, tx, file, tableName); err != nil {
return err
}
}
// 例程先于依赖它的触发器创建;例程定义不执行其中的业务语句。
if err := dumpMySQLRoutines(ctx, tx, file, routines); err != nil {
return err
}
// 必须先恢复所有基础数据,再创建触发器,避免导入时重放业务副作用。
if err := dumpMySQLTriggers(ctx, tx, file); err != nil {
return err
}
if _, err := fmt.Fprint(file, "SET FOREIGN_KEY_CHECKS=1;\n"); err != nil {
return fmt.Errorf("写入 MySQL 备份尾失败:%w", err)
}
if err := tx.Commit(); err != nil {
return fmt.Errorf("结束 MySQL 一致性备份事务失败:%w", err)
}
if err := file.Sync(); err != nil {
return fmt.Errorf("同步 MySQL 备份文件失败:%w", err)
}
if err := file.Close(); err != nil {
return fmt.Errorf("关闭 MySQL 备份文件失败:%w", err)
}
if err := os.Chmod(temporaryPath, 0o600); err != nil {
return fmt.Errorf("设置 MySQL 备份文件权限失败:%w", err)
}
if err := ctx.Err(); err != nil {
return err
}
if err := os.Rename(temporaryPath, output); err != nil {
return fmt.Errorf("保存 MySQL 备份文件失败:%w", err)
}
removeTemporary = false
return nil
}
// createMySQLRestoreBackup 在恢复前保留目标数据库快照,供失败时回滚使用。
// 快照目录不会在恢复成功后自动删除,便于管理员在需要时继续排查或手动恢复。
func createMySQLRestoreBackup(ctx context.Context, cfg config.Config, connection config.DatabaseConfig) (string, error) {
backupRoot := filepath.Clean(strings.TrimSpace(cfg.Paths.Backup))
if backupRoot == "." || backupRoot == "" {
return "", fmt.Errorf("MySQL 恢复前备份目录不能为空")
}
if err := os.MkdirAll(backupRoot, 0o700); err != nil {
return "", fmt.Errorf("创建 MySQL 恢复前备份目录失败:%w", err)
}
info, err := os.Lstat(backupRoot)
if err != nil {
return "", fmt.Errorf("检查 MySQL 恢复前备份目录失败:%w", err)
}
if info.Mode()&os.ModeSymlink != 0 || !info.IsDir() {
return "", fmt.Errorf("MySQL 恢复前备份目录必须是普通目录")
}
if err := os.Chmod(backupRoot, 0o700); err != nil {
return "", fmt.Errorf("设置 MySQL 恢复前备份目录权限失败:%w", err)
}
rollbackDirectory, err := os.MkdirTemp(backupRoot, "scert-before-restore-")
if err != nil {
return "", fmt.Errorf("创建 MySQL 恢复快照目录失败:%w", err)
}
rollbackPath := filepath.Join(rollbackDirectory, "scert.sql")
if err := backupMySQLDatabase(ctx, connection, rollbackPath); err != nil {
return "", fmt.Errorf("创建 MySQL 恢复前快照失败:%w", err)
}
return rollbackPath, nil
}
func dumpMySQLTable(ctx context.Context, db *sql.Tx, output *os.File, tableName string) error {
quotedTable := quoteMySQLIdentifier(tableName)
var name, createSQL string
if err := db.QueryRowContext(ctx, "SHOW CREATE TABLE "+quotedTable).Scan(&name, &createSQL); err != nil {
return fmt.Errorf("读取 MySQL 表结构失败(%s):%w", tableName, err)
}
if _, err := fmt.Fprintf(output, "DROP TABLE IF EXISTS %s;\n%s;\n\n", quotedTable, createSQL); err != nil {
return fmt.Errorf("写入 MySQL 表结构失败(%s):%w", tableName, err)
}
columns, err := mysqlInsertableColumns(ctx, db, tableName)
if err != nil {
return err
}
// 显式投影可写列:SELECT * 会遗漏不可见列,并错误地包含生成列的计算结果。
projection := quoteMySQLColumns(columns)
if len(columns) == 0 {
// 只有生成列的表仍有行数,使用占位读取并导出空列 INSERT 保留每一行。
projection = "1"
}
rows, err := db.QueryContext(ctx, "SELECT "+projection+" FROM "+quotedTable)
if err != nil {
return fmt.Errorf("读取 MySQL 表数据失败(%s):%w", tableName, err)
}
defer rows.Close()
selectedColumns, err := rows.Columns()
if err != nil {
return fmt.Errorf("读取 MySQL 表字段失败(%s):%w", tableName, err)
}
columnTypes, err := rows.ColumnTypes()
if err != nil {
return fmt.Errorf("读取 MySQL 表字段类型失败(%s):%w", tableName, err)
}
for rows.Next() {
values := make([]any, len(selectedColumns))
pointers := make([]any, len(values))
for index := range values {
pointers[index] = &values[index]
}
if err := rows.Scan(pointers...); err != nil {
return fmt.Errorf("读取 MySQL 表行失败(%s):%w", tableName, err)
}
literals := make([]string, len(columns))
for index := range columns {
literals[index] = mysqlColumnSQLLiteral(values[index], columnTypes[index].DatabaseTypeName())
}
if _, err := fmt.Fprintf(output, "INSERT INTO %s (%s) VALUES (%s);\n", quotedTable, quoteMySQLColumns(columns), strings.Join(literals, ", ")); err != nil {
return fmt.Errorf("写入 MySQL 表数据失败(%s):%w", tableName, err)
}
}
if err := rows.Err(); err != nil {
return fmt.Errorf("遍历 MySQL 表数据失败(%s):%w", tableName, err)
}
_, err = fmt.Fprintln(output)
return err
}
func mysqlInsertableColumns(ctx context.Context, db *sql.Tx, tableName string) ([]string, error) {
rows, err := db.QueryContext(ctx, "SELECT COLUMN_NAME FROM information_schema.COLUMNS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = ? AND COALESCE(GENERATION_EXPRESSION, '') = '' ORDER BY ORDINAL_POSITION", tableName)
if err != nil {
return nil, fmt.Errorf("读取 MySQL 可写字段失败(%s):%w", tableName, err)
}
defer rows.Close()
var columns []string
for rows.Next() {
var name string
if err := rows.Scan(&name); err != nil {
return nil, fmt.Errorf("读取 MySQL 可写字段名失败(%s):%w", tableName, err)
}
columns = append(columns, name)
}
if err := rows.Err(); err != nil {
return nil, fmt.Errorf("遍历 MySQL 可写字段失败(%s):%w", tableName, err)
}
return columns, nil
}
func quoteMySQLIdentifier(value string) string {
return "`" + strings.ReplaceAll(value, "`", "``") + "`"
}
func quoteMySQLColumns(columns []string) string {
quoted := make([]string, len(columns))
for index, column := range columns {
quoted[index] = quoteMySQLIdentifier(column)
}
return strings.Join(quoted, ", ")
}
func mysqlColumnSQLLiteral(value any, columnType string) string {
// 驱动将 DECIMAL 返回为文本字节;十六进制字面量在数值列中会被当作整数。
// 使用文本字面量保留任意精度,不经浮点转换;真正的二进制列仍按原样导出。
if columnType == "DECIMAL" {
switch typed := value.(type) {
case sql.RawBytes:
return mysqlStringLiteral(string(typed))
case []byte:
return mysqlStringLiteral(string(typed))
}
}
return mysqlSQLLiteral(value)
}
func mysqlSQLLiteral(value any) string {
switch typed := value.(type) {
case nil:
return "NULL"
case sql.RawBytes:
return "X'" + hex.EncodeToString(typed) + "'"
case []byte:
return "X'" + hex.EncodeToString(typed) + "'"
case string:
return mysqlStringLiteral(typed)
case time.Time:
return "'" + typed.UTC().Format("2006-01-02 15:04:05.999999") + "'"
case bool:
if typed {
return "1"
}
return "0"
case int64:
return strconv.FormatInt(typed, 10)
case uint64:
return strconv.FormatUint(typed, 10)
case float64:
return strconv.FormatFloat(typed, 'g', -1, 64)
case float32:
return strconv.FormatFloat(float64(typed), 'g', -1, 32)
default:
return mysqlStringLiteral(fmt.Sprint(typed))
}
}
func mysqlStringLiteral(value string) string {
var builder strings.Builder
builder.Grow(len(value) + 2)
builder.WriteByte('\'')
for index := 0; index < len(value); index++ {
switch value[index] {
case '\\':
builder.WriteString(`\\`)
case '\x00':
builder.WriteString(`\0`)
case '\n':
builder.WriteString(`\n`)
case '\r':
builder.WriteString(`\r`)
case '\x1a':
builder.WriteString(`\Z`)
case '\'':
builder.WriteString(`''`)
default:
builder.WriteByte(value[index])
}
}
builder.WriteByte('\'')
return builder.String()
}
// restoreMySQL 执行 Scert 生成的 MySQL SQL 备份。
func restoreMySQL(ctx context.Context, cfg config.DatabaseConfig, input string) error {
script, err := os.ReadFile(input)
if err != nil {
return fmt.Errorf("读取 MySQL 备份文件失败:%w", err)
}
db, err := database.Open(ctx, cfg)
if err != nil {
return fmt.Errorf("打开 MySQL 恢复连接失败:%w", err)
}
defer db.Close()
// 会话变量与外键开关必须留在同一条连接上;失败后返回,不切换连接重放。
connection, err := db.DB.Conn(ctx)
if err != nil {
return fmt.Errorf("获取 MySQL 恢复会话失败:%w", err)
}
defer connection.Close()
statements, err := splitMySQLStatements(string(script))
if err != nil {
return err
}
for _, statement := range statements {
if _, err := connection.ExecContext(ctx, statement); err != nil {
return fmt.Errorf("执行 MySQL 恢复语句失败:%w", err)
}
}
return nil
}
func splitMySQLStatements(script string) ([]string, error) {
script = strings.TrimPrefix(script, "\uFEFF")
var statements []string
var statement strings.Builder
delimiter := ";"
var quote byte
lineComment := false
blockComment := false
executableComment := false
escaped := false
flush := func() {
value := strings.TrimSpace(statement.String())
if value != "" {
statements = append(statements, value)
}
statement.Reset()
}
for index := 0; index < len(script); index++ {
current := script[index]
if lineComment {
if current == '\n' {
lineComment = false
statement.WriteByte('\n')
}
continue
}
if blockComment {
if current == '*' && index+1 < len(script) && script[index+1] == '/' {
blockComment = false
index++
statement.WriteByte(' ')
}
continue
}
if executableComment {
statement.WriteByte(current)
if current == '*' && index+1 < len(script) && script[index+1] == '/' {
statement.WriteByte(script[index+1])
index++
executableComment = false
}
continue
}
if quote != 0 {
statement.WriteByte(current)
if escaped {
escaped = false
continue
}
if current == '\\' {
escaped = true
continue
}
if current == quote {
if index+1 < len(script) && script[index+1] == quote {
statement.WriteByte(script[index+1])
index++
continue
}
quote = 0
}
continue
}
if (index == 0 || script[index-1] == '\n') && strings.TrimSpace(statement.String()) == "" {
end := strings.IndexByte(script[index:], '\n')
if end < 0 {
end = len(script) - index
}
line := strings.TrimSpace(script[index : index+end])
if len(line) >= len("delimiter") && strings.EqualFold(line[:len("delimiter")], "delimiter") &&
(len(line) == len("delimiter") || line[len("delimiter")] == ' ' || line[len("delimiter")] == '\t') {
value := strings.TrimSpace(line[len("delimiter"):])
if len(value) >= 2 && (value[0] == '\'' || value[0] == '"') && value[len(value)-1] == value[0] {
value = value[1 : len(value)-1]
}
if value == "" || strings.ContainsAny(value, " \t\r\n") || strings.ContainsRune(value, '\\') || strings.ContainsRune(value, '\'') || strings.ContainsRune(value, '"') || strings.ContainsRune(value, '`') {
return nil, fmt.Errorf("MySQL 备份中的 DELIMITER 指令无效")
}
delimiter = value
statement.Reset()
index += end
continue
}
}
if strings.HasPrefix(script[index:], delimiter) {
flush()
index += len(delimiter) - 1
continue
}
if current == '\'' || current == '"' || current == '`' {
quote = current
statement.WriteByte(current)
continue
}
if current == '#' {
lineComment = true
continue
}
if current == '-' && index+2 < len(script) && script[index+1] == '-' && (script[index+2] == ' ' || script[index+2] == '\t' || script[index+2] == '\n') {
lineComment = true
index++
continue
}
if current == '/' && index+1 < len(script) && script[index+1] == '*' {
if index+2 < len(script) && (script[index+2] == '!' || script[index+2] == '+') {
statement.WriteByte(current)
statement.WriteByte(script[index+1])
index++
executableComment = true
continue
}
blockComment = true
index++
continue
}
statement.WriteByte(current)
}
if quote != 0 || blockComment || executableComment {
return nil, fmt.Errorf("MySQL 备份包含未闭合的字符串、标识符或注释")
}
flush()
return statements, nil
}