114 lines
4.8 KiB
Go
114 lines
4.8 KiB
Go
package cli
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import (
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"context"
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"database/sql"
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"fmt"
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"io"
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"strings"
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"unicode/utf8"
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)
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func listMySQLEvents(ctx context.Context, tx *sql.Tx) ([]string, error) {
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if err := requireMySQLEventVisibility(ctx, tx); err != nil {
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return nil, err
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}
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rows, err := tx.QueryContext(ctx, "SELECT EVENT_NAME FROM information_schema.EVENTS WHERE EVENT_SCHEMA = DATABASE() ORDER BY EVENT_NAME")
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if err != nil {
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return nil, fmt.Errorf("读取 MySQL 事件列表失败：%w", err)
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}
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defer rows.Close()
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var names []string
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for rows.Next() {
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var name string
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if err := rows.Scan(&name); err != nil {
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return nil, err
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}
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names = append(names, name)
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}
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return names, rows.Err()
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}
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func dumpMySQLEvents(ctx context.Context, tx *sql.Tx, output io.Writer, names []string) error {
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if len(names) == 0 {
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return nil
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}
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var databaseCollation string
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if err := tx.QueryRowContext(ctx, "SELECT @@collation_database").Scan(&databaseCollation); err != nil {
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return err
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}
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if _, err := fmt.Fprintln(output, `SET @scert_event_sql_mode = @@SESSION.sql_mode;
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SET @scert_event_charset = @@SESSION.character_set_client;
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SET @scert_event_collation = @@SESSION.collation_connection;
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SET @scert_event_time_zone = @@SESSION.time_zone;`); err != nil {
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return err
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}
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for _, name := range names {
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var expired sql.NullBool
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var status, completion string
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query := `SELECT CASE
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WHEN EXECUTE_AT IS NOT NULL THEN EXECUTE_AT <= CONVERT_TZ(UTC_TIMESTAMP(), '+00:00', TIME_ZONE)
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WHEN ENDS IS NOT NULL THEN ENDS <= CONVERT_TZ(UTC_TIMESTAMP(), '+00:00', TIME_ZONE)
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ELSE FALSE END, STATUS, ON_COMPLETION
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FROM information_schema.EVENTS WHERE EVENT_SCHEMA = DATABASE() AND EVENT_NAME = ?`
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if err := tx.QueryRowContext(ctx, query, name).Scan(&expired, &status, &completion); err != nil {
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return fmt.Errorf("读取 MySQL 事件到期状态失败：%w", err)
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}
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if !expired.Valid || (expired.Bool && (status == "ENABLED" || completion == "NOT PRESERVE")) {
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return fmt.Errorf("MySQL 事件已到期或时区不可验证，重新创建将改变状态或删除对象，拒绝生成不完整备份：%s", name)
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}
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definition, err := readMySQLStoredDefinition(ctx, tx, "EVENT", name, "Create Event")
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if err != nil {
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return err
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}
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zone, exists := definition["time_zone"]
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if !exists || zone == "" {
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return fmt.Errorf("MySQL 事件时区字段不完整：%s", name)
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}
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if err := normalizeMySQLEventMetadata(ctx, tx, name, definition); err != nil {
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return err
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}
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if _, err := fmt.Fprintf(output, "SET SESSION time_zone = %s;\n", mysqlStringLiteral(zone)); err != nil {
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return err
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}
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drop := "DROP EVENT IF EXISTS " + quoteMySQLIdentifier(name)
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if err := writeMySQLStoredDefinition(ctx, tx, output, definition, "Create Event", drop); err != nil {
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return fmt.Errorf("写入 MySQL 事件失败（%s）：%w", name, err)
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}
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}
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_, err := fmt.Fprintf(output, "ALTER DATABASE COLLATE %s;\nSET SESSION sql_mode = @scert_event_sql_mode;\nSET SESSION character_set_client = @scert_event_charset;\nSET SESSION collation_connection = @scert_event_collation;\nSET SESSION time_zone = @scert_event_time_zone;\n\n", quoteMySQLIdentifier(databaseCollation))
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return err
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}
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// 两个版本的事件声明头均来自 UTF-8 目录，正文仍使用原客户端编码。
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// 先与目录正文比对边界，再单独反解声明头；失败不写回部分转换结果。
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func normalizeMySQLEventMetadata(ctx context.Context, tx *sql.Tx, name string, definition map[string]string) error {
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charset := definition["character_set_client"]
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if charset == "utf8" || charset == "utf8mb3" || charset == "utf8mb4" {
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return nil
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}
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var body string
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if err := tx.QueryRowContext(ctx, "SELECT EVENT_DEFINITION FROM information_schema.EVENTS WHERE EVENT_SCHEMA = DATABASE() AND EVENT_NAME = ?", name).Scan(&body); err != nil {
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return fmt.Errorf("读取 MySQL 事件编码元数据失败：%w", err)
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}
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original := definition["Create Event"]
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if body == "" || !strings.HasSuffix(original, body) {
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return fmt.Errorf("MySQL 事件正文与目录元数据不一致，拒绝猜测编码：%s", name)
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}
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header := original[:len(original)-len(body)]
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if !strings.HasSuffix(header, " DO ") {
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return fmt.Errorf("MySQL 事件声明头不完整：%s", name)
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}
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identifier := quoteMySQLIdentifier(charset)
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var encoded, roundTrip []byte
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query := "SELECT CAST(CONVERT(? USING " + identifier + ") AS BINARY), CAST(CONVERT(CONVERT(? USING " + identifier + ") USING utf8mb4) AS BINARY)"
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if err := tx.QueryRowContext(ctx, query, header, header).Scan(&encoded, &roundTrip); err != nil {
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return fmt.Errorf("MySQL 事件目录元数据无法无损还原为 UTF-8（%s）：%w", name, err)
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}
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if string(roundTrip) != header || !utf8.Valid(encoded) {
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return fmt.Errorf("MySQL 事件目录元数据无法无损还原为 UTF-8：%s", name)
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}
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definition["Create Event"] = string(encoded) + body
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return nil
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}
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