| | | 1 | | using System.Text.RegularExpressions; |
| | | 2 | | using MySqlConnector; |
| | | 3 | | |
| | | 4 | | namespace Services.DataServices.TriggerSelfHealing; |
| | | 5 | | |
| | | 6 | | /// <summary> |
| | | 7 | | /// Пересоздаёт триггеры таблицы через <c>CREATE OR REPLACE TRIGGER</c> из тела, которое хранит сам |
| | | 8 | | /// сервер (information_schema.TRIGGERS). Атомарно, без окна «без триггера», не требует RELOAD |
| | | 9 | | /// (в отличие от FLUSH TABLES) — достаточно привилегии TRIGGER, которая у пользователя приложения есть. |
| | | 10 | | /// </summary> |
| | 0 | 11 | | public sealed class MySqlTriggerReloader(string connectionString) : ITriggerReloader |
| | | 12 | | { |
| | 0 | 13 | | private static readonly Regex SafeIdentifier = new("^[A-Za-z0-9_]+$", RegexOptions.Compiled); |
| | | 14 | | |
| | | 15 | | public async Task<int> ReloadAsync(string table, CancellationToken cancellationToken) |
| | | 16 | | { |
| | 0 | 17 | | if (!SafeIdentifier.IsMatch(table)) |
| | 0 | 18 | | throw new ArgumentException($"Недопустимое имя таблицы: {table}", nameof(table)); |
| | | 19 | | |
| | 0 | 20 | | await using var connection = new MySqlConnection(connectionString); |
| | 0 | 21 | | await connection.OpenAsync(cancellationToken); |
| | | 22 | | |
| | 0 | 23 | | var triggers = new List<(string Name, string Timing, string Event, string Body)>(); |
| | 0 | 24 | | await using (var select = connection.CreateCommand()) |
| | | 25 | | { |
| | 0 | 26 | | select.CommandText = """ |
| | 0 | 27 | | SELECT TRIGGER_NAME, ACTION_TIMING, EVENT_MANIPULATION, ACTION_STATEMENT |
| | 0 | 28 | | FROM information_schema.TRIGGERS |
| | 0 | 29 | | WHERE TRIGGER_SCHEMA = DATABASE() AND EVENT_OBJECT_TABLE = @table |
| | 0 | 30 | | ORDER BY ACTION_TIMING, EVENT_MANIPULATION, ACTION_ORDER |
| | 0 | 31 | | """; |
| | 0 | 32 | | select.Parameters.AddWithValue("@table", table); |
| | 0 | 33 | | await using var reader = await select.ExecuteReaderAsync(cancellationToken); |
| | 0 | 34 | | while (await reader.ReadAsync(cancellationToken)) |
| | 0 | 35 | | triggers.Add((reader.GetString(0), reader.GetString(1), reader.GetString(2), reader.GetString(3))); |
| | 0 | 36 | | } |
| | | 37 | | |
| | 0 | 38 | | if (triggers.Count == 0) |
| | 0 | 39 | | return 0; |
| | | 40 | | |
| | | 41 | | // DDL берёт эксклюзивный MDL на таблицу: не встаём в очередь надолго, если таблица занята. |
| | 0 | 42 | | await using (var timeout = connection.CreateCommand()) |
| | | 43 | | { |
| | 0 | 44 | | timeout.CommandText = "SET SESSION lock_wait_timeout = 10"; |
| | 0 | 45 | | await timeout.ExecuteNonQueryAsync(cancellationToken); |
| | | 46 | | } |
| | | 47 | | |
| | 0 | 48 | | foreach (var (name, timing, @event, body) in triggers) |
| | | 49 | | { |
| | 0 | 50 | | if (!SafeIdentifier.IsMatch(name)) |
| | | 51 | | continue; |
| | | 52 | | |
| | 0 | 53 | | await using var ddl = connection.CreateCommand(); |
| | 0 | 54 | | ddl.CommandText = $"CREATE OR REPLACE TRIGGER `{name}` {timing} {@event} ON `{table}` FOR EACH ROW {body}"; |
| | 0 | 55 | | ddl.CommandTimeout = 30; |
| | 0 | 56 | | await ddl.ExecuteNonQueryAsync(cancellationToken); |
| | 0 | 57 | | } |
| | | 58 | | |
| | 0 | 59 | | return triggers.Count; |
| | 0 | 60 | | } |
| | | 61 | | } |