Merge pull request #6 from MikeAmputer/kravtsov/migration-fail-handling

Migration fail handling
MikeAmputer · Oct 24, 2023 · 63b1b9a · 63b1b9a
2 parents 3079d23 + b49d8ec
commit 63b1b9a
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Showing 4 changed files with 62 additions and 39 deletions.
diff --git a/src/ClickHouse.Facades/Migrations/ClickHouseMigrationFacade.cs b/src/ClickHouse.Facades/Migrations/ClickHouseMigrationFacade.cs
@@ -6,15 +6,28 @@ namespace ClickHouse.Facades.Migrations;
 internal sealed class ClickHouseMigrationFacade : ClickHouseFacade<ClickHouseMigrationContext>
 {
 	private const string MigrationsTable = "db_migrations_history";
-	internal string DbName { get; set; } = string.Empty;
 
-	internal async Task EnsureMigrationsTableCreatedAsync(CancellationToken cancellationToken)
+	private readonly IClickHouseMigrationInstructions _migrationInstructions;
+	private readonly string _dbName;
+
+	public ClickHouseMigrationFacade(IClickHouseMigrationInstructions migrationInstructions)
 	{
-		ThrowIfDatabaseNotSet();
+		_migrationInstructions = migrationInstructions
+			?? throw new ArgumentNullException(nameof(migrationInstructions));
+
+		if (_migrationInstructions.DatabaseName.IsNullOrWhiteSpace())
+		{
+			throw new ArgumentException($"Migrations database name is null or white space.");
+		}
+
+		_dbName = _migrationInstructions.DatabaseName;
+	}
 
+	internal async Task EnsureMigrationsTableCreatedAsync(CancellationToken cancellationToken)
+	{
 		var builder = CreateTableSqlBuilder.Create
 			.IfNotExists()
-			.WithDatabase(DbName)
+			.WithDatabase(_dbName)
 			.WithTableName(MigrationsTable)
 			.AddColumn(builder => builder
 				.WithName("id")
@@ -42,11 +55,9 @@ internal async Task EnsureMigrationsTableCreatedAsync(CancellationToken cancella
 	internal async Task EnsureDatabaseCreatedAsync(
 		CancellationToken cancellationToken)
 	{
-		ThrowIfDatabaseNotSet();
-
 		var builder = CreateDatabaseSqlBuilder.Create
 			.IfNotExists()
-			.WithDbName(DbName)
+			.WithDbName(_dbName)
 			.WithEngine(builder => builder.WithEngine(ClickHouseDatabaseEngine.Atomic));
 
 		var statement = builder.BuildSql();
@@ -55,12 +66,10 @@ internal async Task EnsureDatabaseCreatedAsync(
 	}
 
 	private string GetAppliedMigrationsSql =>
-		$"select id, name from {DbName}.{MigrationsTable} final";
+		$"select id, name from {_dbName}.{MigrationsTable} final";
 
 	internal async Task<IEnumerable<AppliedMigration>> GetAppliedMigrationsAsync(CancellationToken cancellationToken)
 	{
-		ThrowIfDatabaseNotSet();
-
 		var migrations = await ExecuteQueryAsync(
 				GetAppliedMigrationsSql,
 				AppliedMigration.FromReader,
@@ -74,7 +83,6 @@ internal async Task<IEnumerable<AppliedMigration>> GetAppliedMigrationsAsync(Can
 
 	internal async Task ApplyMigrationAsync(ClickHouseMigration migration, CancellationToken cancellationToken)
 	{
-		ThrowIfDatabaseNotSet();
 		ExceptionHelpers.ThrowIfNull(migration);
 
 		var migrationBuilder = ClickHouseMigrationBuilder.Create;
@@ -83,28 +91,39 @@ internal async Task ApplyMigrationAsync(ClickHouseMigration migration, Cancellat
 
 		cancellationToken.ThrowIfCancellationRequested();
 
-		foreach (var statement in migrationBuilder.Statements)
+		try
 		{
-			await ExecuteNonQueryAsync(statement, CancellationToken.None);
-		}
-
-		var addAppliedMigrationSql = string.Format(
-			AddAppliedMigrationSql,
-			new object[]
+			foreach (var statement in migrationBuilder.Statements)
 			{
-				$"{DbName}.{MigrationsTable}",
-				migration.Index,
-				migration.Name,
-			});
+				await ExecuteNonQueryAsync(statement, CancellationToken.None);
+			}
+
+			var addAppliedMigrationSql = string.Format(
+				AddAppliedMigrationSql,
+				new object[]
+				{
+					$"{_dbName}.{MigrationsTable}",
+					migration.Index,
+					migration.Name,
+				});
+
+			await ExecuteNonQueryAsync(addAppliedMigrationSql, CancellationToken.None);
+		}
+		catch (Exception migrationException)
+		{
+			var rolledBack = await TryRollbackMigrationAsync(migration);
+			var verb = rolledBack ? "has been" : "has not been";
 
-		await ExecuteNonQueryAsync(addAppliedMigrationSql, CancellationToken.None);
+			throw new AggregateException(
+				$"Failed to apply migration '{migration.Name}'. Migration {verb} rolled back.",
+				migrationException);
+		}
 	}
 
 	private const string AddRolledBackMigrationSql = "insert into {0} values ({1}, '{2}', 1)";
 
 	internal async Task RollbackMigrationAsync(ClickHouseMigration migration, CancellationToken cancellationToken)
 	{
-		ThrowIfDatabaseNotSet();
 		ExceptionHelpers.ThrowIfNull(migration);
 
 		var migrationBuilder = ClickHouseMigrationBuilder.Create;
@@ -122,19 +141,30 @@ internal async Task RollbackMigrationAsync(ClickHouseMigration migration, Cancel
 			AddRolledBackMigrationSql,
 			new object[]
 			{
-				$"{DbName}.{MigrationsTable}",
+				$"{_dbName}.{MigrationsTable}",
 				migration.Index,
 				migration.Name,
 			});
 
 		await ExecuteNonQueryAsync(addAppliedMigrationSql, CancellationToken.None);
 	}
 
-	private void ThrowIfDatabaseNotSet()
+	private async Task<bool> TryRollbackMigrationAsync(ClickHouseMigration migration)
 	{
-		if (DbName.IsNullOrWhiteSpace())
+		if (!_migrationInstructions.RollbackOnMigrationFail)
+		{
+			return false;
+		}
+
+		try
+		{
+			await RollbackMigrationAsync(migration, CancellationToken.None);
+
+			return true;
+		}
+		catch (Exception)
 		{
-			throw new InvalidOperationException($"{nameof(DbName)} is not set.");
+			return false;
 		}
 	}
 }
diff --git a/src/ClickHouse.Facades/Migrations/ClickHouseMigrator.cs b/src/ClickHouse.Facades/Migrations/ClickHouseMigrator.cs
@@ -7,8 +7,6 @@ internal class ClickHouseMigrator : IClickHouseMigrator
 	private readonly IClickHouseContextFactory<ClickHouseMigrationContext> _migrationContextFactory;
 	private readonly IClickHouseMigrationsLocator _migrationsLocator;
 
-	private readonly string _migrationsDatabase;
-
 	public ClickHouseMigrator(
 		IClickHouseContextFactory<ClickHouseMigrationContext> migrationContextFactory,
 		IClickHouseMigrationsLocator migrationsLocator,
@@ -21,21 +19,13 @@ public ClickHouseMigrator(
 			?? throw new ArgumentNullException(nameof(migrationsLocator));
 
 		ExceptionHelpers.ThrowIfNull(instructions);
-
-		_migrationsDatabase = instructions.DatabaseName;
-
-		if (_migrationsDatabase.IsNullOrWhiteSpace())
-		{
-			throw new ArgumentException($"Migrations database name is null or white space.");
-		}
 	}
 
 	public async Task ApplyMigrationsAsync(CancellationToken cancellationToken = default)
 	{
 		await using var context = _migrationContextFactory.CreateContext();
 
 		var facade = context.GetFacade<ClickHouseMigrationFacade>();
-		facade.DbName = _migrationsDatabase;
 
 		await EnsureDatabaseCreated(context, cancellationToken);
 		await facade.EnsureMigrationsTableCreatedAsync(cancellationToken);
@@ -58,7 +48,6 @@ public async Task RollbackAsync(ulong targetMigrationId, CancellationToken cance
 		await using var context = _migrationContextFactory.CreateContext();
 
 		var facade = context.GetFacade<ClickHouseMigrationFacade>();
-		facade.DbName = _migrationsDatabase;
 
 		var migrationsResolver = new MigrationsResolver(
 			await facade.GetAppliedMigrationsAsync(cancellationToken),

diff --git a/src/ClickHouse.Facades/Migrations/IClickHouseMigrator.cs b/src/ClickHouse.Facades/Migrations/IClickHouseMigrator.cs
@@ -3,4 +3,6 @@
 public interface IClickHouseMigrator
 {
 	public Task ApplyMigrationsAsync(CancellationToken cancellationToken = default);
+
+	public Task RollbackAsync(ulong targetMigrationId, CancellationToken cancellationToken = default);
 }
diff --git a/src/ClickHouse.Facades/Migrations/Instructions/IClickHouseMigrationInstructions.cs b/src/ClickHouse.Facades/Migrations/Instructions/IClickHouseMigrationInstructions.cs
@@ -12,4 +12,6 @@ public interface IClickHouseMigrationInstructions
 	/// </summary>
 	string DatabaseName => GetConnectionString().GetConnectionStringParameters()["database"]
 		?? throw new InvalidOperationException("Unable to get 'database' parameter from connection string.");
+
+	bool RollbackOnMigrationFail => false;
 }