force-down-migration.md

To Force a Down Migration to Run

1. Find the MigratePlugins method within the Global.asax.cs file
2. Find this section:

// Iterate each assembly that contains plugin migrations
foreach ( var assemblyMigrations in assemblies )
{
    try
    {
        // Get the versions that have already been installed
        var installedVersions = pluginMigrationService.Queryable()
            .Where( m => m.PluginAssemblyName == assemblyMigrations.Key )
            .ToList();

        // Iterate each migration in the assembly in MigrationNumber order
        foreach ( var migrationType in assemblyMigrations.Value.OrderBy( t => t.Key ) )
        {
            // Check to make sure migration has not already been run
            if ( !installedVersions.Any( v => v.MigrationNumber == migrationType.Key ) )
            {
                using ( var sqlTxn = con.BeginTransaction() )
                {
                    bool transactionActive = true;
                    try
                    {
                        // Create an instance of the migration and run the up migration
                        var migration = Activator.CreateInstance( migrationType.Value ) as Rock.Plugin.Migration;
                        migration.SqlConnection = con;
                        migration.SqlTransaction = sqlTxn;
                        migration.Up();
                        sqlTxn.Commit();
                        transactionActive = false;

                        // Save the plugin migration version so that it is not run again
                        var pluginMigration = new PluginMigration();
                        pluginMigration.PluginAssemblyName = assemblyMigrations.Key;
                        pluginMigration.MigrationNumber = migrationType.Key;
                        pluginMigration.MigrationName = migrationType.Value.Name;
                        pluginMigrationService.Add( pluginMigration );
                        rockContext.SaveChanges();

                        result = true;
                    }
                    catch ( Exception ex )
                    {
                        if ( transactionActive )
                        {
                            sqlTxn.Rollback();
                        }
                        throw new Exception( string.Format( "Plugin Migration error occurred in {0}, {1}",
                            assemblyMigrations.Key, migrationType.Value.Name ), ex );
                    }
                }
            }
        }
    }
    catch ( Exception ex )
    {
        // If an exception occurs in an an assembly, log the error, and continue with next assembly
        LogError( ex, null );
    }
}

3. Change this line foreach ( var migrationType in assemblyMigrations.Value.OrderBy( t => t.Key ) ) to be foreach ( var migrationType in assemblyMigrations.Value.Where( t => t.Name == "MIGRATION_NAME_HERE" ) )
4. Change this migration.Up(); to migration.Down();
5. Delete this section:

// Save the plugin migration version so that it is not run again
var pluginMigration = new PluginMigration();
pluginMigration.PluginAssemblyName = assemblyMigrations.Key;
pluginMigration.MigrationNumber = migrationType.Key;
pluginMigration.MigrationName = migrationType.Value.Name;
pluginMigrationService.Add( pluginMigration );
rockContext.SaveChanges();

6. After testing locally, change your database connection strings to point to the database server you wish to modify, such as staging.
7. Run it.
8. Remove record from PluginMigrations table so that the migration's up will run again if desired.
9. Do not commit your changes to the Global.asax.cs file or gremlins will destroy your car.