error-handlers.go

package sqldb

import "strings"

/*
This file lists a bunch of example ErrorHandler funcs. These funcs are used to
ignore/bypass errors returned from running a DeployQuery or UpdateQuery.
*/

// ErrorHandler is a function that determines if an error returned from
// [database/sql.Exec] when DeploySchema() is called can be ignored. An error handler
// is typically used to ignore errors that arise from a query being run multiple times
// but the result already being applied (think, renaming a table or column).
//
// Error handlers typically have an "is this error handler applicable, if so check if
// the error should be ignore, and if so, ignore the error"
//
// Ex:
//
//	func IgnoreDuplicateColumnError (q query, err error) bool {
//	  if !strings.Contains(q, "ADD COLUMN") && strings.Contains(err.Error(), "duplicate column") {
//		    return true
//	  }
//
//	  return false
//	 }
type ErrorHandler func(string, error) bool

// IgnoreErrorDuplicateColumn checks if an error occurred because a column with the
// same name already exists. This is useful to for running ALTER TABLE ADD COLUMN or
// RENAME COLUMN.
//
// This error usually occurs because UpdateSchema() is being rerun.
//
//Ex.: ALTER TABLE my_table RENAME COLUMN old_column_name TO new_column_name.
func IgnoreErrorDuplicateColumn(query string, err error) bool {
	if strings.Contains(strings.ToUpper(query), "ADD COLUMN") && strings.Contains(strings.ToLower(err.Error()), "duplicate column") {
		return true
	}

	return false
}

// IgnoreErrorDropColumn checks if an error occurred because a column you are trying
// to DROP does not exist. This can occur if you already DROPped the column.
//
// This error usually occurs because UpdateSchema() is being rerun.
//
//Ex.: ALTER TABLE my_table DROP COLUMN my_column.
func IgnoreErrorDropColumn(query string, err error) bool {
	if !strings.Contains(strings.ToUpper(query), "DROP COLUMN") {
		return false
	}

	//MariaDB.
	if strings.Contains(err.Error(), "Error 1091") && strings.Contains(err.Error(), "check that it exists") {
		return true
	}

	//SQLite.
	if strings.Contains(err.Error(), "no such column") {
		return true
	}

	return false
}

// IgnoreErrorDropForeignKey checks if an error occurred because a foreign key you
// are trying to DROP does not exist. This can occur if you already DROPped the
// foreign key.
//
// This error usually occurs because UpdateSchema() is being rerun.
//
//Ex.:
// - MariaDB: ALTER TABLE my_table DROP FOREIGN KEY my_foreign_key.
// - SQLite: You will have to turn foreign keys off, create a new table, and copy over
//   data.
func IgnoreErrorDropForeignKey(query string, err error) bool {
	if !strings.Contains(strings.ToUpper(query), "DROP FOREIGN KEY") {
		return false
	}

	//MariaDB.
	if strings.Contains(err.Error(), "Error 1091") && strings.Contains(err.Error(), "check that it exists") {
		return true
	}

	return false
}

// IgnoreErrorDropTable checks if an error occurred because a table you are trying to
// DROP does not exist. This can occur if you already DROPped the table.
//
// This error usually occurs because UpdateSchema() is being rerun.
//
// Ex.: DROP TABLE my_table.
func IgnoreErrorDropTable(query string, err error) bool {
	if !strings.Contains(strings.ToUpper(query), "DROP TABLE") {
		return false
	}

	//MariaDB.
	if strings.Contains(err.Error(), "Error 1051") && strings.Contains(err.Error(), "Unknown table") {
		return true
	}

	//SQLite.
	if strings.Contains(err.Error(), "no such table") {
		return true
	}

	return false
}

// IgnoreErrorTableDoesNotExist checks if an error occurred because you are trying to
// modify a table in some manner but the table does not exist in the database.
func IgnoreErrorTableDoesNotExist(query string, err error) bool {
	//MariaDB.
	if strings.Contains(err.Error(), "Error 1146") && strings.Contains(err.Error(), "Table") && strings.Contains(err.Error(), "doesn't exist") {
		return true
	}

	//SQLite.
	if strings.Contains(err.Error(), "no such table") {
		return true
	}

	return false
}

// IgnoreErrorColumnDoesNotExist checks if an error occurred because you are trying to
// update a column in some manner but the column does not exist.
func IgnoreErrorColumnDoesNotExist(query string, err error) bool {
	//MariaDB.
	if strings.Contains(query, "UPDATE") && strings.Contains(err.Error(), "Unknown column") {
		return true
	}

	//SQLite.
	if strings.Contains(query, "UPDATE") && strings.Contains(err.Error(), "no such column") {
		return true
	}

	return false
}

// IgnoreErrorSQLiteModify checks if an error occured becaused a query is attempting
// to MODIFY a column for a SQLite database. SQLite does not support MODIFY. This is
// somewhat okay since SQLite allows storing any type of data in any colum (unless
// STRICT tables are used) and the data read from the database will be read into a
// Golang type anyway.
//
// To get around this error, you should create a new table with the new schema, copy
// the old data to the new table, delete the old table, and rename the new table to
// the old table.
func IgnoreErrorSQLiteModify(query string, err error) bool {
	//lint:ignore S1008 - i don't really like "return strings.Contains()", i don't think it is as clear.
	if strings.Contains(query, "MODIFY COLUMN") {
		return true
	}

	return false
}

// IgnoreErrorRenameDoesNotExist checks is an error occured because a column or table
// that does not exist is trying to be renamed.
//
// This error usually occurs because UpdateSchema() is being rerun.
func IgnoreErrorRenameDoesNotExist(query string, err error) bool {
	//MariaDB.
	if strings.Contains(query, "RENAME COLUMN") && strings.Contains(err.Error(), "Unknown column") {
		return true
	}
	if strings.Contains(query, "RENAME TO") && strings.Contains(err.Error(), "Table") && strings.Contains(err.Error(), "already exists") {
		return true
	}

	//SQLite.
	if strings.Contains(query, "RENAME COLUMN") && strings.Contains(err.Error(), "no such column") {
		return true
	}
	if strings.Contains(query, "RENAME TO") && strings.Contains(err.Error(), "no such table") {
		return true
	}

	return false
}