woodpecker/pkg/database/migrate/sqlite.go
2014-02-19 07:38:53 +07:00

283 lines
6.6 KiB
Go

package migrate
import (
"database/sql"
"fmt"
"strings"
"github.com/dchest/uniuri"
_ "github.com/mattn/go-sqlite3"
)
type SQLiteDriver MigrationDriver
func SQLite(tx *sql.Tx) Operation {
return &SQLiteDriver{Tx: tx}
}
func (s *SQLiteDriver) Exec(query string, args ...interface{}) (sql.Result, error) {
return s.Tx.Exec(query, args...)
}
func (s *SQLiteDriver) Query(query string, args ...interface{}) (*sql.Rows, error) {
return s.Tx.Query(query, args...)
}
func (s *SQLiteDriver) QueryRow(query string, args ...interface{}) *sql.Row {
return s.Tx.QueryRow(query, args...)
}
func (s *SQLiteDriver) CreateTable(tableName string, args []string) (sql.Result, error) {
return s.Tx.Exec(fmt.Sprintf("CREATE TABLE %s (%s);", tableName, strings.Join(args, ", ")))
}
func (s *SQLiteDriver) RenameTable(tableName, newName string) (sql.Result, error) {
return s.Tx.Exec(fmt.Sprintf("ALTER TABLE %s RENAME TO %s;", tableName, newName))
}
func (s *SQLiteDriver) DropTable(tableName string) (sql.Result, error) {
return s.Tx.Exec(fmt.Sprintf("DROP TABLE IF EXISTS %s;", tableName))
}
func (s *SQLiteDriver) AddColumn(tableName, columnSpec string) (sql.Result, error) {
return s.Tx.Exec(fmt.Sprintf("ALTER TABLE %s ADD COLUMN %s;", tableName, columnSpec))
}
func (s *SQLiteDriver) DropColumns(tableName string, columnsToDrop []string) (sql.Result, error) {
var err error
var result sql.Result
if len(columnsToDrop) == 0 {
return nil, fmt.Errorf("No columns to drop.")
}
tableSQL, err := s.getDDLFromTable(tableName)
if err != nil {
return nil, err
}
columns, err := fetchColumns(tableSQL)
if err != nil {
return nil, err
}
columnNames := selectName(columns)
var preparedColumns []string
for k, column := range columnNames {
listed := false
for _, dropped := range columnsToDrop {
if column == dropped {
listed = true
break
}
}
if !listed {
preparedColumns = append(preparedColumns, columns[k])
}
}
if len(preparedColumns) == 0 {
return nil, fmt.Errorf("No columns match, drops nothing.")
}
// fetch indices for this table
oldSQLIndices, err := s.getDDLFromIndex(tableName)
if err != nil {
return nil, err
}
var oldIdxColumns [][]string
for _, idx := range oldSQLIndices {
idxCols, err := fetchColumns(idx)
if err != nil {
return nil, err
}
oldIdxColumns = append(oldIdxColumns, idxCols)
}
var indices []string
for k, idx := range oldSQLIndices {
listed := false
OIdxLoop:
for _, oidx := range oldIdxColumns[k] {
for _, cols := range columnsToDrop {
if oidx == cols {
listed = true
break OIdxLoop
}
}
}
if !listed {
indices = append(indices, idx)
}
}
// Rename old table, here's our proxy
proxyName := fmt.Sprintf("%s_%s", tableName, uniuri.NewLen(16))
if result, err := s.RenameTable(tableName, proxyName); err != nil {
return result, err
}
// Recreate table with dropped columns omitted
if result, err = s.CreateTable(tableName, preparedColumns); err != nil {
return result, err
}
// Move data from old table
if result, err = s.Tx.Exec(fmt.Sprintf("INSERT INTO %s SELECT %s FROM %s;", tableName,
strings.Join(selectName(preparedColumns), ", "), proxyName)); err != nil {
return result, err
}
// Clean up proxy table
if result, err = s.DropTable(proxyName); err != nil {
return result, err
}
// Recreate Indices
for _, idx := range indices {
if result, err = s.Tx.Exec(idx); err != nil {
return result, err
}
}
return result, err
}
func (s *SQLiteDriver) RenameColumns(tableName string, columnChanges map[string]string) (sql.Result, error) {
var err error
var result sql.Result
tableSQL, err := s.getDDLFromTable(tableName)
if err != nil {
return nil, err
}
columns, err := fetchColumns(tableSQL)
if err != nil {
return nil, err
}
// We need a list of columns name to migrate data to the new table
var oldColumnsName = selectName(columns)
// newColumns will be used to create the new table
var newColumns []string
for k, column := range oldColumnsName {
added := false
for Old, New := range columnChanges {
if column == Old {
columnToAdd := strings.Replace(columns[k], Old, New, 1)
newColumns = append(newColumns, columnToAdd)
added = true
break
}
}
if !added {
newColumns = append(newColumns, columns[k])
}
}
// fetch indices for this table
oldSQLIndices, err := s.getDDLFromIndex(tableName)
if err != nil {
return nil, err
}
var idxColumns [][]string
for _, idx := range oldSQLIndices {
idxCols, err := fetchColumns(idx)
if err != nil {
return nil, err
}
idxColumns = append(idxColumns, idxCols)
}
var indices []string
for k, idx := range oldSQLIndices {
added := false
IdcLoop:
for _, oldIdx := range idxColumns[k] {
for Old, New := range columnChanges {
if oldIdx == Old {
indx := strings.Replace(idx, Old, New, 2)
indices = append(indices, indx)
added = true
break IdcLoop
}
}
}
if !added {
indices = append(indices, idx)
}
}
// Rename current table
proxyName := fmt.Sprintf("%s_%s", tableName, uniuri.NewLen(16))
if result, err := s.RenameTable(tableName, proxyName); err != nil {
return result, err
}
// Create new table with the new columns
if result, err = s.CreateTable(tableName, newColumns); err != nil {
return result, err
}
// Migrate data
if result, err = s.Tx.Exec(fmt.Sprintf("INSERT INTO %s SELECT %s FROM %s", tableName,
strings.Join(oldColumnsName, ", "), proxyName)); err != nil {
return result, err
}
// Clean up proxy table
if result, err = s.DropTable(proxyName); err != nil {
return result, err
}
for _, idx := range indices {
if result, err = s.Tx.Exec(idx); err != nil {
return result, err
}
}
return result, err
}
func (s *SQLiteDriver) getDDLFromTable(tableName string) (string, error) {
var sql string
query := `SELECT sql FROM sqlite_master WHERE type='table' and name=?;`
err := s.Tx.QueryRow(query, tableName).Scan(&sql)
if err != nil {
return "", err
}
return sql, nil
}
func (s *SQLiteDriver) getDDLFromIndex(tableName string) ([]string, error) {
var sqls []string
query := `SELECT sql FROM sqlite_master WHERE type='index' and tbl_name=?;`
rows, err := s.Tx.Query(query, tableName)
if err != nil {
return sqls, err
}
for rows.Next() {
var sql string
if err := rows.Scan(&sql); err != nil {
// This error came from autoindex, since its sql value is null,
// we want to continue.
if strings.Contains(err.Error(), "Scan pair: <nil> -> *string") {
continue
}
return sqls, err
}
sqls = append(sqls, sql)
}
if err := rows.Err(); err != nil {
return sqls, err
}
return sqls, nil
}