package main import ( "io/ioutil" "os" "strings" ) func migrate() error { return migrateFromDir(os.Getenv("STATIC") + "/db") } func migrateFromDir(dir string) error { files, err := ioutil.ReadDir(dir) if err != nil { logger.Errorf("cannot read directory for migrations: %v", err) return err } statement := ` SELECT filename FROM migrations; ` rows, err := db.Query(statement) if err != nil { logger.Errorf("cannot query migrations: %v", err) return err } defer rows.Close() filenames := make(map[string]bool) for rows.Next() { var filename string if err = rows.Scan(&filename); err != nil { logger.Errorf("cannot scan filename: %v", err) return err } filenames[filename] = true } logger.Infof("%d migrations already installed, looking for more", len(filenames)) completed := 0 for _, file := range files { if strings.HasSuffix(file.Name(), ".sql") { if !filenames[file.Name()] { f := dir + string(os.PathSeparator) + file.Name() contents, err := ioutil.ReadFile(f) if err != nil { logger.Errorf("cannot read file %s: %v", file.Name(), err) return err } if _, err = db.Exec(string(contents)); err != nil { logger.Errorf("cannot execute the SQL in %s: %v", f, err) return err } statement = ` INSERT INTO migrations (filename) VALUES ($1 ); ` _, err = db.Exec(statement, file.Name()) if err != nil { logger.Errorf("cannot insert filename into the migrations table: %v", err) return err } completed++ } } } if completed > 0 { logger.Infof("%d new migrations completed (%d total)", completed, len(filenames)+completed) } else { logger.Infof("none found") } return nil }