feat(database): add automatic database creation for MySQL and PostgreSQL

repository/db.go

@@ -1,6 +1,9 @@
 package repository
 
 import (
+	"context"
+	"database/sql"
+	"errors"
 	"os"
 	"path/filepath"
 	"strings"
@@ -9,7 +12,10 @@ import (
 	"github.com/basketikun/infinite-canvas/config"
 	"github.com/basketikun/infinite-canvas/model"
 	"github.com/glebarez/sqlite"
-	"gorm.io/driver/mysql"
+	mysqldriver "github.com/go-sql-driver/mysql"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+	gormmysql "gorm.io/driver/mysql"
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
 )
@@ -41,6 +47,18 @@ func DB() (*gorm.DB, error) {
 		if driver == "sqlite" && dsn != ":memory:" {
 			_ = os.MkdirAll(filepath.Dir(dsn), 0755)
 		}
+		if isPostgresDriver(driver) {
+			dbErr = ensurePostgresDatabase(dsn)
+			if dbErr != nil {
+				return
+			}
+		}
+		if driver == "mysql" {
+			dbErr = ensureMySQLDatabase(dsn)
+			if dbErr != nil {
+				return
+			}
+		}
 		db, dbErr = gorm.Open(dialector(driver, dsn), &gorm.Config{})
 		if dbErr != nil {
 			return
@@ -59,10 +77,103 @@ func DB() (*gorm.DB, error) {
 func dialector(driver string, dsn string) gorm.Dialector {
 	switch driver {
 	case "mysql":
-		return mysql.Open(dsn)
+		return gormmysql.Open(dsn)
 	case "postgres", "postgresql":
 		return postgres.Open(dsn)
 	default:
 		return sqlite.Open(dsn)
 	}
 }
+
+func isPostgresDriver(driver string) bool {
+	return driver == "postgres" || driver == "postgresql"
+}
+
+func ensureMySQLDatabase(dsn string) error {
+	cfg, err := mysqldriver.ParseDSN(dsn)
+	if err != nil {
+		return err
+	}
+	target := strings.TrimSpace(cfg.DBName)
+	if target == "" {
+		return nil
+	}
+	ctx := context.Background()
+	targetDB, err := sql.Open("mysql", dsn)
+	if err != nil {
+		return err
+	}
+	err = targetDB.PingContext(ctx)
+	_ = targetDB.Close()
+	if err == nil {
+		return nil
+	}
+	if !isMySQLError(err, 1049) {
+		return err
+	}
+
+	maintenance := cfg.Clone()
+	maintenance.DBName = ""
+	serverDB, err := sql.Open("mysql", maintenance.FormatDSN())
+	if err != nil {
+		return err
+	}
+	defer serverDB.Close()
+
+	_, err = serverDB.ExecContext(ctx, "CREATE DATABASE "+quoteMySQLIdentifier(target)+" CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci")
+	if isMySQLError(err, 1007) {
+		return nil
+	}
+	return err
+}
+
+func ensurePostgresDatabase(dsn string) error {
+	cfg, err := pgx.ParseConfig(dsn)
+	if err != nil {
+		return err
+	}
+	target := strings.TrimSpace(cfg.Database)
+	if target == "" {
+		return nil
+	}
+	ctx := context.Background()
+	conn, err := pgx.ConnectConfig(ctx, cfg)
+	if err == nil {
+		_ = conn.Close(ctx)
+		return nil
+	}
+	if !isPostgresError(err, "3D000") {
+		return err
+	}
+
+	maintenance := cfg.Copy()
+	maintenance.Database = "postgres"
+	if strings.EqualFold(target, "postgres") {
+		maintenance.Database = "template1"
+	}
+	conn, err = pgx.ConnectConfig(ctx, maintenance)
+	if err != nil {
+		return err
+	}
+	defer conn.Close(ctx)
+
+	_, err = conn.Exec(ctx, "CREATE DATABASE "+pgx.Identifier{target}.Sanitize(), pgx.QueryExecModeExec)
+	if isPostgresError(err, "42P04") {
+		return nil
+	}
+	return err
+}
+
+func isMySQLError(err error, number uint16) bool {
+	var mysqlErr *mysqldriver.MySQLError
+	return errors.As(err, &mysqlErr) && mysqlErr.Number == number
+}
+
+func isPostgresError(err error, code string) bool {
+	var pgErr *pgconn.PgError
+	return errors.As(err, &pgErr) && pgErr.Code == code
+}
+
+func quoteMySQLIdentifier(name string) string {
+	return "`" + strings.ReplaceAll(name, "`", "``") + "`"
+}