我试图在go中编写一个程序,该程序能够将mysql
数据库(使用mysqldump
(导出到.sql
文件中,但不知何故scanner.Text()
只读取了mysqldump
输出的一半。以下main
包:
func main() {
// Just to get list of database name from
// []string{dbA, dbB}
databases := pkg.GetDatabases()
// Just to get mysql connection config
dbConfig := pkg.NewConnection()
var wg sync.WaitGroup
// How many goroutines need to be waited
wg.Add(len(databases.Name))
// databases.Name is a type []string hold database's name
for _, name := range databases.Name {
go dumping(name, dbConfig, &wg)
}
wg.Wait()
fmt.Print("Main program exit!")
}
func dumping (name string, c *pkg.Connection, wg *sync.WaitGroup) {
defer wg.Done()
args := []string{
fmt.Sprintf("--port=%s", c.Port),
fmt.Sprintf("--host=%s", c.Host),
fmt.Sprintf("--password=%s", ""),
}
args = append(args, name)
log.Printf("exec mysqldump with %v", args)
cmd := exec.Command("mysqldump", args...)
stdout, err := cmd.StdoutPipe()
if err != nil {
log.Fatalf("Error to execute mysqlump command: ", err)
os.Exit(1)
}
scanner := bufio.NewScanner(stdout)
go func() {
for scanner.Scan() {
fmt.Printf("%sn", scanner.Text())
}
}()
err = cmd.Start()
if err != nil {
fmt.Fprintln(os.Stderr, "Error starting Cmd", err)
os.Exit(1)
}
err = cmd.Wait()
if err != nil {
fmt.Fprintln(os.Stderr, "Error waiting for Cmd", err.Error())
os.Exit(1)
}
}
FMT 的输出。Printf("%s", scanner.文本(((:
2019/05/31 15:43:03 exec mysqldump with [--port=3306 --host=127.0.0.1 --password= dbA]
-- MySQL dump 10.16 Distrib 10.3.9-MariaDB, for osx10.13 (x86_64)
--
-- Host: 127.0.0.1 Database: dbA
-- -----------------------------------------------------
-- Server version 10.3.9-MariaDB
/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
Error waiting for Cmd exit status 2
exit status 1
如果我直接从终端mysqldump -P 3306 -h 127.0.0.1 -u root --password="" dbA
运行此命令,则仍然留下了很多sql语句。我错过了什么吗?
谢谢。
找到了罪魁祸首。真正的问题是我没有向 exec 命令提供--user=%s
参数。应该是:
args := []string{
fmt.Sprintf("--port=%s", c.Port),
fmt.Sprintf("--host=%s", c.Host),
fmt.Sprintf("--user=%s", c.User), <-- here
fmt.Sprintf("--password=%s", ""),
}
我是怎么找到的?错误实际上转到cmd.Stderr
:
var out bytes.Buffer
cmd.Stderr = &out
if err != nil {
log.Fatalf("Error to execute mysqlump command: ", err)
os.Exit(1)
}
fmt.Printf("%qn", out.String())
它输出真正的错误,如下所示:
"mysqldump: Got error: 1044: "Access denied for user ''@'localhost' to database 'dbA'" when selecting the databasen"