douxiong5438
douxiong5438
2017-10-23 17:02

如何使用exec.Command在Golang中执行Mysql脚本

已采纳

Hi i am trying to execute a script to fill data into a database using Golang

func executeTestScript(){
    cmd := exec.Command("/usr/local/mysql/bin/mysql", "-h127.0.0.1", "-P3333", "-uusr", "-pPassxxx", "-Ddtb_test",  "< /Users/XXX/Documents/test/scripts/olds/SCRIPT_XXX.sql")

    var out, stderr bytes.Buffer

    cmd.Stdout = &out
    cmd.Stderr = &stderr

    err := cmd.Run()
    if err != nil {
        fmt.Println(fmt.Sprintf("Error executing query. Command Output: %+v
: %+v, %v", out.String(), stderr.String(), err))
        log.Fatalf("Error executing query. Command Output: %+v
: %+v, %v", out.String(), stderr.String(), err)
    }
}

The problem is that i am getting the error:

ERROR 1049 (42000): Unknown database '< /Users/XXX/Documents/test/scripts/olds/SCRIPT_XXX.sql'

i think the problem is the last param (the sql script path) that the exec thinks is the dbname

The following command in the terminal is working:

/usr/local/mysql/bin/mysql --host=127.0.0.1 --port=3333 --user=usr --password=Passxxx --database=dtb_test < /Users/XXX/Documents/roseula/scripts/olds/SCRIPT_XXX.sql

but i try to replicate in Go to automatize the execution of the script.

The script have drop tables, create tables, inserts, and PK with FK relationships its a very complete one so i cant execute line by line, because of that i decided to execute de mysql program to insert the data in the database.

Any suggestions?

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2条回答

  • dongziya9863 dongziya9863 4年前

    +1 to answer from @MatteoRagni for showing how to do stdin redirection in Golang.

    But here's a simple alternative that I use:

    cmd := exec.Command("/usr/local/mysql/bin/mysql", "-h127.0.0.1", "-P3333", 
      "-uusr", "-pPassxxx", "-Ddtb_test",
      "-e", "source /Users/XXX/Documents/test/scripts/olds/SCRIPT_XXX.sql")
    

    You don't have to make the mysql client read the script using stdin redirection. Instead, you can make the mysql client execute a specific command, which is source <scriptname>.

    P.S.: I also would not put the host, port, user, and password in your code. That means you have to recompile your program any time you change those connection parameters. Also it's not secure to use passwords in plaintext on the command-line. Instead, I'd put all the connection parameters into a defaults file and use mysql --defaults-file=FILENAME.

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  • dongmaobeng7145 dongmaobeng7145 4年前

    This is a little example that runs something like:

    cat < test.txt
    

    that is what I think you are missing in your code:

    package main
    
    import (
      "fmt"
      "os/exec"
      "os"
    )
    
    func main() {
    
      cmd := exec.Command("cat")
      file, _ := os.Open("test.txt")
    
      cmd.Stdin = file
    
      out, _ := cmd.Output()
    
      fmt.Printf("%s
    ", out)
    }
    

    That prints in the console the content of test.txt, as read by cat. You will need to adapt it to your problem.

    Something like:

    func executeTestScript(){
        cmd := exec.Command("/usr/local/mysql/bin/mysql", "-h127.0.0.1", "-P3333", "-uusr", "-pPassxxx", "-Ddtb_test")
    
        dump, dump_err = os.Open("/Users/XXX/Documents/test/scripts/olds/SCRIPT_XXX.sql")
        if dump_err != nil {
          /* Handle the error if file not opened */
        }
        cmd.Stdin = dump
    
        var out, stderr bytes.Buffer
    
        cmd.Stdout = &out
        cmd.Stderr = &stderr
    
        err := cmd.Run()
        if err != nil {
            fmt.Println(fmt.Sprintf("Error executing query. Command Output: %+v
    : %+v, %v", out.String(), stderr.String(), err))
            log.Fatalf("Error executing query. Command Output: %+v
    : %+v, %v", out.String(), stderr.String(), err)
        }
    }
    

    if I'm not wrong...

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