mysqldump not working when run from within an ASP .NET web app as a new process

Question

This, when run from the "run" window , works properly.

cmd.exe /K mysqldump --add-drop-database --add-drop-table --user=root --password=thepassword --databases theDatabase > C:\Backup\theBackup.sql

However, the same command, when I try to execute from my web application by calling an external process, fails.

Here's the code:

ProcessStartInfo processInfo = new ProcessStartInfo("cmd.exe", @"/K mysqldump --add-drop-database --add-drop-table --user=root --password=thepassword --databases theDatabase > C:\Backup\theBackup" + ".sql");

Process p = Process.Start(processInfo);

This is what I get...

alt text http://img40.imageshack.us/img40/8121/mysqldumperror.gif

Interestingly, the file - theBackup.sql - gets created, but is empty.

It isn't an environment PATH variable problem; the MySql bin directory path, which contains mysqldump is added into the environment PATH variable. To check this, if I open the command prompt, navigate to the path mentioned in the screenshot above and type mysqldump command manually, it recognizes the command...as shown below...

alt text http://img40.imageshack.us/img40/6879/mysqldumppathproper.gif

The problem is mysqldump specific, since the following piece of code works

ProcessStartInfo processInfo = new ProcessStartInfo("cmd.exe", "/K ping stackoverflow.com");

What's wrong here?

Answer 1

my guess would be that the $PATH variable isn't defined to include the path to MySQL in the environment that ASP.NET is running in (either for the that user, or ASP.NET cleans out the environment).

Two things to try:

1. (might work) Make sure the mysql directory is added to the global path -- not just the user-specific PATH variable. (note: this will require at least recycling IIS, maybe a reboot to take effect)
2. Use the fully-qualified path to mysqldump (you will need to do something to quote or escape any spaces in the path).

Answer 2

An exemple for mysqldump

Private sw As IO.StreamWriter

Public Sub ExecuteBackup()
    Try

        Dim mysqlDump As New Process
        mysqlDump.StartInfo.FileName = "PahtToMysqlDump\mysqldump.exe"
        mysqlDump.StartInfo.Arguments = "--user=myuser --password=mypassword --routines --all-databases"
        mysqlDump.StartInfo.RedirectStandardOutput = True
        mysqlDump.StartInfo.CreateNoWindow = True
        mysqlDump.StartInfo.UseShellExecute = False

        Console.WriteLine("Arguments:")
        Console.WriteLine("mysqldump.exe " & mysqlDump.StartInfo.Arguments)

        sw = New IO.StreamWriter("backup.sql")

        AddHandler mysqlDump.OutputDataReceived, AddressOf mysqlDumpNewData

        mysqlDump.Start()
        mysqlDump.BeginOutputReadLine()
        mysqlDump.WaitForExit()

        sw.Close()

        Console.WriteLine("Backup completed")

    Catch ex As Exception   
        Console.WriteLine("BackupEngine.ExecuteBackup.", ex)        
    End Try
End Sub

Private Sub mysqlDumpNewData(sender As Object, e As DataReceivedEventArgs)

    Dim line = e.Data
    If line IsNot Nothing Then
        sw.WriteLine(line)
        If line.StartsWith("USE") Then
            Dim ln = line.Split("`")(1)
            Console.WriteLine("Database : " & ln.ToUpper)
        End If
        If line.StartsWith("CREATE TABLE") Then
            Dim ln = line.Split("`")(1)
            Console.WriteLine(" Table : " & ln.ToUpper)
        End If
    End If

End Sub