如何编写Expect脚本以安装mariadb？

环境：centos7 + mariadb5.5.64。
让我在运行时在屏幕上显示安装信息mysql_secure_installation。

# mysql_secure_installation

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we'll need the current
password for the root user.  If you've just installed MariaDB, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none): 
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

Set root password? [Y/n] y
New password: 
Re-enter new password: 
Password updated successfully!
Reloading privilege tables..
 ... Success!


By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] y
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] y
 ... Success!

By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] y
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] y
 ... Success!

Cleaning up...

All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

我编写了一个自动化的期望脚本来安装mariadb。

  vim secure.exp
  set timeout 60
  spawn mysql_secure_installation
  expect {
      "Enter current password for root (enter for none): " {send "\r";exp_continue}
      "Set root password? [Y/n] " {send "y\r";exp_continue}
      "New password:" {send "123456\r";exp_continue}
      "Re-enter new password:" {send "123456\r";exp_continue}
      "Remove anonymous users? [Y/n]" {send "y\r";exp_continue}
      "Disallow root login remotely? [Y/n]" {send "y\r";exp_continue}
      "Remove test database and access to it? [Y/n]" {send "y\r";exp_continue}
      "Reload privilege tables now? [Y/n]" {send "y\r";exp_continue}
  }

要执行/usr/bin/expect secure.exp，我遇到了错误：

spawn mysql_secure_installation
invalid command name "Y/n"
    while executing
"Y/n"
    invoked from within
"expect {
          "Enter current password for root (enter for none): " {send "\r";exp_continue}
          "Set root password? [Y/n] " {send "y\r";exp..."
    (file "secure.exp" line 3)

编写如下代码是没有用的：

  set timeout 60
  spawn mysql_secure_installation
  expect {
      "Enter current password for root (enter for none): " {send "\r";exp_continue}
      "Set root password? \\[Y/n] " {send "y\r";exp_continue}
      "New password:" {send "123456\r";exp_continue}
      "Re-enter new password:" {send "123456\r";exp_continue}
      "Remove anonymous users? \\[Y/n]" {send "y\r";exp_continue}
      "Disallow root login remotely? \\[Y/n]" {send "y\r";exp_continue}
      "Remove test database and access to it? \\[Y/n]" {send "y\r";exp_continue}
      "Reload privilege tables now? \\[Y/n]" {send "y\r";exp_continue}
  }

同样的错误：

invalid command name "Y/n"
    while executing
"Y/n"
    invoked from within
"expect {
      "Enter current password for root (enter for none): " {send "\r";exp_continue}
      "Set root password? \\[Y/n] " {send "y\r";exp_conti..."
    (file "secure.exp" line 3)

那怎么解决我的exp脚本呢？

这些脚本等待接收可选输出（timeout -1表示“无超时”），它们可以区分不同的响应，这是yum install和 所要求的mysql_secure_installation。使用#!/bin/expect -fas shebang，将脚本设置为即可执行chmod +x。

A）首先，mariadb_yum.exp（需要su或sudo）：

#!/bin/expect -f
set timeout 30
if {[llength $argv] == 0} {
    send_user "Usage: mariadb_yum.exp \[linux sudo password\]\n"
    exit 1
}
set USERNAME "[exec whoami]"
set PASSWORD [lindex $argv 0];

# optionally, redirect output to log file (silent install)
# log_user 0
# log_file -a "/home/$USERNAME/mariadb_install.log"

spawn sudo yum -y install MariaDB-server
set yum_spawn_id $spawn_id

# On GCE it will never ask for a sudo password:
expect -ex "\[sudo\] password for $USERNAME: " {
   exp_send "$PASSWORD\r"
}

expect {
    # when the package was already installed
    -ex "Nothing to do" {
        send_user "package was already installed\n"
    }
    # when the package had been installed
    -ex "Complete!" {
        send_user "package had been installed\n"
    }
}

expect eof
close $yum_spawn_id
exit 0

B）然后mariadb_sec.exp（不需要sudo）：

#!/bin/expect -f
set timeout 1
if {[llength $argv] == 0} {
    send_user "Usage: mariadb_sec.exp \[mysql root password\]\n"
    exit 1
}
set PASSWORD [lindex $argv 0];

spawn mysql_secure_installation
set mysql_spawn_id $spawn_id

# optionally, redirect output to log file (silent install)
# log_user 0
# log_file -a "/home/[exec whoami]/mariadb_install.log"

# when there is no password set, this probably should be "\r"
expect -ex "Enter current password for root (enter for none): "
exp_send "$PASSWORD\r"

expect {
    # await an eventual error message
    -ex "ERROR 1045" {
        send_user "\nMariaDB > An invalid root password had been provided.\n"
        close $mysql_spawn_id
        exit 1
    }
    # when there is a root password set
    -ex "Change the root password? \[Y/n\] " {
        exp_send "n\r"
    }
    # when there is no root password set (could not test this branch).
    -ex "Set root password? \[Y/n\] " {
        exp_send "Y\r"
        expect -ex "New password: "
        exp_send "$PASSWORD\r"
        expect -ex "Re-enter new password: "
        exp_send "$PASSWORD\r"
    }
}
expect -ex "Remove anonymous users? \[Y/n\] "
exp_send "Y\r"
expect -ex "Disallow root login remotely? \[Y/n\] "
exp_send "Y\r"
expect -ex "Remove test database and access to it? \[Y/n\] "
exp_send "Y\r"
expect -ex "Reload privilege tables now? \[Y/n\] "
exp_send "Y\r"

expect eof
close $mysql_spawn_id
exit 0

为了调试目的或验证答案，可以expect使用log-level 运行strace 4。就编写expect脚本而言，这可能是源所获得的声誉，因为它很好地显示了正在发生的事情，最重要的是，事情发生的顺序是：

expect -c "strace 4" ./mariadb_yum.exp [linux sudo password]
expect -c "strace 4" ./mariadb_sec.exp [mysql root password]

指令set exp_internal 1可用于获取正则表达式匹配的输出。

可能产生混乱的原因是，其中一个人生成了进程-例如，一个人可以在各个主机上生成多个进程。ssh在本地，然后yum和mysql_secure_installation远程控制。添加$spawn_id到脚本；下一个close电话可能是多余的，因为它已经是EOF（只是如何展现给spawn和close流程）：

Thanks for using MariaDB!
 1  close $mysql_spawn_id
 1  exit 0
 2  rename _close.pre_expect close

结论：该mariadb_sec.exp脚本可能需要进一步改进，例如。最初不发送密码并查看会发生什么情况时-然后发送密码ERROR 1045（如果之前已设置密码）。可以假设在刚安装服务器时必须设置密码（除非yum reinstall提供相同的结果）。只是没有空白的CentOS容器来测试所有情况。除非在root外壳中运行，否则从安装到安装后自动执行这两种操作都需要将两种密码都传递到一个脚本中。

可能值得注意的是，在GCE上，sudo不会要求输入密码。实际上，根据环境的不同，因为这些CentOS容器映像的行为不同。在这种情况下（由于没有su检测到或没有检测到容器映像），mariadb_yum.exp脚本可能会停留30几秒钟，然后继续。

我可以提供的最有信誉的资源是expectDon Libes @ NIST编写的手册和TCL / TK手册expect，以及恰好被称为的SourceForge项目expect。

方括号不仅用于命令替换，而且还特别适用于glob模式。

您可以在使用-exact引号将方括号转义时使用该开关：

spawn mysql_secure_installation
expect {
    ...
    -exact "Set root password? \[Y/n\] " {send "y\r";exp_continue}
    ...
}

或使用大括号代替引号：

spawn mysql_secure_installation
expect {
    ...
    {Set root password? \[Y/n\] } {send "y\r";exp_continue}
    ...
}

仅供参考，您可以使用autoexpect以下命令为您生成期望脚本：

autoexpect ./mysql_secure_installation

这将script.exp在您当前的工作目录中生成一个期望脚本。