Expect 自动交互实现
Contents
Environment Setup
Expect是一个用来处理交互的命令。借助Expect,我们可以将交互过程写在一个脚本上,使之自动化完成。形象的说,ssh登录,ftp登录等都符合交互的定义。因此,程序的安装,远程服务器的控制等,都可以使用expect来实现自动化。
Ubuntu Install
Use below command to install this command on Ubuntu
$sudo apt install expect
$ sudo apt install expect
Usage
Command
Expect中常用命令:
- send:用于向进程发送字符串
- expect:从进程接收字符串
- spawn:启动新的进程
- interact:允许用户交互
- autoexpect : 记录执行的过程使其自动化。
send
send命令接收一个字符串参数,并将该参数发送到进程。
expect1.1> send “hello world\n”
hello world
expect
expect命令和send命令正好相反,expect通常是用来等待一个进程的反馈。expect可以接收一个字符串参数,也可以接收正则表达式参数。和上文的send命令结合,
简单来讲,就是等到标准输入,然后执行指定命令。
spawn命令
上文的所有demo都是和标准输入输出进行交互,但是我们跟希望他可以和某一个进程进行交互。spawm命令就是用来启动新的进程的。spawn后的send和expect命令都是和spawn打开的进程进行交互的。结合上文的send和expect命令我们可以看一下更复杂的程序段了。
set timeout -1
spawn ftp ftp.test.com //打开新的进程,该进程用户连接远程ftp服务器
expect "Name" //进程返回Name时
send "user\r" //向进程输入anonymous\r
expect "Password:" //进程返回Password:时
send "123456\r" //向进程输入don@libes.com\r
expect "ftp> " //进程返回ftp>时
send "binary\r" //向进程输入binary\r
expect "ftp> " //进程返回ftp>时
send "get test.tar.gz\r" //向进程输入get test.tar.gz\r
这段代码的作用是登录到ftp服务器ftp ftp.uu.net上,并以二进制的方式下载服务器上的文件test.tar.gz。程序中有详细的注释。
interact
到现在为止,我们已经可以结合spawn、expect、send自动化的完成很多任务了。但是,如何让人在适当的时候干预这个过程了。比如下载完ftp文件时,仍然可以停留在ftp命令行状态,以便手动的执行后续命令。interact可以达到这些目的。下面的demo在自动登录ftp后,允许用户交互。
spawn ftp ftp.test.com
expect "Name"
send "user\r"
expect "Password:"
send "123456\r"
interact
语法: 模式-动作
expect最常用的语法是来自tcl语言的模式-动作。这种语法极其灵活,下面我们就各种语法分别说明。
单一分支模式语法:
expect "hi" {send "You said hi"}
匹配到hi后,会输出”you said hi”
多分支模式语法:
expect "hi" { send "You said hi\n" } \
"hello" { send "Hello yourself\n" } \
"bye" { send "That was unexpected\n" }
匹配到hi,hello,bye任意一个字符串时,执行相应的输出。等同于如下写法:
expect {
"hi" { send "You said hi\n"}
"hello" { send "Hello yourself\n"}
"bye" { send "That was unexpected\n"}
}
Example
SDK Install
#!/usr/bin/expect -f
#############################################################################################
# This script is using for installing the keywriter #
# @Author : Fredy Zhang # #
# @date :2022-02-18
# @update : fredy V1 #
##############################################################################################
# ---Args
# 1 install package name
set Pkg_PATH [lindexargv 0]
# 2 install package
set Install_PATH [lindexargv 1]
set Pkg_Name [exec echo Install_PATH | cut -d / -f 6 ]
set timeout 600
# set time [exec date +%Y%m%d]
# set PSDKLA [exec echo "SJ_PATH_PSDKRA"]
# set run_command env(HOME)
set UserNameenv(USER)
puts "--- Pkg_PATH : Pkg_PATH"
puts "--- Install_PATH :Install_PATH"
puts "--- Pkg_Name : Pkg_Name"
puts "--- UserName :UserName"
spawn Pkg_PATH
set count 100;
while {count > 0 } {
expect {
"Please choose an option" { send "13\r"; exp_continue }
"Enter] to continue:" { send "\r"; exp_continue }
"Do you accept this license?" { send "y\r"; exp_continue }
"/home/UserName/Pkg_Name" { send "Install_PATH\r"; exp_continue }
"Do you want to continue?" { send "Y\r"; exp_continue }
"View Readme file?" { send "Y\r"; exp_continue }
eof { }
timeout { puts "timeout waiting for response" ; close ; exit }
}
set times [ exprcount-1];
}
Remote SSH
#!/usr/bin/expect -f
#############################################################################################
# This script is using for remote ssh #
# @Author : Fredy Zhang # #
# @date :2022-03-19 #
# @update : fredy V1 #
##############################################################################################
# ---Args
# 1 install package name
set SERVER_IP [lindexargv 0]
# 2 install package
set REMOTE_IP [lindexargv 1]
set timeout 600
set time [exec date +%Y_%m_%d]
# set PSDKLA [exec echo "SJ_PATH_PSDKRA"]
# set run_commandenv(HOME)
set UserName env(USER)
puts "--- SERVER_IP :SERVER_IP"
puts "--- REMOTE_IP : REMOTE_IP"
puts "--- time :time"
puts "--- UserName -- : UserName"
spawn ssh fredy@SERVER_IP
expect "password:"
send "***\r";
expect "Last login:"
send "scp /home/UserName/atlassian/share/backups/backup-time.zip fredy@REMOTE_IP:/home/fredy/backup \r";
expect "fredy@REMOTE_IP's password:"
send "*****\r";
expect "100%"
send "exit\r "
expect eof
Reference
- https://www.geeksforgeeks.org/expect-command-in-linux-with-examples/
- https://www.thegeekstuff.com/2011/01/expect-expressions-loops-conditions/
- https://www.cnblogs.com/dion-90/articles/8570601.html
- https://linux.die.net/man/1/expect