python - pexpect - multiple expect, spawn, kill child

python - pexpect - multiple expect, spawn, kill child

pexpect - multiple expect:

i = child.expect(['first', 'second'])

The expect() method returns the index of the pattern that was matched. So in your example:

if i == 0:
    # do something with 'first' match
else: # i == 1
    # do something with 'second' match

Spawn:

• The more powerful interface is the spawn class. 
• You can use this to spawn an external child command and then interact with the child by sending lines and expecting responses.

child = pexpect.spawn('scp foo myname@host.example.com:.')
child.expect ('Password:')
child.sendline (mypassword)

close(force=True)

• This closes the connection with the child application. 
• Note that calling close() more than once is valid. 
• This emulates standard Python behavior with files. 
• Set force to True if you want to make sure that the child is terminated (SIGKILL is sent if the child ignores SIGHUP and SIGINT).

child.close() 

or child.close(force=true)

Program:

import pexpect

import getpass

import sys

PASSWORD = "admin123"

def child_kill(child_pro):

    if child_pro.isalive():

        print "Still child is live 1 \n"

        child_pro.close()       # Kill the child, give argument as force=true then also same behaviour

    if child_pro.isalive():

        print "Still child is live 2\n\n"

    else:

        print "Child is dead"

def child_read_command(child_pro, command, expect_str):

    child_pro.sendline (command)

    child_pro.expect (expect_str)

# use list format, string format is not working

    output = []

    done = False

    while True:

        try:

            if not child_pro.isalive():

                line = child_pro.readline()

                done = True

            else:

# Wait on multiple expect eg: i = child.expect(['first', 'second'])

# i retrun 0 for first, and 1 for second

                i = child_pro.expect(['\n', expect_str])

                if i == 0:

                    line = child_pro.before

                    print(line)

                else:

                    line = child_pro.before

                    print(line)

                    break

            output.append(line)

            if done:

                raise pexpect.EOF(0)

                print "Rasie the pexect EOF"

        except pexpect.EOF:

            print "Break of EOF"

            break

    print "\n\nOutput value = ", output

    child_kill(child_pro)

Reference: http://www.bx.psu.edu/~nate/pexpect/pexpect.html