python pexpect: SSHing then updating the date

Question

I have finally have my python pexpect script working except for the most important part updating the date! I am able to SSH in the box but my second command does not execute properly. I have been banging my head on the wall trying to figure out why. I have checked the output of the sting and it should be working based on whats coded. I am not a expert when it comes to python or pexpect so I am in need of a bit of help figuring out why my time is not updating.

my original code:

list = ["089"]
sn = 0

ssh_new_conn = 'Are you sure you want to continue connecting'

class ThreadClass(threading.Thread):
def __init__(self, index):
super(ThreadClass, self).__init__()
self.index = index
def run(self):

sn = storelist[self.index]


#easterndate = (currenttime + datetime.timedelta(0, 3600))
#easterndate = easterndate

est = timezone('US/Eastern')
cst = timezone('US/Central')
#currenttime = (datetime.now())
currenttime = cst.localize(datetime.now())
#easterndate = (currenttime + timedelta(0, 3600))
#easterndate = easterndate.strftime("%a %b %d %H:%M:%S %Z %Y")
easterndate = currenttime.astimezone(est).strftime("%a %b %d %H:%M:%S %Z %Y")
command1 = "/usr/bin/ssh %(username)s@%(hostname)s" % locals()
command2 = " sudo date -s\"%(easterndate)s\"" % locals()
command3 = " sudo date -s\"%(currenttime)s\"" % locals()
now = datetime.now()

#central
if sn == "073" or sn == "066" or sn == "016": #or sn == "022":
    p = pexpect.spawn((command1 + command3), timeout=360)


#eastern
else:
    print(command1 + command2)
    p = pexpect.spawn((command1 + command2), timeout=360)


# Handles the 3 possible connection outcomes:
# a) Ssh to the remote host for the first time, triggering 'Are you sure you want to continue connecting'
# b) ask you for password
# c) No password is needed at all, because you already have the key.
i = p.expect([ssh_new_conn,'[pP]assword:',pexpect.EOF])
print ' Initial pexpect command output: ', i
if i == 0:
    # send 'yes'
    p.sendline('yes')
    i = p.expect(['[pP]assword:',pexpect.EOF])
    print 'sent yes. pexpect command output', i
    if i == 0:
        # send the password
        print "logging into box %(sn)s" % locals()
        p.sendline(password)
        print "login successful"
        print "Setting the time..."

elif i == 1:
    # send the password
    print "logging into box %(sn)s" % locals()
    p.sendline(password)
    print "login successful"
    print "Setting the time..."
    p.close()

elif i == 2:
    print "pexpect faced key or connection timeout"
    pass

print p.before

for i in range(len(list)):
  t = ThreadClass(i)
  t.start()

New Code:

class ThreadClass(threading.Thread):
def __init__(self, index):
   super(ThreadClass, self).__init__()
   self.index = index
def run(self):

    try:
        sn = storelist[self.index]
        username = raw_input('username: ')
        password = raw_input('password: ')
        hostname = "[hostname]"
        est = timezone('US/Eastern')
        cst = timezone('US/Central')
        #currenttime = (datetime.now())
        currenttime = cst.localize(datetime.now())
        #easterndate = (currenttime + timedelta(0, 3600))
        #easterndate = easterndate.strftime("%a %b %d %H:%M:%S %Z %Y")
        easterndate = currenttime.astimezone(est).strftime("%a %b %d %H:%M:%S %Z %Y")
        ssh = pxssh.pxssh()

        print(hostname + " " + username + " " + password)
        ssh.login(hostname, username, password)

        if sn == "073" or sn == "066" or sn == "016": #or sn == "022":
            ssh.sendline ('date')       # run a command
            ssh.prompt()                # match the prompt
            print(s.before)           # print everything before the prompt.
            ssh.sendline ('sudo date -s\"%(currenttime)s\"' % locals())  # run a command
            ssh.expect('(?i)password.*:')  # match password prompt for sudo
            ssh.sendline(password)
            ssh.prompt()
            print(s.before)
            ssh.logout()
        else:
            ssh.sendline ('date')       # run a command
            ssh.prompt()                # match the prompt
            print(s.before)           # print everything before the prompt.
            ssh.sendline ('sudo date -s\"%(easterndate)s\"' % locals())  # run a command
            ssh.expect('(?i)password.*:')  # match password prompt for sudo
            ssh.sendline(password)
            ssh.prompt()
            print(s.before)
            ssh.logout()

    except pxssh.ExceptionPxssh as e:
        print(e)


for i in range(len(storelist)):
  t = ThreadClass(i)
  t.start()

New Error I am getting:

Traceback (most recent call last):
  File "./sshtest.py", line 8, in <module>
    s.login (hostname, username, password)
  File "/usr/lib/python2.6/dist-packages/pxssh.py", line 243, in login
    if not self.synch_original_prompt():
  File "/usr/lib/python2.6/dist-packages/pxssh.py", line 134, in synch_original_prompt
    self.read_nonblocking(size=10000,timeout=1) # GAS: Clear out the cache before getting the prompt
  File "/usr/lib/python2.6/dist-packages/pexpect.py", line 824, in read_nonblocking
    raise TIMEOUT ('Timeout exceeded in read_nonblocking().')
pexpect.TIMEOUT: Timeout exceeded in read_nonblocking().

SOLUTION TO ERROR

I figured out the solution to the error I was getting. Due to a known bug I had to add the following lines to usr/lib/python.2.6/dist-packages/pxssh.py:

self.sendline()       #line 134
time.sleep(0.5)       #line 135
self.read_nonblocking(size=10000,timeout=1) # GAS: Clear out the cache before getting the prompt

Answer 1

SOLUTION TO ERROR

I figured out the solution to the error I was getting. Due to a known bug I had to add the following lines to usr/lib/python.2.6/dist-packages/pxssh.py:

self.sendline()       #line 134
time.sleep(0.5)       #line 135
self.read_nonblocking(size=10000,timeout=1) # GAS: Clear out the cache before getting the prompt

Answer 2

You should probably handle the sudo password prompt (+ -t ssh option to get a tty) and use p.expect(EOF) before p.close() to avoid killing the child process prematurely.

Here's an example based on pexpect docs:

import pxssh
try:
    s = pxssh.pxssh()
    s.login (hostname, username, password)
    s.sendline ('date')       # run a command
    s.prompt()                # match the prompt
    print(s.before)           # print everything before the prompt.
    s.sendline ('sudo date')  # run a command
    s.expect('(?i)password.*:')  # match password prompt for sudo
    s.sendline(password)
    s.prompt()
    print(s.before)
    s.logout()
except pxssh.ExceptionPxssh as e:
    print(e)

You could also try fabric:

# fabfile.py
from fabric.api import run, sudo

def date():
    run('date')
    sudo('date')

Usage:

$ fab -H localhost,user@host date

Answer 3

To any other poor souls like me stuck with python 2.6 in 2019 and not wanting to hack their site-packages, I was able to fix this issue with setting maxread to 1 in the constructor.

pxssh.pxssh(maxread=1)