Question

I’m having trouble programmatically running a local script over ssh.
I’m unsure if this is a problem with the shell variable substitution on the local host.

When manually running,

ssh monit@server1 'bash -s' < /u02/splunk/splunk/etc/apps/Splunk_TA_nix/bin/cpu.sh

I get the expected output,

CPU pctUser pctNice pctSystem pctIowait pctIdle
all 11.21 0.00 1.50 0.31 86.98
0 0.00 0.00 0.00 0.00 100.00
1 3.00 0.00 1.00 0.00 96.00
….

but I get

bash: /u02/splunk/splunk/etc/apps/Splunk_TA_nix/bin/cpu.sh: No such file or directory

when running the following code,

splunk_bin_dir = '/u02/splunk/splunk/etc/apps/Splunk_TA_nix/bin'
hostname = 'server1'
username = 'monit'
password = 'monit#_'


command = "/usr/bin/ssh %(username)s@%(hostname)s 'bash -s' < %(splunk_bin_dir)s/cpu.sh" % locals()
print command

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

p = pexpect.spawn(command, 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
        p.sendline(password)
        p.expect(pexpect.EOF)
elif i == 1:
    # send the password
    p.sendline(password)
    p.expect(pexpect.EOF)
elif i == 2:
    print "pexpect faced key or connection timeout"
    pass

print p.before

These are the printed outputs,

/usr/bin/ssh monit@server1 ‘bash -s’ < /u02/splunk/splunk/etc/apps/Splunk_TA_nix/bin/cpu.sh
Initial pexpect command output: 1
bash: /u02/splunk/splunk/etc/apps/Splunk_TA_nix/bin/cpu.sh: No such file or directory

pexpect is bumping into the [pP]assword line so I guess the password is being correctly passed,

Answer 1

Here the note from pexpect manual:

Remember that Pexpect does NOT interpret shell meta characters such as
redirect, pipe, or wild cards (>, |, or *). This is a common mistake.
If you want to run a command and pipe it through another command then
you must also start a shell.

This is the working line

command = """/bin/bash -c "/usr/bin/ssh  %(username)s@%(hostname)s 'bash -s' < %(splunk_bin_dir)s/cpu.sh" """ % locals()