Improved simple monitor script

git-svn-id: http://pexpect.svn.sourceforge.net/svnroot/pexpect/trunk@164 656d521f-e311-0410-88e0-e7920216d269

1 files changed, 64 insertions, 14 deletions

diff --git a/pexpect/examples/monitor.py b/pexpect/examples/monitor.py
index 723813e..fbed084 100755
--- a/pexpect/examples/monitor.py
+++ b/pexpect/examples/monitor.py
@@ -1,40 +1,90 @@
 #!/usr/bin/env python
-'''This runs "uname" on a remote host using SSH.
+'''This runs some commands on a remote host using SSH.
     At the prompts enter hostname, user, and password.
+
+   It works like this:
+        Login via SSH (This is the hardest part).
+        Run and parse 'uptime'.
+        Run 'iostat'.
+        Run 'vmstat'.
+        Run 'free'.
+        Exit the remote host.
+
 '''
 import pexpect
 import getpass
 
+#
+# Some constants
+#
+                # This is the prompt we get if SSH does not have the remote host's
+                # public key stored in the cache yet.
 SSH_NEWKEY = 'Are you sure you want to continue connecting (yes/no)?'
+TERMINAL_PROMPT = 'Terminal type?'
+TERMINAL_TYPE = 'vt100'
+COMMAND_PROMPT = '[$#] ' ### This is way too simple for industrial use :-) ...
 
+
+print 'Enter the host that you wish to monitor.'
 host = raw_input('Hostname: ')
 user = raw_input('User: ')
 password = getpass.getpass('Password: ')
 
-child = pexpect.spawn("ssh -l %s %s"%(user, host))
+#
+# Login via SSH
+#
+child = pexpect.spawn('ssh -l %s %s'%(user, host))
 i = child.expect([pexpect.TIMEOUT, SSH_NEWKEY, 'password: '])
-if i == 1:
-	child.sendline ('yes')
-	child.expect ('password: ')
+if i == 0: # Timeout
+        print 'ERROR!'
+        print 'SSH could not login. Here is what SSH said:'
+        print child.before, child.after
+        sys.exit (1)
+if i == 1: # SSH does not have the public key. Just accept it.
+        child.sendline ('yes')
+        child.expect ('password: ')
 child.sendline(password)
-i = child.expect (['[#$] ', 'Terminal type?'])
+        # Now we are either at the command prompt or
+        # the login process is asking for our terminal type.
+i = child.expect ([COMMAND_PROMPT, TERMINAL_PROMPT])
 if i == 1:
-	child.sendline ('vt100')
-	child.expect ('[#$] ')
+        child.sendline (TERMINAL_TYPE)
+        child.expect (COMMAND_PROMPT)
 
-child.sendline ('uptime')
+# Now we should be at the command prompt and
+# ready to run some commands.
+print
+print '---------------------------------------'
+print 'Report of commands run on remote host.'
 
+# Run and parse 'uptime'.
+child.sendline ('uptime')
 child.expect ('up ([0-9]+) days?,.*?,\s+([0-9]+) users?,\s+load averages?: ([0-9]+\.[0-9][0-9]), ([0-9]+\.[0-9][0-9]), ([0-9]+\.[0-9][0-9])')
 duration, users, av1, av5, av15 = child.match.groups()
-print '%s days, %s users, %s (1 min), %s (5 min), %s (15 min)' % (
+print
+print 'Uptime: %s days, %s users, %s (1 min), %s (5 min), %s (15 min)' % (
     duration, users, av1, av5, av15)
+child.expect (COMMAND_PROMPT)
 
-child.expect ('[#$] ')
+# Run iostat.
 child.sendline ('iostat')
-child.expect ('[#$] ')
+child.expect (COMMAND_PROMPT)
+print
+print child.before
+
+# Run vmstat.
+child.sendline ('vmstat')
+child.expect (COMMAND_PROMPT)
+print
 print child.before
-child.sendline ('exit')
-child.expect(pexpect.EOF)
 
+# Run free.
+child.sendline ('free') # Linux systems only.
+child.expect (COMMAND_PROMPT)
+print
 print child.before
 
+# Now exit the remote host.
+child.sendline ('exit')
+child.expect(pexpect.EOF)
+