Class10 exercise

learnpy_ecourse/class10/main_program.py

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+'''
+
+This is a solution to the below problem given the content we have
+discussed in class.  It is not necessarily the best solution to the problem.
+In other words, I generally only use things we have covered up to this point
+in the class (with some exceptions which I will usually note). 
+
+Python for Network Engineers
+https://pynet.twb-tech.com
+Learning Python
+
+
+Create a script that can login to a network device (using either telnet or SSH) 
+and retrieve 'show version' from the device.  
+
+Process the 'show version' output and store the below attributes in a 
+NetworkDevice object:
+
+NetworkObject
+    hostname
+    ip
+    username    
+    password 
+    device_type          # router, switch, firewall, etc.
+    vendor
+    model
+    os_version
+    uptime               # seconds
+    serial_number
+
+
+This object should be stored to a file using pickle. 
+
+
+Here is the output of running essentially this code against a test device 
+(password stripped):
+
+$ python main_program.py 
+
+Using SSH:
+       hostname: twb-sf-881                              
+             ip: 10.220.88.1                             
+       username: pynet                                   
+       password: *
+    device_type: router                                  
+         vendor: Cisco                                   
+          model: 881                                     
+     os_version: 15.0(1)M4                               
+         uptime: 8978280                                 
+  serial_number: FTX1512038X                             
+
+Using telnet:
+       hostname: twb-sf-881                              
+             ip: 10.220.88.1                             
+       username: pynet                                   
+       password: *
+    device_type: router                                  
+         vendor: Cisco                                   
+          model: 881                                     
+     os_version: 15.0(1)M4                               
+         uptime: 8978280                                 
+  serial_number: FTX1512038X                             
+
+
+
+Reading objects from pickle files:
+       hostname: twb-sf-881                              
+             ip: 10.220.88.1                             
+       username: pynet                                   
+       password: *
+    device_type: router                                  
+         vendor: Cisco                                   
+          model: 881                                     
+     os_version: 15.0(1)M4                               
+         uptime: 8978280                                 
+  serial_number: FTX1512038X                             
+
+       hostname: twb-sf-881                              
+             ip: 10.220.88.1                             
+       username: pynet                                   
+       password: *
+    device_type: router                                  
+         vendor: Cisco                                   
+          model: 881                                     
+     os_version: 15.0(1)M4                               
+         uptime: 8978280                                 
+  serial_number: FTX1512038X                             
+
+'''
+
+
+import time
+import pickle
+
+import ssh_connection as ssh
+import telnet_connection as telnet
+from show_version_parser import process_show_version
+
+
+class NetworkDevice(object):
+    def __init__(self, ip, username, password):
+        self.ip = ip
+        self.username = username
+        self.password = password
+
+
+def ssh_main():
+    '''
+    Process show version using SSH
+    '''
+
+    ip = '10.220.88.1'
+    username = 'pynet'
+    password = '*'
+
+    test_device = NetworkDevice(ip, username, password)
+
+    (remote_conn_pre, remote_conn, output) = ssh.establish_connection(ip, username, password)
+    output = ssh.disable_paging(remote_conn)
+
+    remote_conn.send("\n")
+    remote_conn.send("show version\n")
+
+    # Read the output from the 'show version' command
+    test_device.show_version = ssh.read_ssh_data(remote_conn)
+
+    remote_conn_pre.close()
+    process_show_version(test_device)
+
+    # Print to stdout for verification
+    net_device_verification(test_device)
+
+    # Write object to a file
+    with open('ssh_file.pkl', 'wb') as f:
+        pickle.dump(test_device, f)
+
+
+def telnet_main():
+    '''
+    Process show version using telnet
+    '''
+
+    ip = '10.220.88.1'
+    username = 'pynet'
+    password = '*'
+
+    test_device2 = NetworkDevice(ip, username, password)
+
+    remote_conn = telnet.establish_connection(ip, username, password)
+
+    telnet.disable_paging(remote_conn)
+
+    remote_conn.write("\n")
+    remote_conn.write("show version\n")
+
+    time.sleep(1)
+    test_device2.show_version = remote_conn.read_very_eager()
+
+    remote_conn.close() 
+    process_show_version(test_device2)
+
+    # Print to stdout for verification
+    net_device_verification(test_device2)
+
+    # Write object to a file
+    with open('telnet_file.pkl', 'wb') as f:
+        pickle.dump(test_device2, f)
+
+
+def net_device_verification(net_device):
+    '''
+    Prints out a set of attributes for a NetworkDevice object
+    '''
+
+    print_attr = [    
+        'hostname',
+        'ip',
+        'username',
+        'password',
+        'device_type',
+        'vendor',
+        'model',
+        'os_version',
+        'uptime',
+        'serial_number',
+    ]
+
+    # Uses getattr to get the right attribute
+    for field in print_attr:
+        val = getattr(net_device, field)
+        print "%15s: %-40s" % (field, val)
+
+    print
+
+if __name__ == "__main__":
+
+    print
+    print "Using SSH:"
+    ssh_main()
+
+    print "Using telnet:"
+    telnet_main()
+
+    print "\n"
+    print "Reading objects from pickle files:"
+    my_files = ['ssh_file.pkl', 'telnet_file.pkl']
+    for a_file in my_files:
+        with open(a_file, 'rb') as f:
+            netdev_obj = pickle.load(f)
+            net_device_verification(netdev_obj)
+

learnpy_ecourse/class10/show_version_parser.py

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+import re
+from uptime import Uptime
+
+def process_show_version(net_device):
+    '''
+    Process the show_version output for net_device
+
+    Assign the following attributes to the net_device object
+
+    hostname
+    device_type          # router, switch, firewall, etc.
+    vendor
+    model
+    os_version
+    uptime               # seconds
+    serial_number
+
+    '''
+
+    show_ver = net_device.show_version
+
+    # Process show_version output
+    net_device.vendor, net_device.model = obtain_vendor_model(show_ver)
+    net_device.os_version = obtain_os_version(show_ver)
+    net_device.uptime = obtain_uptime(show_ver)
+    net_device.hostname = obtain_hostname(show_ver)
+    net_device.serial_number = obtain_serial_number(show_ver)
+    net_device.device_type = obtain_device_type(net_device.model)
+
+
+def obtain_vendor_model(show_ver):
+
+    # '(.+?) ' means any sequence of one or more characters followed by space (shortest match)
+    match = re.search(r"Cisco (.+?) .+bytes of memory", show_ver)
+    if match:
+        return ("Cisco", match.group(1))
+    else:
+        return None
+
+def obtain_os_version(show_ver):
+
+    # (.+?), means any sequence of one or more characters followed by comma (shortest match)
+    match = re.search(r"Cisco IOS Software.*Version (.+?),", show_ver)
+    if match:
+        return match.group(1)
+    else:
+        return None
+
+def obtain_uptime(show_ver):
+
+    match = re.search(r".* uptime is .*", show_ver)
+
+    if match:
+        uptime_str = match.group().strip()
+        uptime_obj = Uptime(uptime_str)
+        return uptime_obj.uptime_seconds()
+    else:
+        return None
+
+def obtain_hostname(show_ver):
+    '''
+    Example string from Cisco IOS:
+    twb-sf-881 uptime is 14 weeks, 4 days, 22 hours, 59 minutes
+    
+    return the hostname, else None
+    '''
+
+    match = re.search(r"(.+) uptime is .+", show_ver)
+    if match:
+        return match.group(1)
+    else:
+        return None
+
+def obtain_serial_number(show_ver):
+    '''
+    Example string from Cisco IOS:
+    Processor board ID FTX1000008X
+
+    return the serial_number, else None
+    '''
+
+    match = re.search(r"Processor board ID (.+)", show_ver)
+    if match:
+        return match.group(1).strip()
+    else:
+        return None
+
+def obtain_device_type(model):
+    '''
+    Determine the device_type based on the model
+    '''
+
+    if '881' in model:
+        return 'router'
+    else:
+        return None
+

learnpy_ecourse/class10/ssh_connection.py

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+import paramiko
+import time
+
+def disable_paging(remote_conn, command="terminal length 0\n", delay=1):
+
+    remote_conn.send("\n")
+    remote_conn.send(command)
+
+    # Wait for the command to complete
+    time.sleep(delay)
+
+    output = remote_conn.recv(65535)
+
+    return output
+
+
+def establish_connection(ip, username='', password=''):
+    '''
+    Use Paramiko to establish an SSH channel to the device
+
+    Must return both return_conn_pre and return_conn so that the SSH
+    connection is not garbage collected
+    
+    '''
+
+    remote_conn_pre = paramiko.SSHClient()
+    remote_conn_pre.set_missing_host_key_policy(
+        paramiko.AutoAddPolicy())
+
+    remote_conn_pre.connect(ip, username=username, password=password)
+
+    remote_conn = remote_conn_pre.invoke_shell()
+
+    # Clear banner and prompt
+    output = remote_conn.recv(65535)
+
+    return (remote_conn_pre, remote_conn, output)
+
+
+def read_ssh_data(remote_conn, delay=1):
+    '''
+    Read the data from the ssh channel
+
+    Uses a delay based mechansim
+    '''
+
+    # Wait for the command to complete
+    time.sleep(delay)
+    return remote_conn.recv(65535)
+
+
+if __name__ == "__main__":
+
+    ip = '10.220.88.1'
+    username = 'pynet'
+    password = '*'
+
+    (remote_conn_pre, remote_conn, output) = establish_connection(ip, username, password)
+    output = disable_paging(remote_conn)
+
+    remote_conn.send("\n")
+    remote_conn.send("show version\n")
+
+    output = read_ssh_data(remote_conn)
+    print output
+
+    remote_conn_pre.close()