Net::CLI::Interact::Manual::Tutorial(3pm) User Contributed Perl Documentation Net::CLI::Interact::Manual::Tutorial(3pm)
NAME
Net::CLI::Interact::Manual::Tutorial - Guide for new users
Introduction
Automating command line interface (CLI) interactions is not a new idea, but can be tricky to implement. Net::CLI::Interact aims to provide
a simple and manageable interface to CLI interactions, supporting:
o SSH, Telnet and Serial-Line connections
o Unix and Windows support
o Reusable device command phrasebooks
The module exists to support developers of applications and libraries which must interact with a command line interface. The SYNOPSIS
section of Net::CLI::Interact has an overview of the commands demonstrated in this document.
Getting Started
Like many other Perl modules, you need to load the library and then create a new Net::CLI::Interact instance (which is $s in the example,
below):
use Net::CLI::Interact;
my $s = Net::CLI::Interact->new({
transport => 'Serial',
personality => 'cisco',
});
Your application can have multiple independent instances (that is, connect to different devices at the same time); simply repeat the above
example more times for variables other than $s.
Note that at the time you create the instance, as in the example above, the library does not connect to the device. That comes later.
There were two options provided to the "new" call, above, both of which are required for all new instances. Let's look at them in turn:
transport
How do you want to connect to your CLI? The current choices are Telnet, SSH and a Serial line (that is, a console cable). In this
option you need to tell the library which underlying transport is to be used.
Some of the transports have additional options that are either required, or optional. For example, the Telnet and SSH transports both
need to know which post name or IP address should be contacted. You pass this in another option to "new", like so:
my $s = Net::CLI::Interact->new({
transport => 'Telnet',
connect_options => { host => 'my.server.example.com' },
personality => 'cisco',
});
See the manual page of the transport module for the option details.
personality
What language does the connected device speak? For instance one common format is Cisco's IOS, which is widely cloned on other vendor
equipment CLIs. In this option you need to pass the name of a personality that's used to load a Phrasebook.
A phrasebook is simply a library, or dictionary, of pre-configured phrases you can use on the CLI. This makes life simple, because
Net::CLI::Interact then can automate some of the more difficult tasks. For example, if you issue a command and the output is "paged" so
you hit Space or Return to see the next page, the phrasebook can tell Net::CLI::Interact how to slurp all these pages into one body of
output before returning it to you.
See the Phrasebook user guide for a list of the possible values for the "personality" option.
Connecting
This is done automatically for you the first time you send a command to the device, so skip this step and move on!
Sending Commands
But first, Prompts
The idea of sending a command is, usually, to see some output. The most important part of this process is knowing when the output has all
been sent, otherwise the library would sit forever, waiting to gather more text!
Between each command sent, the connected device prints a CLI Prompt. This prompt is where you type commands, and it's what tells us that
all the output has been sent from our last command. Prompts are loaded in the phrasebook, and given friendly names.
If your personality's phrasebook is sufficiently mature, then the prompts might be fully automated, and just like the Connecting step
above, you can skip doing anything manually. Consult the Phrasebook user guide for details.
However if you need to set it manually, do the following:
$s->set_prompt('friendly_name');
Sometimes you might not know what state the CLI is in; typically this applies to Serial lines. In that case you can ask to find the
matching prompt:
$s->find_prompt('wake_up');
The option "wake_up" asks to "hit the Return key", to make the device spit out its prompt. That is only done if needed, and you can remove
"wake_up" to skip this step.
Literal Commands
There's not a lot to it. Remember that with a mature personality loaded, you were probably able to skip the previous prompt step and go
straight to:
my $output = $s->cmd('show ip interfaces brief');
Here you will get all the output from the command together in one variable, $output. If you prefer an array where each item is one line of
output, simply use @output instead in the above example.
Macros
Life gets more complicated when your command has things like confirmation steps (e.g. reboot), other prompts (e.g. extended ping), etc. For
these situations we have Macros in the phrasebook.
A macro is simply a sequence of commands we could issue using "$s->cmd()", bundled together and given a friendly name. Macros are also
smart enough either to handle simple confirmation steps themselves, or to allow you to pass in parameters. Some examples probably help:
# saves config, accepting the default "startup-config" when prompted
$s->macro('write_mem');
# logs in, passing a username and password at the prompts
$s->macro('to_user_exec', {
params => ['my_username', 'my_password'],
});
# simply a parameterized command
$s->macro('show_interfaces_x', {
params => ['GigabitEthernet 3/4'],
});
Slurping Output
As mentioned above, output at the CLI is often "paged" with the user hitting Space or Return to show the next page. Most macros can deal
with this automatically if well implemented.
If the Phrasebook user guide says your personality has a named default Continuation for handling paged output, then set it like so:
$s->set_default_continuation('friendly_name');
Disconnecting
This is nothing more fancy than issuing the appropriate CLI commands to close the network connection. In the case of the Serial line
transport you can usually only log out, and not fully disconnect. Simply end your application and the library will tidy things up as best
it can.
perl v5.14.2 2012-06-12 Net::CLI::Interact::Manual::Tutorial(3pm)