NAME
Net::Appliance::Session - Run command-line sessions to network
appliances
VERSION
version 4.122730
SYNOPSIS
use Net::Appliance::Session;
my $s = Net::Appliance::Session->new({
personality => 'ios',
transport => 'SSH',
host => 'hostname.example',
privileged_paging => 1, # only if using ASA/PIX OS 7+
# and there are other behaviour options, see below
});
try {
$s->connect({ username => 'username', password => 'loginpass' });
$s->begin_privileged({ password => 'privilegedpass' });
print $s->cmd('show access-list');
$s->end_privileged;
}
catch {
warn "failed to execute command: $_";
}
finally {
$s->close;
};
DESCRIPTION
Use this module to establish an interactive command-line session with a
network appliance. There is special support for moving into "privileged"
mode and "configure" mode, along with the ability to send commands to
the connected device and retrieve returned output.
There are other CPAN modules that cover similar ground, but they are
less robust and do not handle native SSH, Telnet and Serial Line
connections with a single interface on both Unix and Windows platforms.
Built-in commands come from a phrasebook which supports many network
device vendors (Cisco, HP, etc) or you can install a new phrasebook.
Most phases of the connection are configurable for different device
behaviours.
METHODS
As in the synopsis above, the first step is to create a new instance.
Recommended practice is to wrap all other calls (except "close()") in a
"try" block, to catch errors (typically time-outs waiting for CLI
response). This module exports the "try/catch/finally" methods (from
Try::Tiny) into your namespace as a simpler alternative to using
"eval()".
For a full demonstration of usage, see the example script shipped with
this distribution.
Net::Appliance::Session->new( \%options )
my $s = Net::Appliance::Session->new({
personality => 'ios',
transport => 'SSH',
host => 'hostname.example',
});
Prepares a new session for you, but will not connect to any device. Some
options are required, others optional:
"personality => $name" (required)
Tells the module which "language" to use when talking to the
connected device, for example "ios" for Cisco IOS devices. There's a
list of all the supported platforms in the Phrasebook documentation.
It's also possible to write new phrasebooks.
"transport => $backend" (required)
The name of the transport backend used for the session, which may be
one of Telnet, SSH, or Serial.
"app => $location" (required on Windows)
On Windows platforms, you must download the "plink.exe" program, and
pass its location in this parameter.
"host => $hostname" (required for Telnet and SSH transports)
When using the Telnet and SSH transports, you must provide the IP or
host name of the target device in this parameter.
"connect_options => \%options"
Some of the transport backends can take their own options. For
example with a serial line connection you might specify the port
speed, etc. See the respective manual pages for each transport
backend for further details (SSH, Telnet, Serial).
"add_library => $directory"
If you've added to the built-in phrasebook with your own macros,
then use this option to load your new phrasebook file(s). The path
here should be the directory within which all your personalities are
located, such as:
${directory}/cisco/ios/pb
${directory}/other/device/pb
Usually the phrasebook files are called ""pb"" and to the
"personality" option you pass the containing directory name, for
example "ios" or "device" in the examples shown. See
Net::CLI::Interact::Manual::Tutorial for further details.
connect( \%options )
$s->connect({ username => $myname, password => $mysecret });
To establish a connection to the device, and possibly also log in, call
this method. Following a successful connection, paging of device output
will be disabled using commands appropriate to the platform. This
feature can be suppressed (see "CONFIGURATION", below).
Options available to this method, sometimes required, are:
"username => $name"
The login username for the device. Whether this is required depends
both on how the device is configured, and how you have configured
this module to act. If it looks like the device presented a Username
prompt. and you don't pass the username a Perl exception will be
thrown.
The username is cached within the module for possible use later on
when entering "privileged" mode.
"password => $secret"
The login password for the device. Whether this is required depends
both on how the device is configured, and how you have configured
this module to act. If it looks like the device presented a Username
prompt. and you don't pass the username a Perl exception will be
thrown.
The password is cached within the module for possible use later on
when entering "privileged" mode.
"privileged_password => $secret" (optional)
In the situation where you've activated "privileged paging", yet
your device uses a different password for privileged mode than
login, you'll need to set that other password here.
Otherwise, because the module tries to disable paging, it first goes
into privileged mode as you instructed, and fails with the wrong
(login) password.
begin_privileged and end_privileged
$s->begin_privileged;
# do some work
$s->end_privileged;
Once you have connected to the device, change to "privileged" mode by
calling the "begin_privileged" method. The appropriate command will be
issued for your device platform, from the phrasebook. Likewise to exit
"privileged" mode call the "end_privileged" method.
Sometimes authentication is required to enter "privileged" mode. In that
case, the module defaults to using the username and password first
passed in the "connect" method. However to either override those or set
them in case they were not passed to "connect", use either or both of
the following options to "begin_privileged":
$s->begin_privileged({ username => $myname, password => $mysecret });
begin_configure and end_configure
$s->begin_configure;
# make some changes
$s->end_configure;
To enter "configuration" mode for your device platform, call the
"begin_configure" method. This checks you are already in "privileged"
mode, as the module assumes this is necessary. If it isn't necessary
then see "CONFIGURATION" below to modify this behaviour. Likewise to
exit "configure" mode, call the "end_configure" method.
cmd( $command )
my $config = $s->cmd('show running-config');
my @interfaces = $s->cmd('show interfaces brief');
Execute a single command statement on the connected device. The
statement is executed verbatim on the device, with a newline appended.
In scalar context the response is returned as a single string. In list
context the gathered response is returned as a list of lines. In both
cases your local platform's newline character will end all lines.
You can also call the "last_response" method which returns the same data
with the same contextual behaviour.
This method accepts a hashref of options following the $command, which
can include a "timeout" value to permit long running commands to have
all their output gathered.
To handle more complicated interactions, for example commands which
prompt for confirmation or optional parameters, you should use a Macro.
These are set up in the phrasebook and issued via the "$s->macro($name)"
method call. See the Phrasebook and Cookbook manual pages for further
details.
If you receive response text with a "mangled" copy of the issued command
at the start, then it's likely you need to set the terminal width. This
prevents the connected device from line-wrapping long commands. Issue
something like:
$s->begin_privileged;
$s->cmd('terminal width 512');
close
$s->close;
Once you have finished work with the device, call this method. It
attempts to back out of any "privileged" or "configuration" mode you've
entered, re-enable paging (unless suppressed) and then disconnect.
If a macro named "disconnect" exists in the loaded phrasebook then it's
called just before disconnection. This allows you to issue a command
such as "exit" to cleanly log out.
CONFIGURATION
Each of the entries below may either be passed as a parameter in the
options to the "new" method, or called as a method in its own right and
passed the appropriate setting. If doing the latter, it should be before
you call the "connect" method.
do_login
Defaults to true. Pass a zero (false) to disable logging in to the
device with a username and password, should you get a command prompt
immediately upon connection.
do_privileged_mode
Defaults to true. If on connecting to the device your user is
immediately in "privieleged" mode, then set this to zero (false),
which permits immediate access to "configure" mode.
do_configure_mode
Defaults to true. If you set this to zero (false), the module
assumes you're in "configure" mode immediately upon entering
"privileged" mode. I can't think why this would be useful but you
never know.
do_paging
Defaults to true. Pass a zero (false) to disable the post-login
reconfiguration of a device which avoids paged command output. If
you cleanly "close" the device connection then paging is re-enabled.
Use this option to suppress these steps.
privileged_paging
Defaults to false. On some series of devices, in particular the
Cisco ASA and PIXOS7+ you must be in privileged mode in order to
alter the pager. If that is the case for your device, call this
method with a true value to instruct the module to better manage the
situation.
pager_enable_lines
Defaults to 24. The command issued to re-enable paging (on
disconnect) typically takes a parameter which is the number of lines
per page. If you want a different value, set it in this option.
pager_disable_lines
Defaults to zero. The command issued to disable paging typically
takes a parameter which is the number of lines per page (zero begin
to disable paging). If your device uses a different number here, set
it in this option.
wake_up
When first connecting to the device, the most common scenario is
that a Username (or some other) prompt is shown. However if no
output is forthcoming and nothing matches, the "enter" key is
pressed, in the hope of triggering the display of a new prompt. This
is typically most useful on Serial connected devices.
Set this configuration option to zero to suppress this behaviour, or
to the number of times "enter" should be pressed and output waited
for. The default is to press "enter" once.
ASYNCHRONOUS BEHAVIOUR
The standard, and recommended way to use this module is as above,
whereby the application is blocked waiting for command response. It's
also possible to send a command, and separately return to ask for output
at a later time.
$s->say('show clock');
This will send the command "show clock" to the connected device,
followed by a newline character.
$s->gather();
This will gather and return output, with similar behaviour to "cmd()",
above. That is, it blocks waiting for output and a prompt, will timeout,
and accepts the same options.
You can still use "last_response" after calling "gather", however be
aware that the command (from "say") may be echoed at the start of the
output, depending on device and connection transport.
DIAGNOSTICS
To see a log of all the processes within this module, and a copy of all
data sent to and received from the device, call the following method:
$s->set_global_log_at('notice');
In place of "notice" you can have other log levels (e.g. "debug" for
more, or "info" for less), and via the embedded Logger at
"$s->nci->logger" it's possible to finely control the diagnostics.
INTERNALS
See Net::CLI::Interact.
THANKS
Over several years I have received many patches and suggestions for
improvement from users of this module. My heartfelt thanks to all, for
their contributions.
AUTHOR
Oliver Gorwits <oliver@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2012 by Oliver Gorwits.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.