Basics – Experimenting with the REST API in NetWorker

Overview

As I mentioned in the previous article, NetWorker 9 SP1 has introduced a REST API. I’ve never previously got around to playing with REST API interfaces, but as is always the case with programming, you either do it because you’re getting paid to or because it’s something that strikes you as interesting.

Accessing NetWorker via a REST API does indeed strike me as interesting. Even more so if I can do it using my favourite language, Perl.

This is by no means meant to be a programming tutorial, nor am I claiming to be the first to experiment with it. If you want to check out an in-development use of the REST API, check out Karsten Bott’s PowerShell work to date over at the NetWorker Community Page. This post covers just the process of bootstrapping myself to the point I have working code – the real fun and work comes next!

What you’ll need

For this to work, you’ll need a suitably recent Perl 5.x implementation. I’m practicing on my Mac laptop, running Perl 5.18.2.

You’ll also need the following modules:

• MIME::Base64
• REST::Client
• Data::Dumper
• JSON

And of course, you’ll need a NetWorker server running NetWorker 9, SP1.

Getting started

I’m getting old an crotchety when it comes to resolving dependencies. When I was younger I used to manually download each CPAN module I needed, try to compile, strike dependency requirements, recurse down those modules and keep going until I’d either solved all the dependencies or threw the computer out the window and became a monk.

So to get the above modules I invoked the cpan install function on my Mac as follows:

pmdg@ganymede$ cpan install MIME::Base64
pmdg@ganymede$ cpan install REST::Client
pmdg@ganymede$ cpan install Data::Dumper
pmdg@ganymede$ cpan install JSON

There was a little bit of an exception thrown in the REST::Client installation about packages that could be used for testing, but overall the CPAN based installer worked well and saved me a lot of headaches.

The code

The code itself is extremely simple – as I mentioned this is a proof of concept, not intended to be an interface as such. It’s from here I’ll start as I play around in greater detail. My goal for the code was as follows:

• Prompt for username and password
• Connect via REST API
• Retrieve a complete list of clients
• Dump out the data in a basic format to confirm it was successful

The actual code therefore is:

pmdg@ganymede$ cat tester.pl

#!/usr/bin/perl -w

use strict;
use MIME::Base64();
use REST::Client;
use Data::Dumper;
use JSON;

my $username = "";
my $password = "";

print "Username: ";
$username = <>;
chomp $username;

print "Password: ";
$password = <>;
chomp $password;

my $encoded = MIME::Base64::encode($username . ":" . $password);
$ENV{PERL_LWP_SSL_VERIFY_HOSTNAME} = 0;
my $client = REST::Client->new();
my $headers = { Accept => 'application/json', Authorization => 'Basic ' . $encoded};
$client->setHost('https://orilla.turbamentis.int:9090');
$client->GET('/nwrestapi/v1/global/clients',$headers);
my $response = from_json($client->responseContent);
print Dumper($response);

Notes on the Code

If you’re copying and pasting the code, about the only thing you should need to change is the hostname in the line starting $client->setHost.

It’s not particularly secure in the password prompt as Perl will automatically echo the password as you’re entering it. There are ways of disabling this echo, but they require the Term::Readkey library and that may not be readily available on all systems. So just keep this in mind…

The Results

Here’s the starting output for the code:

pmdg@ganymede$ ./tester.pl
Username: administrator
Password: MySuperSecretPassword
$VAR1 = {
          'clients' => [
                         {
                           'ndmpMultiStreamsEnabled' => bless( do{\(my $o = 0)}, 'JSON::PP::Boolean' ),
                           'ndmpVendorInformation' => [],
                           'protectionGroups' => [],
                           'resourceId' => {
                                                'sequence' => 79,
                                                'id' => '198.0.72.12.0.0.0.0.132.105.45.87.192.168.100.4'
                                           },
                           'links' => [
                                        {
                                           'rel' => 'item',
                                           'href' => 'https://orilla.turbamentis.int:9090/nwrestapi/v1/global/clients/198.0.72.12.0.0.0.0.132.105.45.87.192.168.100.4'
                                        }
                                      ],
                           'parallelSaveStreamsPerSaveSet' => $VAR1->{'clients'}[0]{'ndmpMultiStreamsEnabled'},
                           'hostname' => 'archon.turbamentis.int',

And so on…

In Summary

The script isn’t pretty at the moment, but I wanted to get it out there as an example. As I hack around with it and get more functionality, I’ll provide updates.

Hopefully however you can see that it’s pretty straight-forward overall to access the REST API!

References

• REST API Getting Started Guide
• REST API Reference Guide
• Writing a REST Client in Perl – I basically used this as supplementary explanations to the CPAN documentation for the REST::Client module.
• Karsten’s PowerShell REST Interface