How To Download Files From The Nagios Exchange Using WGET

Overview

This KB article shows you how to download a file directly from the Nagios Exchange to your Linux server using the WGET command.

This can be handy when you require an additional plugin on your Nagios server or an NRPE client.

Download File

In this example we want to download the plugin check_doomsday.php which is located here:

Doomsday Check

The actual URL for the plugin is:

https://exchange.nagios.org/components/com_mtree/attachment.php?link_id=2862&cf_id=24

As you can see from the URL it doesn't actually include the name of the plugin check_doomsday.php and if you tried to download using wget you would end up with a file named attachment.php?link_id=2862 and it would be empty ... not what you are after.

This is because there is some special http redirecting going on with the Nagios Exchange web server, so instead you would download the file as follows.

First you'll change in the directory you want the file to be downloaded to:

cd /usr/local/nagios/libexec/

Downloaded the file using this command:

wget "https://exchange.nagios.org/components/com_mtree/attachment.php?link_id=2862&cf_id=24" -O check_doomsday.php

Which will produce something like this:

--2016-08-02 16:53:19--  https://exchange.nagios.org/components/com_mtree/attachment.php?link_id=2862&cf_id=24
Resolving exchange.nagios.org... 66.228.58.94, 2600:3c02::f03c:91ff:fedf:d653
Connecting to exchange.nagios.org|66.228.58.94|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 5307 (5.2K) [application/octet-stream]
Saving to: “check_doomsday.php”

100%[=====================================================================>] 5,307       --.-K/s   in 0.003s  

2016-08-02 16:53:21 (1.59 MB/s) - “check_doomsday.php” saved [5307/5307]

The important parts of this command:

• The entire URL is enclosed in "double quotes"

• Use the argument -O filename to redirect the output to a file

  • That's an upper case "oh", not a zero

You should set the appropriate ownership and permissions as well:

chown nagios:nagios check_doomsday.php
chmod 0755 check_doomsday.php

Now you're all set to run the plugin:

php /usr/local/nagios/libexec/check_doomsday.php

Which will produce:

Dec 21, 2012 passed and things are still okay. Whew!

What a relief!

Special Thanks

This KB article would not have been possible without a suggestion from Sean Falzon and additional technical support from Eric Loyd. Both of them are always looking to help make Nagios administration easier.

Final Thoughts

For any support related questions please visit the Nagios Support Forums at:

http://support.nagios.com/forum/