M3 code refactor & DBI support

Pluggable M3 (Monitis Monitor Manager) Framework

Who needs an introduction about M3? – Perhaps no one!
After gaining some reputation with M3, providing extra-easy integration of any monitor into Monitis it was time to take it to the next level.

Generally speaking, the work flow of M3 was described in detail in this article.

After some thought and design, we’ve decided it’d be best if M3 was pluggable. Pluggable in terms of being able to easily add execution and parsing plugins.
The interface and behavior of M3 stayed exactly the same, however now it is much easier to obtain data from any source and parse the data the way you want it.
Saying that, it was time to put the new design for a test. We tried to integrate the DBI support into M3.
Guess what – it was much easier than expected!

The general idea of DB integration with Monitis

DB (as in Database) integration with Monitis has shown to be invaluable. Being able to extract application related data from a DB and load it to Monitis means you can graph anything going on in your database related application. Monitoring your DB is an integral part of server monitoring in today’s world.

Be it maximum number of users at peak hours, gathering statistics about record usage or just checking if your DB is serving requests quickly enough – graphing performance and uptime. Your imagination is the limit – considering your application is DB related of course.

How it’s done – the technicalities beyond

The sharp-eyed among you would notice that M3 got beefed up with a directory named “Execution” and a directory named “Parsing”.
These directories hold the plugins M3 uses for each.

All that I had to do to add DBI support is to create a new execution plugin called “DBI.pm” and fill it up with code from the Monitis DBI module which already existed.

And that my friends, that, was easy. Mission accomplished – Pluggable M3 eases the job for us.

Another way to integrate MySQL

MySQL could have been integrated previously into M3 by executing mysql and feeding it with a query, having something similar to:

 <exectemplate>echo "select count(*) from mysql.user;" | mysql</exectemplate> 

This form of execution will invoke the ‘mysql’ executable, feeding it the above query. Execution of this will result in the response of the query being returned with some other useless output.

Please avoid this form of execution, as now DBI support is fully integrated into M3. In the next paragraph I’ll show how it should be done.

Lets fetch

While conveying ideas about M3, I decided to prefer to provide very simple examples of operation, however, I encourage you, the end user to let your imagination go wild, adding interesting counters which show how your application really perform and behave.

In this example we’ll just count the number of users in an installed MySQL database. An example anyone should be able to imitate and then scale to his own need.

We’ll examine the following example. I suggest opening the mentioned link in a new window while continuing the read.
Looking at this example it is quite straight-forward to understand. The query to execute is over there, together with some other parameters which are mandatory to connect to a database, such as the database name, user name, password, etc.

An explanation should be provided however for the odd db_statistics parameter. Those of you who have read the HTTP extraction article about M3 would have probably remembered the http_statistics parameter. Then, the db_statistics one does more or less the same, providing some meta counters for the query:

1. How long did the query take to process (in seconds)
2. The success/failure of the query (1 for success, 0 for failure)

I encourage to do the parsing of query results, or actually the lack-of-parsing of query results in a way that takes the whole output returns from the query, hence the regular expression of (.*).

If your query returns more than what you need, please tune your query better.
Test your execution with:

 # ./DryRun.pl dbi_sample.xml DB: 'root@DBI:mysql:mysql:localhost', Query: 'select count(*) from mysql.user;' at MonitisMonitorManager.pm line 223 Matched '(.*)'=>'6' in '6' at MonitisMonitorManager.pm line 237 OK This is a dry run, data for monitor 'Sample MySQL Monitor' was not really updated. at ./DryRun.pl line 18 

It should work. Then you can work your query to fit your own needs.

Next in line

We’re looking for some more new ideas to add as plugins for M3. If you have any idea about any plugin (execution or parsing plugin) that you would like to see in M3 – we want to hear you!

Integrating software into the powerful Monitis has never been easier, now that you have M3!

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