From: Alexander Lamb <Alexander.J.Lamb@...>
Date: 2005-10-21T23:09:28+09:00
Subject: Re: Threads, timing and HTTP

>
>
>> I am implementing a very simple script to ping web servers or
>> services (to monitor how our environment is functionning).
>>
>
> This thread seems to thrashing around a bit.
>
> By what criteria do you establish how your environment is  
> functioning? Once you know that you can look into how to monitor  
> those criteria alone and no others.
>
> A 'ping' is really testing the network and web server  
> responsiveness (assuming the ping task is simple). You can't  
> separate those. Establish a base line and compare to that. I'd  
> think that if the network or server is stalling for any reason  
> you'd like to know, and when comparing to a base line you have a  
> chance of detecting that.
>
> The application responsiveness is probably best measured on the  
> server by the application itself, possibly by recording the time  
> between first touch on the app through to the close or flush of the  
> socket. You'd have to ask the application to report on this.
>
>
Yes, you are right. This ping is really only the first building block  
(but you can't imagine how many times we had problems because of a  
simple Apache server which didn't restart gracefully at midnight:-)  
at the same time the apps were running fine... just nobody could get  
to them, which is rather annoying in a hospital.

That's why we have a monitoring system which monitors not only the  
Apache servers but some key WebServices as well. To monitor  
WebServices we either do some kind of dummy search (e.g. give me the  
list of patients in this unit) or implement a specific service which  
shall test a few things and reply with some information about speed  
of the transaction and other things.

What you saw in my post is the first block ( a simple HTTP Ping  
probe) for the new system I wish to develop in Ruby. I will then have  
a sort of master process which will consolidate the states of the  
various probes and display (to be defined: how) the situation. If  
some situation seems critical, then some kind of alert will be  
escalated.

This brings to another question (sorry I am a beginner in Ruby): is  
there a rule engine available in Ruby where you could express rules a  
bit like with Jess in Java?

Thanks

Alex