Re: putting mod_scoreboard_send in core?

[Stas Bekman]

Sander van Zoest wrote:
> On Wed, 13 Mar 2002, Doug MacEachern wrote:
> 
> 
>>in general, the concept is to serialize the scoreboard in such a way
>>that it can transfered over the network via http and "thawed" on
>>another machine.  i'm sure there's a better way to do this than
>>the mod_scoreboard_send thinger.
>>
> 
> I have done this in two ways with tools that are not in the httpd core.
> 
> - have SNMP polls to mod_nsmp(1) and then display it using MRTG, HP OpenView
>   Scotty, or whatever
> 
> - use mod_status_xml(2) and do periodic GET and use XSLT/SVG to merge
>   the content into a pretty graph/HTML page.

Both are cool, but compared to working with raw data they:

1. incur a huge overhead of creating xml or SNMP MIB compared to sending 
raw data.
2. won't let you use the same code one uses to work directly with 
scoreboard image.

How about adding a new mode for mod_status, so it'll send a raw image on 
demand? This will not require a new module and sounds like a good thing 
to do.

The scoreboard in 2.0 is not much different from 1.x so you can still 
freeze the raw data and thaw it later. Of course using the network 
byteorder needs to be added, which could be an option so those wanted 
the fastest retrieve times can still get the native byte ordering.




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Re: putting mod_scoreboard_send in core?

[Sander van Zoest]

On Wed, 13 Mar 2002, Doug MacEachern wrote:

> in general, the concept is to serialize the scoreboard in such a way
> that it can transfered over the network via http and "thawed" on
> another machine.  i'm sure there's a better way to do this than
> the mod_scoreboard_send thinger.

I have done this in two ways with tools that are not in the httpd core.

- have SNMP polls to mod_nsmp(1) and then display it using MRTG, HP OpenView
  Scotty, or whatever

- use mod_status_xml(2) and do periodic GET and use XSLT/SVG to merge
  the content into a pretty graph/HTML page.

I really do not see why this needs to be in the httpd core.

1) the SNMPv3 capable 
   or 
2)  with some contributed
   changes.
--
Sander van Zoest  [EMAIL PROTECTED]
San Diego, CA, US http://Sander.vanZoest.com/

Re: putting mod_scoreboard_send in core?

[Doug MacEachern]

a few notes on this.. the purpose of mod_scoreboard_send was to "download" 
the scoreboard image on a remote machine.  the scoreboard image was then 
used on the client machine to generate fancy graphical images to make our 
boss feel like he knew what was going on.  sorta like a graphical 
mod_status, but could also combine stats of a server farm into one browser
window.

anyhoo, the module should not go in as-is, it was designed to incur as 
little overhead as possible, pretty much sends the binary data as-is.  and 
hence isn't portable since it uses native byte order rather than network 
order.  which was ok for us since the client machine was the same 
architecture as the servers.  and the concept might not apply at all to 
the 2.0 scoreboard, i haven't looked at it.  in general, the concept is to 
serialize the scoreboard in such a way that it can transfered over the 
network via http and "thawed" on another machine.  i'm sure there's a 
better way to do this than the mod_scoreboard_send thinger.

putting mod_scoreboard_send in core?

[Stas Bekman]

The Apache::Scoreboard distribution for 1.x includes 
mod_scoreboard_send.c, which allows you to collect the scoreboards from 
many machines for various purposes. This is a special standalone C 
version which doesn't require mod_perl.

There is a C code which freeze()s the scoreboard and sends it to the 
client, which can then be thaw()ed to retrieve the scoreboard.

Apache::Scoreboard is now going to be folded into the mod_perl 2.0 core, 
therefore we cannot distribute mod_scoreboard_send.c any longer since 
there is no Apache-Scoreboard distribution. And those who will want to 
use mod_scoreboard_send.c won't want to grab mod_perl sources for it.

We think that the best place for this module is in the core. I haven't 
ported it to 2.0 yet, and plan to do it shortly. It's a very small modules.

Where should it go: modules/generators/mod_scoreboard_send?

p.s. all this cool stuff is a courtesy of Doug MacEachern, I'm just 
porting it to 2.0 ;)

_
Stas Bekman JAm_pH  --   Just Another mod_perl Hacker
http://stason.org/  mod_perl Guide   http://perl.apache.org/guide
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