[collectd] Plain text protocol question

[Jean Baptiste FAVRE]

Hello Mariusz,

XANi a écrit :
> On Thu, 08 Oct 2009 12:00:13 +0200, Jean Baptiste FAVRE
> <collectd at jbfavre.org> wrote:
>> Heelo,
>> I'm new on the list, but already using collectd since a few months.
> Hi,
>> In order to be able to improve data display, I'm trying to stream them
>> to a web page. I plan to use either lightstreamer
>> (http://www.lightstreamer.com/) or ape-project
>> (http://www.ape-project.org/)
>>
>> But the first step is to be able to get values. Therefore, I activated
>> Unix Socket plugin and try to get data.
>> I'm now able to use LISTVAL (despite some strange display effects,
>> mostly due to my client code I think), but facing issues with GETVAL.
>>
>> If possible, I would rather prefer using sort of wildcard, for
>> example: GETVAL hostname/*
>>
>> Is there any way to achieve it, or will I have to parse each line of
>> LISTVAL to get it working ?
> Atm you would have to do LISTVAL then GETVAL. Also (afaik) atm. there
> is no way to get info about updates so you have to do LISTVAL every x
> seconds to check which values got updated and then do GETVAL (because
> GETVAL doesn't return timestamp of last update)
Hmm, did not tought about that. Just wanted to get data as quickly as
possible, but so I'll do this way.

> Atm im writing simple daemon to "publish" data from rrd and unixsocks
> (and probably other sources like DBs) as JSON/XML (lot of ppl seem to
> be interested about some way of getting data out of collectd thru JSON)
That could be usefull

> and I had similar problems, basically:
> 1. No way to "subscribe" for data  like "plz if data from path matching
> host/interface/if_octets.*" change then send it to me"
I think this could be solved using APE or something equivalent. The idea
is that collectd send *all* new data to APE.
Then APE in turn push new data to web browser. This way, you could
imagine having a page per monitored host so that you "magically" get
data update each time collectd insert them into APE.

> 2. GETVAL dont have last update in output so u have to do LISTVAL
> anyway if u wanna know if data is stall or fresh
Yep, I'll have to deal with data freshness as well.

Regards,
JB