Hi,
just for the record / archives..
On 2015-04-22 01:29, Ken McDonell wrote:
> On 21/04/15 22:43, Marko Myllynen wrote:
>> ...
>> hmm, so it is possible to provide a redirected metric from another
>> domain in C but is there a way to do that in Perl or Python? And is it
>> possible to read a metric from another domain to be used to calculate or
>> construct a new metrics in the current domain, not just redirect?
>
> In general this is not possible.
>
> Think about the flow of a request (you're building pmda A and pmda B has
> the metrics you're interested in):
>
> client -> pmcd -> pmda A -> ???
>
> If pmda A tries to use pmcd to get to pmcd B we have a callback into
> pmcd and all sorts of timeout headaches ... pmie in "secret agent mode"
> for the summary PMDA does this, but I would not recommend that as a
> precedent to be copied!
>
> If pmda B has some non-pcp export channel (as well) that could be used.
>
> Otherwise, source code replication from pmda B into pmda A is likely to
> be the simplest (and most efficient) strategy.
I think derived metrics would be helpful in the case I was thinking,
i.e., to construct a new metric based on metrics provided by pmda A and
by pmda B.
Thanks,
--
Marko Myllynen
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