kmb at mssl.ucl.ac.uk
Wed Dec 7 08:21:14 PST 2005
Yes this is sounding quite good. I like the idea of a more centralized
logging service where by other services can push the data to the central
Now for the central logging service I don't think in this first version
it would need a "push" model, I would prefer to let clients/apps come
and get the data.
A possible suggestion is "OAI" for obtaining the data from centralized
logging services. Deals with dates such as "from" or "until". One of
the IVOA components "registry" currently uses it. And also deals with
large amounts of data with the notion of a "resumptionToken" allowing a
client to page through the results. And finally there are already
several OAI tools to help the implementation.
Doug Tody wrote:
> One way this could work:
> o Each site operates a logging service which is distinct from
> service instances (for data access, computation, etc.).
> o Services send lightweight messages to the local, centralized
> logging service whenever anything happens. This helps keeps the
> services simple and stateless.
> o The logging service has the ability to both push logging data to
> subscribers, as well as respond to queries for logging data.
> o In push or publish/subscribe mode, it would be relatively
> easy to
> buffer data and send a message containing logging data only
> periodically. This would avoid the problems of managing very
> large amounts of logging data, but would still be efficient due
> to the buffering.
> o The logging service could also expose a query interface for
> a client to directly access logging data, e.g., by a range of
> dates, everything since a certain date, or some other method.
> Since it is a separate service this does not complicate other
> service interfaces.
> o If security is an issue it can easily be dealt with by the
> service. This is a somewhat different case than for normal
> data access/analysis services, as only grid infrastructure needs
> to access logging information.
> It would also be possible for simple services which are not heavily used
> (small sites) to send small amounts of logging information to a remote
> logging service, to avoid the need for small sites to support a logging
> service locally. - Doug
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