An open discussion list for topics related to the eduGAIN interfederation service.

[Tomasz Wolniewicz <twoln AT umk.pl>]

Hi Leif,

W dniu 27.11.2019 o 10:35, Leif Johansson pisze:
> Having said that I believe it would be better for edugain to spend
> some time to describe a more precise way to express the desired
> outcome when an entity appears in multiple feeds and then we can
> get that implemented instead of relying on the current method which
> is pretty brittle and depends on a side-effect on how pyFF handles
> parallelism.

The current solution is of course something that has always been a
questionable choice but it has one big advantage, the algorithm does not
depend on per-entity history. If we were to go, what I would consider a
more natural way, that is server the entity from the federation that
published it first, we would need to remember it and consult it during
aggregation. We would also need to decide what happens if an entity
drops out from the supplying feed and what happens if it returns, will
the algorithm depend on the length of this break etc.

We did spend a considerable amount of time considering various dark
corners, things were discussed in the early days of eduGAIN when the
current aggregator was being built. No one was really pushing the
problem and we decided that relying on the current ordering approach is
giving reasonably predictable results and is easy to implement so this
is what was done.

You now seem to be saying that the aggregation result done with pyFF may
be unpredictible, this might mean that the incoming feeds would already
need to be stripped down so that no clashes may acrually appear. That
would mean that a considerable amount of side programming would be
needed. I think that the only way forward is do discuss what you might
want to implement in pyFF and what should be adjusted to make eduGAIN
work up to everybody's expectations.

Cheers

Tomasz


-- 
Tomasz Wolniewicz    
          twoln AT umk.pl        http://www.home.umk.pl/~twoln

Uniwersyteckie Centrum Informatyczne   Information&Communication Technology 
Centre
Uniwersytet Mikolaja Kopernika     Nicolaus Copernicus University,
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