[openstack-dev] [ceilometer][all] the max length of an id

Chris Dent chdent at redhat.com
Sat Jun 27 08:29:44 UTC 2015

I suppose it is redundant to point out the following, but hey, you know
without a bit of dogma each and every day on a mailing list how could
we call ourselves a real open source project? Apologies to people
for whom this is review.

An identifier which is derived from its context and contains
meaningful information cannot be considered any of:

* universal
* unique
* persistent
* portable

and thus doesn't really qualify as a good identifier, especially in
distributed systems.

Providing or displaying meaning is why we have other fields or
lookup by reference. An id and title are not the same thing.

The easiest way to follow the rules (that is to create unique,
universal, persistent, portable and meaningless identifiers) is to use
solely a UUID and nothing else when creating resource ids. If you then
need to get additional information on that thing you know you've got a
good id with which to get that information because it is an actual
identifier, by definition.

I assume it is probably too late to go back and make this true
everywhere, but we should do what we can to make it real

Chris Dent tw:@anticdent freenode:cdent

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