freshnessWarningThreshold config option

[Tom Scavo]

For a metadata document with a constant 14-day validity window, the
following consumer policy statements are equivalent:

1. Log a warning if NOW is within 8 days of the metadata expiration date

2. Log a warning if NOW is within 6 days of the metadata creation date

In the above example, expirationWarningThreshold=”P8D”. [1]

For the use case I have in mind, relying on the creation date is
preferable since it does not depend on @validUntil. The latter is a
critical policy decision point communicated by the metadata producer
to all consumers. OTOH, the creation date of the document is fact, not
policy.

I don’t dispute that expirationWarningThreshold is a necessary config
option. What I think is needed, however, is a complementary
freshnessWarningThreshold config option that keys off @creationInstant
(if present):

/md:EntitiesDescriptor/md:Extensions/mdrpi:PublicationInfo/@creationInstant

Similar to the RequiredValidUntil metadata filter, a filter that
requires the @creationInstant attribute would be useful. Moreover, the
filter should enforce the fact that consecutively published metadata
documents must have @creationInstant values that are monotonically
increasing. If a document fails this check, a consumer may conclude
that the document has been replayed, intentionally or otherwise.

Tom

[1] expirationWarningThreshold http://marc.info/?t=149472172300002&r=1&w=2