It appears that in mine and everybody else's work capturing object changes is a
must-have. We have these discussions on user@ periodically, and 70% of my
clients have one or another implementation in their apps. So maybe we can do
something about it in Cayenne. The first attempt at it is already available
since 3.1 [1]. Still AuditableFilter is more like an example to follow, than a
drop-in implementation. So everyone keeps coming back with that same question
about audit.
The challenge here is spare the user from the change analysis, but allow to
customize a few extra things:
1. the mechanism where this data is stored (can be saved in the DB, broadcast
via MQ, stored in Kafka, etc.)
2. additional contents of the audit trail (security context, transaction id,
client IP address, etc.)
3. filtering entities we want to audit from other data changes.
I think I'll be able to open-source a new version of the AuditableFilter that
is pretty close to this. It emits a stream of changes as JSON:
{"ts":1427090346831,"by":"someuser","serverIP":"127.0.0.1","op":"UPDATE","id":"MyEntity:954619","changes":{"email":["r...@example.com","r...@example.org"]}}
The stream is a complete change log that doesn't lose anything. This includes
all possible object graph operations (create, update, delete, relationship
changes, ID changes). The object model behind this framework is quite reusable.
Filtering can be done either with entity annotations, or straight on the change
object stream. STDOUT can be the default storage (and JSON - the default format
for that), and we let the users to override it.
Does it sound like something you can use to rewrite your current audit
framework?
Comments?
Andrus
[1]
https://github.com/apache/cayenne/tree/master/cayenne-lifecycle/src/main/java/org/apache/cayenne/lifecycle/audit
