Hi All-
I wanted to kick off a thread discussing some changes to the internal
model we would like to make. The driver for these are:
* to allow arbitrary relationships between items to be expressed
(imagine a UI with a rich graph, where you pick which relationships you
are interested in)
* to simplify the internal code by making Feeds, Locations, Policies,
etc all be Entity instances
* to persist entities as YAML -- so the live state of any entity has the
same format as the blueprint which deploys it
Thoughts?
The work to add relations to the AbstractBrooklynObject model is in a
new PR at https://github.com/apache/incubator-brooklyn/pull/987.
This should facilitate the list of proposed next steps described below
(and in the PR).
Best
Alex
Make custom relations usable:
* add CAMP YAML `brooklyn.relations` field to allow callers to specify
relations
* add REST API to query relations
* update UI to show relations
Replace management and group membership with relations:
* new "active_child" relationship for a managed child which is important
enough to call out in the UI
* add subscriptions for relations on an entity
* replace 'members' field in Group with GROUP_CONTAINS relationship
leave old field there for deserialization for one release cycle,
but empty it and move everything to be a relation
use subscription to update count
* replace `parent/children` fields in Entity with use of relations
* again leaving fields in place for one release cycle in order to
update count
* add `addChild(Entity, boolean isActive)` such that last item can
be set false to establish a management-only relationship
* REST API call for "children" to show only ACTIVE children
Finally simplify persistence:
* make Policy, Enricher Feed, etc all be Entities
* make Location be Entities and replace the LocationRegistry with use of
locations in catalog
* use IN_LOCATION, HAS_POLICY, HAS_FEED, etc relations for them, instead
of custom persistence
* allow Catalog to support arbitrary types (i.e. it becomes a Registry
of types, rather than a Catalog)
* with warning or fail if we try to persist an unknown type
* with serialization info (to allow migration across versions)
* persist as YAML
END
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