The original design for workload identities and ACLs allows for operators to
extend the automatic capabilities of a workload by using a specially-named
policy. This has shown to be potentially unsafe because of naming collisions, so
instead we'll allow operators to explicitly attach a policy to a workload
identity.
This changeset adds workload identity fields to ACL policy objects and threads
that all the way down to the command line. It also a new secondary index to the
ACL policy table on namespace and job so that claim resolution can efficiently
query for related policies.
Making the ACL Role listing return object a stub future-proofs the
endpoint. In the event the role object grows, we are not bound by
having to return all fields within the list endpoint or change the
signature of the endpoint to reduce the list return size.
