Previously the consul_keys resource did double-duty as both a reader and
writer of values from the Consul key/value store, but that made its
interface rather confusing and complex, as well as having all of the other
general problems associated with read-only resources.
Here we split the functionality such that reading is done with the
consul_keys data source while writing is done with the consul_keys
resource.
The old read behavior of the resource is still supported, but it's no
longer documented (except as a deprecation note) and will generate
deprecation warnings when used.
In future it should be possible to simplify the consul_keys resource by
removing all of the read support, but that is deferred for now to give
users a chance to gracefully migrate to the new data source.
Seth Vargo