We already parse this information out anyways, so might as well add it
to the API output JSON. This can be leveraged by the Prometheus endpoint
as well to avoid duplicate listings.
This significantly simplifies cluster state handling by removing most of
the superfluous get_list() calls, replacing them with basic child reads
since most of them are just for a count anyways. The ones that require
states simplify this down to a child read plus direct reads for the
exact items required while leveraging the new read_many() function.
Adds a function, "read_many", which can take in multiple ZK keys and
return the values from all of them, using asyncio to avoid reading
sequentially.
Initial tests show a marked improvement in read performance of multiple
read()-heavy functions (e.g. "get_list()" functions) with this method.
Avoids multiple coordinators trying to write updated cluster-wide fault
events. Instead, they are now only written by the primary (or the
incoming primary if still in a transition).
Instead of using random hex characters from an md5sum, use a nice name
in all-caps similar to how Ceph does. This further helps prevent dupes
but also permits a changing health delta within a single event (which
would really only ever apply to plugin faults).
Since we already had a "details" field, simply move where it gets added
to the message later, in generate_fault, after the main message value
was used to generate the ID.
This ensures that certain faults e.g. Ceph status faults, will be
combined despite the added text in brackets, while still keeping them
mostly separate.
Also ensure the health text is updated each time to assist with this, as
this health text may now change independent of the fault ID.
