The streaming cache type for service health has no way to handle v1/health/ingress/:service queries as there is no equivalent topic that would return the appropriate data.
Ensure that attempts to use this endpoint will use the old cache-type for now so that they return appropriate data when streaming is enabled.
So that all the client side filtering is in the same place. Previously
only the bexpr filter was in the cache-entry.
Also makes a small change to the filtering so that instead of rebuilding
slices of items, the filtering can return a bool to determine if the
event payload is saved or not.
Send empty array [] instead of [""] in DNS requests when TagFilter is not set
Do not change case sensitivity of services anymore in `getServiceNodes()` since
cache keys are now case insensitive
This new package provides a client agent implementation of an interface
for fetching the health of services.
This approach has a number of benefits:
1. It provides a much more explicit interface. Instead of everything
dependency on `RPC()` and `Cache.Get()` for many unrelated things
they can depend on a type that are named according to the behaviour
it provides.
2. It gives us a single place to vary the behaviour and migrate to
a new form of RPC (gRPC). The current implementation has two options
(cache, or direct RPC), and in the future we will have more.
It is also a great opporunity to start adding `context.Context` args
to these operations, which in the future will allow us to cancel
the operations.
3. As a concequence of the first, in the Server agent where we make
these calls we can replace the current in-memory RPC calls with
a thin adapter for the real method. This removes the `net/rpc`
machinery from the call in places where it is not needed.
This new package is quite small right now, but I think we can expect it
to grow to a more reasonable size as other RPC calls are replaced.
This change also happens to replace two very similar implementations with
a single implementation.
