open-consul/agent/rpcclient
Daniel Nephin 04c5b9adf5 rpcclient: Add health.Client and use it in http and dns
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.
2020-10-04 18:55:02 -04:00
..
health rpcclient: Add health.Client and use it in http and dns 2020-10-04 18:55:02 -04:00