tree a3d34c7ac52f16650de55ba28d3621add81e5f99
parent 886d2892d1717bc130cfa008742c06c29f7ff186
author Serge Bazanski <serge@nexantic.com> 1618324814 +0200
committer Leopold Schabel <leo@nexantic.com> 1618336271 +0200

m/n/c/consensus: add client

This implementes a thin wrapper around etcd's clientv3.Client, with the
following advantages:

 - Only implements KV, Watcher and Lease interfaces, ie. unprivileged
   namespaceable interfaces - not cluster management interfaces. These
   will be available to both remote and local etcd connections.
 - Adds recursive namespacing functionality, which permits different
   parts of the subsystem to receive their own somewhat-sandboxed etcd
   subtree. This not only makes the etcd keyspace layout more strict,
   but also simplifies passing around etcd clients, as major components
   (like the kubernetes subsystem) can hand out its own sub-clients,
   instead of them having to be globally declared ahead of time.

Test Plan: Exercised by tests.

X-Origin-Diff: phab/D756
GitOrigin-RevId: 03fead9a89c301a2e70df8a007b7ecb60b2364c7