commit 41ebabf2eb618b33fd30ad1821ccbda9d6390010
author Andrew Wong <awong@cloudera.com> Sat Aug 28 13:55:47 2021 -0700
committer Andrew Wong <awong@cloudera.com> Tue Sep 21 22:36:29 2021 +0000
tree d22ad5f5dad71d2c25ab0638e1765fb0df62cd6f
parent 246505b538a6449eda7a9936609e9fec4632fe5d

[rpc] KUDU-75: refresh DNS entries if proxies hit a network error

This patch aims to tackle the following issues that revolve around
changes in addresses at runtime.
- KUDU-1885: master long-lived tserver proxies need to be re-resolved in
  case nodes are assigned different addresses; today we just retry at
  the same location forever.
- KUDU-1620: tablet consensus long-lived proxies need to be re-resolved
  on failure.
- C++ clients' usages of RemoteTabletServer also have long-lived proxies
  and are likely to run into similar problems if tservers are restarted
  and assigned new physical addresses.

It addresses this by plumbing a DnsResolver into the rpc::Proxy class,
and chaining the asynchronous callback to an asynchronous refresh of the
address with the newly introduced refreshing capabilities of the
DnsResolver.

The new style of proxy isn't currently used, but a test is added
exercising the new functionality.

Change-Id: I777d169bd3a461294e5721f05071b726ced70f7e
Reviewed-on: http://gerrit.cloudera.org:8080/17839
Tested-by: Kudu Jenkins
Reviewed-by: Alexey Serbin <aserbin@cloudera.com>