HBASE-23304: RPCs needed for client meta information lookup (apache#904)

[bharathv]

This patch implements the RPCs needed for the meta information
lookup during connection init. New tests added to cover the RPC
code paths. HBASE-23305 builds on this to implement the client
side logic.

Fixed a bunch of checkstyle nits around the places the patch
touches.

Signed-off-by: Andrew Purtell apurtell@apache.org

[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Comment
+0 🆗	reexec	0m 35s	Docker mode activated.
		_ Prechecks _
+1 💚	dupname	0m 1s	No case conflicting files found.
+0 🆗	prototool	0m 0s	prototool was not available.
+1 💚	hbaseanti	0m 0s	Patch does not have any anti-patterns.
+1 💚	@author	0m 0s	The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s	The patch appears to include 19 new or modified test files.
		_ branch-2 Compile Tests _
+0 🆗	mvndep	0m 16s	Maven dependency ordering for branch
+1 💚	mvninstall	5m 22s	branch-2 passed
+1 💚	compile	2m 25s	branch-2 passed
+1 💚	checkstyle	2m 15s	branch-2 passed
+1 💚	shadedjars	4m 16s	branch has no errors when building our shaded downstream artifacts.
+1 💚	javadoc	1m 34s	branch-2 passed
+0 🆗	spotbugs	0m 34s	Used deprecated FindBugs config; considering switching to SpotBugs.
+1 💚	findbugs	7m 51s	branch-2 passed
		_ Patch Compile Tests _
+0 🆗	mvndep	0m 15s	Maven dependency ordering for patch
+1 💚	mvninstall	4m 55s	the patch passed
+1 💚	compile	2m 24s	the patch passed
+1 💚	cc	2m 24s	the patch passed
+1 💚	javac	2m 24s	the patch passed
+1 💚	checkstyle	0m 12s	The patch passed checkstyle in hbase-protocol-shaded
+1 💚	checkstyle	0m 37s	hbase-client: The patch generated 0 new + 194 unchanged - 1 fixed = 194 total (was 195)
+1 💚	checkstyle	0m 13s	The patch passed checkstyle in hbase-zookeeper
+1 💚	checkstyle	1m 12s	hbase-server: The patch generated 0 new + 119 unchanged - 13 fixed = 119 total (was 132)
+1 💚	whitespace	0m 0s	The patch has no whitespace issues.
+1 💚	shadedjars	4m 19s	patch has no errors when building our shaded downstream artifacts.
+1 💚	hadoopcheck	15m 39s	Patch does not cause any errors with Hadoop 2.8.5 2.9.2 or 3.1.2.
+1 💚	hbaseprotoc	2m 17s	the patch passed
+1 💚	javadoc	1m 33s	the patch passed
+1 💚	findbugs	8m 20s	the patch passed
		_ Other Tests _
+1 💚	unit	0m 42s	hbase-protocol-shaded in the patch passed.
+1 💚	unit	3m 45s	hbase-client in the patch passed.
+1 💚	unit	0m 53s	hbase-zookeeper in the patch passed.
+1 💚	unit	153m 34s	hbase-server in the patch passed.
+1 💚	asflicense	2m 12s	The patch does not generate ASF License warnings.
		235m 0s

Subsystem	Report/Notes
Docker	Client=19.03.5 Server=19.03.5 base: https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-1098/1/artifact/out/Dockerfile
GITHUB PR	#1098
JIRA Issue	HBASE-23304
Optional Tests	dupname asflicense javac javadoc unit spotbugs findbugs shadedjars hadoopcheck hbaseanti checkstyle compile cc hbaseprotoc prototool
uname	Linux 1aaa31531bb2 4.15.0-58-generic #64-Ubuntu SMP Tue Aug 6 11:12:41 UTC 2019 x86_64 GNU/Linux
Build tool	maven
Personality	/home/jenkins/jenkins-slave/workspace/Base-PreCommit-GitHub-PR_PR-1098/out/precommit/personality/provided.sh
git revision	branch-2 / e0f9133
Default Java	1.8.0_181
Test Results	https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-1098/1/testReport/
Max. process+thread count	6066 (vs. ulimit of 10000)
modules	C: hbase-protocol-shaded hbase-client hbase-zookeeper hbase-server U: .
Console output	https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-1098/1/console
versions	git=2.11.0 maven=2018-06-17T18:33:14Z) findbugs=3.1.11
Powered by	Apache Yetus 0.11.1 https://yetus.apache.org

This message was automatically generated.

[wchevreuil]

LGTM

[ndimiduk]

@bharathv@apurtell What exactly was this commit? The message looks like it contains everything from the feature branch, but the changed files is just HBASE-23304.

Anyway, we haven't merged the feature branch to master yet; we're not quite ready to back port to branch-2. I think this should be reverted.

[bharathv]

Ya, so this is a squashed commit up until HBASE-23304. I'm ok with reverting it. I can submit a single PR with all the commits later, once the feature branch merges with master.

[apurtell]

Copying my comment from the JIRA:

There were multiple PRs opened for the same set of changes. I merged the one @bharathv indicated.

If you want to do it per JIRA per branch, fine. One PR per JIRA per branch. However that's a lot of noise for what it's worth.

I think it better one PR/merge for the whole backport per branch, with commit message incorporating all relevant JIRA references. These changes for the most part aren't useful in isolation.

[ndimiduk]

I see your reasoning. Squishing all the commits makes accounting more difficult, IMHO. The larger issue is that we're still stabilizing the tests vs. master; none of these commits have landed on master yet.

[ndimiduk]

I should say -- I propose one PR per branch containing all the commits, but land it using "rebase and merge" instead of "squash and merge" so that the individual commits are preserved. That make the accounting I refer to simpler. Agreed there's no need for one PR per commit.