Upgrade Netty to 4.1.x

[drcrallen]

Spark 2.3.0 upgrades Netty support to a 4.1 branch as per apache/spark#19884 . This PR upgrades various dependencies to all use Netty 4.1.x.

Solves #4390

((assuming the extension upgrades to spark 2.3 or greater))

[drcrallen]

This is being proposed because I'm doing some gRPC extensions internally. And the gRPC java libraries require netty 4.1

[leventov]

#5059 no longer an issue?

[drcrallen]

@leventov I don't have a great way to tell right now (we don't use http emitter internally) but looking at #4973 (comment) I was able to pinpoint the offending library causing all kinds of netty versions to be brought in. It was upgraded to a version that uses netty 4.1.29-Final

[drcrallen]

The dependencies now look like this:

https://gist.github.com/drcrallen/848d56a9aa409e15aab350b63eed7bd5

[drcrallen]

Noteably the following still have "old" netty dependencies:

• com.alibaba.rocketmq:rocketmq-remoting (added exclusion)
• org.apache.hadoop:hadoop-hdfs (but only in tests)

[drcrallen]

I'm going to explicitly exclude the rocket mq dependency on netty-all in the extension

[drcrallen]

@himanshug do you happen to have a way to reproduce the prior error in the new build environment?

java util is part of the main druid now.

[gianm]

LGTM based on the fact that #4390 and #4973 don't seem as relevant (Spark upgraded its Netty version, and java-util has been inlined into Druid). We should keep an eye on it during release validation for 0.13.0.

[drcrallen]

I put a Release Notes tag since we don't have a "might need more validation during release" kind of tag

[leventov]

@drcrallen please don't merge such important PRs with just one approve and without waiting for 3 working days (so that everybody has a chance to review it), as the current policy prescribes. I would say this PR should have been labelled Design Review

[drcrallen]

Whop, sorry about that

[drcrallen]

On a side not, I don't see how a version change qualifies as a design review. Can you explain the thought process there more?

[leventov]

I mean, this is an important decision that more than one party (apart from the PR author) should agree with. At Metamarkets we decided that we could upgrade to Netty 4.1, but already after this PR was merged. And we still don't know what people who care about Hadoop support (@nishantmonu51 / @b-slim) think

[gianm]

FWIW we will definitely be putting this through the paces hadoop-support wise before voting on the 0.13.0 release. So if it causes anything bad to happen then we will speak up then. @nishantmonu51 / @b-slim probably will too.

[nishantmonu51]

+1 from my side, If we face compatibility issues in our internal testing with the RC, will raise this again.