dnstap: adds message_types option for filtering

[mathetake]

Note: I am completely open to discuss the naming of the option

1. Why is this pull request needed and what does it do?

This resolves #4198 and #6640 by introducing message_types configuration in the dnstap plugin.

2. Which issues (if any) are related?

#4198 and #6640

3. Which documentation changes (if any) need to be made?

dnstap/README.md

4. Does this introduce a backward incompatible change or deprecation?

No.

---

~I left this as draft until we agreed on the naming of the option. I would appreciate it if you folks can take a look @rdrozhdzh @miekg (pinging the people in the original issue #4198)~

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 58.33333% with 25 lines in your changes are missing coverage. Please review.

Project coverage is 59.28%. Comparing base (93c57b6) to head (2a493b7). Report is 1184 commits behind head on master.

Files	Patch %	Lines
plugin/forward/dnstap.go	0.00%	22 Missing :warning:
plugin/dnstap/setup.go	83.33%	2 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6643      +/-   ##
==========================================
+ Coverage   55.70%   59.28%   +3.58%     
==========================================
  Files         224      252      +28     
  Lines       10016    13501    +3485     
==========================================
+ Hits         5579     8004    +2425     
- Misses       3978     4904     +926     
- Partials      459      593     +134     

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[mathetake]

@rdrozhdzh thank you for the thorough reviews. I think I addressed all your comments, so I would appreciate it if you can take a look again!

[rdrozhdzh]

@mathetake , just curious, are you going to implement the dnstap message filtering based on the DNS response RCODE, as you mentioned in your original request?

[mathetake]

@rdrozhdzh actually, I am not planning to introduce that RCODE based filter as that seems not worth it vs the complexity in the API.

[mathetake]

kindly ping any codeowner for a quick look?

[mathetake]

I really hate to be nagging, and I understand all of you guys are busy doing other stuff, but by any chance could one of you code owners take a look? @johnbelamaric @miekg @Tantalor93 @chrisohaver @yongtang

[mathetake]

sorry let me ping again - this is the last time I won't do that again.

[mathetake]

Unfortunately at this point I have to think at the point CoreDNS is no longer willing to accept contributions any more despite all the helps from multiple people in the community. I'm really sorry to see this happen but I am no longer able to engage here. 😔 closing.