Refactoring prior to informers-cache rework

[jotak]

Description

Related: #681

This is a preliminary work preparing the ground for NETOBSERV-1248. No functional change here.
The goal is to minimize rebase hassle in #681

Details:
- Kafka read/write logic extracted from ingest/encode pipelines and put
  into a dedicated kafka package
- New k8s "datasource" struct for k8s enrichment - currently only has
  the usual informers datasource, but later will include a kafka-based
datasource as well
- Config related to k8s datasource moved into its own package. It
  includes the SecondaryNetwork config.
- Some minor variables/functions renaming

Dependencies

n/a

Checklist

If you are not familiar with our processes or don't know what to answer in the list below, let us know in a comment: the maintainers will take care of that.

• Will this change affect NetObserv / Network Observability operator? If not, you can ignore the rest of this checklist.
• Is this PR backed with a JIRA ticket? If so, make sure it is written as a title prefix (in general, PRs affecting the NetObserv/Network Observability product should be backed with a JIRA ticket - especially if they bring user facing changes).
• Does this PR require product documentation?
  • If so, make sure the JIRA epic is labelled with "documentation" and provides a description relevant for doc writers, such as use cases or scenarios. Any required step to activate or configure the feature should be documented there, such as new CRD knobs.
• Does this PR require a product release notes entry?
  • If so, fill in "Release Note Text" in the JIRA.
• Is there anything else the QE team should know before testing? E.g: configuration changes, environment setup, etc.
  • If so, make sure it is described in the JIRA ticket.
• QE requirements (check 1 from the list):
  • Standard QE validation, with pre-merge tests unless stated otherwise.
  • Regression tests only (e.g. refactoring with no user-facing change).
  • No QE (e.g. trivial change with high reviewer's confidence, or per agreement with the QE team).

[github-actions]

New image:
quay.io/netobserv/flowlogs-pipeline:3129586

It will expire after two weeks.

To deploy this build, run from the operator repo, assuming the operator is running:

USER=netobserv VERSION=3129586 make set-flp-image

[jpinsonneau]

Looks good. Do you plan to skip QE checks here ?

[codecov]

Codecov Report

Attention: Patch coverage is 63.79822% with 122 lines in your changes missing coverage. Please review.

Project coverage is 65.16%. Comparing base (e86b95a) to head (df33930).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...peline/transform/kubernetes/informers/informers.go	21.42%	55 Missing ⚠️
pkg/kafka/writer.go	51.92%	21 Missing and 4 partials ⚠️
pkg/kafka/reader.go	71.42%	19 Missing and 5 partials ⚠️
...line/transform/kubernetes/datasource/datasource.go	40.00%	6 Missing ⚠️
pkg/pipeline/transform/kubernetes/enrich.go	82.75%	4 Missing and 1 partial ⚠️
...e/transform/kubernetes/informers/informers-mock.go	93.47%	3 Missing ⚠️
pkg/pipeline/encode/encode_kafka.go	50.00%	1 Missing and 1 partial ⚠️
pkg/pipeline/ingest/ingest_kafka.go	83.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #847      +/-   ##
==========================================
+ Coverage   65.08%   65.16%   +0.08%     
==========================================
  Files         113      117       +4     
  Lines        8621     8650      +29     
==========================================
+ Hits         5611     5637      +26     
- Misses       2684     2685       +1     
- Partials      326      328       +2     

Flag	Coverage Δ
unittests	65.16% <63.79%> (+0.08%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
.../pipeline/transform/kubernetes/informers/config.go	100.00% <100.00%> (ø)
pkg/pipeline/transform/transform_network.go	65.11% <100.00%> (ø)
pkg/pipeline/encode/encode_kafka.go	64.70% <50.00%> (+7.20%)	⬆️
pkg/pipeline/ingest/ingest_kafka.go	58.26% <83.33%> (-5.15%)	⬇️
...e/transform/kubernetes/informers/informers-mock.go	95.00% <93.47%> (-2.48%)	⬇️
pkg/pipeline/transform/kubernetes/enrich.go	76.47% <82.75%> (-1.41%)	⬇️
...line/transform/kubernetes/datasource/datasource.go	40.00% <40.00%> (ø)
pkg/kafka/reader.go	71.42% <71.42%> (ø)
pkg/kafka/writer.go	51.92% <51.92%> (ø)
...peline/transform/kubernetes/informers/informers.go	19.25% <21.42%> (-3.89%)	⬇️

... and 2 files with indirect coverage changes

[jotak]

@jpinsonneau thanks - yes I'll add no-qe, the whole thing can be tested through NETOBSERV-1248

[jotak]

/approve

[openshift-ci]

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