fix(service-insights): Show gateway services in service-insights

[lahabana]

Summary

We were hidding gateway in service-insights.

This was unintuitive and also caused problems by not showing
up in the serviceMap in grafana

Full changelog

• add gateway in service insights computation.

Testing

• Unit tests
• E2E tests
• Manual testing on Universal
• Manual testing on Kubernetes

Backwards compatibility

• Add backport-to-stable label if the code is backwards compatible. Otherwise, list breaking changes.

[lahabana]

It really feels like this resyncer could be simplified and end up being quicker and require less read/writes.

[lobkovilya]

@lahabana that would be great, do you have anything particular in mind?

[codecov-commenter]

Codecov Report

Merging #2711 (2ab144f) into master (b636a9a) will increase coverage by 0.06%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2711      +/-   ##
==========================================
+ Coverage   52.20%   52.27%   +0.06%     
==========================================
  Files         865      865              
  Lines       49297    49299       +2     
==========================================
+ Hits        25737    25771      +34     
+ Misses      21478    21440      -38     
- Partials     2082     2088       +6     

Impacted Files	Coverage Δ
pkg/insights/resyncer.go	67.16% <100.00%> (+0.99%)	⬆️
pkg/xds/generator/direct_access_proxy_generator.go	83.90% <0.00%> (+1.14%)	⬆️
pkg/core/resources/model/rest/resource.go	69.23% <0.00%> (+1.28%)	⬆️
pkg/plugins/resources/memory/store.go	82.06% <0.00%> (+4.34%)	⬆️
pkg/core/bootstrap/autoconfig.go	54.46% <0.00%> (+8.03%)	⬆️
.../core/managers/apis/ratelimit/ratelimit_manager.go	45.16% <0.00%> (+9.67%)	⬆️
pkg/core/resources/store/customizable_store.go	88.88% <0.00%> (+11.11%)	⬆️
pkg/insights/components.go	100.00% <0.00%> (+30.00%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b636a9a...2ab144f. Read the comment docs.

[lahabana]

Yes the main thing is that the meshInsight never needs to get recomputed if the serviceInsights haven't changed. So we'd check if any of the serviceInsight change before computing the meshInsight.

We'd also wouldn't need to read the serviceInsight again when computing the meshInsight (as we've just computed them).
I'd also would quite like to avoid the goroutine in the Start as it seems to be unnecessary (Recv could simply return a channel).

[lobkovilya]

Isn't it vice versa? MeshInsight also includes policies, so MeshInsight could change while ServiceInsight is the same

[lahabana]

Yes you are right. Though I believe we'd still avoid some level a recomputation and reading things twice.