koordlet: add GetNodeMetricSpec in statesInformer interface

[j4ckstraw]

add func GetNodeMetricSpec, so we can get nodeMetricSpec conveniently by statesInformer interface

Ⅰ. Describe what this PR does

add GetNodeMetricSpec in statesInformer interface
prepare for #2273

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

V. Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests
• All checks passed in make test

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 66.06%. Comparing base (ceff9cd) to head (53221fd).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...kg/koordlet/statesinformer/impl/states_informer.go	50.00%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2278   +/-   ##
=======================================
  Coverage   66.06%   66.06%           
=======================================
  Files         454      454           
  Lines       53405    53413    +8     
=======================================
+ Hits        35281    35288    +7     
  Misses      15586    15586           
- Partials     2538     2539    +1     

Flag	Coverage Δ
unittests	66.06% <50.00%> (+<0.01%)	⬆️

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[saintube]

/lgtm

[saintube]

@j4ckstraw BTW, in which cases does the state informer need to export the NodeMetric? As it is an aggregated result, we usually fetch the metric resource from the metric cache instead.

[j4ckstraw]

@j4ckstraw BTW, in which cases does the state informer need to export the NodeMetric? As it is an aggregated result, we usually fetch the metric resource from the metric cache instead.

To support memoryCollectPolicy in #2273 (comment)

[saintube]

@j4ckstraw BTW, in which cases does the state informer need to export the NodeMetric? As it is an aggregated result, we usually fetch the metric resource from the metric cache instead.

To support memoryCollectPolicy in #2273 (comment)

@j4ckstraw This usage could be problematic. The metric advisor is the node metrics' data resource, so its collection should avoid depending on the node metrics due to circular reference. Perhaps, we can introduce the GetNodeMetricSpec to prevent misuse.

[j4ckstraw]

@j4ckstraw BTW, in which cases does the state informer need to export the NodeMetric? As it is an aggregated result, we usually fetch the metric resource from the metric cache instead.

To support memoryCollectPolicy in #2273 (comment)

@j4ckstraw This usage could be problematic. The metric advisor is the node metrics' data resource, so its collection should avoid depending on the node metrics due to circular reference. Perhaps, we can introduce the GetNodeMetricSpec to prevent misuse.

OK, I'll change the pr.

[j4ckstraw]

PTAL @saintube