fix(metrics-api-scaler): Fix division by 0 for expectedNbMetric

[dttung2905]

When the metrics-api scaler aggregates metrics from multiple Kubernetes service endpoints with aggregationType: average (the default), and every endpoint request fails, aggregateMetricsFromMultipleEndpoints still divides the aggregated value by expectedNbMetrics after it has been decremented to 0.

keda/pkg/scalers/metrics_api_scaler.go

Lines 457 to 458 in ef9df93

	if s.metadata.AggregationType == AverageAggregationType {
	aggregation /= float64(expectedNbMetrics)

Checklist

• When introducing a new scaler, I agree with the scaling governance policy
• I have verified that my change is according to the deprecations & breaking changes policy
• Tests have been added (if applicable)
• Ensure make generate-scalers-schema has been run to update any outdated generated files
• Changelog has been updated and is aligned with our changelog requirements, only when the change impacts end users
• Commits are signed with Developer Certificate of Origin (DCO - learn more)

Fixes #7742

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[dttung2905]

/run-e2e metrics_api
Update: You can check the progress here

[rickbrouwer]

/run-e2e metrics_api
Update: You can check the progress here

[rickbrouwer]

@dttung2905 can you check the race error?

[dttung2905]

/run-e2e metrics_api
Update: You can check the progress here

[dttung2905]

Hi @rickbrouwer , I have fixed the race condition in the CI test now. Can you help to check it again?

[rickbrouwer]

lgtm

[wozniakjan]

/run-e2e metrics_api
Update: You can check the progress here

passed tests: 1

Execution of tests/scalers/metrics_api/metrics_api_test.go, has passed after "one" attempts

failed tests: 0

[JorTurFer]

I❤️🫖