Fix PartitionSizeAnomalyFinder, to be able to handle custom SELF_HEALING_PARTITION_SIZE_THRESHOLD_MB value

[k0b3rIT]

Summary

1. Why: I ran into the following exception when I tried to customize the SELF_HEALING_PARTITION_SIZE_THRESHOLD_MB in PartitionSizeAnomalyFinder

java.lang.ClassCastException: class java.lang.String cannot be cast to class java.lang.Integer (java.lang.String and java.lang.Integer are in module java.base of loader 'bootstrap')
	at com.linkedin.kafka.cruisecontrol.detector.PartitionSizeAnomalyFinder.configure(PartitionSizeAnomalyFinder.java:111) ~[classes/:?]
	at com.linkedin.kafka.cruisecontrol.config.KafkaCruiseControlConfig.getConfiguredInstances(KafkaCruiseControlConfig.java:119) ~[classes/:?]
	at com.linkedin.kafka.cruisecontrol.detector.TopicAnomalyDetector.<init>(TopicAnomalyDetector.java:32) ~[classes/:?]
	at com.linkedin.kafka.cruisecontrol.detector.AnomalyDetectorManager.<init>(AnomalyDetectorManager.java:120) ~[classes/:?]

3. What:
   I have fixed the config reader code to parse the integer value

Expected Behavior

Be able to reconfigure the SELF_HEALING_PARTITION_SIZE_THRESHOLD_MB

Actual Behavior

I cant reconfigure the SELF_HEALING_PARTITION_SIZE_THRESHOLD_MB

Steps to Reproduce

1. Enable the PartitionSizeAnomaly finder topic.anomaly.finder.class=com.linkedin.kafka.cruisecontrol.detector.PartitionSizeAnomalyFinder
2. Provide a custom value for self.healing.partition.size.threshold.mb=1024
3. Start CC

Known Workarounds

NO

Categorization

• documentation
• bugfix
• new feature
• refactor
• security/CVE
• other

[viktorsomogyi]

@mhratson would you please review this?

[Manicben]

Suggested change

	_partitionSizeThresholdInMb = DEFAULT_SELF_HEALING_PARTITION_SIZE_THRESHOLD_MB;
	if (partitionSizeThresholdStr != null) {
	_partitionSizeThresholdInMb = Integer.parseInt(partitionSizeThresholdStr.trim());
	}
	_partitionSizeThresholdInMb = partitionSizeThreshold == null ? DEFAULT_SELF_HEALING_PARTITION_SIZE_THRESHOLD_MB
	: Integer.parseInt(partitionSizeThresholdStr.trim());

Preserves style, similar to TopicReplicationFactorAnomalyFinder.
Personally I'd also remove the trim() to maintain the same behaviour as other numerical configs.

[mhratson]

@k0b3rIT please apply the suggestion

[k0b3rIT]

Sure, I have applied it!

[Manicben]

Thanks for raising this, we've ran into the same issue and I was going to raise a PR of my own. Would be great to get this reviewed and merged 🙏

[viktorsomogyi]

@mhratson would you please review this?

[viktorsomogyi]

@CCisGG would you please review this if you have some time?