JMX Metrics with yaml: need the ability to filter negative values

[SylvainJuge]

For some metrics like jvm.cpu.time and jvm.cpu.recent_utilization, the JVM can return a negative value as the underlying data might not be available as indicated by OperatingSystemMXBean.getCpuLoad() javadoc.

This corner case is properly handled in the runtime-telemetry implementation for JVM metrics as seen here, but this is not the case for metrics that are defined in YAML, hence preventing to being 100% compliant with semconv for JVM metrics.

Also, the same issue is likely to happen with other systems for which metrics are captured through a yaml definition because returning a negative value is a common pattern to indicate something is not available.

This was discovered while working on #13392 where we try to capture JVM metrics that are compliant with semantic conventions for java runtime.

Support for this could look like this in yaml:

  - bean: java.lang:type=OperatingSystem
    prefix: jvm.
    mapping:
      # jvm.cpu.recent_utilization
      ProcessCpuLoad:
        metric: cpu.recent_utilization
        type: gauge
        unit: '1'
        negativeValues: false
        desc: Recent CPU utilization for the process as reported by the JVM.

This is currently blocking progress on #13392

Suggestions on naming, feedback and suggestions are welcome:

• discardNegativeValues: true to remove negative values
• dropNegative
• negativeValues : true (default), false would discard values

I tend to prefer negativeValues as it's short and it sounds a bit more positive (pun not intentional here).

[trask]

I like "drop" over "discard" because it aligns with metric view terminology: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#drop-aggregation

I think I like "dropNegativeValues" overall, but curious what others think