OTel-instrument-creation.md

Complicated API

• As a user, it is somewhat complex and quite puzzling using the API
• There are a lot of components
• The components are doing different things as I would expect based on their names
• I think it would worth a review and refactor to make it more usable.

Examples

• GlobalMetricsProvider
  • Based on its name, it should provide Metrics instances
  • In fact, it provides two things neither of them are Metrics
    • get returns a MeterProvider
    • getMeter returns a Meter
• MeterProvider
  • Based on its name, it should provide Meter instances
  • Its get method does return a Meter instance
  • But getDefault (means "get the default Meter") returns a MeterProvider
  • Should not getDefault be getDefaultInstance?
• Meter
  • Its javadoc says: "Meter is a simple, interface that allows users to record measurements (metrics)."
  • In fact, Meter gives you builders
  • Isn't Meter something that you use to measure something?
  • Like a "thermometer" measures temperature a "barometer" measures pressure, etc.
• Instrument
  • To me, this seems to be the component that should be called Meter
  • Its javadoc is a little confusing too: "Base interface for all metrics defined in this package."
• LongCounterSdk
  • Based on its name, it is a special type of SDK not a special LongCounter
• MetricProducer
  • It has one method: Collection<MetricData> collectAllMetrics();
  • Based on this, shouldn't it be called MetricCollector?
• GlobalMetricsProvider and MetricProducer seems confusing next to each other
• There are “missed” opportunities to use Java functional interfaces like Supplier for the Producer/Provider classes