feat: Dynamic Metrics

[micrusa]

• Add metrics.extraExporters to userConfig. Following changes only apply to extraExporters, not extraReaders
• Add ignored metrics that do not get exported to userConfig defined
  exporters (they do get exported to user defined readers). Under POST/GET/DELETE /metrics/ignored
• Add dynamic exporting interval for userConfig defined exporters (it's
  ignored for user defined readers). Under GET/POST /metrics/export-interval

Changes

• Added extraExporters as configuration. These changes do not apply to extraReaders
• The flow for extraExporters is DynamicPeriodicMetricReader -> FilterExporter -> MultiExporter -> extraExporters
• Added routes for configuration of the feature, including filtering of metrics (ignored metrics) and new dynamic interval

Testing it out

• To run new tests do npm run build & npm test

To test it manually, run dev environment with npm run dev

Dynamic intervals

• Get current export interval: curl -X GET http://localhost:3000/oas-telemetry/metrics/export-interval
• Update interval:

curl -X POST http://localhost:3000/oas-telemetry/metrics/export-interval \
		-H "Content-Type: application/json" \
		-d '{"exportIntervalMillis": 5000}'

Metric filtering (ignored scope names)

• Get current ignore list: curl -X GET http://localhost:3000/oas-telemetry/metrics/ignored
• Adding scopes:

curl -X POST http://localhost:3000/oas-telemetry/metrics/ignored \
		-H "Content-Type: application/json" \
		-d '{"metrics": ["scope1", "scope2"]}'

• Removing specific scopes:

curl -X DELETE http://localhost:3000/oas-telemetry/metrics/ignored \
		-H "Content-Type: application/json" \
		-d '{"metric": "PetClinic"}'

• Clearing ignore list: curl -X DELETE http://localhost:3000/oas-telemetry/metrics/ignored

[motero2k]

I think we should take a closer look at the Views concept. Let's schedule a meeting to discuss the implementation.