> The resource attributes MAY be copied to labels of exported metric families if required by the exporter configuration

[gabrieljones]

Describe the bug
Prometheus metrics exporter is missing config option to copy resource attributes to labels.

The resource attributes MAY be copied to labels of exported metric families if required by the exporter configuration
https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/compatibility/prometheus_and_openmetrics.md#resource-attributes-1

What did you expect to see?
A config option to copy resource attributes to labels on metric families.

https://github.com/open-telemetry/opentelemetry-java/tree/v1.35.0/sdk-extensions/autoconfigure#prometheus-exporter

What did you see instead?
No such config option

What version and what artifacts are you using?
Artifacts: opentelemetry-sdk-extension-autoconfigure, opentelemetry-exporter-prometheus
Version: v1.35.0

[gabrieljones]

I see #6179 just got merged.

[gabrieljones]

Looks like you guys already discussed this:
#6179 (comment)

[breedx-splk]

@gabrieljones Are you cool with this outcome, or is there something else you're looking for?

[gabrieljones]

I'd like to avoid using a customizer here. A customizer would require adding code to 10+ different microservices.

I have a simple function that turns hocon config into System.setProperty calls for all the otel auto config properties.

[gabrieljones]

//application.conf
//...
otel-attributes {
  service-namespace = NAMESPACE-missing //something other than empty string, in case env var below is missing
  service-namespace = ${?NAMESPACE}
  deployment-environment = PAAS_ENV-missing
  deployment-environment = ${?PAAS_ENV}
  service-instance-id = HOSTNAME-missing
  service-instance-id = ${?HOSTNAME}
  service-cluster = CLUSTER_ENV-missing
  service-cluster = ${?CLUSTER_ENV}
  service-version = VERSION_JAR-missing
  service-version = ${?VERSION_JAR}
}

otel {
  exporter.otlp.endpoint = "https://<otlp inbox>"
  service.name = ${APP_NAME}
  resource {
    attributes = "service.namespace="${otel-attributes.service-namespace}
    attributes = ${otel.resource.attributes}",deployment.environment="${otel-attributes.deployment-environment}
    attributes = ${otel.resource.attributes}",service.instance.id="${otel-attributes.service-instance-id}
    attributes = ${otel.resource.attributes}",service.cluster="${otel-attributes.service-cluster}
    attributes = ${otel.resource.attributes}",service.version="${otel-attributes.service-version}
  }
  metrics.exporter = prometheus
  logs.exporter = otlp
}

//Main.scala
//...

    val configRoot: Config = ConfigFactory.load()

    val configOpenTelemetry: Config = configRoot.withOnlyPath("otel")

    configOpenTelemetry.entrySet().asScala.foreach { e =>
      val k = e.getKey
      val v = e.getValue.unwrapped().toString
      // .- is used to denote properties that share a name with a config object name
      // https://github.com/lightbend/config/blob/v1.4.2/HOCON.md#:~:text=there%20is%20an-,intractable%20case,-where%20a%20single
      // eg
      // `otel.traces.sampler.- = parentbased_traceidratio`
      // becomes
      // `System.setProperty("otel.traces.sampler", "parentbased_traceidratio")`
      val km = k.replaceAll("""\.-$""", "")
      System.setProperty(km, v)
    }

    val openTelemetry: OpenTelemetry = AutoConfiguredOpenTelemetrySdk.builder.build().getOpenTelemetrySdk

Result:

System.setProoerty("otel.exporter.otlp.endpoint", "https://<otlp inbox>")
System.setProoerty("otel.logs.exporter", "otlp")
System.setProoerty("otel.resource.attributes", "service.namespace=some-namespace,deployment.environment=dev,service.instance.id=some-deployment-78648ffc65-9p8jj,service.cluster=devc,service.version=3.4.1-55758a5")
System.setProoerty("otel.service.name", "some-service-name")
System.setProoerty("otel.metrics.exporter", "prometheus")

[jack-berg]

I'd like to avoid using a customizer here. A customizer would require adding code to 10+ different microservices.

The system properties and environment variables we interpret in autoconfigure is governed by the specification. There's currently no spec'd environment variable for configuring the prometheus resource attributes. There's a moratorium in place preventing any non-essential environment variable extensions while file configuration is being worked out. Hence, my comment about adding programmatic configuration but not adding environment variable / system property support.

[gabrieljones]

Given the moratorium I guess this part of the spec is in limbo until file config is finished.

The resource attributes MAY be copied to labels of exported metric families if required by the exporter configuration
https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/compatibility/prometheus_and_openmetrics.md#resource-attributes-1

Hardcoding it is then. After #6231 goes in that is.

I don't suppose Prometheus allows for creating "views" over join queries?

This[joins] is not a common pattern in Prometheus, and we recommend copying the most common resource attributes into metric labels.
https://grafana.com/blog/2023/07/20/a-practical-guide-to-data-collection-with-opentelemetry-and-prometheus/#2-copy-common-resource-attributes