Add resource provider for CloudFoundry

[KarstenSchnitter]

Adds a module to provide a resource provider for applications deployed to CloudFoundry. It parses the VCAP_APPLICATION environment variable to fill in the attributes specified in the semantic conventions[1].

The implementation follows the OsResource in the resources module.

[1] https://github.com/open-telemetry/semantic-conventions/blob/main/docs/attributes-registry/cloudfoundry.md

[KarstenSchnitter]

This change addresses #12861. Since this is my first contribution, please let me know, if I violated any guidelines. I was unsure, whether this is a library or javaagent instrumentation.

Note, this feature can be enhanced by adding a service name detector, that provides the cloudfoundry.app.name as service.name when there is no other service name, yet. This could work similar to the SpringBootServiceNameDetector.

[laurit]

Aws resource and gcp resource providers are in opentelemetry-java-contrib repository.

I was unsure, whether this is a library or javaagent instrumentation.

Javaagent instrumentations are embedded inside the agent and only work with the agent, library instrumentations can be added to the application. Resource providers are like library instrumentations, they can be used without the agent.

[KarstenSchnitter]

@laurit thanks for the clarification. Are you suggesting, I take this PR to opentelemetry-java-contrib?

[KarstenSchnitter]

Do I understand, that I would add the code to a submodule of opentelemetry-java-contrib and reference this at

opentelemetry-java-instrumentation/dependencyManagement/build.gradle.kts

Lines 102 to 105 in 4f074ec

	"io.opentelemetry.contrib:opentelemetry-aws-resources:${otelContribVersion}",
	"io.opentelemetry.contrib:opentelemetry-aws-xray-propagator:${otelContribVersion}",
	"io.opentelemetry.contrib:opentelemetry-gcp-resources:${otelContribVersion}",
	"io.opentelemetry.contrib:opentelemetry-baggage-processor:${otelContribVersion}",

within this project?

[laurit]

Do I understand, that I would add the code to a submodule of opentelemetry-java-contrib and reference this at

Besides adding it to the dependency management you would also need to add it to

opentelemetry-java-instrumentation/javaagent-tooling/build.gradle.kts

Line 44 in 96eccaf

implementation("io.opentelemetry.contrib:opentelemetry-aws-resources")

to include it in the agent and

opentelemetry-java-instrumentation/instrumentation/spring/starters/spring-boot-starter/build.gradle.kts

Line 24 in 96eccaf

implementation("io.opentelemetry.contrib:opentelemetry-aws-resources")

to include it in the spring starter (your current PR does not include the provider in the agent).
Since this resource provider is considerably simpler than gcp and aws another option that could be considered is having it in https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/resources/library @trask what is your preference?

[trask]

I think I prefer for it to have its own module (instead of adding to io.opentelemetry.instrumentation:opentelemetry-resources)

probably contrib is the most consistent with the existing cloud resource providers, so I'm 👍 that route

[breedx-splk]

Oops, forgot to "Submit review" a few days ago, sorry...

[breedx-splk]

nit: I would name the variable builder instead of attributes.

[KarstenSchnitter]

I have to strong feelings about that. My thoughts were to make it clear, that only the attributes are being built, not the entire resource.

[trask]

Oops, forgot to "Submit review" a few days ago, sorry...

been there, and I think it's really weird how GitHub shows the comments with the date you made them instead of the date you posted them

[KarstenSchnitter]

probably contrib is the most consistent with the existing cloud resource providers, so I'm 👍 that route

The same discussion is going on in #12861, the enhancement proposal for this PR. I have no problem taking this code to the contrib repository. But I still want to point out, that CloudFoundry is open source and governed by the CloudFoundry Foundation a member of the Linux Foundation. This is a difference to cloud providers like AWS or GCP. If you still think, this resource provider should go to the contrib repository, let me know. I will move it to the repository if necessary.

[trask]

we may revisit this in the future open-telemetry/opentelemetry-java-contrib#1603 (comment)

I'd prefer to explore moving contrib components into the instrumentation repo if we are including them in the java agent distribution

but for now I believe the best place is in the contrib repo where we have a different component ownership model and so you can continue to own the module

[KarstenSchnitter]

I migrated the code to the contrib repository with open-telemetry/opentelemetry-java-contrib#1613.