spring boot starter: add service.version detection, improve service.name detection

[zeitlinger]

Don't use the spring resource detector library, because that inspects a spring application from the outside - inside a spring app it's much easier.

service.name is detected in the following order (highest priority first)

• otel.service.name
• otel.resource.attributes entry
• spring.application.name
• maven/gradle project name created by snipped below (maven)
• name of jar file

springBoot {
  buildInfo()
}

Fixes #10368

[zeitlinger]

@jeanbisutti in this PR, where the test uses graalvm native, the following is needed to read the version:

springBoot {
  buildInfo()
}

In smoke-tests (no graalvm native), it's not needed: #10515

Does this make sense?

[jeanbisutti]

@jeanbisutti in this PR, where the test uses graalvm native, the following is needed to read the version:

springBoot {
  buildInfo()
}

In smoke-tests (no graalvm native), it's not needed: #10515

Does this make sense?

FYI, the OtelSpringStarterSmokeTest test class can be executed both with a JVM runtime (./gradlew nativeTest) or a GraalVM native runtime (./gradlew test). The native mode is executed once a day with this Github action.

In smoke-tests (no graalvm native), it's not needed: #10515

I guess you are refering to this code change in #10515:

This code is related to a smoke test for which a Spring Boot application is package as a JAR and included in a Docker image. So, without buildInfo(), my guess is that the service name is retrieved from the JAR name (or perhaps otel.service.name or spring.application.name).

With OtelSpringStarterSmokeTest, no JAR is created during the test execution. And by adding buildInfo(), the service name is retrieved from the generated build info file.

[zeitlinger]

removed the jar detector, because the manifest detector will always find a name and version for spring boot.

[trask]

I didn't understand this note?

[zeitlinger]

In spring, there's a resource provider that uses the always correct, pre-computed value from the spring environment.

[trask]

sorry, still not following

[zeitlinger]

the spring boot starter uses SpringResourceProvider, which doesn't need to parse any application.yaml, etc. file, because when you run inside a sprig application, you can just ask the environment.

In this case, the lookup is here:

opentelemetry-java-instrumentation/instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/resources/SpringConfigProperties.java

Line 45 in d8aa0f5

String value = environment.getProperty(name, String.class);

[trask]

so SpringBootServiceNameDetector should only be used by the Java agent?

[zeitlinger]

yes, exactly.

The provider will actually notice if a name found using shouldApply - so it's just a note about the intended usage.

[trask]

could SpringBootServiceNameDetector be moved to a (new) spring-boot-resources/javaagent to make this extra clear?

[zeitlinger]

I've done this move in #10621 - because this

PR moves SystemHelper to the common resource project (for other reasons).
Hope this makes sense.