fix micrometer bridge auto configuration annotation (#13083)

Co-authored-by: Trask Stalnaker <[email protected]>

Author: zeitlinger

instrumentation/spring/spring-boot-actuator-autoconfigure-2.0/javaagent/build.gradle.kts

@@ -15,6 +15,7 @@ muzzle {
 dependencies {
   library("org.springframework.boot:spring-boot-actuator-autoconfigure:2.0.0.RELEASE")
   library("io.micrometer:micrometer-core:1.5.0")
+  testLibrary("io.micrometer:micrometer-registry-prometheus:1.0.1")
 
   implementation(project(":instrumentation:micrometer:micrometer-1.5:javaagent"))
 

instrumentation/spring/spring-boot-actuator-autoconfigure-2.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/spring/actuator/v2_0/OpenTelemetryMeterRegistryAutoConfiguration.java

@@ -7,7 +7,15 @@
 
 import io.micrometer.core.instrument.Clock;
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
 import io.opentelemetry.javaagent.instrumentation.micrometer.v1_5.MicrometerSingletons;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.boot.actuate.autoconfigure.metrics.CompositeMeterRegistryAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
@@ -32,4 +40,32 @@ public class OpenTelemetryMeterRegistryAutoConfiguration {
   public MeterRegistry otelMeterRegistry() {
     return MicrometerSingletons.meterRegistry();
   }
+
+  @Bean
+  // static to avoid "is not eligible for getting processed by all BeanPostProcessors" warning
+  static BeanPostProcessor postProcessCompositeMeterRegistry() {
+    return new BeanPostProcessor() {
+      @Override
+      public Object postProcessAfterInitialization(Object bean, String beanName) {
+        if (bean instanceof CompositeMeterRegistry) {
+          CompositeMeterRegistry original = (CompositeMeterRegistry) bean;
+          List<MeterRegistry> list = new ArrayList<>(original.getRegistries());
+          // sort otel registry last since it doesn't support reading metric values
+          // and the actuator endpoint reads metrics from the first registry
+          list.sort(
+              Comparator.comparingInt(
+                  value -> value == MicrometerSingletons.meterRegistry() ? 1 : 0));
+          Set<MeterRegistry> registries = new LinkedHashSet<>(list);
+          return new CompositeMeterRegistry(
+              original.config().clock(), Collections.singletonList(original)) {
+            @Override
+            public Set<MeterRegistry> getRegistries() {
+              return registries;
+            }
+          };
+        }
+        return bean;
+      }
+    };
+  }
 }

instrumentation/spring/spring-boot-actuator-autoconfigure-2.0/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/spring/actuator/v2_0/ActuatorTest.java

@@ -15,6 +15,8 @@
 import io.opentelemetry.instrumentation.testing.junit.AgentInstrumentationExtension;
 import io.opentelemetry.instrumentation.testing.junit.InstrumentationExtension;
 import io.opentelemetry.javaagent.instrumentation.spring.actuator.v2_0.SpringApp.TestBean;
+import java.util.ArrayList;
+import java.util.Set;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 import org.springframework.boot.SpringApplication;
@@ -57,9 +59,12 @@ void shouldInjectOtelMeterRegistry() {
                                                         "value"))))));
 
     MeterRegistry meterRegistry = context.getBean(MeterRegistry.class);
-    assertThat(meterRegistry).isNotNull().isInstanceOf(CompositeMeterRegistry.class);
-    assertThat(((CompositeMeterRegistry) meterRegistry).getRegistries())
-        .anyMatch(r -> r.getClass().getSimpleName().equals("OpenTelemetryMeterRegistry"))
-        .anyMatch(r -> r.getClass().getSimpleName().equals("SimpleMeterRegistry"));
+    assertThat(meterRegistry).isInstanceOf(CompositeMeterRegistry.class);
+
+    Set<MeterRegistry> registries = ((CompositeMeterRegistry) meterRegistry).getRegistries();
+    ArrayList<MeterRegistry> list = new ArrayList<>(registries);
+
+    String last = list.get(list.size() - 1).getClass().getSimpleName();
+    assertThat(last).isEqualTo("OpenTelemetryMeterRegistry");
   }
 }

instrumentation/spring/spring-boot-actuator-autoconfigure-2.0/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/spring/actuator/v2_0/SpringApp.java

@@ -10,7 +10,9 @@
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
 
-@SpringBootApplication
+@SpringBootApplication(
+    excludeName =
+        "org.springframework.boot.actuate.autoconfigure.metrics.export.prometheus.PrometheusSimpleclientMetricsExportAutoConfiguration")
 public class SpringApp {
 
   @Bean