Add OTLP for metrics entry

Closes gh-1598

start-site/src/main/java/io/spring/start/site/extension/dependency/observability/ObservabilityActuatorBuildCustomizer.java

@@ -31,7 +31,7 @@
 class ObservabilityActuatorBuildCustomizer implements BuildCustomizer<Build> {
 
 	private static final List<String> STANDARD_REGISTRY_IDS = Arrays.asList("datadog", "distributed-tracing",
-			"dynatrace", "graphite", "influx", "new-relic", "wavefront", "zipkin");
+			"dynatrace", "graphite", "influx", "new-relic", "otlp-metrics", "wavefront", "zipkin");
 
 	@Override
 	public void customize(Build build) {

start-site/src/main/java/io/spring/start/site/extension/dependency/springmodulith/SpringModulithBuildCustomizer.java

@@ -37,7 +37,7 @@
 class SpringModulithBuildCustomizer implements BuildCustomizer<Build> {
 
 	private static final Collection<String> OBSERVABILITY_DEPENDENCIES = List.of("actuator", "datadog", "graphite",
-			"influx", "new-relic", "prometheus", "wavefront", "zipkin");
+			"influx", "new-relic", "otlp-metrics", "prometheus", "wavefront", "zipkin");
 
 	private static final Collection<String> PERSISTENCE = List.of("jdbc", "jpa", "mongodb");
 

start-site/src/main/resources/application.yml

@@ -995,6 +995,16 @@ initializr:
           links:
             - rel: reference
               href: https://docs.spring.io/spring-boot/docs/{bootVersion}/reference/htmlsingle/index.html#actuator.metrics.export.newrelic
+        - name: OTLP for metrics
+          id: otlp-metrics
+          groupId: io.micrometer
+          artifactId: micrometer-registry-otlp
+          scope: runtime
+          starter: false
+          description: Publish Micrometer metrics to an OTLP capable backend.
+          links:
+            - rel: reference
+              href: https://docs.spring.io/spring-boot/reference/actuator/metrics.html#actuator.metrics.export.otlp
         - name: Prometheus
           id: prometheus
           groupId: io.micrometer

start-site/src/test/java/io/spring/start/site/extension/dependency/observability/ObservabilityActuatorBuildCustomizerTests.java

@@ -34,8 +34,8 @@ class ObservabilityActuatorBuildCustomizerTests extends AbstractExtensionTests {
 	private static final String SPRING_BOOT_VERSION = "3.3.0";
 
 	@ParameterizedTest
-	@ValueSource(strings = { "datadog", "dynatrace", "influx", "graphite", "new-relic", "distributed-tracing", "zipkin",
-			"wavefront" })
+	@ValueSource(strings = { "datadog", "dynatrace", "influx", "graphite", "new-relic", "otlp-metrics",
+			"distributed-tracing", "zipkin", "wavefront" })
 	void actuatorIsAddedWithObservabilityEntries(String dependency) {
 		assertThat(generateProject(SPRING_BOOT_VERSION, dependency)).mavenBuild()
 			.hasDependency(getDependency("actuator"));

start-site/src/test/java/io/spring/start/site/extension/dependency/springmodulith/SpringModulithBuildCustomizerTests.java

@@ -55,8 +55,8 @@ void registersActuatorStarterIfActuatorsIsPresent() {
 	}
 
 	@ParameterizedTest
-	@ValueSource(
-			strings = { "actuator", "datadog", "graphite", "influx", "new-relic", "prometheus", "wavefront", "zipkin" })
+	@ValueSource(strings = { "actuator", "datadog", "graphite", "influx", "new-relic", "otlp-metrics", "prometheus",
+			"wavefront", "zipkin" })
 	void registersObservabilityStarterIfObservabilityDependencyIsPresent(String dependency) {
 		Build build = createBuild("modulith");
 		build.dependencies().add(dependency);