Add spring-boot-micrometer-tracing if distributed tracing is selected with Boot 4

Closes gh-1951

Author: mhalbritter

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

@@ -20,14 +20,26 @@
 import io.spring.initializr.generator.buildsystem.Dependency;
 import io.spring.initializr.generator.buildsystem.DependencyScope;
 import io.spring.initializr.generator.spring.build.BuildCustomizer;
+import io.spring.initializr.generator.version.Version;
+import io.spring.initializr.generator.version.VersionParser;
+import io.spring.initializr.generator.version.VersionRange;
 
 /**
  * Configures distributed tracing if necessary.
  *
  * @author Stephane Nicoll
+ * @author Moritz Halbritter
  */
 class ObservabilityDistributedTracingBuildCustomizer implements BuildCustomizer<Build> {
 
+	private static final VersionRange SPRING_BOOT_4_OR_LATER = VersionParser.DEFAULT.parseRange("4.0.0-M1");
+
+	private final Version bootVersion;
+
+	ObservabilityDistributedTracingBuildCustomizer(Version bootVersion) {
+		this.bootVersion = bootVersion;
+	}
+
 	@Override
 	public void customize(Build build) {
 		// Zipkin without distributed tracing make no sense
@@ -40,6 +52,19 @@ public void customize(Build build) {
 						Dependency.withCoordinates("io.micrometer", "micrometer-tracing-reporter-wavefront")
 							.scope(DependencyScope.RUNTIME));
 		}
+		if (build.dependencies().has("distributed-tracing") && isBoot4OrLater()) {
+			build.dependencies()
+				.add("spring-boot-micrometer-tracing",
+						Dependency.withCoordinates("org.springframework.boot", "spring-boot-micrometer-tracing"));
+			build.dependencies()
+				.add("spring-boot-micrometer-tracing-test",
+						Dependency.withCoordinates("org.springframework.boot", "spring-boot-micrometer-tracing-test")
+							.scope(DependencyScope.TEST_COMPILE));
+		}
+	}
+
+	private boolean isBoot4OrLater() {
+		return SPRING_BOOT_4_OR_LATER.match(this.bootVersion);
 	}
 
 }

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

@@ -36,8 +36,9 @@ ObservabilityActuatorBuildCustomizer observabilityActuatorBuildCustomizer() {
 	}
 
 	@Bean
-	ObservabilityDistributedTracingBuildCustomizer observabilityDistributedTracingBuildCustomizer() {
-		return new ObservabilityDistributedTracingBuildCustomizer();
+	ObservabilityDistributedTracingBuildCustomizer observabilityDistributedTracingBuildCustomizer(
+			ProjectDescription description) {
+		return new ObservabilityDistributedTracingBuildCustomizer(description.getPlatformVersion());
 	}
 
 	@Bean

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

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2012 - present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.spring.start.site.extension.dependency.observability;
+
+import io.spring.initializr.metadata.Dependency;
+import io.spring.initializr.web.project.ProjectRequest;
+import io.spring.start.site.SupportedBootVersion;
+import io.spring.start.site.extension.AbstractExtensionTests;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ObservabilityDistributedTracingBuildCustomizer}.
+ *
+ * @author Moritz Halbritter
+ */
+class ObservabilityDistributedTracingBuildCustomizerTests extends AbstractExtensionTests {
+
+	@Test
+	void shouldAddMicrometerTracingOnBoot4OrLater() {
+		ProjectRequest request = createProjectRequest(SupportedBootVersion.V4_0, "distributed-tracing");
+		assertThat(mavenPom(request)).hasDependency("org.springframework.boot", "spring-boot-micrometer-tracing");
+		assertThat(mavenPom(request)).hasDependency("org.springframework.boot", "spring-boot-micrometer-tracing-test",
+				null, Dependency.SCOPE_TEST);
+	}
+
+	@Test
+	void shouldNotAddMicrometerTracingOnBootBefore4() {
+		ProjectRequest request = createProjectRequest(SupportedBootVersion.V3_5, "distributed-tracing");
+		assertThat(mavenPom(request)).doesNotHaveDependency("org.springframework.boot",
+				"spring-boot-micrometer-tracing");
+		assertThat(mavenPom(request)).doesNotHaveDependency("org.springframework.boot",
+				"spring-boot-micrometer-tracing-test");
+	}
+
+}