Adds a check for Sleuth with 2022 cloud (#1175)

spring-cloud-commons/src/main/java/org/springframework/cloud/configuration/CompatibilityVerifierAutoConfiguration.java

@@ -50,4 +50,9 @@ public class CompatibilityVerifierAutoConfiguration {
 		return new SpringBootVersionVerifier(properties.getCompatibleBootVersions());
 	}
 
+	@Bean
+	SleuthPresentVerifier sleuthPresentVerifier() {
+		return new SleuthPresentVerifier();
+	}
+
 }

spring-cloud-commons/src/main/java/org/springframework/cloud/configuration/SleuthPresentVerifier.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2012-2020 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 org.springframework.cloud.configuration;
+
+import org.springframework.util.ClassUtils;
+
+/**
+ * Verifies if Spring Cloud Sleuth is present on the classpath.
+ */
+class SleuthPresentVerifier implements CompatibilityVerifier {
+
+	private static final String TRACER_CLASS = "org.springframework.cloud.sleuth.Tracer";
+
+	private static final String ERROR_DESCRIPTION = "Spring Cloud Sleuth is not compatible with this Spring Cloud release train";
+
+	private static final String ACTION = """
+						Migrate from Spring Cloud Sleuth to Micrometer Tracing .
+						You can check the Sleuth 3.1 Migration Guide over here [https://github.com/micrometer-metrics/tracing/wiki/Spring-Cloud-Sleuth-3.1-Migration-Guide].\s
+						If you want to disable this check, just set the property [spring.cloud.compatibility-verifier.enabled=false]""";
+
+	@Override
+	public VerificationResult verify() {
+		boolean present = sleuthPresent();
+		if (!present) {
+			return VerificationResult.compatible();
+		}
+		return VerificationResult.notCompatible(ERROR_DESCRIPTION, ACTION);
+	}
+
+	boolean sleuthPresent() {
+		return ClassUtils.isPresent(TRACER_CLASS, null);
+	}
+
+}

spring-cloud-commons/src/test/java/org/springframework/cloud/configuration/SleuthPresentVerifierTests.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2012-2020 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 org.springframework.cloud.configuration;
+
+import org.assertj.core.api.BDDAssertions;
+import org.junit.jupiter.api.Test;
+
+class SleuthPresentVerifierTests {
+
+	@Test
+	void should_be_compatible_when_sleuth_is_not_on_the_classpath() {
+		VerificationResult verify = new SleuthPresentVerifier() {
+			@Override
+			boolean sleuthPresent() {
+				return false;
+			}
+		}.verify();
+
+		BDDAssertions.then(verify.isNotCompatible()).isFalse();
+	}
+
+	@Test
+	void should_not_be_compatible_when_sleuth_is_on_the_classpath() {
+		VerificationResult verify = new SleuthPresentVerifier() {
+			@Override
+			boolean sleuthPresent() {
+				return true;
+			}
+		}.verify();
+
+		BDDAssertions.then(verify.isNotCompatible()).isTrue();
+
+	}
+
+}