Kafka instrumentation enhancements (#1936)

* Bump javadocs since version to 3.1.0

* Extend integration tests to cover all Kafka clients

* Add autoconfiguration module for kafka instrumentation

* Refactor instrumentation for reactive Kafka Receiver

* Refactor instrumentation for reactive Kafka Receiver

* Add docs for Kafka instrumentation

* Revert "Refactor instrumentation for reactive Kafka Receiver"

This reverts commit 58c8f2fa

* Revert "Revert "Refactor instrumentation for reactive Kafka Receiver""

This reverts commit 450a9f8c

* Remove empty test

* Resolve comments from PR 1936

* Revert whitespaces

* Revert whitespaces in common tests pom.xml

* Fix autoconfig to consider generics when registering beans.
Only register reactor-kafka beans if the dependency is on the classpath.

* Split autoconfig for kafka and reactor-kafka

spring-cloud-sleuth-autoconfigure/pom.xml

@@ -275,6 +275,11 @@
 			<artifactId>spring-jms</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>io.projectreactor.kafka</groupId>
+			<artifactId>reactor-kafka</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<!-- GRPC Optional Dependencies -->
 		<dependency>
 			<groupId>io.github.lognet</groupId>

spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/instrument/kafka/TracingKafkaAutoConfiguration.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2013-2021 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.sleuth.autoconfig.instrument.kafka;
+
+import org.apache.kafka.clients.KafkaClient;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.producer.ProducerRecord;
+
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.cloud.sleuth.Tracer;
+import org.springframework.cloud.sleuth.autoconfig.brave.BraveAutoConfiguration;
+import org.springframework.cloud.sleuth.instrument.kafka.TracingKafkaPropagatorGetter;
+import org.springframework.cloud.sleuth.instrument.kafka.TracingKafkaPropagatorSetter;
+import org.springframework.cloud.sleuth.propagation.Propagator;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * {@link org.springframework.boot.autoconfigure.EnableAutoConfiguration
+ * Auto-configuration} that registers instrumentation for Kafka.
+ *
+ * @author Anders Clausen
+ * @author Flaviu Muresan
+ * @since 3.1.0
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnClass(KafkaClient.class)
+@ConditionalOnBean(Tracer.class)
+@AutoConfigureAfter(BraveAutoConfiguration.class)
+@ConditionalOnProperty(value = "spring.sleuth.kafka.enabled", matchIfMissing = true)
+public class TracingKafkaAutoConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean(value = ProducerRecord.class, parameterizedContainer = Propagator.Setter.class)
+	Propagator.Setter<ProducerRecord<?, ?>> tracingKafkaPropagationSetter() {
+		return new TracingKafkaPropagatorSetter();
+	}
+
+	@Bean
+	@ConditionalOnMissingBean(value = ConsumerRecord.class, parameterizedContainer = Propagator.Getter.class)
+	Propagator.Getter<ConsumerRecord<?, ?>> tracingKafkaPropagationGetter() {
+		return new TracingKafkaPropagatorGetter();
+	}
+
+	@Bean
+	static TracingKafkaProducerBeanPostProcessor tracingKafkaProducerBeanPostProcessor(BeanFactory beanFactory) {
+		return new TracingKafkaProducerBeanPostProcessor(beanFactory);
+	}
+
+	@Bean
+	static TracingKafkaConsumerBeanPostProcessor tracingKafkaConsumerBeanPostProcessor(BeanFactory beanFactory) {
+		return new TracingKafkaConsumerBeanPostProcessor(beanFactory);
+	}
+
+}

spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/instrument/kafka/TracingKafkaConsumerBeanPostProcessor.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2013-2021 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.sleuth.autoconfig.instrument.kafka;
+
+import org.apache.kafka.clients.consumer.Consumer;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.cloud.sleuth.instrument.kafka.TracingKafkaConsumer;
+
+/**
+ * Bean post processor for {@link org.apache.kafka.clients.consumer.Consumer}.
+ *
+ * @author Anders Clausen
+ * @author Flaviu Muresan
+ * @since 3.1.0
+ */
+public class TracingKafkaConsumerBeanPostProcessor implements BeanPostProcessor {
+
+	private final BeanFactory beanFactory;
+
+	public TracingKafkaConsumerBeanPostProcessor(BeanFactory beanFactory) {
+		this.beanFactory = beanFactory;
+	}
+
+	@Override
+	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+		if (bean instanceof Consumer && !(bean instanceof TracingKafkaConsumer)) {
+			return new TracingKafkaConsumer<>((Consumer) bean, beanFactory);
+		}
+		return bean;
+	}
+
+}

spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/instrument/kafka/TracingKafkaProducerBeanPostProcessor.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2013-2021 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.sleuth.autoconfig.instrument.kafka;
+
+import org.apache.kafka.clients.producer.Producer;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.cloud.sleuth.instrument.kafka.TracingKafkaProducer;
+
+/**
+ * Bean post processor for {@link org.apache.kafka.clients.producer.Producer}.
+ *
+ * @author Anders Clausen
+ * @author Flaviu Muresan
+ * @since 3.1.0
+ */
+public class TracingKafkaProducerBeanPostProcessor implements BeanPostProcessor {
+
+	private final BeanFactory beanFactory;
+
+	public TracingKafkaProducerBeanPostProcessor(BeanFactory beanFactory) {
+		this.beanFactory = beanFactory;
+	}
+
+	@Override
+	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+		if (bean instanceof Producer && !(bean instanceof TracingKafkaProducer)) {
+			return new TracingKafkaProducer<>((Producer) bean, beanFactory);
+		}
+		return bean;
+	}
+
+}

spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/instrument/kafka/TracingReactorKafkaAutoConfiguration.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2013-2021 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.sleuth.autoconfig.instrument.kafka;
+
+import reactor.kafka.receiver.KafkaReceiver;
+
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.cloud.sleuth.Tracer;
+import org.springframework.cloud.sleuth.autoconfig.brave.BraveAutoConfiguration;
+import org.springframework.cloud.sleuth.instrument.kafka.TracingKafkaConsumerFactory;
+import org.springframework.cloud.sleuth.instrument.kafka.TracingKafkaProducerFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * {@link org.springframework.boot.autoconfigure.EnableAutoConfiguration
+ * Auto-configuration} that registers instrumentation for Reactor Kafka.
+ *
+ * @author Anders Clausen
+ * @author Flaviu Muresan
+ * @since 3.1.0
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnClass(KafkaReceiver.class)
+@ConditionalOnBean(Tracer.class)
+@AutoConfigureAfter(BraveAutoConfiguration.class)
+@ConditionalOnProperty(value = "spring.sleuth.kafka.enabled", matchIfMissing = true)
+public class TracingReactorKafkaAutoConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean
+	TracingKafkaProducerFactory tracingKafkaProducerFactory(BeanFactory beanFactory) {
+		return new TracingKafkaProducerFactory(beanFactory);
+	}
+
+	@Bean
+	@ConditionalOnMissingBean
+	TracingKafkaConsumerFactory tracingKafkaConsumerFactory(BeanFactory beanFactory) {
+		return new TracingKafkaConsumerFactory(beanFactory);
+	}
+
+}

spring-cloud-sleuth-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/instrument/messaging/TraceSpringMessagingAutoConfiguration.java

@@ -45,13 +45,13 @@ class TraceSpringMessagingAutoConfiguration {
 	}
 
 	@Bean
-	@ConditionalOnMissingBean
+	@ConditionalOnMissingBean(value = MessageHeaderAccessor.class, parameterizedContainer = Propagator.Setter.class)
 	Propagator.Setter<MessageHeaderAccessor> traceMessagePropagationSetter() {
 		return new MessageHeaderPropagatorSetter();
 	}
 
 	@Bean
-	@ConditionalOnMissingBean
+	@ConditionalOnMissingBean(value = MessageHeaderAccessor.class, parameterizedContainer = Propagator.Getter.class)
 	Propagator.Getter<MessageHeaderAccessor> traceMessagePropagationGetter() {
 		return new MessageHeaderPropagatorGetter();
 	}

spring-cloud-sleuth-autoconfigure/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -41,6 +41,12 @@
       "description": "Enable tracing for WebSockets.",
       "defaultValue": true
     },
+    {
+      "name": "spring.sleuth.kafka.enabled",
+      "type": "java.lang.Boolean",
+      "description": "Enable instrumenting of Apache Kafka clients.",
+      "defaultValue": true
+    },
     {
       "name": "spring.sleuth.async.enabled",
       "type": "java.lang.Boolean",

spring-cloud-sleuth-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -1,5 +1,6 @@
 # Auto Configuration
 org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
+org.springframework.cloud.sleuth.autoconfig.instrument.kafka.TracingKafkaAutoConfiguration,\
 org.springframework.cloud.sleuth.autoconfig.instrument.async.TraceAsyncAutoConfiguration,\
 org.springframework.cloud.sleuth.autoconfig.instrument.async.TraceAsyncCustomAutoConfiguration,\
 org.springframework.cloud.sleuth.autoconfig.instrument.async.TraceAsyncDefaultAutoConfiguration,\