Add configurable OpenTelemetry kafka-clients interceptors

instrumentation/kafka/kafka-clients/kafka-clients-2.6/library/README.md

@@ -35,18 +35,59 @@ The Kafka clients API provides a way to "intercept" messages before they are sen
 The OpenTelemetry instrumented Kafka library provides two interceptors to be configured to add tracing information automatically.
 The interceptor class has to be set in the properties bag used to create the Kafka client.
 
-Use the `TracingProducerInterceptor` for the producer in order to create a "send" span automatically, each time a message is sent.
+##### Recommended approach: Configuring interceptors with KafkaTelemetry
+
+The recommended way to use interceptors is to configure them with a `KafkaTelemetry` instance.
+Interceptors will use system properties for additional configuration like captured headers and receive telemetry settings.
+
+For the producer:
+
+```java
+KafkaTelemetry telemetry = KafkaTelemetry.create(openTelemetry);
+
+Map<String, Object> props = new HashMap<>();
+props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
+props.putAll(telemetry.producerInterceptorConfigProperties());
+
+Producer<String, String> producer = new KafkaProducer<>(props);
+```
+
+For the consumer:
+
+```java
+KafkaTelemetry telemetry = KafkaTelemetry.create(openTelemetry);
+
+Map<String, Object> props = new HashMap<>();
+props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
+props.put(ConsumerConfig.GROUP_ID_CONFIG, "my-group");
+props.putAll(telemetry.consumerInterceptorConfigProperties());
+
+Consumer<String, String> consumer = new KafkaConsumer<>(props);
+```
+
+##### Alternative: Using interceptors with global OpenTelemetry
+
+If you don't explicitly configure the interceptors with a `KafkaTelemetry` instance, they will fall back to using
+`GlobalOpenTelemetry.get()` and system properties for configuration.
+
+Use the `OpenTelemetryProducerInterceptor` for the producer in order to create a "send" span automatically, each time a message is sent.
 
 ```java
-props.setProperty(ProducerConfig.INTERCEPTOR_CLASSES_CONFIG, TracingProducerInterceptor.class.getName());
+props.setProperty(ProducerConfig.INTERCEPTOR_CLASSES_CONFIG, OpenTelemetryProducerInterceptor.class.getName());
 ```
 
-Use the `TracingConsumerInterceptor` for the consumer in order to create a "receive" span automatically, each time a message is received.
+Use the `OpenTelemetryConsumerInterceptor` for the consumer in order to create a "receive" span automatically, each time a message is received.
 
 ```java
-props.setProperty(ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG, TracingConsumerInterceptor.class.getName());
+props.setProperty(ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG, OpenTelemetryConsumerInterceptor.class.getName());
 ```
 
+Note: The `TracingProducerInterceptor` and `TracingConsumerInterceptor` classes are still available for backwards compatibility, but new code should use the `OpenTelemetry*` variants.
+
+The interceptors will use the following system properties for configuration:
+- `otel.instrumentation.messaging.experimental.receive-telemetry.enabled` - Enable receive telemetry (default: false)
+- `otel.instrumentation.messaging.experimental.capture-headers` - List of headers to capture as span attributes
+
 #### Wrapping clients
 
 The other way is by wrapping the Kafka client with a tracing enabled Kafka client.

instrumentation/kafka/kafka-clients/kafka-clients-2.6/library/src/main/java/io/opentelemetry/instrumentation/kafkaclients/v2_6/KafkaTelemetry.java

@@ -38,12 +38,14 @@
 import java.util.logging.Logger;
 import org.apache.kafka.clients.CommonClientConfigs;
 import org.apache.kafka.clients.consumer.Consumer;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
 import org.apache.kafka.clients.consumer.ConsumerRecord;
 import org.apache.kafka.clients.consumer.ConsumerRecords;
 import org.apache.kafka.clients.consumer.KafkaConsumer;
 import org.apache.kafka.clients.producer.Callback;
 import org.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.clients.producer.Producer;
+import org.apache.kafka.clients.producer.ProducerConfig;
 import org.apache.kafka.clients.producer.ProducerRecord;
 import org.apache.kafka.clients.producer.RecordMetadata;
 import org.apache.kafka.common.TopicPartition;
@@ -207,6 +209,62 @@ <K, V> ConsumerRecords<K, V> addTracing(
     return Collections.unmodifiableMap(config);
   }
 
+  /**
+   * Returns configuration properties that can be used to enable OpenTelemetry instrumentation via
+   * {@code OpenTelemetryProducerInterceptor}. Add these resulting properties to the configuration
+   * map used to initialize a {@link org.apache.kafka.clients.producer.KafkaProducer}.
+   *
+   * <p>Example usage:
+   *
+   * <pre>{@code
+   * //    KafkaTelemetry telemetry = KafkaTelemetry.create(openTelemetry);
+   * //    Map<String, Object> config = new HashMap<>();
+   * //    config.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, ...);
+   * //    config.putAll(telemetry.producerInterceptorConfigProperties());
+   * //    try (KafkaProducer<?, ?> producer = new KafkaProducer<>(config)) { ... }
+   * }</pre>
+   *
+   * @return the kafka producer interceptor config properties
+   */
+  public Map<String, ?> producerInterceptorConfigProperties() {
+    Map<String, Object> config = new HashMap<>();
+    config.put(
+        ProducerConfig.INTERCEPTOR_CLASSES_CONFIG,
+        OpenTelemetryProducerInterceptor.class.getName());
+    config.put(
+        OpenTelemetryProducerInterceptor.CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER,
+        new KafkaTelemetrySupplier(this));
+    return Collections.unmodifiableMap(config);
+  }
+
+  /**
+   * Returns configuration properties that can be used to enable OpenTelemetry instrumentation via
+   * {@code OpenTelemetryConsumerInterceptor}. Add these resulting properties to the configuration
+   * map used to initialize a {@link org.apache.kafka.clients.consumer.KafkaConsumer}.
+   *
+   * <p>Example usage:
+   *
+   * <pre>{@code
+   * //    KafkaTelemetry telemetry = KafkaTelemetry.create(openTelemetry);
+   * //    Map<String, Object> config = new HashMap<>();
+   * //    config.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, ...);
+   * //    config.putAll(telemetry.consumerInterceptorConfigProperties());
+   * //    try (KafkaConsumer<?, ?> consumer = new KafkaConsumer<>(config)) { ... }
+   * }</pre>
+   *
+   * @return the kafka consumer interceptor config properties
+   */
+  public Map<String, ?> consumerInterceptorConfigProperties() {
+    Map<String, Object> config = new HashMap<>();
+    config.put(
+        ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG,
+        OpenTelemetryConsumerInterceptor.class.getName());
+    config.put(
+        OpenTelemetryConsumerInterceptor.CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER,
+        new KafkaTelemetrySupplier(this));
+    return Collections.unmodifiableMap(config);
+  }
+
   /**
    * Build and inject span into record.
    *

instrumentation/kafka/kafka-clients/kafka-clients-2.6/library/src/main/java/io/opentelemetry/instrumentation/kafkaclients/v2_6/KafkaTelemetrySupplier.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.kafkaclients.v2_6;
+
+import java.io.Serializable;
+import java.util.Objects;
+import java.util.function.Supplier;
+
+/**
+ * Wrapper for KafkaTelemetry that can be injected into kafka configuration without breaking
+ * serialization.
+ *
+ * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
+ * at any time.
+ */
+final class KafkaTelemetrySupplier implements Supplier<Object>, Serializable {
+  private static final long serialVersionUID = 1L;
+  private final transient Object kafkaTelemetry;
+
+  KafkaTelemetrySupplier(Object kafkaTelemetry) {
+    Objects.requireNonNull(kafkaTelemetry);
+    this.kafkaTelemetry = kafkaTelemetry;
+  }
+
+  @Override
+  public Object get() {
+    return kafkaTelemetry;
+  }
+
+  private Object writeReplace() {
+    // serialize this object to null
+    return null;
+  }
+}

instrumentation/kafka/kafka-clients/kafka-clients-2.6/library/src/main/java/io/opentelemetry/instrumentation/kafkaclients/v2_6/OpenTelemetryConsumerInterceptor.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.kafkaclients.v2_6;
+
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.instrumentation.api.internal.Timer;
+import io.opentelemetry.instrumentation.kafkaclients.common.v0_11.internal.KafkaConsumerContext;
+import io.opentelemetry.instrumentation.kafkaclients.common.v0_11.internal.KafkaConsumerContextUtil;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.Supplier;
+import javax.annotation.Nullable;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.clients.consumer.ConsumerInterceptor;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.apache.kafka.clients.consumer.OffsetAndMetadata;
+import org.apache.kafka.common.TopicPartition;
+
+/**
+ * A ConsumerInterceptor that adds OpenTelemetry instrumentation. Add this interceptor's class name
+ * or class via ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG property to your Consumer's properties to
+ * get it instantiated and used. See more details on ConsumerInterceptor usage in its Javadoc.
+ *
+ * <p>To configure the interceptor, use {@link KafkaTelemetry#consumerInterceptorConfigProperties}
+ * to obtain the configuration properties and add them to your consumer configuration.
+ *
+ * @see KafkaTelemetry#consumerInterceptorConfigProperties()
+ */
+public class OpenTelemetryConsumerInterceptor<K, V> implements ConsumerInterceptor<K, V> {
+
+  public static final String CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER =
+      "opentelemetry.kafka-telemetry.supplier";
+
+  @Nullable private KafkaTelemetry telemetry;
+  private String consumerGroup;
+  private String clientId;
+
+  @Override
+  @CanIgnoreReturnValue
+  public ConsumerRecords<K, V> onConsume(ConsumerRecords<K, V> records) {
+    if (telemetry == null) {
+      return records;
+    }
+    // timer should be started before fetching ConsumerRecords, but there is no callback for that
+    Timer timer = Timer.start();
+    Context receiveContext = telemetry.buildAndFinishSpan(records, consumerGroup, clientId, timer);
+    if (receiveContext == null) {
+      receiveContext = Context.current();
+    }
+    KafkaConsumerContext consumerContext =
+        KafkaConsumerContextUtil.create(receiveContext, consumerGroup, clientId);
+    return telemetry.addTracing(records, consumerContext);
+  }
+
+  @Override
+  public void onCommit(Map<TopicPartition, OffsetAndMetadata> offsets) {}
+
+  @Override
+  public void close() {}
+
+  @Override
+  public void configure(Map<String, ?> configs) {
+    consumerGroup = Objects.toString(configs.get(ConsumerConfig.GROUP_ID_CONFIG), null);
+    clientId = Objects.toString(configs.get(ConsumerConfig.CLIENT_ID_CONFIG), null);
+
+    Object telemetrySupplier = configs.get(CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER);
+    if (telemetrySupplier == null) {
+      return;
+    }
+
+    if (!(telemetrySupplier instanceof Supplier)) {
+      throw new IllegalStateException(
+          "Configuration property "
+              + CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER
+              + " is not instance of Supplier");
+    }
+
+    Object kafkaTelemetry = ((Supplier<?>) telemetrySupplier).get();
+    if (!(kafkaTelemetry instanceof KafkaTelemetry)) {
+      throw new IllegalStateException(
+          "Configuration property "
+              + CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER
+              + " supplier does not return KafkaTelemetry instance");
+    }
+
+    this.telemetry = (KafkaTelemetry) kafkaTelemetry;
+  }
+}

instrumentation/kafka/kafka-clients/kafka-clients-2.6/library/src/main/java/io/opentelemetry/instrumentation/kafkaclients/v2_6/OpenTelemetryProducerInterceptor.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.kafkaclients.v2_6;
+
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.Supplier;
+import javax.annotation.Nullable;
+import org.apache.kafka.clients.producer.ProducerConfig;
+import org.apache.kafka.clients.producer.ProducerInterceptor;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.clients.producer.RecordMetadata;
+
+/**
+ * A ProducerInterceptor that adds OpenTelemetry instrumentation. Add this interceptor's class name
+ * or class via ProducerConfig.INTERCEPTOR_CLASSES_CONFIG property to your Producer's properties to
+ * get it instantiated and used. See more details on ProducerInterceptor usage in its Javadoc.
+ *
+ * <p>To configure the interceptor, use {@link KafkaTelemetry#producerInterceptorConfigProperties}
+ * to obtain the configuration properties and add them to your producer configuration.
+ *
+ * @see KafkaTelemetry#producerInterceptorConfigProperties()
+ */
+public class OpenTelemetryProducerInterceptor<K, V> implements ProducerInterceptor<K, V> {
+
+  public static final String CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER =
+      "opentelemetry.kafka-telemetry.supplier";
+
+  @Nullable private KafkaTelemetry telemetry;
+  @Nullable private String clientId;
+
+  @Override
+  @CanIgnoreReturnValue
+  public ProducerRecord<K, V> onSend(ProducerRecord<K, V> producerRecord) {
+    if (telemetry != null) {
+      telemetry.buildAndInjectSpan(producerRecord, clientId);
+    }
+    return producerRecord;
+  }
+
+  @Override
+  public void onAcknowledgement(RecordMetadata recordMetadata, Exception e) {}
+
+  @Override
+  public void close() {}
+
+  @Override
+  public void configure(Map<String, ?> configs) {
+    clientId = Objects.toString(configs.get(ProducerConfig.CLIENT_ID_CONFIG), null);
+
+    Object telemetrySupplier = configs.get(CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER);
+    if (telemetrySupplier == null) {
+      return;
+    }
+
+    if (!(telemetrySupplier instanceof Supplier)) {
+      throw new IllegalStateException(
+          "Configuration property "
+              + CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER
+              + " is not instance of Supplier");
+    }
+
+    Object kafkaTelemetry = ((Supplier<?>) telemetrySupplier).get();
+    if (!(kafkaTelemetry instanceof KafkaTelemetry)) {
+      throw new IllegalStateException(
+          "Configuration property "
+              + CONFIG_KEY_KAFKA_TELEMETRY_SUPPLIER
+              + " supplier does not return KafkaTelemetry instance");
+    }
+
+    this.telemetry = (KafkaTelemetry) kafkaTelemetry;
+  }
+}

instrumentation/kafka/kafka-clients/kafka-clients-2.6/library/src/main/java/io/opentelemetry/instrumentation/kafkaclients/v2_6/TracingConsumerInterceptor.java

@@ -26,7 +26,10 @@
  * A ConsumerInterceptor that adds tracing capability. Add this interceptor's class name or class
  * via ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG property to your Consumer's properties to get it
  * instantiated and used. See more details on ConsumerInterceptor usage in its Javadoc.
+ *
+ * @deprecated Use {@link OpenTelemetryConsumerInterceptor} instead.
  */
+@Deprecated
 public class TracingConsumerInterceptor<K, V> implements ConsumerInterceptor<K, V> {
 
   private static final KafkaTelemetry telemetry =

instrumentation/kafka/kafka-clients/kafka-clients-2.6/library/src/main/java/io/opentelemetry/instrumentation/kafkaclients/v2_6/TracingProducerInterceptor.java

@@ -22,7 +22,12 @@
  * A ProducerInterceptor that adds tracing capability. Add this interceptor's class name or class
  * via ProducerConfig.INTERCEPTOR_CLASSES_CONFIG property to your Producer's properties to get it
  * instantiated and used. See more details on ProducerInterceptor usage in its Javadoc.
+ *
+ * @deprecated Use {@link OpenTelemetryProducerInterceptor} instead. This class uses {@link
+ *     GlobalOpenTelemetry} and is not configurable. The new class allows you to pass a configured
+ *     {@link KafkaTelemetry} instance.
  */
+@Deprecated
 public class TracingProducerInterceptor<K, V> implements ProducerInterceptor<K, V> {
 
   private static final KafkaTelemetry telemetry =