Add Micrometer Observation support. (#3249)

Signed-off-by: Maryanto <54889592+maryantocinn@users.noreply.github.com>

Author: maryantocinn

pom.xml

@@ -355,7 +355,13 @@
 			<scope>test</scope>
 		</dependency>
 
-	</dependencies>
+        <dependency>
+            <groupId>io.micrometer</groupId>
+            <artifactId>micrometer-observation-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
 
 	<build>
 		<resources>

src/main/java/org/springframework/data/elasticsearch/client/elc/DefaultElasticsearchObservationConvention.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2026-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 org.springframework.data.elasticsearch.client.elc;
+
+import io.micrometer.common.KeyValues;
+
+/**
+ * Default {@link ElasticsearchObservationConvention} implementation.
+ *
+ * @author maryantocinn
+ * @since 6.1
+ */
+public class DefaultElasticsearchObservationConvention implements ElasticsearchObservationConvention {
+
+	public static final DefaultElasticsearchObservationConvention INSTANCE = new DefaultElasticsearchObservationConvention();
+
+	@Override
+	public String getName() {
+		return ElasticsearchObservation.ELASTICSEARCH_COMMAND_OBSERVATION.getName();
+	}
+
+	@Override
+	public String getContextualName(ElasticsearchObservationContext context) {
+
+		String indexName = context.getIndexName();
+		if (indexName != null) {
+			return context.getOperationName().getValue() + " " + indexName;
+		}
+		return context.getOperationName().getValue();
+	}
+
+	@Override
+	public KeyValues getLowCardinalityKeyValues(ElasticsearchObservationContext context) {
+
+		KeyValues keyValues = KeyValues.of(
+				ElasticsearchObservation.LowCardinalityKeyNames.OPERATION.withValue(context.getOperationName().getValue()));
+
+		String indexName = context.getIndexName();
+		if (indexName != null) {
+			keyValues = keyValues.and(ElasticsearchObservation.LowCardinalityKeyNames.COLLECTION.withValue(indexName));
+		}
+
+		return keyValues;
+	}
+
+	@Override
+	public KeyValues getHighCardinalityKeyValues(ElasticsearchObservationContext context) {
+
+		Integer batchSize = context.getBatchSize();
+		if (batchSize != null) {
+			return KeyValues.of(
+					ElasticsearchObservation.HighCardinalityKeyNames.BATCH_SIZE.withValue(String.valueOf(batchSize)));
+		}
+
+		return KeyValues.empty();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/client/elc/ElasticsearchObservation.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2026-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 org.springframework.data.elasticsearch.client.elc;
+
+import io.micrometer.common.docs.KeyName;
+import io.micrometer.observation.Observation;
+import io.micrometer.observation.ObservationConvention;
+import io.micrometer.observation.docs.ObservationDocumentation;
+
+/**
+ * {@link ObservationDocumentation} for Spring Data Elasticsearch template operations.
+ *
+ * @author maryantocinn
+ * @since 6.1
+ */
+public enum ElasticsearchObservation implements ObservationDocumentation {
+
+	/**
+	 * Timer created around a Spring Data Elasticsearch template operation.
+	 */
+	ELASTICSEARCH_COMMAND_OBSERVATION {
+		@Override
+		public String getName() {
+			return "spring.data.elasticsearch.command";
+		}
+
+		@Override
+		public Class<? extends ObservationConvention<? extends Observation.Context>> getDefaultConvention() {
+			return DefaultElasticsearchObservationConvention.class;
+		}
+
+		@Override
+		public KeyName[] getLowCardinalityKeyNames() {
+			return LowCardinalityKeyNames.values();
+		}
+
+		@Override
+		public KeyName[] getHighCardinalityKeyNames() {
+			return HighCardinalityKeyNames.values();
+		}
+	};
+
+	/**
+	 * Low cardinality key names for Spring Data Elasticsearch observations. These become metric dimensions and MUST be
+	 * present on every observation to satisfy backends like Prometheus that require consistent tag key sets.
+	 */
+	enum LowCardinalityKeyNames implements KeyName {
+
+		/**
+		 * The Spring Data operation being performed (e.g., save, search, delete, bulk).
+		 */
+		OPERATION {
+			@Override
+			public String asString() {
+				return "spring.data.operation";
+			}
+		},
+
+		/**
+		 * The target collection (index) name. Only present when the operation targets a specific index.
+		 */
+		COLLECTION {
+			@Override
+			public String asString() {
+				return "spring.data.collection";
+			}
+		}
+	}
+
+	/**
+	 * High cardinality key names for Spring Data Elasticsearch observations. These appear only on traces/spans, not on
+	 * metrics, because their values are unbounded or optional per operation.
+	 */
+	enum HighCardinalityKeyNames implements KeyName {
+
+		/**
+		 * The number of operations included in a batch (bulk) request. Only present for bulk operations.
+		 */
+		BATCH_SIZE {
+			@Override
+			public String asString() {
+				return "spring.data.batch.size";
+			}
+		}
+	}
+}

src/main/java/org/springframework/data/elasticsearch/client/elc/ElasticsearchObservationContext.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2026-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 org.springframework.data.elasticsearch.client.elc;
+
+import org.jspecify.annotations.Nullable;
+import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
+
+import io.micrometer.observation.Observation;
+
+/**
+ * {@link Observation.Context} for Spring Data Elasticsearch operations. One instance is created per observed operation.
+ * It carries contextual data that conventions use to produce observation names and key-values.
+ *
+ * @author maryantocinn
+ * @since 6.1
+ */
+public class ElasticsearchObservationContext extends Observation.Context {
+
+	private final ElasticsearchOperationName operationName;
+	@Nullable
+	private final IndexCoordinates indexCoordinates;
+	@Nullable
+	private Integer batchSize;
+
+	public ElasticsearchObservationContext(ElasticsearchOperationName operationName,
+			@Nullable IndexCoordinates indexCoordinates) {
+		this.operationName = operationName;
+		this.indexCoordinates = indexCoordinates;
+	}
+
+	/**
+	 * @return the Spring Data operation being performed.
+	 */
+	public ElasticsearchOperationName getOperationName() {
+		return operationName;
+	}
+
+	/**
+	 * @return the target index coordinates, or {@literal null} if the operation is not index-specific.
+	 */
+	@Nullable
+	public IndexCoordinates getIndexCoordinates() {
+		return indexCoordinates;
+	}
+
+	/**
+	 * @return the comma-joined index name(s), or {@literal null} if no index coordinates are set.
+	 */
+	@Nullable
+	public String getIndexName() {
+		return indexCoordinates != null ? String.join(",", indexCoordinates.getIndexNames()) : null;
+	}
+
+	/**
+	 * @return the batch size, or {@literal null} if not a batch operation.
+	 */
+	@Nullable
+	public Integer getBatchSize() {
+		return batchSize;
+	}
+
+	/**
+	 * Set the number of operations included in a batch (bulk) request.
+	 *
+	 * @param batchSize the batch size, can be {@literal null}
+	 */
+	public void setBatchSize(@Nullable Integer batchSize) {
+		this.batchSize = batchSize;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/client/elc/ElasticsearchObservationConvention.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2026-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 org.springframework.data.elasticsearch.client.elc;
+
+import io.micrometer.observation.Observation;
+import io.micrometer.observation.ObservationConvention;
+
+/**
+ * {@link ObservationConvention} for Spring Data Elasticsearch operations. Implement this interface and register it as a
+ * bean to customize observation names and key-values.
+ *
+ * @author maryantocinn
+ * @since 6.1
+ */
+public interface ElasticsearchObservationConvention extends ObservationConvention<ElasticsearchObservationContext> {
+
+	@Override
+	default boolean supportsContext(Observation.Context context) {
+		return context instanceof ElasticsearchObservationContext;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/client/elc/ElasticsearchOperationName.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2026-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 org.springframework.data.elasticsearch.client.elc;
+
+/**
+ * Enumeration of Spring Data Elasticsearch operation names used in observations.
+ *
+ * @author maryantocinn
+ * @since 6.1
+ */
+public enum ElasticsearchOperationName {
+
+	SAVE("save"), //
+	INDEX("index"), //
+	GET("get"), //
+	MULTI_GET("multiGet"), //
+	EXISTS("exists"), //
+	DELETE("delete"), //
+	DELETE_BY_QUERY("deleteByQuery"), //
+	BULK("bulk"), //
+	UPDATE("update"), //
+	UPDATE_BY_QUERY("updateByQuery"), //
+	COUNT("count"), //
+	SEARCH("search");
+
+	private final String value;
+
+	ElasticsearchOperationName(String value) {
+		this.value = value;
+	}
+
+	/**
+	 * @return the operation name as a string value used in observation key values.
+	 */
+	public String getValue() {
+		return value;
+	}
+
+	@Override
+	public String toString() {
+		return value;
+	}
+}