GH-513 fix: Support custom field names for Milvus VectorStore collection

- Add configuration properties to override the default field names for doc_id, content, metadata and embedding
- Add support to allow auto-id when enabled
- Add tests

Resolves #513

Author: ilayaperumalg

spring-ai-spring-boot-autoconfigure/src/main/java/org/springframework/ai/autoconfigure/vectorstore/milvus/MilvusVectorStoreAutoConfiguration.java

@@ -42,6 +42,7 @@
  * @author Christian Tzolov
  * @author Eddú Meléndez
  * @author Soby Chacko
+ * @author Ilayaperumal Gopinathan
  */
 @AutoConfiguration
 @ConditionalOnClass({ MilvusVectorStore.class, EmbeddingModel.class })
@@ -75,6 +76,11 @@ public MilvusVectorStore vectorStore(MilvusServiceClient milvusClient, Embedding
 			.withMetricType(MetricType.valueOf(properties.getMetricType().name()))
 			.withIndexParameters(properties.getIndexParameters())
 			.withEmbeddingDimension(properties.getEmbeddingDimension())
+			.withIDFieldName(properties.getIdFieldName())
+			.withAutoId(properties.isAutoId())
+			.withContentFieldName(properties.getContentFieldName())
+			.withMetadataFieldName(properties.getMetadataFieldName())
+			.withEmbeddingFieldName(properties.getEmbeddingFieldName())
 			.build();
 
 		return new MilvusVectorStore(milvusClient, embeddingModel, config, properties.isInitializeSchema(),

spring-ai-spring-boot-autoconfigure/src/main/java/org/springframework/ai/autoconfigure/vectorstore/milvus/MilvusVectorStoreProperties.java

@@ -21,8 +21,11 @@
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.util.Assert;
 
+import java.util.List;
+
 /**
  * @author Christian Tzolov
+ * @author Ilayaperumal Gopinathan
  */
 @ConfigurationProperties(MilvusVectorStoreProperties.CONFIG_PREFIX)
 public class MilvusVectorStoreProperties extends CommonVectorStoreProperties {
@@ -59,6 +62,31 @@ public class MilvusVectorStoreProperties extends CommonVectorStoreProperties {
 	 */
 	private String indexParameters = "{\"nlist\":1024}";
 
+	/**
+	 * The ID field name for the collection.
+	 */
+	private String idFieldName = MilvusVectorStore.DOC_ID_FIELD_NAME;
+
+	/**
+	 * Boolean flag to indicate if the auto-id is used.
+	 */
+	private boolean isAutoId = false;
+
+	/**
+	 * The content field name for the collection.
+	 */
+	private String contentFieldName = MilvusVectorStore.CONTENT_FIELD_NAME;
+
+	/**
+	 * The metadata field name for the collection.
+	 */
+	private String metadataFieldName = MilvusVectorStore.METADATA_FIELD_NAME;
+
+	/**
+	 * The embedding field name for the collection.
+	 */
+	private String embeddingFieldName = MilvusVectorStore.EMBEDDING_FIELD_NAME;
+
 	public String getDatabaseName() {
 		return this.databaseName;
 	}
@@ -113,6 +141,50 @@ public void setIndexParameters(String indexParameters) {
 		this.indexParameters = indexParameters;
 	}
 
+	public String getIdFieldName() {
+		return this.idFieldName;
+	}
+
+	public void setIdFieldName(String idFieldName) {
+		Assert.notNull(idFieldName, "idFieldName can not be null");
+		this.idFieldName = idFieldName;
+	}
+
+	public boolean isAutoId() {
+		return this.isAutoId;
+	}
+
+	public void setAutoId(boolean autoId) {
+		this.isAutoId = autoId;
+	}
+
+	public String getContentFieldName() {
+		return this.contentFieldName;
+	}
+
+	public void setContentFieldName(String contentFieldName) {
+		Assert.notNull(contentFieldName, "contentFieldName can not be null");
+		this.contentFieldName = contentFieldName;
+	}
+
+	public String getMetadataFieldName() {
+		return this.metadataFieldName;
+	}
+
+	public void setMetadataFieldName(String metadataFieldName) {
+		Assert.notNull(metadataFieldName, "metadataFieldName can not be null");
+		this.metadataFieldName = metadataFieldName;
+	}
+
+	public String getEmbeddingFieldName() {
+		return this.embeddingFieldName;
+	}
+
+	public void setEmbeddingFieldName(String embeddingFieldName) {
+		Assert.notNull(embeddingFieldName, "embeddingFieldName can not be null");
+		this.embeddingFieldName = embeddingFieldName;
+	}
+
 	public enum MilvusMetricType {
 
 		/**

spring-ai-spring-boot-autoconfigure/src/test/java/org/springframework/ai/autoconfigure/vectorstore/milvus/MilvusVectorStoreAutoConfigurationIT.java

@@ -109,6 +109,57 @@ public void addAndSearch() {
 			});
 	}
 
+	@Test
+	public void searchWithCustomFields() {
+		contextRunner
+			.withPropertyValues("spring.ai.vectorstore.milvus.metricType=COSINE",
+					"spring.ai.vectorstore.milvus.indexType=IVF_FLAT",
+					"spring.ai.vectorstore.milvus.embeddingDimension=384",
+					"spring.ai.vectorstore.milvus.collectionName=myCustomCollection",
+					"spring.ai.vectorstore.milvus.idFieldName=identity",
+					"spring.ai.vectorstore.milvus.contentFieldName=text",
+					"spring.ai.vectorstore.milvus.embeddingFieldName=vectors",
+					"spring.ai.vectorstore.milvus.metadataFieldName=meta",
+					"spring.ai.vectorstore.milvus.initializeSchema=true",
+					"spring.ai.vectorstore.milvus.client.host=" + milvus.getHost(),
+					"spring.ai.vectorstore.milvus.client.port=" + milvus.getMappedPort(19530))
+			.run(context -> {
+				VectorStore vectorStore = context.getBean(VectorStore.class);
+				TestObservationRegistry observationRegistry = context.getBean(TestObservationRegistry.class);
+
+				vectorStore.add(documents);
+
+				assertObservationRegistry(observationRegistry, VectorStoreProvider.MILVUS,
+						VectorStoreObservationContext.Operation.ADD);
+				observationRegistry.clear();
+
+				List<Document> results = vectorStore.similaritySearch(SearchRequest.query("Spring").withTopK(1));
+
+				assertThat(results).hasSize(1);
+				Document resultDoc = results.get(0);
+				assertThat(resultDoc.getId()).isEqualTo(documents.get(0).getId());
+				assertThat(resultDoc.getContent()).contains(
+						"Spring AI provides abstractions that serve as the foundation for developing AI applications.");
+				assertThat(resultDoc.getMetadata()).hasSize(2);
+				assertThat(resultDoc.getMetadata()).containsKeys("spring", "distance");
+
+				assertObservationRegistry(observationRegistry, VectorStoreProvider.MILVUS,
+						VectorStoreObservationContext.Operation.QUERY);
+				observationRegistry.clear();
+
+				// Remove all documents from the store
+				vectorStore.delete(documents.stream().map(doc -> doc.getId()).toList());
+
+				results = vectorStore.similaritySearch(SearchRequest.query("Spring").withTopK(1));
+				assertThat(results).hasSize(0);
+
+				assertObservationRegistry(observationRegistry, VectorStoreProvider.MILVUS,
+						VectorStoreObservationContext.Operation.DELETE);
+				observationRegistry.clear();
+
+			});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class Config {