[8.19] Adding configurable inference service (#127939)

docs/changelog/127939.yaml

@@ -0,0 +1,5 @@
+pr: 127939
+summary: Add Custom inference service
+area: Machine Learning
+type: enhancement
+issues: []

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -228,6 +228,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion ML_INFERENCE_HUGGING_FACE_RERANK_ADDED_8_19 = def(8_841_0_36);
     public static final TransportVersion ML_INFERENCE_SAGEMAKER_CHAT_COMPLETION_8_19 = def(8_841_0_37);
     public static final TransportVersion ML_INFERENCE_VERTEXAI_CHATCOMPLETION_ADDED_8_19 = def(8_841_0_38);
+    public static final TransportVersion INFERENCE_CUSTOM_SERVICE_ADDED_8_19 = def(8_841_0_39);
 
     /*
      * STOP! READ THIS FIRST! No, really,

test/test-clusters/src/main/java/org/elasticsearch/test/cluster/FeatureFlag.java

@@ -17,7 +17,8 @@
  */
 public enum FeatureFlag {
     TIME_SERIES_MODE("es.index_mode_feature_flag_registered=true", Version.fromString("8.0.0"), null),
-    SUB_OBJECTS_AUTO_ENABLED("es.sub_objects_auto_feature_flag_enabled=true", Version.fromString("8.16.0"), null);
+    SUB_OBJECTS_AUTO_ENABLED("es.sub_objects_auto_feature_flag_enabled=true", Version.fromString("8.16.0"), null),
+    INFERENCE_CUSTOM_SERVICE_ENABLED("es.inference_custom_service_feature_flag_enabled=true", Version.fromString("8.19.0"), null);
 
     public final String systemProperty;
     public final Version from;

x-pack/plugin/inference/qa/inference-service-tests/src/javaRestTest/java/org/elasticsearch/xpack/inference/BaseMockEISAuthServerTest.java

@@ -14,6 +14,7 @@
 import org.elasticsearch.common.util.concurrent.ThreadContext;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
+import org.elasticsearch.test.cluster.FeatureFlag;
 import org.elasticsearch.test.cluster.local.distribution.DistributionType;
 import org.elasticsearch.test.rest.ESRestTestCase;
 import org.junit.ClassRule;
@@ -46,6 +47,7 @@ public class BaseMockEISAuthServerTest extends ESRestTestCase {
         // This plugin is located in the inference/qa/test-service-plugin package, look for TestInferenceServicePlugin
         .plugin("inference-service-test")
         .user("x_pack_rest_user", "x-pack-test-password")
+        .feature(FeatureFlag.INFERENCE_CUSTOM_SERVICE_ENABLED)
         .build();
 
     // The reason we're doing this is to make sure the mock server is initialized first so we can get the address before communicating

x-pack/plugin/inference/qa/inference-service-tests/src/javaRestTest/java/org/elasticsearch/xpack/inference/InferenceBaseRestTest.java

@@ -20,6 +20,7 @@
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.inference.TaskType;
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
+import org.elasticsearch.test.cluster.FeatureFlag;
 import org.elasticsearch.test.cluster.local.distribution.DistributionType;
 import org.elasticsearch.test.rest.ESRestTestCase;
 import org.elasticsearch.xcontent.XContentBuilder;
@@ -50,6 +51,7 @@ public class InferenceBaseRestTest extends ESRestTestCase {
         .setting("xpack.security.enabled", "true")
         .plugin("inference-service-test")
         .user("x_pack_rest_user", "x-pack-test-password")
+        .feature(FeatureFlag.INFERENCE_CUSTOM_SERVICE_ENABLED)
         .build();
 
     @ClassRule

x-pack/plugin/inference/qa/inference-service-tests/src/javaRestTest/java/org/elasticsearch/xpack/inference/InferenceGetServicesIT.java

@@ -25,7 +25,7 @@ public class InferenceGetServicesIT extends BaseMockEISAuthServerTest {
 
     public void testGetServicesWithoutTaskType() throws IOException {
         List<Object> services = getAllServices();
-        assertThat(services.size(), equalTo(22));
+        assertThat(services.size(), equalTo(23));
 
         var providers = providers(services);
 
@@ -39,6 +39,7 @@ public void testGetServicesWithoutTaskType() throws IOException {
                     "azureaistudio",
                     "azureopenai",
                     "cohere",
+                    "custom",
                     "deepseek",
                     "elastic",
                     "elasticsearch",
@@ -70,7 +71,7 @@ private Iterable<String> providers(List<Object> services) {
 
     public void testGetServicesWithTextEmbeddingTaskType() throws IOException {
         List<Object> services = getServices(TaskType.TEXT_EMBEDDING);
-        assertThat(services.size(), equalTo(16));
+        assertThat(services.size(), equalTo(17));
 
         var providers = providers(services);
 
@@ -83,6 +84,7 @@ public void testGetServicesWithTextEmbeddingTaskType() throws IOException {
                     "azureaistudio",
                     "azureopenai",
                     "cohere",
+                    "custom",
                     "elasticsearch",
                     "googleaistudio",
                     "googlevertexai",
@@ -101,7 +103,7 @@ public void testGetServicesWithTextEmbeddingTaskType() throws IOException {
 
     public void testGetServicesWithRerankTaskType() throws IOException {
         List<Object> services = getServices(TaskType.RERANK);
-        assertThat(services.size(), equalTo(8));
+        assertThat(services.size(), equalTo(9));
 
         var providers = providers(services);
 
@@ -111,6 +113,7 @@ public void testGetServicesWithRerankTaskType() throws IOException {
                 List.of(
                     "alibabacloud-ai-search",
                     "cohere",
+                    "custom",
                     "elasticsearch",
                     "googlevertexai",
                     "jinaai",
@@ -124,7 +127,7 @@ public void testGetServicesWithRerankTaskType() throws IOException {
 
     public void testGetServicesWithCompletionTaskType() throws IOException {
         List<Object> services = getServices(TaskType.COMPLETION);
-        assertThat(services.size(), equalTo(12));
+        assertThat(services.size(), equalTo(13));
 
         var providers = providers(services);
 
@@ -138,6 +141,7 @@ public void testGetServicesWithCompletionTaskType() throws IOException {
                     "azureaistudio",
                     "azureopenai",
                     "cohere",
+                    "custom",
                     "deepseek",
                     "googleaistudio",
                     "openai",
@@ -173,7 +177,7 @@ public void testGetServicesWithChatCompletionTaskType() throws IOException {
 
     public void testGetServicesWithSparseEmbeddingTaskType() throws IOException {
         List<Object> services = getServices(TaskType.SPARSE_EMBEDDING);
-        assertThat(services.size(), equalTo(6));
+        assertThat(services.size(), equalTo(7));
 
         var providers = providers(services);
 
@@ -182,6 +186,7 @@ public void testGetServicesWithSparseEmbeddingTaskType() throws IOException {
             containsInAnyOrder(
                 List.of(
                     "alibabacloud-ai-search",
+                    "custom",
                     "elastic",
                     "elasticsearch",
                     "hugging_face",

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/CustomServiceFeatureFlag.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.inference;
+
+import org.elasticsearch.common.util.FeatureFlag;
+
+public class CustomServiceFeatureFlag {
+    /**
+     * {@link org.elasticsearch.xpack.inference.services.custom.CustomService} feature flag. When the feature is complete,
+     * this flag will be removed.
+     * Enable feature via JVM option: `-Des.inference_custom_service_feature_flag_enabled=true`.
+     */
+    public static final FeatureFlag CUSTOM_SERVICE_FEATURE_FLAG = new FeatureFlag("inference_custom_service");
+
+    private CustomServiceFeatureFlag() {}
+}

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/InferenceNamedWriteablesProvider.java

@@ -59,6 +59,15 @@
 import org.elasticsearch.xpack.inference.services.cohere.embeddings.CohereEmbeddingsTaskSettings;
 import org.elasticsearch.xpack.inference.services.cohere.rerank.CohereRerankServiceSettings;
 import org.elasticsearch.xpack.inference.services.cohere.rerank.CohereRerankTaskSettings;
+import org.elasticsearch.xpack.inference.services.custom.CustomSecretSettings;
+import org.elasticsearch.xpack.inference.services.custom.CustomServiceSettings;
+import org.elasticsearch.xpack.inference.services.custom.CustomTaskSettings;
+import org.elasticsearch.xpack.inference.services.custom.response.CompletionResponseParser;
+import org.elasticsearch.xpack.inference.services.custom.response.CustomResponseParser;
+import org.elasticsearch.xpack.inference.services.custom.response.NoopResponseParser;
+import org.elasticsearch.xpack.inference.services.custom.response.RerankResponseParser;
+import org.elasticsearch.xpack.inference.services.custom.response.SparseEmbeddingResponseParser;
+import org.elasticsearch.xpack.inference.services.custom.response.TextEmbeddingResponseParser;
 import org.elasticsearch.xpack.inference.services.deepseek.DeepSeekChatCompletionModel;
 import org.elasticsearch.xpack.inference.services.elastic.ElasticInferenceServiceSparseEmbeddingsServiceSettings;
 import org.elasticsearch.xpack.inference.services.elastic.completion.ElasticInferenceServiceCompletionServiceSettings;
@@ -108,6 +117,8 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.elasticsearch.xpack.inference.CustomServiceFeatureFlag.CUSTOM_SERVICE_FEATURE_FLAG;
+
 public class InferenceNamedWriteablesProvider {
 
     private InferenceNamedWriteablesProvider() {}
@@ -158,6 +169,7 @@ public static List<NamedWriteableRegistry.Entry> getNamedWriteables() {
         addAlibabaCloudSearchNamedWriteables(namedWriteables);
         addJinaAINamedWriteables(namedWriteables);
         addVoyageAINamedWriteables(namedWriteables);
+        addCustomNamedWriteables(namedWriteables);
 
         addUnifiedNamedWriteables(namedWriteables);
 
@@ -169,6 +181,42 @@ public static List<NamedWriteableRegistry.Entry> getNamedWriteables() {
         return namedWriteables;
     }
 
+    private static void addCustomNamedWriteables(List<NamedWriteableRegistry.Entry> namedWriteables) {
+        if (CUSTOM_SERVICE_FEATURE_FLAG.isEnabled() == false) {
+            return;
+        }
+
+        namedWriteables.add(
+            new NamedWriteableRegistry.Entry(ServiceSettings.class, CustomServiceSettings.NAME, CustomServiceSettings::new)
+        );
+
+        namedWriteables.add(new NamedWriteableRegistry.Entry(TaskSettings.class, CustomTaskSettings.NAME, CustomTaskSettings::new));
+
+        namedWriteables.add(new NamedWriteableRegistry.Entry(SecretSettings.class, CustomSecretSettings.NAME, CustomSecretSettings::new));
+
+        namedWriteables.add(
+            new NamedWriteableRegistry.Entry(CustomResponseParser.class, TextEmbeddingResponseParser.NAME, TextEmbeddingResponseParser::new)
+        );
+
+        namedWriteables.add(
+            new NamedWriteableRegistry.Entry(
+                CustomResponseParser.class,
+                SparseEmbeddingResponseParser.NAME,
+                SparseEmbeddingResponseParser::new
+            )
+        );
+
+        namedWriteables.add(
+            new NamedWriteableRegistry.Entry(CustomResponseParser.class, RerankResponseParser.NAME, RerankResponseParser::new)
+        );
+
+        namedWriteables.add(new NamedWriteableRegistry.Entry(CustomResponseParser.class, NoopResponseParser.NAME, NoopResponseParser::new));
+
+        namedWriteables.add(
+            new NamedWriteableRegistry.Entry(CustomResponseParser.class, CompletionResponseParser.NAME, CompletionResponseParser::new)
+        );
+    }
+
     private static void addUnifiedNamedWriteables(List<NamedWriteableRegistry.Entry> namedWriteables) {
         var writeables = UnifiedCompletionRequest.getNamedWriteables();
         namedWriteables.addAll(writeables);

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/InferencePlugin.java

@@ -121,6 +121,7 @@
 import org.elasticsearch.xpack.inference.services.azureaistudio.AzureAiStudioService;
 import org.elasticsearch.xpack.inference.services.azureopenai.AzureOpenAiService;
 import org.elasticsearch.xpack.inference.services.cohere.CohereService;
+import org.elasticsearch.xpack.inference.services.custom.CustomService;
 import org.elasticsearch.xpack.inference.services.deepseek.DeepSeekService;
 import org.elasticsearch.xpack.inference.services.elastic.ElasticInferenceService;
 import org.elasticsearch.xpack.inference.services.elastic.ElasticInferenceServiceComponents;
@@ -150,8 +151,10 @@
 import java.util.Set;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
+import java.util.stream.Stream;
 
 import static java.util.Collections.singletonList;
+import static org.elasticsearch.xpack.inference.CustomServiceFeatureFlag.CUSTOM_SERVICE_FEATURE_FLAG;
 import static org.elasticsearch.xpack.inference.action.filter.ShardBulkInferenceActionFilter.INDICES_INFERENCE_BATCH_SIZE;
 import static org.elasticsearch.xpack.inference.common.InferenceAPIClusterAwareRateLimitingFeature.INFERENCE_API_CLUSTER_AWARE_RATE_LIMITING_FEATURE_FLAG;
 
@@ -381,7 +384,11 @@ public void loadExtensions(ExtensionLoader loader) {
     }
 
     public List<InferenceServiceExtension.Factory> getInferenceServiceFactories() {
-        return List.of(
+        List<InferenceServiceExtension.Factory> conditionalServices = CUSTOM_SERVICE_FEATURE_FLAG.isEnabled()
+            ? List.of(context -> new CustomService(httpFactory.get(), serviceComponents.get()))
+            : List.of();
+
+        List<InferenceServiceExtension.Factory> availableServices = List.of(
             context -> new HuggingFaceElserService(httpFactory.get(), serviceComponents.get()),
             context -> new HuggingFaceService(httpFactory.get(), serviceComponents.get()),
             context -> new OpenAiService(httpFactory.get(), serviceComponents.get()),
@@ -400,6 +407,8 @@ public List<InferenceServiceExtension.Factory> getInferenceServiceFactories() {
             context -> new DeepSeekService(httpFactory.get(), serviceComponents.get()),
             ElasticsearchInternalService::new
         );
+
+        return Stream.concat(availableServices.stream(), conditionalServices.stream()).toList();
     }
 
     @Override

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/external/http/retry/BaseResponseHandler.java

@@ -36,7 +36,7 @@ public abstract class BaseResponseHandler implements ResponseHandler {
     public static final String METHOD_NOT_ALLOWED = "Received a method not allowed status code";
 
     protected final String requestType;
-    private final ResponseParser parseFunction;
+    protected final ResponseParser parseFunction;
     private final Function<HttpResult, ErrorResponse> errorParseFunction;
     private final boolean canHandleStreamingResponses;