[Inference API] Prevent inference endpoints from being deleted if the…

…y are referenced by semantic text (#110399)

Following on #109123

docs/changelog/110399.yaml

@@ -0,0 +1,6 @@
+pr: 110399
+summary: "[Inference API] Prevent inference endpoints from being deleted if they are\
+  \ referenced by semantic text"
+area: Machine Learning
+type: enhancement
+issues: []

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

@@ -208,6 +208,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion TEXT_SIMILARITY_RERANKER_RETRIEVER = def(8_699_00_0);
     public static final TransportVersion ML_INFERENCE_GOOGLE_VERTEX_AI_RERANKING_ADDED = def(8_700_00_0);
     public static final TransportVersion VERSIONED_MASTER_NODE_REQUESTS = def(8_701_00_0);
+    public static final TransportVersion ML_INFERENCE_DONT_DELETE_WHEN_SEMANTIC_TEXT_EXISTS = def(8_702_00_0);
 
     /*
      * STOP! READ THIS FIRST! No, really,

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/DeleteInferenceEndpointAction.java

@@ -13,6 +13,7 @@
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.core.Nullable;
 import org.elasticsearch.inference.TaskType;
 import org.elasticsearch.xcontent.XContentBuilder;
 
@@ -105,10 +106,16 @@ public static class Response extends AcknowledgedResponse {
 
         private final String PIPELINE_IDS = "pipelines";
         Set<String> pipelineIds;
+        private final String REFERENCED_INDEXES = "indexes";
+        Set<String> indexes;
+        private final String DRY_RUN_MESSAGE = "error_message"; // error message only returned in response for dry_run
+        String dryRunMessage;
 
-        public Response(boolean acknowledged, Set<String> pipelineIds) {
+        public Response(boolean acknowledged, Set<String> pipelineIds, Set<String> semanticTextIndexes, @Nullable String dryRunMessage) {
             super(acknowledged);
             this.pipelineIds = pipelineIds;
+            this.indexes = semanticTextIndexes;
+            this.dryRunMessage = dryRunMessage;
         }
 
         public Response(StreamInput in) throws IOException {
@@ -118,6 +125,15 @@ public Response(StreamInput in) throws IOException {
             } else {
                 pipelineIds = Set.of();
             }
+
+            if (in.getTransportVersion().onOrAfter(TransportVersions.ML_INFERENCE_DONT_DELETE_WHEN_SEMANTIC_TEXT_EXISTS)) {
+                indexes = in.readCollectionAsSet(StreamInput::readString);
+                dryRunMessage = in.readOptionalString();
+            } else {
+                indexes = Set.of();
+                dryRunMessage = null;
+            }
+
         }
 
         @Override
@@ -126,12 +142,18 @@ public void writeTo(StreamOutput out) throws IOException {
             if (out.getTransportVersion().onOrAfter(TransportVersions.ML_INFERENCE_ENHANCE_DELETE_ENDPOINT)) {
                 out.writeCollection(pipelineIds, StreamOutput::writeString);
             }
+            if (out.getTransportVersion().onOrAfter(TransportVersions.ML_INFERENCE_DONT_DELETE_WHEN_SEMANTIC_TEXT_EXISTS)) {
+                out.writeCollection(indexes, StreamOutput::writeString);
+                out.writeOptionalString(dryRunMessage);
+            }
         }
 
         @Override
         protected void addCustomFields(XContentBuilder builder, Params params) throws IOException {
             super.addCustomFields(builder, params);
             builder.field(PIPELINE_IDS, pipelineIds);
+            builder.field(REFERENCED_INDEXES, indexes);
+            builder.field(DRY_RUN_MESSAGE, dryRunMessage);
         }
 
         @Override
@@ -142,6 +164,11 @@ public String toString() {
             for (String entry : pipelineIds) {
                 returnable.append(entry).append(", ");
             }
+            returnable.append(", semanticTextFieldsByIndex: ");
+            for (String entry : indexes) {
+                returnable.append(entry).append(", ");
+            }
+            returnable.append(", dryRunMessage: ").append(dryRunMessage);
             return returnable.toString();
         }
     }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/utils/SemanticTextInfoExtractor.java

@@ -0,0 +1,48 @@
+/*
+ * 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.
+ *
+ * this file was contributed to by a Generative AI
+ */
+
+package org.elasticsearch.xpack.core.ml.utils;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.elasticsearch.cluster.metadata.IndexMetadata;
+import org.elasticsearch.cluster.metadata.InferenceFieldMetadata;
+import org.elasticsearch.cluster.metadata.Metadata;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class SemanticTextInfoExtractor {
+    private static final Logger logger = LogManager.getLogger(SemanticTextInfoExtractor.class);
+
+    public static Set<String> extractIndexesReferencingInferenceEndpoints(Metadata metadata, Set<String> endpointIds) {
+        assert endpointIds.isEmpty() == false;
+        assert metadata != null;
+
+        Set<String> referenceIndices = new HashSet<>();
+
+        Map<String, IndexMetadata> indices = metadata.indices();
+
+        indices.forEach((indexName, indexMetadata) -> {
+            if (indexMetadata.getInferenceFields() != null) {
+                Map<String, InferenceFieldMetadata> inferenceFields = indexMetadata.getInferenceFields();
+                if (inferenceFields.entrySet()
+                    .stream()
+                    .anyMatch(
+                        entry -> entry.getValue().getInferenceId() != null && endpointIds.contains(entry.getValue().getInferenceId())
+                    )) {
+                    referenceIndices.add(indexName);
+                }
+            }
+        });
+
+        return referenceIndices;
+    }
+}

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

@@ -126,6 +126,25 @@ protected void deleteModel(String modelId, TaskType taskType) throws IOException
         assertOkOrCreated(response);
     }
 
+    protected void putSemanticText(String endpointId, String indexName) throws IOException {
+        var request = new Request("PUT", Strings.format("%s", indexName));
+        String body = Strings.format("""
+            {
+                "mappings": {
+                "properties": {
+                    "inference_field": {
+                        "type": "semantic_text",
+                            "inference_id": "%s"
+                    }
+                }
+                }
+            }
+            """, endpointId);
+        request.setJsonEntity(body);
+        var response = client().performRequest(request);
+        assertOkOrCreated(response);
+    }
+
     protected Map<String, Object> putModel(String modelId, String modelConfig, TaskType taskType) throws IOException {
         String endpoint = Strings.format("_inference/%s/%s", taskType, modelId);
         return putRequest(endpoint, modelConfig);

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

@@ -16,6 +16,7 @@
 
 import java.io.IOException;
 import java.util.List;
+import java.util.Set;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.hasSize;
@@ -124,14 +125,15 @@ public void testDeleteEndpointWhileReferencedByPipeline() throws IOException {
         putPipeline(pipelineId, endpointId);
 
         {
+            var errorString = new StringBuilder().append("Inference endpoint ")
+                .append(endpointId)
+                .append(" is referenced by pipelines: ")
+                .append(Set.of(pipelineId))
+                .append(". ")
+                .append("Ensure that no pipelines are using this inference endpoint, ")
+                .append("or use force to ignore this warning and delete the inference endpoint.");
             var e = expectThrows(ResponseException.class, () -> deleteModel(endpointId));
-            assertThat(
-                e.getMessage(),
-                containsString(
-                    "Inference endpoint endpoint_referenced_by_pipeline is referenced by pipelines and cannot be deleted. "
-                        + "Use `force` to delete it anyway, or use `dry_run` to list the pipelines that reference it."
-                )
-            );
+            assertThat(e.getMessage(), containsString(errorString.toString()));
         }
         {
             var response = deleteModel(endpointId, "dry_run=true");
@@ -146,4 +148,76 @@ public void testDeleteEndpointWhileReferencedByPipeline() throws IOException {
         }
         deletePipeline(pipelineId);
     }
+
+    public void testDeleteEndpointWhileReferencedBySemanticText() throws IOException {
+        String endpointId = "endpoint_referenced_by_semantic_text";
+        putModel(endpointId, mockSparseServiceModelConfig(), TaskType.SPARSE_EMBEDDING);
+        String indexName = randomAlphaOfLength(10).toLowerCase();
+        putSemanticText(endpointId, indexName);
+        {
+
+            var errorString = new StringBuilder().append(" Inference endpoint ")
+                .append(endpointId)
+                .append(" is being used in the mapping for indexes: ")
+                .append(Set.of(indexName))
+                .append(". ")
+                .append("Ensure that no index mappings are using this inference endpoint, ")
+                .append("or use force to ignore this warning and delete the inference endpoint.");
+            var e = expectThrows(ResponseException.class, () -> deleteModel(endpointId));
+            assertThat(e.getMessage(), containsString(errorString.toString()));
+        }
+        {
+            var response = deleteModel(endpointId, "dry_run=true");
+            var entityString = EntityUtils.toString(response.getEntity());
+            assertThat(entityString, containsString("\"acknowledged\":false"));
+            assertThat(entityString, containsString(indexName));
+        }
+        {
+            var response = deleteModel(endpointId, "force=true");
+            var entityString = EntityUtils.toString(response.getEntity());
+            assertThat(entityString, containsString("\"acknowledged\":true"));
+        }
+    }
+
+    public void testDeleteEndpointWhileReferencedBySemanticTextAndPipeline() throws IOException {
+        String endpointId = "endpoint_referenced_by_semantic_text";
+        putModel(endpointId, mockSparseServiceModelConfig(), TaskType.SPARSE_EMBEDDING);
+        String indexName = randomAlphaOfLength(10).toLowerCase();
+        putSemanticText(endpointId, indexName);
+        var pipelineId = "pipeline_referencing_model";
+        putPipeline(pipelineId, endpointId);
+        {
+
+            var errorString = new StringBuilder().append("Inference endpoint ")
+                .append(endpointId)
+                .append(" is referenced by pipelines: ")
+                .append(Set.of(pipelineId))
+                .append(". ")
+                .append("Ensure that no pipelines are using this inference endpoint, ")
+                .append("or use force to ignore this warning and delete the inference endpoint.")
+                .append(" Inference endpoint ")
+                .append(endpointId)
+                .append(" is being used in the mapping for indexes: ")
+                .append(Set.of(indexName))
+                .append(". ")
+                .append("Ensure that no index mappings are using this inference endpoint, ")
+                .append("or use force to ignore this warning and delete the inference endpoint.");
+
+            var e = expectThrows(ResponseException.class, () -> deleteModel(endpointId));
+            assertThat(e.getMessage(), containsString(errorString.toString()));
+        }
+        {
+            var response = deleteModel(endpointId, "dry_run=true");
+            var entityString = EntityUtils.toString(response.getEntity());
+            assertThat(entityString, containsString("\"acknowledged\":false"));
+            assertThat(entityString, containsString(indexName));
+            assertThat(entityString, containsString(pipelineId));
+        }
+        {
+            var response = deleteModel(endpointId, "force=true");
+            var entityString = EntityUtils.toString(response.getEntity());
+            assertThat(entityString, containsString("\"acknowledged\":true"));
+        }
+        deletePipeline(pipelineId);
+    }
 }