[ML] add new delete trained model aliases API

docs/reference/ml/df-analytics/apis/delete-trained-models-aliases.asciidoc

@@ -0,0 +1,62 @@
+[role="xpack"]
+[testenv="platinum"]
+[[delete-trained-models-aliases]]
+= Delete Trained Model Aliases API
+[subs="attributes"]
+++++
+<titleabbrev>Delete Trained Model Aliases</titleabbrev>
+++++
+
+Deletes a trained model alias.
+
+beta::[]
+
+[[ml-delete-trained-models-aliases-request]]
+== {api-request-title}
+
+`DELETE _ml/trained_models/<model_id>/model_aliases/<model_alias>`
+
+
+[[ml-delete-trained-models-aliases-prereq]]
+== {api-prereq-title}
+
+If the {es} {security-features} are enabled, you must have the following
+built-in roles and privileges:
+
+* `machine_learning_admin`
+
+For more information, see <<built-in-roles>>, <<security-privileges>>, and
+{ml-docs-setup-privileges}.
+
+[[ml-delete-trained-models-aliases-desc]]
+== {api-description-title}
+
+This API deletes an existing model alias that refers to a trained model.
+
+If the model alias is missing or refers to a model other than the one identified by
+the `model_id`, this API will return an error.
+
+[[ml-delete-trained-models-aliases-path-params]]
+== {api-path-parms-title}
+
+`model_id`::
+(Required, string)
+The trained model ID to which the model alias refers.
+
+`model_alias`::
+(Required, string)
+The model alias to delete.
+
+[[ml-delete-trained-models-aliases-example]]
+== {api-examples-title}
+
+[[ml-delete-trained-models-aliases-example-delete]]
+=== Deleting a model alias
+
+The following example shows how to delete a model alias for a trained model ID.
+
+[source,console]
+--------------------------------------------------
+DELETE _ml/trained_models/flight-delay-prediction-1574775339910/model_aliases/flight_delay_model
+--------------------------------------------------
+// TEST[skip:setup kibana sample data]

docs/reference/ml/df-analytics/apis/index.asciidoc

@@ -8,6 +8,7 @@ include::update-dfanalytics.asciidoc[leveloffset=+2]
 //DELETE
 include::delete-dfanalytics.asciidoc[leveloffset=+2]
 include::delete-trained-models.asciidoc[leveloffset=+2]
+include::delete-trained-models-aliases.asciidoc[leveloffset=+2]
 //EVALUATE
 include::evaluate-dfanalytics.asciidoc[leveloffset=+2]
 //ESTIMATE_MEMORY_USAGE

docs/reference/ml/df-analytics/apis/ml-df-analytics-apis.asciidoc

@@ -23,6 +23,7 @@ You can use the following APIs to perform {infer} operations.
 * <<get-trained-models-stats>>
 * <<delete-trained-models>>
 * <<put-trained-models-aliases>>
+* <<delete-trained-models-aliases>>
 
 You can deploy a trained model to make predictions in an ingest pipeline or in
 an aggregation. Refer to the following documentation to learn more.

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/DeleteTrainedModelAliasAction.java

@@ -0,0 +1,85 @@
+/*
+ * 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.core.ml.action;
+
+import org.elasticsearch.action.ActionRequestValidationException;
+import org.elasticsearch.action.ActionType;
+import org.elasticsearch.action.support.master.AcknowledgedRequest;
+import org.elasticsearch.action.support.master.AcknowledgedResponse;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.xpack.core.ml.inference.TrainedModelConfig;
+import org.elasticsearch.xpack.core.ml.utils.ExceptionsHelper;
+
+import java.io.IOException;
+import java.util.Objects;
+
+
+public class DeleteTrainedModelAliasAction extends ActionType<AcknowledgedResponse> {
+
+    public static final DeleteTrainedModelAliasAction INSTANCE = new DeleteTrainedModelAliasAction();
+    public static final String NAME = "cluster:admin/xpack/ml/inference/model_aliases/delete";
+
+    private DeleteTrainedModelAliasAction() {
+        super(NAME, AcknowledgedResponse::readFrom);
+    }
+
+    public static class Request extends AcknowledgedRequest<Request> {
+
+        public static final String MODEL_ALIAS = "model_alias";
+
+        private final String modelAlias;
+        private final String modelId;
+
+        public Request(String modelAlias, String modelId) {
+            this.modelAlias = ExceptionsHelper.requireNonNull(modelAlias, MODEL_ALIAS);
+            this.modelId = ExceptionsHelper.requireNonNull(modelId, TrainedModelConfig.MODEL_ID);
+        }
+
+        public Request(StreamInput in) throws IOException {
+            super(in);
+            this.modelAlias = in.readString();
+            this.modelId = in.readString();
+        }
+
+        public String getModelAlias() {
+            return modelAlias;
+        }
+
+        public String getModelId() {
+            return modelId;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws  IOException {
+            super.writeTo(out);
+            out.writeString(modelAlias);
+            out.writeString(modelId);
+        }
+
+        @Override
+        public ActionRequestValidationException validate() {
+            return null;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Request request = (Request) o;
+            return Objects.equals(modelAlias, request.modelAlias)
+                && Objects.equals(modelId, request.modelId);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(modelAlias, modelId);
+        }
+
+    }
+}

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/action/DeleteTrainedModelAliasActionRequestTests.java

@@ -0,0 +1,31 @@
+/*
+ * 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.core.ml.action;
+
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.test.AbstractWireSerializingTestCase;
+import org.elasticsearch.xpack.core.ml.action.DeleteTrainedModelAliasAction.Request;
+
+
+public class DeleteTrainedModelAliasActionRequestTests extends AbstractWireSerializingTestCase<Request> {
+
+    @Override
+    protected Request createTestInstance() {
+        return new Request(randomAlphaOfLength(10), randomAlphaOfLength(10));
+    }
+
+    @Override
+    protected Writeable.Reader<Request> instanceReader() {
+        return Request::new;
+    }
+
+    public void testCtor() {
+        expectThrows(Exception.class, () -> new Request(null, randomAlphaOfLength(10)));
+        expectThrows(Exception.class, () -> new Request(randomAlphaOfLength(10), null));
+    }
+
+}

x-pack/plugin/ml/qa/ml-with-security/build.gradle

@@ -149,6 +149,8 @@ tasks.named("yamlRestTest").configure {
     'ml/inference_crud/Test update model alias with bad alias',
     'ml/inference_crud/Test update model alias where alias exists but old model id is different inference type',
     'ml/inference_crud/Test update model alias where alias exists but reassign is false',
+    'ml/inference_crud/Test delete model alias with missing alias',
+    'ml/inference_crud/Test delete model alias where alias points to different model',
     'ml/inference_processor/Test create processor with missing mandatory fields',
     'ml/inference_stats_crud/Test get stats given missing trained model',
     'ml/inference_stats_crud/Test get stats given expression without matches and allow_no_match is false',

x-pack/plugin/ml/qa/single-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/InferenceProcessorIT.java

@@ -226,6 +226,27 @@ public void testDeleteModelWhileAliasReferencedByPipeline() throws Exception {
         waitForStats();
     }
 
+    public void testDeleteModelAliasWhileAliasReferencedByPipeline() throws Exception {
+        putRegressionModel();
+        putModelAlias("regression_to_delete", MODEL_ID);
+        createdPipelines.add("first_pipeline");
+        putPipeline("regression_to_delete", "first_pipeline");
+        Exception ex = expectThrows(Exception.class,
+            () -> client().performRequest(
+                new Request(
+                    "DELETE",
+                    "_ml/trained_models/" + MODEL_ID + "/model_aliases/regression_to_delete"
+                )
+            ));
+        assertThat(
+            ex.getMessage(),
+            containsString("Cannot delete model_alias [regression_to_delete] as it is still referenced by ingest processors")
+        );
+        infer("first_pipeline");
+        deletePipeline("first_pipeline");
+        waitForStats();
+    }
+
     public void testDeleteModelWhileReferencedByPipeline() throws Exception {
         putRegressionModel();
         createdPipelines.add("first_pipeline");

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/MachineLearning.java

@@ -91,6 +91,7 @@
 import org.elasticsearch.xpack.core.ml.action.DeleteJobAction;
 import org.elasticsearch.xpack.core.ml.action.DeleteModelSnapshotAction;
 import org.elasticsearch.xpack.core.ml.action.DeleteTrainedModelAction;
+import org.elasticsearch.xpack.core.ml.action.DeleteTrainedModelAliasAction;
 import org.elasticsearch.xpack.core.ml.action.EstimateModelMemoryAction;
 import org.elasticsearch.xpack.core.ml.action.EvaluateDataFrameAction;
 import org.elasticsearch.xpack.core.ml.action.ExplainDataFrameAnalyticsAction;
@@ -170,6 +171,7 @@
 import org.elasticsearch.xpack.ml.action.TransportDeleteJobAction;
 import org.elasticsearch.xpack.ml.action.TransportDeleteModelSnapshotAction;
 import org.elasticsearch.xpack.ml.action.TransportDeleteTrainedModelAction;
+import org.elasticsearch.xpack.ml.action.TransportDeleteTrainedModelAliasAction;
 import org.elasticsearch.xpack.ml.action.TransportEstimateModelMemoryAction;
 import org.elasticsearch.xpack.ml.action.TransportEvaluateDataFrameAction;
 import org.elasticsearch.xpack.ml.action.TransportExplainDataFrameAnalyticsAction;
@@ -317,6 +319,7 @@
 import org.elasticsearch.xpack.ml.rest.filter.RestPutFilterAction;
 import org.elasticsearch.xpack.ml.rest.filter.RestUpdateFilterAction;
 import org.elasticsearch.xpack.ml.rest.inference.RestDeleteTrainedModelAction;
+import org.elasticsearch.xpack.ml.rest.inference.RestDeleteTrainedModelAliasAction;
 import org.elasticsearch.xpack.ml.rest.inference.RestGetTrainedModelsAction;
 import org.elasticsearch.xpack.ml.rest.inference.RestGetTrainedModelsStatsAction;
 import org.elasticsearch.xpack.ml.rest.inference.RestPutTrainedModelAction;
@@ -939,6 +942,7 @@ public List<RestHandler> getRestHandlers(Settings settings, RestController restC
             new RestPutTrainedModelAction(),
             new RestUpgradeJobModelSnapshotAction(),
             new RestPutTrainedModelAliasAction(),
+            new RestDeleteTrainedModelAliasAction(),
             // CAT Handlers
             new RestCatJobsAction(),
             new RestCatTrainedModelsAction(),
@@ -1023,6 +1027,7 @@ public List<RestHandler> getRestHandlers(Settings settings, RestController restC
                 new ActionHandler<>(PutTrainedModelAction.INSTANCE, TransportPutTrainedModelAction.class),
                 new ActionHandler<>(UpgradeJobModelSnapshotAction.INSTANCE, TransportUpgradeJobModelSnapshotAction.class),
                 new ActionHandler<>(PutTrainedModelAliasAction.INSTANCE, TransportPutTrainedModelAliasAction.class),
+                new ActionHandler<>(DeleteTrainedModelAliasAction.INSTANCE, TransportDeleteTrainedModelAliasAction.class),
                 usageAction,
                 infoAction);
     }

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/action/TransportDeleteTrainedModelAction.java

@@ -77,7 +77,7 @@ protected void masterOperation(Task task,
                                    ActionListener<AcknowledgedResponse> listener) {
         String id = request.getId();
         IngestMetadata currentIngestMetadata = state.metadata().custom(IngestMetadata.TYPE);
-        Set<String> referencedModels = getReferencedModelKeys(currentIngestMetadata);
+        Set<String> referencedModels = getReferencedModelKeys(currentIngestMetadata, ingestService);
 
         if (referencedModels.contains(id)) {
             listener.onFailure(new ElasticsearchStatusException("Cannot delete model [{}] as it is still referenced by ingest processors",
@@ -142,7 +142,7 @@ public ClusterState execute(final ClusterState currentState) {
         });
     }
 
-    private Set<String> getReferencedModelKeys(IngestMetadata ingestMetadata) {
+    static Set<String> getReferencedModelKeys(IngestMetadata ingestMetadata, IngestService ingestService) {
         Set<String> allReferencedModelKeys = new HashSet<>();
         if (ingestMetadata == null) {
             return allReferencedModelKeys;