ES|QL Views prototype

rest-api-spec/src/main/resources/rest-api-spec/api/esql.delete_view.json

@@ -0,0 +1,35 @@
+{
+  "esql.delete_view": {
+    "documentation": {
+      "url": "https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-esql-view-delete",
+      "description": "Delete a non-materialized VIEW for ESQL."
+    },
+    "stability": "experimental",
+    "visibility": "feature_flag",
+    "feature_flag": "esql_views",
+    "headers": {
+      "accept": [
+        "application/json"
+      ],
+      "content_type": [
+        "application/json"
+      ]
+    },
+    "url": {
+      "paths": [
+        {
+          "path": "/_query/view/{name}",
+          "methods": [
+            "DELETE"
+          ],
+          "parts": {
+            "name": {
+              "type": "string",
+              "description": "The name of the view to delete"
+            }
+          }
+        }
+      ]
+    }
+  }
+}

rest-api-spec/src/main/resources/rest-api-spec/api/esql.get_query.json

@@ -5,7 +5,8 @@
       "description": "Get a specific running ES|QL query information"
     },
     "stability": "experimental",
-    "visibility": "public",
+    "visibility": "feature_flag",
+    "feature_flag": "esql_views",
     "headers": {
       "accept": [
         "application/json"

rest-api-spec/src/main/resources/rest-api-spec/api/esql.get_view.json

@@ -0,0 +1,41 @@
+{
+  "esql.get_view": {
+    "documentation": {
+      "url": "https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-esql-view-get",
+      "description": "Get a non-materialized VIEW for ESQL."
+    },
+    "stability": "experimental",
+    "visibility": "feature_flag",
+    "feature_flag": "esql_views",
+    "headers": {
+      "accept": [
+        "application/json"
+      ],
+      "content_type": [
+        "application/json"
+      ]
+    },
+    "url": {
+      "paths": [
+        {
+          "path": "/_query/view/{name}",
+          "methods": [
+            "GET"
+          ],
+          "parts": {
+            "name": {
+              "type": "list",
+              "description": "A comma-separated list of view names"
+            }
+          }
+        },
+        {
+          "path": "/_query/view",
+          "methods": [
+            "GET"
+          ]
+        }
+      ]
+    }
+  }
+}

rest-api-spec/src/main/resources/rest-api-spec/api/esql.put_view.json

@@ -0,0 +1,38 @@
+{
+  "esql.put_view": {
+    "documentation": {
+      "url": "https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-esql-view-put",
+      "description": "Creates a non-materialized VIEW for ESQL."
+    },
+    "stability": "experimental",
+    "visibility": "public",
+    "headers": {
+      "accept": [
+        "application/json"
+      ],
+      "content_type": [
+        "application/json"
+      ]
+    },
+    "url": {
+      "paths": [
+        {
+          "path": "/_query/view/{name}",
+          "methods": [
+            "PUT"
+          ],
+          "parts": {
+            "name": {
+              "type": "string",
+              "description": "The name of the view to create or update"
+            }
+          }
+        }
+      ]
+    },
+    "body": {
+      "description": "Use the `query` element to define the ES|QL query to use as a non-materialized VIEW.",
+      "required": true
+    }
+  }
+}

server/src/main/java/org/elasticsearch/cluster/metadata/View.java

@@ -0,0 +1,108 @@
+/*
+ * 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", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+package org.elasticsearch.cluster.metadata;
+
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.xcontent.ConstructingObjectParser;
+import org.elasticsearch.xcontent.ParseField;
+import org.elasticsearch.xcontent.ToXContentFragment;
+import org.elasticsearch.xcontent.XContentBuilder;
+import org.elasticsearch.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Represents a single view definition, which is simply a name and a query string.
+ */
+public final class View implements Writeable, ToXContentFragment {
+    private static final ParseField NAME = new ParseField("name");
+    private static final ParseField QUERY = new ParseField("query");
+
+    // Parser that includes the name field (eg. serializing/deserializing the full object)
+    static final ConstructingObjectParser<View, Void> PARSER = new ConstructingObjectParser<>(
+        "view",
+        false,
+        (args, ctx) -> new View((String) args[0], (String) args[1])
+    );
+
+    static {
+        PARSER.declareString(ConstructingObjectParser.constructorArg(), NAME);
+        PARSER.declareString(ConstructingObjectParser.constructorArg(), QUERY);
+    }
+
+    // Parser that excludes the name field (eg. when the name is provided externally, in the URL path)
+    public static ConstructingObjectParser<View, Void> parser(String name) {
+        ConstructingObjectParser<View, Void> parser = new ConstructingObjectParser<>(
+            "view",
+            false,
+            (args, ctx) -> new View(name, (String) args[0])
+        );
+        parser.declareString(ConstructingObjectParser.constructorArg(), QUERY);
+        return parser;
+    }
+
+    private final String name;
+    private final String query;
+
+    public View(String name, String query) {
+        this.name = name;
+        this.query = query;
+    }
+
+    public View(StreamInput in) throws IOException {
+        this.name = in.readString();
+        this.query = in.readString();
+    }
+
+    public static View fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(name);
+        out.writeString(query);
+    }
+
+    public String name() {
+        return name;
+    }
+
+    public String query() {
+        return query;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field(NAME.getPreferredName(), name);
+        builder.field(QUERY.getPreferredName(), query);
+        return builder;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        View other = (View) o;
+        return Objects.equals(name, other.name) && Objects.equals(query, other.query);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, query);
+    }
+
+    public String toString() {
+        return Strings.toString(this);
+    }
+}

server/src/main/java/org/elasticsearch/cluster/metadata/ViewMetadata.java

@@ -0,0 +1,157 @@
+/*
+ * 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", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+package org.elasticsearch.cluster.metadata;
+
+import org.elasticsearch.TransportVersion;
+import org.elasticsearch.cluster.AbstractNamedDiffable;
+import org.elasticsearch.cluster.NamedDiff;
+import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.ChunkedToXContentHelper;
+import org.elasticsearch.xcontent.ObjectParser;
+import org.elasticsearch.xcontent.ParseField;
+import org.elasticsearch.xcontent.ToXContent;
+import org.elasticsearch.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Objects;
+
+import static org.elasticsearch.common.io.stream.StreamOutput.GENERIC_LIST_HEADER;
+
+/**
+ * Encapsulates view definitions as custom metadata inside ProjectMetadata within cluster state.
+ */
+public final class ViewMetadata extends AbstractNamedDiffable<Metadata.ProjectCustom> implements Metadata.ProjectCustom {
+    public static final String TYPE = "esql_view";
+    public static final List<NamedWriteableRegistry.Entry> ENTRIES = List.of(
+        new NamedWriteableRegistry.Entry(Metadata.ProjectCustom.class, TYPE, ViewMetadata::readFromStream),
+        new NamedWriteableRegistry.Entry(NamedDiff.class, TYPE, in -> ViewMetadata.readDiffFrom(Metadata.ProjectCustom.class, TYPE, in))
+    );
+    private static final TransportVersion ESQL_VIEWS = TransportVersion.fromName("esql_views");
+
+    static final ParseField VIEWS = new ParseField("views");
+
+    public static final ViewMetadata EMPTY = new ViewMetadata(Collections.emptyList());
+
+    @SuppressWarnings("unchecked")
+    private static final ObjectParser<ViewMetadata, Void> PARSER = new ObjectParser<>("view_metadata", ViewMetadata::new);
+
+    static {
+        PARSER.declareObjectArrayOrNull((viewMetadata, views) -> views.forEach(viewMetadata::add), (p, c) -> View.fromXContent(p), VIEWS);
+    }
+
+    public static ViewMetadata fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+
+    private final ArrayList<View> views;
+
+    public static ViewMetadata readFromStream(StreamInput in) throws IOException {
+        assert in.readByte() == GENERIC_LIST_HEADER;
+        int count = in.readVInt();
+        ArrayList<View> views = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) {
+            views.add(new View(in));
+        }
+        return new ViewMetadata(views);
+    }
+
+    public ViewMetadata() {
+        this(List.of());
+    }
+
+    public ViewMetadata(List<View> views) {
+        this.views = new ArrayList<>(views);
+    }
+
+    public void add(View view) {
+        views.add(view);
+    }
+
+    public List<View> views() {
+        return views;
+    }
+
+    public List<String> viewNames() {
+        return views.stream().map(View::name).toList();
+    }
+
+    public View getView(String name) {
+        return views.stream().filter(v -> v.name().equals(name)).findAny().orElse(null);
+    }
+
+    @Override
+    public EnumSet<Metadata.XContentContext> context() {
+        return Metadata.ALL_CONTEXTS;
+    }
+
+    @Override
+    public TransportVersion getMinimalSupportedVersion() {
+        return ESQL_VIEWS;
+    }
+
+    @Override
+    public String getWriteableName() {
+        return TYPE;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeGenericList(views, StreamOutput::writeWriteable);
+    }
+
+    @Override
+    public Iterator<? extends ToXContent> toXContentChunked(ToXContent.Params ignored) {
+        return ChunkedToXContentHelper.array(VIEWS.getPreferredName(), new ViewIterator(views));
+    }
+
+    public static class ViewIterator implements Iterator<ToXContent> {
+        private final Iterator<View> internal;
+
+        public ViewIterator(List<View> views) {
+            this.internal = views.iterator();
+        }
+
+        @Override
+        public boolean hasNext() {
+            return internal.hasNext();
+        }
+
+        @Override
+        public ToXContent next() {
+            View view = internal.next();
+            return (builder, params) -> {
+                builder.startObject();
+                view.toXContent(builder, params);
+                builder.endObject();
+                return builder;
+            };
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ViewMetadata that = (ViewMetadata) o;
+        return views.equals(that.views);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(views);
+    }
+
+}

server/src/main/resources/transport/definitions/referable/esql_views.csv

@@ -0,0 +1 @@
+9232000

server/src/main/resources/transport/upper_bounds/9.3.csv

@@ -1 +1 @@
-esql_use_minimum_version_for_enrich_resolution,9231000
+esql_views,9232000