Allow specifying index in pinned queries (elastic#74873)

The current `ids` option doesn't allow pinning a specific document in a
single index when searching over multiple indices. This introduces a
`documents` option, which is an array of `_id` and `_index`
fields to allow index-specific pins.

Closes elastic#67855.

client/rest-high-level/src/test/java/org/elasticsearch/client/SearchIT.java

@@ -1380,13 +1380,25 @@ public void testCountAllIndicesMatchQuery() throws IOException {
     public void testSearchWithBasicLicensedQuery() throws IOException {
         SearchRequest searchRequest = new SearchRequest("index");
         SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
-        PinnedQueryBuilder pinnedQuery = new PinnedQueryBuilder(new MatchAllQueryBuilder(), "2", "1");
-        searchSourceBuilder.query(pinnedQuery);
-        searchRequest.source(searchSourceBuilder);
-        SearchResponse searchResponse = execute(searchRequest, highLevelClient()::search, highLevelClient()::searchAsync);
-        assertSearchHeader(searchResponse);
-        assertFirstHit(searchResponse, hasId("2"));
-        assertSecondHit(searchResponse, hasId("1"));
+        {
+            PinnedQueryBuilder pinnedQuery = new PinnedQueryBuilder(new MatchAllQueryBuilder(), "2", "1");
+            searchSourceBuilder.query(pinnedQuery);
+            searchRequest.source(searchSourceBuilder);
+            SearchResponse searchResponse = execute(searchRequest, highLevelClient()::search, highLevelClient()::searchAsync);
+            assertSearchHeader(searchResponse);
+            assertFirstHit(searchResponse, hasId("2"));
+            assertSecondHit(searchResponse, hasId("1"));
+        }
+        {
+            PinnedQueryBuilder pinnedQuery = new PinnedQueryBuilder(new MatchAllQueryBuilder(),
+                new PinnedQueryBuilder.Item("index", "2"), new PinnedQueryBuilder.Item("index", "1"));
+            searchSourceBuilder.query(pinnedQuery);
+            searchRequest.source(searchSourceBuilder);
+            SearchResponse searchResponse = execute(searchRequest, highLevelClient()::search, highLevelClient()::searchAsync);
+            assertSearchHeader(searchResponse);
+            assertFirstHit(searchResponse, hasId("2"));
+            assertSecondHit(searchResponse, hasId("1"));
+        }
     }
 
     public void testPointInTime() throws Exception {

docs/reference/query-dsl/pinned-query.asciidoc

@@ -4,7 +4,7 @@
 === Pinned Query
 Promotes selected documents to rank higher than those matching a given query.
 This feature is typically used to guide searchers to curated documents that are
-promoted over and above any "organic" matches for a search.  
+promoted over and above any "organic" matches for a search.
 The promoted or "pinned" documents are identified using the document IDs stored in
 the <<mapping-id-field,`_id`>> field.
 
@@ -31,6 +31,53 @@ GET /_search
 ==== Top-level parameters for `pinned`
 
 `ids`::
-An array of <<mapping-id-field, document IDs>> listed in the order they are to appear in results.
+(Optional, array) <<mapping-id-field, Document IDs>> listed in the order they are to appear in results.
+Required if `docs` is not specified.
+`docs`::
+(Optional, array) Documents listed in the order they are to appear in results.
+Required if `ids` is not specified.
+You can specify the following attributes for each document:
++
+--
+`_id`::
+(Required, string) The unique <<mapping-id-field, document ID>>.
+
+`_index`::
+(Required, string) The index that contains the document.
+--
 `organic`::
-Any choice of query used to rank documents which will be ranked below the "pinned" document ids.
+Any choice of query used to rank documents which will be ranked below the "pinned" documents.
+
+==== Pin documents in a specific index
+
+If you're searching over multiple indices, you can pin a document within a specific index using `docs`:
+
+[source,console]
+--------------------------------------------------
+GET /_search
+{
+  "query": {
+    "pinned": {
+      "docs": [
+        {
+          "_index": "my-index-000001",
+          "_id": "1"
+        },
+        {
+          "_index": "my-index-000001",
+          "_id": "4"
+        },
+        {
+          "_index": "my-index-000002",
+          "_id": "100"
+        }
+      ],
+      "organic": {
+        "match": {
+          "description": "iphone"
+        }
+      }
+    }
+  }
+}
+--------------------------------------------------

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/index/query/PinnedQueryBuilder.java

@@ -7,15 +7,18 @@
 package org.elasticsearch.xpack.core.index.query;
 
 import org.apache.lucene.search.Query;
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.xcontent.ParseField;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.index.query.AbstractQueryBuilder;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.SearchExecutionContext;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
@@ -29,34 +32,91 @@ public class PinnedQueryBuilder extends AbstractQueryBuilder<PinnedQueryBuilder>
     public static final String NAME = "pinned";
     protected final QueryBuilder organicQuery;
     protected final List<String> ids;
+    private final List<Item> docs;
     protected static final ParseField IDS_FIELD = new ParseField("ids");
+    private static final ParseField DOCS_FIELD = new ParseField("docs");
     protected static final ParseField ORGANIC_QUERY_FIELD = new ParseField("organic");
 
+    /**
+     * A single item to be used for a {@link PinnedQueryBuilder}.
+     */
+    public static final class Item implements ToXContentObject, Writeable {
+        private static final ParseField INDEX_FIELD = new ParseField("_index");
+        private static final ParseField ID_FIELD = new ParseField("_id");
+
+        private final String index;
+        private final String id;
+
+        public Item(String index, String id) {
+            if (index == null) {
+                throw new IllegalArgumentException("Item requires index to be non-null");
+            }
+            if (Regex.isSimpleMatchPattern(index)) {
+                throw new IllegalArgumentException("Item index cannot contain wildcard expressions");
+            }
+            if (id == null) {
+                throw new IllegalArgumentException("Item requires id to be non-null");
+            }
+            this.index = index;
+            this.id = id;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(index);
+            out.writeString(id);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            builder.field(INDEX_FIELD.getPreferredName(), index);
+            builder.field(ID_FIELD.getPreferredName(), id);
+            return builder.endObject();
+        }
+    }
+
     @Override
     public String getWriteableName() {
         return NAME;
     }
 
+    public PinnedQueryBuilder(QueryBuilder organicQuery, String... ids) {
+        this(organicQuery, Arrays.asList(ids), null);
+    }
+
+    public PinnedQueryBuilder(QueryBuilder organicQuery, Item... docs) {
+        this(organicQuery, null, Arrays.asList(docs));
+    }
+
     /**
      * Creates a new PinnedQueryBuilder
      */
-    public PinnedQueryBuilder(QueryBuilder organicQuery, String... ids) {
+    private PinnedQueryBuilder(QueryBuilder organicQuery, List<String> ids, List<Item> docs) {
       if (organicQuery == null) {
           throw new IllegalArgumentException("[" + NAME + "] organicQuery cannot be null");
       }
       this.organicQuery = organicQuery;
-      if (ids == null) {
-          throw new IllegalArgumentException("[" + NAME + "] ids cannot be null");
+      if (ids == null && docs == null) {
+          throw new IllegalArgumentException("[" + NAME + "] ids and docs cannot both be null");
       }
-      this.ids = new ArrayList<>();
-      Collections.addAll(this.ids, ids);
-
+      if (ids != null && docs != null) {
+          throw new IllegalArgumentException("[" + NAME + "] ids and docs cannot both be used");
+      }
+      this.ids = ids;
+      this.docs = docs;
     }
 
 
     @Override
     protected void doWriteTo(StreamOutput out) throws IOException {
-        out.writeStringCollection(this.ids);
+        out.writeOptionalStringCollection(this.ids);
+        if (docs == null) {
+            out.writeBoolean(false);
+        } else {
+            out.writeBoolean(true);
+            out.writeList(docs);
+        }
         out.writeNamedWriteable(organicQuery);
     }
 
@@ -71,9 +131,22 @@ public QueryBuilder organicQuery() {
      * Returns the pinned ids for the query.
      */
     public List<String> ids() {
+        if (this.ids == null) {
+            return Collections.emptyList();
+        }
         return Collections.unmodifiableList(this.ids);
     }
 
+    /**
+     * Returns the pinned docs for the query.
+     */
+    public List<Item> docs() {
+        if (this.docs == null) {
+            return Collections.emptyList();
+        }
+        return Collections.unmodifiableList(this.docs);
+    }
+
 
     @Override
     protected void doXContent(XContentBuilder builder, Params params) throws IOException {
@@ -82,11 +155,20 @@ protected void doXContent(XContentBuilder builder, Params params) throws IOExcep
             builder.field(ORGANIC_QUERY_FIELD.getPreferredName());
             organicQuery.toXContent(builder, params);
         }
-        builder.startArray(IDS_FIELD.getPreferredName());
-        for (String value : ids) {
-            builder.value(value);
+        if (ids != null) {
+            builder.startArray(IDS_FIELD.getPreferredName());
+            for (String value : ids) {
+                builder.value(value);
+            }
+            builder.endArray();
+        }
+        if (docs != null) {
+            builder.startArray(DOCS_FIELD.getPreferredName());
+            for (Item item : docs) {
+                builder.value(item);
+            }
+            builder.endArray();
         }
-        builder.endArray();
         printBoostAndQueryName(builder);
         builder.endObject();
     }
@@ -99,12 +181,15 @@ protected Query doToQuery(SearchExecutionContext context) throws IOException {
 
     @Override
     protected int doHashCode() {
-        return Objects.hash(ids, organicQuery);
+        return Objects.hash(ids, docs, organicQuery);
     }
 
     @Override
     protected boolean doEquals(PinnedQueryBuilder other) {
-        return Objects.equals(ids, other.ids) && Objects.equals(organicQuery, other.organicQuery) && boost == other.boost;
+        return Objects.equals(ids, other.ids)
+            && Objects.equals(docs, other.docs)
+            && Objects.equals(organicQuery, other.organicQuery)
+            && boost == other.boost;
     }
 
 }