Stop aborting of multiget requests in case of missing index

The MultiGet API stops with a IndexMissingException, if only one of all
requests tries to access a non existing index. This patch creates a
failure for this item without failing the whole request.

Closes #3267

src/main/java/org/elasticsearch/action/get/TransportMultiGetAction.java

@@ -58,9 +58,16 @@ public class TransportMultiGetAction extends TransportAction<MultiGetRequest, Mu
 
         clusterState.blocks().globalBlockedRaiseException(ClusterBlockLevel.READ);
 
+        final MultiGetItemResponse[] responses = new MultiGetItemResponse[request.items.size()];
+
         Map<ShardId, MultiGetShardRequest> shardRequests = new HashMap<ShardId, MultiGetShardRequest>();
         for (int i = 0; i < request.items.size(); i++) {
             MultiGetRequest.Item item = request.items.get(i);
+            if (!clusterState.metaData().hasConcreteIndex(item.index())) {
+                responses[i] = new MultiGetItemResponse(null, new MultiGetResponse.Failure(item.index(), item.type(), item.id(), "[" + item.index() + "] missing"));
+                continue;
+            }
+
             item.routing(clusterState.metaData().resolveIndexRouting(item.routing(), item.index()));
             item.index(clusterState.metaData().concreteIndex(item.index()));
             ShardId shardId = clusterService.operationRouting()
@@ -77,7 +84,6 @@ public class TransportMultiGetAction extends TransportAction<MultiGetRequest, Mu
             shardRequest.add(i, item.type(), item.id(), item.fields());
         }
 
-        final MultiGetItemResponse[] responses = new MultiGetItemResponse[request.items.size()];
         final AtomicInteger counter = new AtomicInteger(shardRequests.size());
 
         for (final MultiGetShardRequest shardRequest : shardRequests.values()) {

src/test/java/org/elasticsearch/test/integration/mget/SimpleMgetTests.java

@@ -0,0 +1,54 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch licenses this
+ * file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.test.integration.mget;
+
+import org.elasticsearch.action.get.MultiGetRequest;
+import org.elasticsearch.action.get.MultiGetResponse;
+import org.elasticsearch.test.integration.AbstractSharedClusterTest;
+import org.testng.annotations.Test;
+
+import java.io.IOException;
+
+import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+public class SimpleMgetTests extends AbstractSharedClusterTest {
+
+    @Test
+    public void testThatMgetShouldWorkWithOneIndexMissing() throws IOException {
+        createIndex("test");
+        ensureYellow();
+
+        client().prepareIndex("test", "test", "1").setSource(jsonBuilder().startObject().field("foo", "bar").endObject()).setRefresh(true).execute().actionGet();
+
+        MultiGetResponse mgetResponse = client().prepareMultiGet()
+                .add(new MultiGetRequest.Item("test", "test", "1"))
+                .add(new MultiGetRequest.Item("nonExistingIndex", "test", "1"))
+            .execute().actionGet();
+        assertThat(mgetResponse.getResponses().length, is(2));
+
+        assertThat(mgetResponse.getResponses()[0].getIndex(), is("test"));
+        assertThat(mgetResponse.getResponses()[0].isFailed(), is(false));
+
+        assertThat(mgetResponse.getResponses()[1].getIndex(), is("nonExistingIndex"));
+        assertThat(mgetResponse.getResponses()[1].isFailed(), is(true));
+        assertThat(mgetResponse.getResponses()[1].getFailure().getMessage(), is("[nonExistingIndex] missing"));
+    }
+}