[TEST] Add test for restoring into a shadowreplica enabled index

src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java

@@ -233,7 +233,6 @@ public class RestoreSnapshotRequestBuilder extends MasterNodeOperationRequestBui
 
     /**
      * Sets index settings that should be added or replaced during restore
-
      * @param settings index settings
      * @return this builder
      */

src/test/java/org/elasticsearch/index/IndexWithShadowReplicasTests.java

@@ -19,6 +19,8 @@
 
 package org.elasticsearch.index;
 
+import org.elasticsearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.elasticsearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
 import org.elasticsearch.action.admin.cluster.state.ClusterStateResponse;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.action.index.IndexRequestBuilder;
@@ -28,19 +30,26 @@ import org.elasticsearch.cluster.routing.RoutingNode;
 import org.elasticsearch.cluster.routing.RoutingNodes;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.index.shard.IndexShard;
+import org.elasticsearch.index.shard.ShadowIndexShard;
+import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.sort.SortOrder;
+import org.elasticsearch.snapshots.SnapshotState;
 import org.elasticsearch.test.ElasticsearchIntegrationTest;
 import org.elasticsearch.test.InternalTestCluster;
 import org.junit.Test;
 
 import java.nio.file.Path;
 import java.util.List;
+import java.util.concurrent.ExecutionException;
 
 import static com.google.common.collect.Lists.newArrayList;
 import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.*;
+import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 
 /**
@@ -49,7 +58,69 @@ import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 @ElasticsearchIntegrationTest.ClusterScope(scope = ElasticsearchIntegrationTest.Scope.TEST, numDataNodes = 0)
 public class IndexWithShadowReplicasTests extends ElasticsearchIntegrationTest {
 
-    @Test
+    /**
+     * Tests the case where we create an index without shadow replicas, snapshot it and then restore into
+     * an index with shadow replicas enabled.
+     */
+    public void testRestoreToShadow() throws ExecutionException, InterruptedException {
+        Settings nodeSettings = ImmutableSettings.builder()
+                .put("node.add_id_to_custom_path", false)
+                .put("node.enable_custom_paths", true)
+                .build();
+
+        internalCluster().startNodesAsync(3, nodeSettings).get();
+        final Path dataPath = newTempDirPath();
+        Settings idxSettings = ImmutableSettings.builder()
+                .put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 0).build();
+        assertAcked(prepareCreate("foo").setSettings(idxSettings));
+        ensureGreen();
+        final int numDocs = randomIntBetween(10, 100);
+        for (int i = 0; i < numDocs; i++) {
+            client().prepareIndex("foo", "doc", ""+i).setSource("foo", "bar").get();
+        }
+        assertNoFailures(client().admin().indices().prepareFlush().setForce(true).setWaitIfOngoing(true).execute().actionGet());
+
+        assertAcked(client().admin().cluster().preparePutRepository("test-repo")
+                .setType("fs").setSettings(ImmutableSettings.settingsBuilder()
+                        .put("location", newTempDirPath())));
+        CreateSnapshotResponse createSnapshotResponse = client().admin().cluster().prepareCreateSnapshot("test-repo", "test-snap").setWaitForCompletion(true).setIndices("foo").get();
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), equalTo(createSnapshotResponse.getSnapshotInfo().totalShards()));
+        assertThat(client().admin().cluster().prepareGetSnapshots("test-repo").setSnapshots("test-snap").get().getSnapshots().get(0).state(), equalTo(SnapshotState.SUCCESS));
+
+        Settings shadowSettings = ImmutableSettings.builder()
+                .put(IndexMetaData.SETTING_DATA_PATH, dataPath.toAbsolutePath().toString())
+                .put(IndexMetaData.SETTING_SHADOW_REPLICAS, true)
+                .put(IndexMetaData.SETTING_SHARED_FILESYSTEM, true)
+                .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 2).build();
+
+        logger.info("--> restore the index into shadow replica index");
+        RestoreSnapshotResponse restoreSnapshotResponse = client().admin().cluster().prepareRestoreSnapshot("test-repo", "test-snap")
+                .setIndexSettings(shadowSettings).setWaitForCompletion(true)
+                .setRenamePattern("(.+)").setRenameReplacement("$1-copy")
+                .execute().actionGet();
+        assertThat(restoreSnapshotResponse.getRestoreInfo().totalShards(), greaterThan(0));
+        ensureGreen();
+        refresh();
+
+        for (IndicesService service : internalCluster().getDataNodeInstances(IndicesService.class)) {
+            if (service.hasIndex("foo-copy")) {
+                IndexShard shard = service.indexServiceSafe("foo-copy").shard(0);
+                if (shard.routingEntry().primary()) {
+                    assertFalse(shard instanceof ShadowIndexShard);
+                } else {
+                    assertTrue(shard instanceof ShadowIndexShard);
+                }
+            }
+        }
+        logger.info("--> performing query");
+        SearchResponse resp = client().prepareSearch("foo-copy").setQuery(matchAllQuery()).get();
+        assertHitCount(resp, numDocs);
+
+    }
+
+        @Test
     public void testIndexWithFewDocuments() throws Exception {
         Settings nodeSettings = ImmutableSettings.builder()
                 .put("node.add_id_to_custom_path", false)