wip on review comments

Author: danhermann

rest-api-spec/src/main/resources/rest-api-spec/test/indices.data_stream/10_basic.yml

@@ -40,7 +40,7 @@
         index: simple-data-stream1
         body: { query: { match_all: {} } }
   - length:   { hits.hits: 1  }
-  - match: { hits.hits.0._index: simple-data-stream1-000000 }
+  - match: { hits.hits.0._index: simple-data-stream1-000001 }
   - match: { hits.hits.0._source.foo: 'bar' }
 
   - do:

server/src/main/java/org/elasticsearch/action/admin/indices/datastream/CreateDataStreamAction.java

@@ -177,11 +177,12 @@ static ClusterState createDataStream(MetadataCreateIndexService metadataCreateIn
             MetadataCreateIndexService.validateIndexOrAliasName(request.name,
                 (s1, s2) -> new IllegalArgumentException("data_stream [" + s1 + "] " + s2));
 
-            String firstBackingIndexName = request.name + "-000000";
+            String firstBackingIndexName = request.name + "-000001";
             CreateIndexClusterStateUpdateRequest createIndexRequest =
                 new CreateIndexClusterStateUpdateRequest("initialize_data_stream", firstBackingIndexName, firstBackingIndexName);
             currentState = metadataCreateIndexService.applyCreateIndexRequest(currentState, createIndexRequest, false);
             IndexMetadata firstBackingIndex = currentState.metadata().index(firstBackingIndexName);
+            assert firstBackingIndex != null;
 
             Metadata.Builder builder = Metadata.builder(currentState.metadata()).put(
                 new DataStream(request.name, request.timestampFieldName, List.of(firstBackingIndex.getIndex())));

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

@@ -252,42 +252,4 @@ private boolean isNonEmpty(List<IndexMetadata> idxMetas) {
             return (Objects.isNull(idxMetas) || idxMetas.isEmpty()) == false;
         }
     }
-
-    class DataStream implements IndexAbstraction {
-
-        private final org.elasticsearch.cluster.metadata.DataStream dataStream;
-        private final List<IndexMetaData> dataStreamIndices;
-        private final IndexMetaData writeIndex;
-
-        public DataStream(org.elasticsearch.cluster.metadata.DataStream dataStream, List<IndexMetaData> dataStreamIndices,
-                          IndexMetaData writeIndex) {
-            this.dataStream = dataStream;
-            this.dataStreamIndices = dataStreamIndices;
-            this.writeIndex = writeIndex;
-        }
-
-        @Override
-        public String getName() {
-            return dataStream.getName();
-        }
-
-        @Override
-        public Type getType() {
-            return Type.DATA_STREAM;
-        }
-
-        @Override
-        public List<IndexMetaData> getIndices() {
-            return dataStreamIndices;
-        }
-
-        public IndexMetaData getWriteIndex() {
-            return writeIndex;
-        }
-
-        @Override
-        public boolean isHidden() {
-            return false;
-        }
-    }
 }

server/src/test/java/org/elasticsearch/cluster/metadata/MetadataTests.java

@@ -939,7 +939,7 @@ public void testBuilderRejectsDataStreamThatConflictsWithAlias() {
 
     public void testBuilderRejectsDataStreamWithConflictingBackingIndices() {
         final String dataStreamName = "my-data-stream";
-        final String conflictingIndex = dataStreamName + "-00001";
+        final String conflictingIndex = dataStreamName + "-000001";
         Metadata.Builder b = Metadata.builder()
             .put(IndexMetadata.builder(conflictingIndex)
                 .settings(settings(Version.CURRENT))