Add ResolvedExpression wrapper (#114592)

**Introduction**

> In order to make adoption of failure stores simpler for all users, we
are introducing a new syntactical feature to index expression
resolution: The selector. > > Selectors, denoted with a :: followed by a
recognized suffix will allow users to specify which component of an
index abstraction they would like to operate on within an API call. In
this case, an index abstraction is a concrete index, data stream, or
alias; Any abstraction that can be resolved to a set of indices/shards.
We define a component of an index abstraction to be some searchable unit
of the index abstraction. > > To start, we will support two components:
data and failures. Concrete indices are their own data components, while
the data component for index aliases are all of the indices contained
therein. For data streams, the data component corresponds to their
backing indices. Data stream aliases mirror this, treating all backing
indices of the data streams they correspond to as their data component.
>  > The failure component is only supported by data streams and data
stream aliases. The failure component of these abstractions refer to the
data streams' failure stores. Indices and index aliases do not have a
failure component.

For more details and examples see
#113144. All this work has
been cherry picked from there.

**Purpose of this PR**

This PR is introducing a wrapper around the resolved expression that
used to be a `String` to create the base on which the selectors are
going to be added.

The current PR is just a refactoring and does not and should not change
any existing behaviour.

Author: gmarouli

server/src/main/java/org/elasticsearch/action/admin/cluster/shards/TransportClusterSearchShardsAction.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
@@ -84,7 +85,7 @@ protected void masterOperation(
         String[] concreteIndices = indexNameExpressionResolver.concreteIndexNames(clusterState, request);
         Map<String, Set<String>> routingMap = indexNameExpressionResolver.resolveSearchRouting(state, request.routing(), request.indices());
         Map<String, AliasFilter> indicesAndFilters = new HashMap<>();
-        Set<String> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(clusterState, request.indices());
+        Set<ResolvedExpression> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(clusterState, request.indices());
         for (String index : concreteIndices) {
             final AliasFilter aliasFilter = indicesService.buildAliasFilter(clusterState, index, indicesAndAliases);
             final String[] aliases = indexNameExpressionResolver.indexAliases(

server/src/main/java/org/elasticsearch/action/admin/indices/resolve/ResolveIndexAction.java

@@ -25,6 +25,7 @@
 import org.elasticsearch.cluster.metadata.IndexAbstraction;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
 import org.elasticsearch.cluster.metadata.Metadata;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
@@ -565,8 +566,8 @@ static void resolveIndices(
             if (names.length == 1 && (Metadata.ALL.equals(names[0]) || Regex.isMatchAllPattern(names[0]))) {
                 names = new String[] { "**" };
             }
-            Set<String> resolvedIndexAbstractions = resolver.resolveExpressions(clusterState, indicesOptions, true, names);
-            for (String s : resolvedIndexAbstractions) {
+            Set<ResolvedExpression> resolvedIndexAbstractions = resolver.resolveExpressions(clusterState, indicesOptions, true, names);
+            for (ResolvedExpression s : resolvedIndexAbstractions) {
                 enrichIndexAbstraction(clusterState, s, indices, aliases, dataStreams);
             }
             indices.sort(Comparator.comparing(ResolvedIndexAbstraction::getName));
@@ -597,12 +598,12 @@ private static void mergeResults(
 
         private static void enrichIndexAbstraction(
             ClusterState clusterState,
-            String indexAbstraction,
+            ResolvedExpression indexAbstraction,
             List<ResolvedIndex> indices,
             List<ResolvedAlias> aliases,
             List<ResolvedDataStream> dataStreams
         ) {
-            IndexAbstraction ia = clusterState.metadata().getIndicesLookup().get(indexAbstraction);
+            IndexAbstraction ia = clusterState.metadata().getIndicesLookup().get(indexAbstraction.resource());
             if (ia != null) {
                 switch (ia.getType()) {
                     case CONCRETE_INDEX -> {

server/src/main/java/org/elasticsearch/action/admin/indices/validate/query/TransportValidateQueryAction.java

@@ -21,6 +21,7 @@
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
 import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
@@ -133,7 +134,7 @@ protected void doExecute(Task task, ValidateQueryRequest request, ActionListener
     @Override
     protected ShardValidateQueryRequest newShardRequest(int numShards, ShardRouting shard, ValidateQueryRequest request) {
         final ClusterState clusterState = clusterService.state();
-        final Set<String> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(clusterState, request.indices());
+        final Set<ResolvedExpression> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(clusterState, request.indices());
         final AliasFilter aliasFilter = searchService.buildAliasFilter(clusterState, shard.getIndexName(), indicesAndAliases);
         return new ShardValidateQueryRequest(shard.shardId(), aliasFilter, request);
     }

server/src/main/java/org/elasticsearch/action/explain/TransportExplainAction.java

@@ -18,6 +18,7 @@
 import org.elasticsearch.action.support.single.shard.TransportSingleShardAction;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.io.stream.Writeable;
@@ -109,7 +110,7 @@ protected boolean resolveIndex(ExplainRequest request) {
 
     @Override
     protected void resolveRequest(ClusterState state, InternalRequest request) {
-        final Set<String> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(state, request.request().index());
+        final Set<ResolvedExpression> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(state, request.request().index());
         final AliasFilter aliasFilter = searchService.buildAliasFilter(state, request.concreteIndex(), indicesAndAliases);
         request.request().filteringAlias(aliasFilter);
     }

server/src/main/java/org/elasticsearch/action/search/TransportSearchAction.java

@@ -37,6 +37,7 @@
 import org.elasticsearch.cluster.metadata.IndexAbstraction;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.cluster.routing.GroupShardsIterator;
@@ -110,6 +111,7 @@
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.LongSupplier;
+import java.util.stream.Collectors;
 
 import static org.elasticsearch.action.search.SearchType.DFS_QUERY_THEN_FETCH;
 import static org.elasticsearch.action.search.SearchType.QUERY_THEN_FETCH;
@@ -203,14 +205,17 @@ public TransportSearchAction(
 
     private Map<String, OriginalIndices> buildPerIndexOriginalIndices(
         ClusterState clusterState,
-        Set<String> indicesAndAliases,
+        Set<ResolvedExpression> indicesAndAliases,
         String[] indices,
         IndicesOptions indicesOptions
     ) {
         Map<String, OriginalIndices> res = Maps.newMapWithExpectedSize(indices.length);
         var blocks = clusterState.blocks();
         // optimization: mostly we do not have any blocks so there's no point in the expensive per-index checking
         boolean hasBlocks = blocks.global().isEmpty() == false || blocks.indices().isEmpty() == false;
+        // Get a distinct set of index abstraction names present from the resolved expressions to help with the reverse resolution from
+        // concrete index to the expression that produced it.
+        Set<String> indicesAndAliasesResources = indicesAndAliases.stream().map(ResolvedExpression::resource).collect(Collectors.toSet());
         for (String index : indices) {
             if (hasBlocks) {
                 blocks.indexBlockedRaiseException(ClusterBlockLevel.READ, index);
@@ -227,8 +232,8 @@ private Map<String, OriginalIndices> buildPerIndexOriginalIndices(
             String[] finalIndices = Strings.EMPTY_ARRAY;
             if (aliases == null
                 || aliases.length == 0
-                || indicesAndAliases.contains(index)
-                || hasDataStreamRef(clusterState, indicesAndAliases, index)) {
+                || indicesAndAliasesResources.contains(index)
+                || hasDataStreamRef(clusterState, indicesAndAliasesResources, index)) {
                 finalIndices = new String[] { index };
             }
             if (aliases != null) {
@@ -247,7 +252,11 @@ private static boolean hasDataStreamRef(ClusterState clusterState, Set<String> i
         return indicesAndAliases.contains(ret.getParentDataStream().getName());
     }
 
-    Map<String, AliasFilter> buildIndexAliasFilters(ClusterState clusterState, Set<String> indicesAndAliases, Index[] concreteIndices) {
+    Map<String, AliasFilter> buildIndexAliasFilters(
+        ClusterState clusterState,
+        Set<ResolvedExpression> indicesAndAliases,
+        Index[] concreteIndices
+    ) {
         final Map<String, AliasFilter> aliasFilterMap = new HashMap<>();
         for (Index index : concreteIndices) {
             clusterState.blocks().indexBlockedRaiseException(ClusterBlockLevel.READ, index.getName());
@@ -1237,7 +1246,10 @@ private void executeSearch(
         } else {
             final Index[] indices = resolvedIndices.getConcreteLocalIndices();
             concreteLocalIndices = Arrays.stream(indices).map(Index::getName).toArray(String[]::new);
-            final Set<String> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(clusterState, searchRequest.indices());
+            final Set<ResolvedExpression> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(
+                clusterState,
+                searchRequest.indices()
+            );
             aliasFilter = buildIndexAliasFilters(clusterState, indicesAndAliases, indices);
             aliasFilter.putAll(remoteAliasMap);
             localShardIterators = getLocalShardsIterator(
@@ -1810,7 +1822,7 @@ List<SearchShardIterator> getLocalShardsIterator(
         ClusterState clusterState,
         SearchRequest searchRequest,
         String clusterAlias,
-        Set<String> indicesAndAliases,
+        Set<ResolvedExpression> indicesAndAliases,
         String[] concreteIndices
     ) {
         var routingMap = indexNameExpressionResolver.resolveSearchRouting(clusterState, searchRequest.routing(), searchRequest.indices());

server/src/main/java/org/elasticsearch/action/search/TransportSearchShardsAction.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.action.support.HandledTransportAction;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
 import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.index.Index;
@@ -127,7 +128,10 @@ public void searchShards(Task task, SearchShardsRequest searchShardsRequest, Act
             searchService.getRewriteContext(timeProvider::absoluteStartMillis, resolvedIndices, null),
             listener.delegateFailureAndWrap((delegate, searchRequest) -> {
                 Index[] concreteIndices = resolvedIndices.getConcreteLocalIndices();
-                final Set<String> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(clusterState, searchRequest.indices());
+                final Set<ResolvedExpression> indicesAndAliases = indexNameExpressionResolver.resolveExpressions(
+                    clusterState,
+                    searchRequest.indices()
+                );
                 final Map<String, AliasFilter> aliasFilters = transportSearchAction.buildIndexAliasFilters(
                     clusterState,
                     indicesAndAliases,