Support index pattern selector syntax in SQL (#120845)

Updates the SQL grammar to include the selector portion of an index pattern. The 
index() method has been updated to include selectors in the resulting expression.

Author: jbaiera

x-pack/plugin/ql/src/test/java/org/elasticsearch/xpack/ql/analyzer/PreAnalyzerTests.java

@@ -42,6 +42,15 @@ public void testBasicIndexWithCatalog() {
         assertThat(result.indices.get(0).id().index(), is("index"));
     }
 
+    public void testBasicIndexWithSelector() {
+        LogicalPlan plan = new UnresolvedRelation(EMPTY, new TableIdentifier(EMPTY, null, "index::failures"), null, false);
+        PreAnalysis result = preAnalyzer.preAnalyze(plan);
+        assertThat(plan.preAnalyzed(), is(true));
+        assertThat(result.indices, hasSize(1));
+        assertThat(result.indices.get(0).id().cluster(), nullValue());
+        assertThat(result.indices.get(0).id().index(), is("index::failures"));
+    }
+
     public void testComplicatedQuery() {
         LogicalPlan plan = new Limit(
             EMPTY,

x-pack/plugin/sql/src/main/antlr/SqlBase.g4

@@ -340,8 +340,8 @@ identifier
     ;
 
 tableIdentifier
-    : (catalog=identifier ':')? TABLE_IDENTIFIER
-    | (catalog=identifier ':')? name=identifier
+    : (catalog=identifier ':')? TABLE_IDENTIFIER ('::' selector=identifier)?
+    | (catalog=identifier ':')? name=identifier ('::' selector=identifier)?
     ;
 
 quoteIdentifier

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/parser/IdentifierBuilder.java

@@ -7,7 +7,9 @@
 package org.elasticsearch.xpack.sql.parser;
 
 import org.antlr.v4.runtime.tree.ParseTree;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.core.Tuple;
 import org.elasticsearch.xpack.ql.plan.TableIdentifier;
 import org.elasticsearch.xpack.ql.tree.Source;
 import org.elasticsearch.xpack.sql.parser.SqlBaseParser.IdentifierContext;
@@ -29,7 +31,56 @@ public TableIdentifier visitTableIdentifier(TableIdentifierContext ctx) {
         ParseTree tree = ctx.name != null ? ctx.name : ctx.TABLE_IDENTIFIER();
         String index = tree.getText();
 
-        return new TableIdentifier(source, visitIdentifier(ctx.catalog), unquoteIdentifier(index));
+        String cluster = visitIdentifier(ctx.catalog);
+        String indexName = unquoteIdentifier(index);
+        String selector = visitIdentifier(ctx.selector);
+
+        if (cluster != null && selector != null) {
+            throw new ParsingException(
+                source,
+                "Invalid index name [{}:{}::{}], Selectors are not yet supported on remote cluster patterns",
+                cluster,
+                indexName,
+                selector
+            );
+        }
+
+        if (selector != null) {
+            try {
+                IndexNameExpressionResolver.SelectorResolver.validateIndexSelectorString(indexName, selector);
+            } catch (Exception e) {
+                throw new ParsingException(source, e.getMessage());
+            }
+        }
+
+        if (indexName.contains(IndexNameExpressionResolver.SelectorResolver.SELECTOR_SEPARATOR)) {
+            if (selector != null) {
+                throw new ParsingException(
+                    source,
+                    "Invalid index name [{}::{}], Invalid usage of :: separator, only one :: separator is allowed per expression",
+                    indexName,
+                    selector
+                );
+            }
+            try {
+                Tuple<String, String> split = IndexNameExpressionResolver.splitSelectorExpression(indexName);
+                indexName = split.v1();
+                selector = split.v2();
+            } catch (Exception e) {
+                throw new ParsingException(source, e.getMessage());
+            }
+            if (selector != null) {
+                try {
+                    IndexNameExpressionResolver.SelectorResolver.validateIndexSelectorString(indexName, selector);
+                } catch (Exception e) {
+                    throw new ParsingException(source, "Invalid index name [{}::{}], {}", indexName, selector, e.getMessage());
+                }
+            }
+        }
+
+        indexName = IndexNameExpressionResolver.combineSelectorExpression(indexName, selector);
+
+        return new TableIdentifier(source, cluster, indexName);
     }
 
     @Override