Added defaults to settings

Author: ivancea

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plan/QuerySettings.java

@@ -16,6 +16,8 @@
 import org.elasticsearch.xpack.esql.parser.ParsingException;
 
 import java.time.ZoneId;
+import java.time.ZoneOffset;
+import java.util.function.Function;
 
 public class QuerySettings {
     // TODO check cluster state and see if project routing is allowed
@@ -30,7 +32,8 @@ public class QuerySettings {
         "A project routing expression, "
             + "used to define which projects to route the query to. "
             + "Only supported if Cross-Project Search is enabled.",
-        (value, settings) -> Foldables.stringLiteralValueOf(value, "Unexpected value")
+        (value, settings) -> Foldables.stringLiteralValueOf(value, "Unexpected value"),
+        (_rcs) -> null
     );
 
     public static final QuerySettingDef<ZoneId> TIME_ZONE = new QuerySettingDef<>(
@@ -47,7 +50,8 @@ public class QuerySettings {
             } catch (Exception exc) {
                 throw new QlIllegalArgumentException("Invalid time zone [" + timeZone + "]");
             }
-        }
+        },
+        (_rcs) -> ZoneOffset.UTC
     );
 
     public static final QuerySettingDef<?>[] ALL_SETTINGS = { PROJECT_ROUTING, TIME_ZONE };
@@ -86,6 +90,7 @@ public static void validate(EsqlStatement statement, RemoteClusterService cluste
      * @param validator A validation function to check the setting value.
      *                  Defaults to calling the {@link #parser} and returning the error message of any exception it throws.
      * @param parser A function to parse the setting value into the final object.
+     * @param defaultValueSupplier A supplier of the default value to be used when the setting is not set.
      * @param <T> The type of the setting value.
      */
     public record QuerySettingDef<T>(
@@ -96,7 +101,8 @@ public record QuerySettingDef<T>(
         boolean snapshotOnly,
         String description,
         Validator validator,
-        Parser<T> parser
+        Parser<T> parser,
+        Function<RemoteClusterService, T> defaultValueSupplier
     ) {
         public QuerySettingDef(
             String name,
@@ -105,7 +111,8 @@ public QuerySettingDef(
             boolean preview,
             boolean snapshotOnly,
             String description,
-            Parser<T> parser
+            Parser<T> parser,
+            Function<RemoteClusterService, T> defaultValueSupplier
         ) {
             this(name, type, serverlessOnly, preview, snapshotOnly, description, (value, rcs) -> {
                 try {
@@ -114,10 +121,13 @@ public QuerySettingDef(
                 } catch (Exception exc) {
                     return exc.getMessage();
                 }
-            }, parser);
+            }, parser, defaultValueSupplier);
         }
 
         public T get(Expression value, RemoteClusterService clusterService) {
+            if (value == null) {
+                return defaultValueSupplier.apply(clusterService);
+            }
             return parser.parse(value, clusterService);
         }
 

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/plan/QuerySettingsTests.java

@@ -19,10 +19,14 @@
 import org.junit.AfterClass;
 
 import java.time.ZoneId;
+import java.time.ZoneOffset;
 import java.util.List;
 
+import static org.hamcrest.Matchers.both;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.nullValue;
 
 public class QuerySettingsTests extends ESTestCase {
     public void testNonExistingSetting() {
@@ -34,6 +38,7 @@ public void testNonExistingSetting() {
     public void testProjectRouting() {
         var setting = QuerySettings.PROJECT_ROUTING;
 
+        assertDefault(setting, nullValue());
         assertValid(setting, Literal.keyword(Source.EMPTY, "my-project"), equalTo("my-project"));
 
         assertInvalid(
@@ -46,6 +51,10 @@ public void testProjectRouting() {
     public void testTimeZone() {
         var setting = QuerySettings.TIME_ZONE;
 
+        assertDefault(setting, both(equalTo(ZoneId.of("Z"))).and(equalTo(ZoneOffset.UTC)));
+
+        assertValid(setting, Literal.keyword(Source.EMPTY, "UTC"), equalTo(ZoneId.of("UTC")));
+        assertValid(setting, Literal.keyword(Source.EMPTY, "Z"), both(equalTo(ZoneId.of("Z"))).and(equalTo(ZoneOffset.UTC)));
         assertValid(setting, Literal.keyword(Source.EMPTY, "Europe/Madrid"), equalTo(ZoneId.of("Europe/Madrid")));
         assertValid(setting, Literal.keyword(Source.EMPTY, "+05:00"), equalTo(ZoneId.of("+05:00")));
         assertValid(setting, Literal.keyword(Source.EMPTY, "+05"), equalTo(ZoneId.of("+05")));
@@ -81,6 +90,12 @@ private static void assertInvalid(String settingName, Expression valueExpression
         );
     }
 
+    private static <T> void assertDefault(QuerySettings.QuerySettingDef<T> settingDef, Matcher<? super T> defaultMatcher) {
+        T value = settingDef.get(null, null);
+
+        assertThat(value, defaultMatcher);
+    }
+
     @AfterClass
     public static void generateDocs() throws Exception {
         for (QuerySettings.QuerySettingDef<?> def : QuerySettings.ALL_SETTINGS) {