Affix record settings

Author: prdoyle

server/src/test/java/org/elasticsearch/common/settings/SettingTests.java

@@ -23,6 +23,7 @@
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.MockLog;
 import org.elasticsearch.test.junit.annotations.TestLogging;
+import org.junit.Test;
 
 import java.lang.invoke.MethodHandles;
 import java.util.Arrays;
@@ -31,6 +32,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
@@ -1610,7 +1612,7 @@ public void testLongSettingBounds() {
     public void testRecordSetting() {
         record TestSetting(int intSetting) {}
         Setting<TestSetting> setting = Setting.recordSetting("record.setting", TestSetting.class, MethodHandles.lookup(), List.of());
-        Settings settings123 = Settings.builder().put("record.setting.int_setting", 123).build();
+        Settings settings123 = Settings.builder().put("record.setting.int_setting", 123).build(); // automatic snake-case for names
         Settings settings456 = Settings.builder().put("record.setting.int_setting", 456).build();
 
         assertEquals(new TestSetting(123), setting.get(settings123));
@@ -1656,4 +1658,48 @@ record TestSetting(int i1, int i2) {}
         assertNull("Updater NOT called when value 'changed' to the default from nothing", watcher.get());
     }
 
+    public void testAffixRecordSetting() {
+        record TestSetting(int intSetting) {}
+        var componentSetting = Setting.affixKeySetting(
+            "things.",
+            "config.int_setting",
+            (n,key)-> Setting.intSetting(key, -1));
+        var setting = Setting.affixKeySetting(
+            "things.",
+            "config",
+            (namespace, key) -> Setting.recordSetting(key, TestSetting.class, MethodHandles.lookup(), List.of(componentSetting.getConcreteSettingForNamespace(namespace)))
+        );
+        Settings settings = Settings.builder()
+            .put("things.thing1.config.int_setting", 123)
+            .put("things.thing2.config.int_setting", 456)
+            .build();
+        assertEquals(new TestSetting(123), setting.getConcreteSetting("things.thing1.config").get(settings));
+        assertEquals(new TestSetting(456), setting.getConcreteSetting("things.thing2.config").get(settings));
+
+        Settings settings1 = Settings.builder()
+            .put("things.thing1.config.int_setting", 123)
+            .build();
+        assertEquals(new TestSetting(123), setting.getConcreteSetting("things.thing1.config").get(settings));
+        assertEquals("Default", new TestSetting(-1), setting.getConcreteSetting("things.thing2.config").get(settings1));
+
+        Map<String, TestSetting> watcher = new ConcurrentHashMap<>();
+        var updater = setting.newAffixUpdater(watcher::put, logger, (k, s)->{});
+
+        // Test the obvious state transitions
+        updater.apply(settings1, Settings.EMPTY);
+        assertEquals(Map.of("thing1", new TestSetting(123)), watcher);
+        updater.apply(settings, settings1);
+        assertEquals(Map.of("thing1", new TestSetting(123), "thing2", new TestSetting(456)), watcher);
+        updater.apply(Settings.EMPTY, settings);
+        assertEquals("Values set to defaults", Map.of("thing1", new TestSetting(-1), "thing2", new TestSetting(-1)), watcher);
+
+        // Test that only the changed keys are updated
+        watcher.clear();
+        updater.apply(settings, settings1);
+        assertEquals("Only thing2 updated", Map.of("thing2", new TestSetting(456)), watcher);
+        watcher.clear();
+        updater.apply(Settings.EMPTY, settings1);
+        assertEquals("thing1 set to default", Map.of("thing1", new TestSetting(-1)), watcher);
+    }
+
 }