Replace group map settings with affix setting (#26819)

We use group settings historically instead of using a prefix setting which is more restrictive and type safe. The majority of the usecases needs to access a key, value map based on the _leave node_ of the setting ie. the setting `index.tag.*` might be used to tag an index with `index.tag.test=42` and `index.tag.staging=12` which then would be turned into a `{"test": 42, "staging": 12}` map. The group settings would always use `Settings#getAsMap` which is loosing type information and uses internal representation of the settings. Using prefix settings allows now to access such a method type-safe and natively.

core/src/main/java/org/elasticsearch/cluster/metadata/IndexMetaData.java

@@ -240,14 +240,18 @@ public class IndexMetaData implements Diffable<IndexMetaData>, ToXContentFragmen
     public static final String INDEX_ROUTING_REQUIRE_GROUP_PREFIX = "index.routing.allocation.require";
     public static final String INDEX_ROUTING_INCLUDE_GROUP_PREFIX = "index.routing.allocation.include";
     public static final String INDEX_ROUTING_EXCLUDE_GROUP_PREFIX = "index.routing.allocation.exclude";
-    public static final Setting<Settings> INDEX_ROUTING_REQUIRE_GROUP_SETTING =
+    public static final Setting.AffixSetting<String> INDEX_ROUTING_REQUIRE_GROUP_SETTING =
-        Setting.groupSetting(INDEX_ROUTING_REQUIRE_GROUP_PREFIX + ".", IP_VALIDATOR, Property.Dynamic, Property.IndexScope);
+        Setting.prefixKeySetting(INDEX_ROUTING_REQUIRE_GROUP_PREFIX + ".", (key) ->
-    public static final Setting<Settings> INDEX_ROUTING_INCLUDE_GROUP_SETTING =
+            Setting.simpleString(key, (value, map) -> IP_VALIDATOR.accept(key, value), Property.Dynamic, Property.IndexScope));
-        Setting.groupSetting(INDEX_ROUTING_INCLUDE_GROUP_PREFIX + ".", IP_VALIDATOR, Property.Dynamic, Property.IndexScope);
+    public static final Setting.AffixSetting<String> INDEX_ROUTING_INCLUDE_GROUP_SETTING =
-    public static final Setting<Settings> INDEX_ROUTING_EXCLUDE_GROUP_SETTING =
+        Setting.prefixKeySetting(INDEX_ROUTING_INCLUDE_GROUP_PREFIX + ".", (key) ->
-        Setting.groupSetting(INDEX_ROUTING_EXCLUDE_GROUP_PREFIX + ".", IP_VALIDATOR, Property.Dynamic, Property.IndexScope);
+            Setting.simpleString(key, (value, map) -> IP_VALIDATOR.accept(key, value), Property.Dynamic, Property.IndexScope));
-    public static final Setting<Settings> INDEX_ROUTING_INITIAL_RECOVERY_GROUP_SETTING =
+    public static final Setting.AffixSetting<String> INDEX_ROUTING_EXCLUDE_GROUP_SETTING =
-        Setting.groupSetting("index.routing.allocation.initial_recovery."); // this is only setable internally not a registered setting!!
+        Setting.prefixKeySetting(INDEX_ROUTING_EXCLUDE_GROUP_PREFIX + ".", (key) ->
+            Setting.simpleString(key, (value, map) -> IP_VALIDATOR.accept(key, value), Property.Dynamic, Property.IndexScope));
+    public static final Setting.AffixSetting<String> INDEX_ROUTING_INITIAL_RECOVERY_GROUP_SETTING =
+        Setting.prefixKeySetting("index.routing.allocation.initial_recovery.", key -> Setting.simpleString(key));
+        // this is only setable internally not a registered setting!!
 
     /**
      * The number of active shard copies to check for before proceeding with a write operation.
@@ -1012,28 +1016,28 @@ public class IndexMetaData implements Diffable<IndexMetaData>, ToXContentFragmen
                     filledInSyncAllocationIds.put(i, Collections.emptySet());
                 }
             }
-            final Map<String, String> requireMap = INDEX_ROUTING_REQUIRE_GROUP_SETTING.get(settings).getAsMap();
+            final Map<String, String> requireMap = INDEX_ROUTING_REQUIRE_GROUP_SETTING.getAsMap(settings);
             final DiscoveryNodeFilters requireFilters;
             if (requireMap.isEmpty()) {
                 requireFilters = null;
             } else {
                 requireFilters = DiscoveryNodeFilters.buildFromKeyValue(AND, requireMap);
             }
-            Map<String, String> includeMap = INDEX_ROUTING_INCLUDE_GROUP_SETTING.get(settings).getAsMap();
+            Map<String, String> includeMap = INDEX_ROUTING_INCLUDE_GROUP_SETTING.getAsMap(settings);
             final DiscoveryNodeFilters includeFilters;
             if (includeMap.isEmpty()) {
                 includeFilters = null;
             } else {
                 includeFilters = DiscoveryNodeFilters.buildFromKeyValue(OR, includeMap);
             }
-            Map<String, String> excludeMap = INDEX_ROUTING_EXCLUDE_GROUP_SETTING.get(settings).getAsMap();
+            Map<String, String> excludeMap = INDEX_ROUTING_EXCLUDE_GROUP_SETTING.getAsMap(settings);
             final DiscoveryNodeFilters excludeFilters;
             if (excludeMap.isEmpty()) {
                 excludeFilters = null;
             } else {
                 excludeFilters = DiscoveryNodeFilters.buildFromKeyValue(OR, excludeMap);
             }
-            Map<String, String> initialRecoveryMap = INDEX_ROUTING_INITIAL_RECOVERY_GROUP_SETTING.get(settings).getAsMap();
+            Map<String, String> initialRecoveryMap = INDEX_ROUTING_INITIAL_RECOVERY_GROUP_SETTING.getAsMap(settings);
             final DiscoveryNodeFilters initialRecoveryFilters;
             if (initialRecoveryMap.isEmpty()) {
                 initialRecoveryFilters = null;

core/src/main/java/org/elasticsearch/cluster/metadata/MetaDataUpdateSettingsService.java

@@ -161,21 +161,20 @@ public class MetaDataUpdateSettingsService extends AbstractComponent implements
         final Settings normalizedSettings = Settings.builder().put(request.settings()).normalizePrefix(IndexMetaData.INDEX_SETTING_PREFIX).build();
         Settings.Builder settingsForClosedIndices = Settings.builder();
         Settings.Builder settingsForOpenIndices = Settings.builder();
-        Settings.Builder skipppedSettings = Settings.builder();
+        final Set<String> skippedSettings = new HashSet<>();
 
         indexScopedSettings.validate(normalizedSettings);
         // never allow to change the number of shards
-        for (Map.Entry<String, String> entry : normalizedSettings.getAsMap().entrySet()) {
+        for (String key : normalizedSettings.getKeys()) {
-            Setting setting = indexScopedSettings.get(entry.getKey());
+            Setting setting = indexScopedSettings.get(key);
             assert setting != null; // we already validated the normalized settings
-            settingsForClosedIndices.put(entry.getKey(), entry.getValue());
+            settingsForClosedIndices.copy(key, normalizedSettings);
             if (setting.isDynamic()) {
-                settingsForOpenIndices.put(entry.getKey(), entry.getValue());
+                settingsForOpenIndices.copy(key, normalizedSettings);
             } else {
-                skipppedSettings.put(entry.getKey(), entry.getValue());
+                skippedSettings.add(key);
             }
         }
-        final Settings skippedSettigns = skipppedSettings.build();
         final Settings closedSettings = settingsForClosedIndices.build();
         final Settings openSettings = settingsForOpenIndices.build();
         final boolean preserveExisting = request.isPreserveExisting();
@@ -210,11 +209,9 @@ public class MetaDataUpdateSettingsService extends AbstractComponent implements
                     }
                 }
 
-                if (!skippedSettigns.isEmpty() && !openIndices.isEmpty()) {
+                if (!skippedSettings.isEmpty() && !openIndices.isEmpty()) {
                     throw new IllegalArgumentException(String.format(Locale.ROOT,
-                            "Can't update non dynamic settings [%s] for open indices %s",
+                            "Can't update non dynamic settings [%s] for open indices %s", skippedSettings, openIndices
-                            skippedSettigns.getAsMap().keySet(),
-                            openIndices
                     ));
                 }
 

core/src/main/java/org/elasticsearch/cluster/node/DiscoveryNode.java

@@ -189,9 +189,8 @@ public class DiscoveryNode implements Writeable, ToXContentFragment {
 
     /** Creates a DiscoveryNode representing the local node. */
     public static DiscoveryNode createLocal(Settings settings, TransportAddress publishAddress, String nodeId) {
-        Map<String, String> attributes = new HashMap<>(Node.NODE_ATTRIBUTES.get(settings).getAsMap());
+        Map<String, String> attributes = Node.NODE_ATTRIBUTES.getAsMap(settings);
         Set<Role> roles = getRolesFromSettings(settings);
-
         return new DiscoveryNode(Node.NODE_NAME_SETTING.get(settings), nodeId, publishAddress, attributes, roles, Version.CURRENT);
     }
 

core/src/main/java/org/elasticsearch/cluster/node/DiscoveryNodeFilters.java

@@ -29,6 +29,7 @@ import org.elasticsearch.common.transport.TransportAddress;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
 public class DiscoveryNodeFilters {
@@ -43,15 +44,10 @@ public class DiscoveryNodeFilters {
      * "_ip", "_host_ip", and "_publish_ip" and ensuring each of their comma separated values
      * that has no wildcards is a valid IP address.
      */
-    public static final Consumer<Settings> IP_VALIDATOR = (settings) -> {
+    public static final BiConsumer<String, String> IP_VALIDATOR = (propertyKey, rawValue) -> {
-        Map<String, String> settingsMap = settings.getAsMap();
+        if (rawValue != null) {
-        for (Map.Entry<String, String> entry : settingsMap.entrySet()) {
+            if (propertyKey.endsWith("._ip") || propertyKey.endsWith("._host_ip") || propertyKey.endsWith("_publish_ip")) {
-            String propertyKey = entry.getKey();
+                for (String value : Strings.tokenizeToStringArray(rawValue, ",")) {
-            if (entry.getValue() == null) {
-                continue; // this setting gets reset
-            }
-            if ("_ip".equals(propertyKey) || "_host_ip".equals(propertyKey) || "_publish_ip".equals(propertyKey)) {
-                for (String value : Strings.tokenizeToStringArray(entry.getValue(), ",")) {
                     if (Regex.isSimpleMatchPattern(value) == false && InetAddresses.isInetAddress(value) == false) {
                         throw new IllegalArgumentException("invalid IP address [" + value + "] for [" + propertyKey + "]");
                     }

core/src/main/java/org/elasticsearch/cluster/routing/allocation/decider/FilterAllocationDecider.java

@@ -31,6 +31,7 @@ import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.settings.Settings;
 
 import java.util.EnumSet;
+import java.util.Map;
 
 import static org.elasticsearch.cluster.node.DiscoveryNodeFilters.IP_VALIDATOR;
 import static org.elasticsearch.cluster.node.DiscoveryNodeFilters.OpType.AND;
@@ -70,12 +71,15 @@ public class FilterAllocationDecider extends AllocationDecider {
     private static final String CLUSTER_ROUTING_REQUIRE_GROUP_PREFIX = "cluster.routing.allocation.require";
     private static final String CLUSTER_ROUTING_INCLUDE_GROUP_PREFIX = "cluster.routing.allocation.include";
     private static final String CLUSTER_ROUTING_EXCLUDE_GROUP_PREFIX = "cluster.routing.allocation.exclude";
-    public static final Setting<Settings> CLUSTER_ROUTING_REQUIRE_GROUP_SETTING =
+    public static final Setting.AffixSetting<String> CLUSTER_ROUTING_REQUIRE_GROUP_SETTING =
-        Setting.groupSetting(CLUSTER_ROUTING_REQUIRE_GROUP_PREFIX + ".", IP_VALIDATOR, Property.Dynamic, Property.NodeScope);
+        Setting.prefixKeySetting(CLUSTER_ROUTING_REQUIRE_GROUP_PREFIX + ".", (key) ->
-    public static final Setting<Settings> CLUSTER_ROUTING_INCLUDE_GROUP_SETTING =
+            Setting.simpleString(key, (value, map) -> IP_VALIDATOR.accept(key, value), Property.Dynamic, Property.NodeScope));
-        Setting.groupSetting(CLUSTER_ROUTING_INCLUDE_GROUP_PREFIX + ".", IP_VALIDATOR, Property.Dynamic, Property.NodeScope);
+    public static final Setting.AffixSetting<String> CLUSTER_ROUTING_INCLUDE_GROUP_SETTING =
-    public static final Setting<Settings> CLUSTER_ROUTING_EXCLUDE_GROUP_SETTING =
+        Setting.prefixKeySetting(CLUSTER_ROUTING_INCLUDE_GROUP_PREFIX + ".", (key) ->
-        Setting.groupSetting(CLUSTER_ROUTING_EXCLUDE_GROUP_PREFIX + ".", IP_VALIDATOR, Property.Dynamic, Property.NodeScope);
+            Setting.simpleString(key, (value, map) -> IP_VALIDATOR.accept(key, value), Property.Dynamic, Property.NodeScope));
+    public static final Setting.AffixSetting<String>CLUSTER_ROUTING_EXCLUDE_GROUP_SETTING =
+        Setting.prefixKeySetting(CLUSTER_ROUTING_EXCLUDE_GROUP_PREFIX + ".", (key) ->
+            Setting.simpleString(key, (value, map) -> IP_VALIDATOR.accept(key, value), Property.Dynamic, Property.NodeScope));
 
     /**
      * The set of {@link RecoverySource.Type} values for which the
@@ -94,12 +98,12 @@ public class FilterAllocationDecider extends AllocationDecider {
 
     public FilterAllocationDecider(Settings settings, ClusterSettings clusterSettings) {
         super(settings);
-        setClusterRequireFilters(CLUSTER_ROUTING_REQUIRE_GROUP_SETTING.get(settings));
+        setClusterRequireFilters(CLUSTER_ROUTING_REQUIRE_GROUP_SETTING.getAsMap(settings));
-        setClusterExcludeFilters(CLUSTER_ROUTING_EXCLUDE_GROUP_SETTING.get(settings));
+        setClusterExcludeFilters(CLUSTER_ROUTING_EXCLUDE_GROUP_SETTING.getAsMap(settings));
-        setClusterIncludeFilters(CLUSTER_ROUTING_INCLUDE_GROUP_SETTING.get(settings));
+        setClusterIncludeFilters(CLUSTER_ROUTING_INCLUDE_GROUP_SETTING.getAsMap(settings));
-        clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_REQUIRE_GROUP_SETTING, this::setClusterRequireFilters);
+        clusterSettings.addAffixMapUpdateConsumer(CLUSTER_ROUTING_REQUIRE_GROUP_SETTING, this::setClusterRequireFilters, (a,b)-> {}, true);
-        clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_EXCLUDE_GROUP_SETTING, this::setClusterExcludeFilters);
+        clusterSettings.addAffixMapUpdateConsumer(CLUSTER_ROUTING_EXCLUDE_GROUP_SETTING, this::setClusterExcludeFilters, (a,b)-> {}, true);
-        clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_INCLUDE_GROUP_SETTING, this::setClusterIncludeFilters);
+        clusterSettings.addAffixMapUpdateConsumer(CLUSTER_ROUTING_INCLUDE_GROUP_SETTING, this::setClusterIncludeFilters, (a,b)-> {}, true);
     }
 
     @Override
@@ -196,13 +200,13 @@ public class FilterAllocationDecider extends AllocationDecider {
         return null;
     }
 
-    private void setClusterRequireFilters(Settings settings) {
+    private void setClusterRequireFilters(Map<String, String> filters) {
-        clusterRequireFilters = DiscoveryNodeFilters.buildFromKeyValue(AND, settings.getAsMap());
+        clusterRequireFilters = DiscoveryNodeFilters.buildFromKeyValue(AND, filters);
     }
-    private void setClusterIncludeFilters(Settings settings) {
+    private void setClusterIncludeFilters(Map<String, String> filters) {
-        clusterIncludeFilters = DiscoveryNodeFilters.buildFromKeyValue(OR, settings.getAsMap());
+        clusterIncludeFilters = DiscoveryNodeFilters.buildFromKeyValue(OR, filters);
     }
-    private void setClusterExcludeFilters(Settings settings) {
+    private void setClusterExcludeFilters(Map<String, String> filters) {
-        clusterExcludeFilters = DiscoveryNodeFilters.buildFromKeyValue(OR, settings.getAsMap());
+        clusterExcludeFilters = DiscoveryNodeFilters.buildFromKeyValue(OR, filters);
     }
 }

core/src/main/java/org/elasticsearch/common/settings/AbstractScopedSettings.java

@@ -207,6 +207,20 @@ public abstract class AbstractScopedSettings extends AbstractComponent {
         addSettingsUpdater(setting.newAffixUpdater(consumer, logger, validator));
     }
 
+    /**
+     * Adds a settings consumer for affix settings. Affix settings have a namespace associated to it that needs to be available to the
+     * consumer in order to be processed correctly. This consumer will get a namespace to value map instead of each individual namespace
+     * and value as in {@link #addAffixUpdateConsumer(Setting.AffixSetting, BiConsumer, BiConsumer)}
+     */
+    public synchronized <T> void addAffixMapUpdateConsumer(Setting.AffixSetting<T> setting,  Consumer<Map<String, T>> consumer,
+                                                        BiConsumer<String, T> validator, boolean omitDefaults) {
+        final Setting<?> registeredSetting = this.complexMatchers.get(setting.getKey());
+        if (setting != registeredSetting) {
+            throw new IllegalArgumentException("Setting is not registered for key [" + setting.getKey() + "]");
+        }
+        addSettingsUpdater(setting.newAffixMapUpdater(consumer, logger, validator, omitDefaults));
+    }
+
     synchronized void addSettingsUpdater(SettingUpdater<?> updater) {
         this.settingUpdaters.add(updater);
     }

core/src/main/java/org/elasticsearch/common/settings/Setting.java

@@ -547,8 +547,9 @@ public class Setting<T> implements ToXContentObject {
                     final Map<AbstractScopedSettings.SettingUpdater<T>, T> result = new IdentityHashMap<>();
                     Stream.concat(matchStream(current), matchStream(previous)).distinct().forEach(aKey -> {
                         String namespace = key.getNamespace(aKey);
+                        Setting<T> concreteSetting = getConcreteSetting(aKey);
                         AbstractScopedSettings.SettingUpdater<T> updater =
-                            getConcreteSetting(aKey).newUpdater((v) -> consumer.accept(namespace, v), logger,
+                            concreteSetting.newUpdater((v) -> consumer.accept(namespace, v), logger,
                                 (v) -> validator.accept(namespace, v));
                         if (updater.hasChanged(current, previous)) {
                             // only the ones that have changed otherwise we might get too many updates
@@ -569,6 +570,43 @@ public class Setting<T> implements ToXContentObject {
             };
         }
 
+        AbstractScopedSettings.SettingUpdater<Map<String, T>> newAffixMapUpdater(Consumer<Map<String, T>> consumer, Logger logger,
+                                                                                 BiConsumer<String, T> validator, boolean omitDefaults) {
+            return new AbstractScopedSettings.SettingUpdater<Map<String, T>>() {
+
+                @Override
+                public boolean hasChanged(Settings current, Settings previous) {
+                    return  Stream.concat(matchStream(current), matchStream(previous)).findAny().isPresent();
+                }
+
+                @Override
+                public Map<String, T> getValue(Settings current, Settings previous) {
+                    // we collect all concrete keys and then delegate to the actual setting for validation and settings extraction
+                    final Map<String, T> result = new IdentityHashMap<>();
+                    Stream.concat(matchStream(current), matchStream(previous)).distinct().forEach(aKey -> {
+                        String namespace = key.getNamespace(aKey);
+                        Setting<T> concreteSetting = getConcreteSetting(aKey);
+                        AbstractScopedSettings.SettingUpdater<T> updater =
+                            concreteSetting.newUpdater((v) -> {}, logger, (v) -> validator.accept(namespace, v));
+                        if (updater.hasChanged(current, previous)) {
+                            // only the ones that have changed otherwise we might get too many updates
+                            // the hasChanged above checks only if there are any changes
+                                T value = updater.getValue(current, previous);
+                            if ((omitDefaults && value.equals(concreteSetting.getDefault(current))) == false) {
+                                result.put(namespace, value);
+                            }
+                        }
+                    });
+                    return result;
+                }
+
+                @Override
+                public void apply(Map<String, T> value, Settings current, Settings previous) {
+                    consumer.accept(value);
+                }
+            };
+        }
+
         @Override
         public T get(Settings settings) {
             throw new UnsupportedOperationException("affix settings can't return values" +
@@ -618,6 +656,18 @@ public class Setting<T> implements ToXContentObject {
         public Stream<Setting<T>> getAllConcreteSettings(Settings settings) {
             return matchStream(settings).distinct().map(this::getConcreteSetting);
         }
+
+        /**
+         * Returns a map of all namespaces to it's values give the provided settings
+         */
+        public Map<String, T> getAsMap(Settings settings) {
+            Map<String, T> map = new HashMap<>();
+            matchStream(settings).distinct().forEach(key -> {
+                Setting<T> concreteSetting = getConcreteSetting(key);
+                map.put(getNamespace(concreteSetting), concreteSetting.get(settings));
+            });
+            return Collections.unmodifiableMap(map);
+        }
     }
 
     /**
@@ -872,6 +922,10 @@ public class Setting<T> implements ToXContentObject {
         return new Setting<>(key, s -> "", Function.identity(), properties);
     }
 
+    public static Setting<String> simpleString(String key, Validator<String> validator, Property... properties) {
+        return new Setting<>(new SimpleKey(key), null, s -> "", Function.identity(), validator, properties);
+    }
+
     public static int parseInt(String s, int minValue, String key) {
         return parseInt(s, minValue, Integer.MAX_VALUE, key);
     }

core/src/main/java/org/elasticsearch/common/settings/Settings.java

@@ -320,6 +320,13 @@ public final class Settings implements ToXContentFragment {
         }
     }
 
+    /**
+     * Returns a set of all keys in this settings object
+     */
+    public Set<String> getKeys() {
+        return Collections.unmodifiableSet(settings.keySet());
+    }
+
     /**
      * We have to lazy initialize the deprecation logger as otherwise a static logger here would be constructed before logging is configured
      * leading to a runtime failure (see {@link LogConfigurator#checkErrorListener()} ). The premature construction would come from any
@@ -894,6 +901,10 @@ public final class Settings implements ToXContentFragment {
             return this;
         }
 
+        public Builder copy(String key, Settings source) {
+            return put(key, source.get(key));
+        }
+
         /**
          * Sets a null value for the given setting key
          */

core/src/main/java/org/elasticsearch/node/Node.java

@@ -190,16 +190,15 @@ public class Node implements Closeable {
     */
     public static final Setting<Boolean> NODE_LOCAL_STORAGE_SETTING = Setting.boolSetting("node.local_storage", true, Property.NodeScope);
     public static final Setting<String> NODE_NAME_SETTING = Setting.simpleString("node.name", Property.NodeScope);
-    public static final Setting<Settings> NODE_ATTRIBUTES = Setting.groupSetting("node.attr.", (settings) -> {
+    public static final Setting.AffixSetting<String> NODE_ATTRIBUTES = Setting.prefixKeySetting("node.attr.", (key) ->
-        Map<String, String> settingsMap = settings.getAsMap();
+        new Setting<>(key, "", (value) -> {
-        for (Map.Entry<String, String> entry : settingsMap.entrySet()) {
+            if (value.length() > 0
-            String value = entry.getValue();
+                && (Character.isWhitespace(value.charAt(0)) || Character.isWhitespace(value.charAt(value.length() - 1)))) {
-            if (Character.isWhitespace(value.charAt(0)) || Character.isWhitespace(value.charAt(value.length() - 1))) {
+                throw new IllegalArgumentException(key + " cannot have leading or trailing whitespace " +
-                throw new IllegalArgumentException("node.attr." + entry.getKey() + " cannot have leading or trailing whitespace " +
+                    "[" + value + "]");
-                                                       "[" + value + "]");
             }
-        }
+            return value;
-    }, Property.NodeScope);
+        }, Property.NodeScope));
     public static final Setting<String> BREAKER_TYPE_KEY = new Setting<>("indices.breaker.type", "hierarchy", (s) -> {
         switch (s) {
             case "hierarchy":

core/src/main/java/org/elasticsearch/transport/TcpTransport.java

@@ -110,7 +110,6 @@ import static java.util.Collections.emptyList;
 import static java.util.Collections.unmodifiableMap;
 import static org.elasticsearch.common.settings.Setting.affixKeySetting;
 import static org.elasticsearch.common.settings.Setting.boolSetting;
-import static org.elasticsearch.common.settings.Setting.groupSetting;
 import static org.elasticsearch.common.settings.Setting.intSetting;
 import static org.elasticsearch.common.settings.Setting.listSetting;
 import static org.elasticsearch.common.settings.Setting.timeSetting;

core/src/test/java/org/elasticsearch/cluster/allocation/FilteringAllocationIT.java

@@ -149,12 +149,12 @@ public class FilteringAllocationIT extends ESIntegTestCase {
 
     public void testInvalidIPFilterClusterSettings() {
         String ipKey = randomFrom("_ip", "_host_ip", "_publish_ip");
-        Setting<Settings> filterSetting = randomFrom(FilterAllocationDecider.CLUSTER_ROUTING_REQUIRE_GROUP_SETTING,
+        Setting<String> filterSetting = randomFrom(FilterAllocationDecider.CLUSTER_ROUTING_REQUIRE_GROUP_SETTING,
             FilterAllocationDecider.CLUSTER_ROUTING_INCLUDE_GROUP_SETTING, FilterAllocationDecider.CLUSTER_ROUTING_EXCLUDE_GROUP_SETTING);
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> client().admin().cluster().prepareUpdateSettings()
             .setTransientSettings(Settings.builder().put(filterSetting.getKey() + ipKey, "192.168.1.1."))
             .execute().actionGet());
-        assertEquals("invalid IP address [192.168.1.1.] for [" + ipKey + "]", e.getMessage());
+        assertEquals("invalid IP address [192.168.1.1.] for [" + filterSetting.getKey() + ipKey + "]", e.getMessage());
     }
 }
 

core/src/test/java/org/elasticsearch/cluster/routing/allocation/decider/FilterAllocationDeciderTests.java

@@ -183,7 +183,7 @@ public class FilterAllocationDeciderTests extends ESAllocationTestCase {
 
     public void testInvalidIPFilter() {
         String ipKey = randomFrom("_ip", "_host_ip", "_publish_ip");
-        Setting<Settings> filterSetting = randomFrom(IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING,
+        Setting<String> filterSetting = randomFrom(IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING,
             IndexMetaData.INDEX_ROUTING_INCLUDE_GROUP_SETTING, IndexMetaData.INDEX_ROUTING_EXCLUDE_GROUP_SETTING);
         String invalidIP = randomFrom("192..168.1.1", "192.300.1.1");
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
@@ -191,12 +191,12 @@ public class FilterAllocationDeciderTests extends ESAllocationTestCase {
             indexScopedSettings.updateDynamicSettings(Settings.builder().put(filterSetting.getKey() + ipKey, invalidIP).build(),
                 Settings.builder().put(Settings.EMPTY), Settings.builder(), "test ip validation");
         });
-        assertEquals("invalid IP address [" + invalidIP + "] for [" + ipKey + "]", e.getMessage());
+        assertEquals("invalid IP address [" + invalidIP + "] for [" + filterSetting.getKey() + ipKey + "]", e.getMessage());
     }
 
     public void testWildcardIPFilter() {
         String ipKey = randomFrom("_ip", "_host_ip", "_publish_ip");
-        Setting<Settings> filterSetting = randomFrom(IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING,
+        Setting<String> filterSetting = randomFrom(IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING,
             IndexMetaData.INDEX_ROUTING_INCLUDE_GROUP_SETTING, IndexMetaData.INDEX_ROUTING_EXCLUDE_GROUP_SETTING);
         String wildcardIP = randomFrom("192.168.*", "192.*.1.1");
         IndexScopedSettings indexScopedSettings = new IndexScopedSettings(Settings.EMPTY, IndexScopedSettings.BUILT_IN_INDEX_SETTINGS);

core/src/test/java/org/elasticsearch/common/settings/ScopedSettingsTests.java

@@ -43,6 +43,7 @@ import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 import static org.hamcrest.CoreMatchers.containsString;
@@ -115,7 +116,7 @@ public class ScopedSettingsTests extends ESTestCase {
 
         IndexScopedSettings settings = new IndexScopedSettings(currentSettings,
             new HashSet<>(Arrays.asList(dynamicSetting, IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING)));
-        Settings s = IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING.get(currentSettings);
+        Map<String, String> s = IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING.getAsMap(currentSettings);
         assertEquals(1, s.size());
         assertEquals("192.168.0.1,127.0.0.1", s.get("_ip"));
         Settings.Builder builder = Settings.builder();
@@ -125,7 +126,7 @@ public class ScopedSettingsTests extends ESTestCase {
         settings.updateDynamicSettings(updates,
             Settings.builder().put(currentSettings), builder, "node");
         currentSettings = builder.build();
-        s = IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING.get(currentSettings);
+        s = IndexMetaData.INDEX_ROUTING_REQUIRE_GROUP_SETTING.getAsMap(currentSettings);
         assertEquals(0, s.size());
         assertEquals(1, dynamicSetting.get(currentSettings).intValue());
         assertEquals(1, currentSettings.size());
@@ -205,6 +206,66 @@ public class ScopedSettingsTests extends ESTestCase {
         assertEquals(1, intResults.size());
     }
 
+    public void testAddConsumerAffixMap() {
+        Setting.AffixSetting<Integer> intSetting = Setting.affixKeySetting("foo.", "bar",
+            (k) ->  Setting.intSetting(k, 1, Property.Dynamic, Property.NodeScope));
+        Setting.AffixSetting<List<Integer>> listSetting = Setting.affixKeySetting("foo.", "list",
+            (k) -> Setting.listSetting(k, Arrays.asList("1"), Integer::parseInt, Property.Dynamic, Property.NodeScope));
+        AbstractScopedSettings service = new ClusterSettings(Settings.EMPTY,new HashSet<>(Arrays.asList(intSetting, listSetting)));
+        Map<String, List<Integer>> listResults = new HashMap<>();
+        Map<String, Integer> intResults = new HashMap<>();
+
+        Consumer<Map<String,Integer>> intConsumer = (map) -> {
+            intResults.clear();
+            intResults.putAll(map);
+        };
+        Consumer<Map<String, List<Integer>>> listConsumer = (map) -> {
+            listResults.clear();
+            listResults.putAll(map);
+        };
+        boolean omitDefaults = randomBoolean();
+        service.addAffixMapUpdateConsumer(listSetting, listConsumer, (s, k) -> {}, omitDefaults);
+        service.addAffixMapUpdateConsumer(intSetting, intConsumer, (s, k) -> {}, omitDefaults);
+        assertEquals(0, listResults.size());
+        assertEquals(0, intResults.size());
+        service.applySettings(Settings.builder()
+            .put("foo.test.bar", 2)
+            .put("foo.test_1.bar", 7)
+            .putArray("foo.test_list.list", "16", "17")
+            .putArray("foo.test_list_1.list", "18", "19", "20")
+            .build());
+        assertEquals(2, intResults.get("test").intValue());
+        assertEquals(7, intResults.get("test_1").intValue());
+        assertEquals(Arrays.asList(16, 17), listResults.get("test_list"));
+        assertEquals(Arrays.asList(18, 19, 20), listResults.get("test_list_1"));
+        assertEquals(2, listResults.size());
+        assertEquals(2, intResults.size());
+
+        listResults.clear();
+        intResults.clear();
+
+        service.applySettings(Settings.builder()
+            .put("foo.test.bar", 2)
+            .put("foo.test_1.bar", 8)
+            .putArray("foo.test_list.list", "16", "17")
+            .putNull("foo.test_list_1.list")
+            .build());
+        assertNull("test wasn't changed", intResults.get("test"));
+        assertEquals(8, intResults.get("test_1").intValue());
+        assertNull("test_list wasn't changed", listResults.get("test_list"));
+        if (omitDefaults) {
+            assertNull(listResults.get("test_list_1"));
+            assertFalse(listResults.containsKey("test_list_1"));
+            assertEquals(0, listResults.size());
+            assertEquals(1, intResults.size());
+        } else {
+            assertEquals(Arrays.asList(1), listResults.get("test_list_1")); // reset to default
+            assertEquals(1, listResults.size());
+            assertEquals(1, intResults.size());
+        }
+
+    }
+
     public void testApply() {
         Setting<Integer> testSetting = Setting.intSetting("foo.bar", 1, Property.Dynamic, Property.NodeScope);
         Setting<Integer> testSetting2 = Setting.intSetting("foo.bar.baz", 1, Property.Dynamic, Property.NodeScope);
@@ -347,10 +408,10 @@ public class ScopedSettingsTests extends ESTestCase {
 
     public void testGet() {
         ClusterSettings settings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
-
+        // affix setting - complex matcher
-        // group setting - complex matcher
         Setting setting = settings.get("cluster.routing.allocation.require.value");
-        assertEquals(setting, FilterAllocationDecider.CLUSTER_ROUTING_REQUIRE_GROUP_SETTING);
+        assertEquals(setting,
+            FilterAllocationDecider.CLUSTER_ROUTING_REQUIRE_GROUP_SETTING.getConcreteSetting("cluster.routing.allocation.require.value"));
 
         setting = settings.get("cluster.routing.allocation.total_shards_per_node");
         assertEquals(setting, ShardsLimitAllocationDecider.CLUSTER_TOTAL_SHARDS_PER_NODE_SETTING);

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

@@ -577,6 +577,25 @@ public class SettingTests extends ESTestCase {
         assertFalse(listAffixSetting.match("foo"));
     }
 
+    public void testAffixAsMap() {
+        Setting.AffixSetting<String> setting = Setting.prefixKeySetting("foo.bar.", key ->
+            Setting.simpleString(key, Property.NodeScope));
+        Settings build = Settings.builder().put("foo.bar.baz", 2).put("foo.bar.foobar", 3).build();
+        Map<String, String> asMap = setting.getAsMap(build);
+        assertEquals(2, asMap.size());
+        assertEquals("2", asMap.get("baz"));
+        assertEquals("3", asMap.get("foobar"));
+
+        setting = Setting.prefixKeySetting("foo.bar.", key ->
+            Setting.simpleString(key, Property.NodeScope));
+        build = Settings.builder().put("foo.bar.baz", 2).put("foo.bar.foobar", 3).put("foo.bar.baz.deep", 45).build();
+        asMap = setting.getAsMap(build);
+        assertEquals(3, asMap.size());
+        assertEquals("2", asMap.get("baz"));
+        assertEquals("3", asMap.get("foobar"));
+        assertEquals("45", asMap.get("baz.deep"));
+    }
+
     public void testGetAllConcreteSettings() {
         Setting.AffixSetting<List<String>> listAffixSetting = Setting.affixKeySetting("foo.", "bar",
             (key) -> Setting.listSetting(key, Collections.emptyList(), Function.identity(), Property.NodeScope));

core/src/test/java/org/elasticsearch/discovery/ZenFaultDetectionTests.java

@@ -145,7 +145,7 @@ public class ZenFaultDetectionTests extends ESTestCase {
                 TransportService.NOOP_TRANSPORT_INTERCEPTOR,
                 (boundAddress) ->
                     new DiscoveryNode(Node.NODE_NAME_SETTING.get(settings), boundAddress.publishAddress(),
-                        Node.NODE_ATTRIBUTES.get(settings).getAsMap(), DiscoveryNode.getRolesFromSettings(settings), version),
+                        Node.NODE_ATTRIBUTES.getAsMap(settings), DiscoveryNode.getRolesFromSettings(settings), version),
                 null);
         transportService.start();
         transportService.acceptIncomingRequests();

core/src/test/java/org/elasticsearch/node/NodeTests.java

@@ -124,7 +124,7 @@ public class NodeTests extends ESTestCase {
         Settings.Builder settings = baseSettings().put(Node.NODE_ATTRIBUTES.getKey() + "test_attr", attr);
         try (Node node = new MockNode(settings.build(), Collections.singleton(getTestTransportPlugin()))) {
             final Settings nodeSettings = randomBoolean() ? node.settings() : node.getEnvironment().settings();
-            assertEquals(attr, Node.NODE_ATTRIBUTES.get(nodeSettings).getAsMap().get("test_attr"));
+            assertEquals(attr, Node.NODE_ATTRIBUTES.getAsMap(nodeSettings).get("test_attr"));
         }
 
         // leading whitespace not allowed

core/src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreIT.java

@@ -964,7 +964,7 @@ public class SharedClusterSnapshotRestoreIT extends AbstractSnapshotIntegTestCas
                         .put("location", randomRepoPath())));
 
         logger.info("-->  creating index that cannot be allocated");
-        prepareCreate("test-idx", 2, Settings.builder().put(IndexMetaData.INDEX_ROUTING_INCLUDE_GROUP_SETTING.getKey() + ".tag", "nowhere").put("index.number_of_shards", 3)).setWaitForActiveShards(ActiveShardCount.NONE).get();
+        prepareCreate("test-idx", 2, Settings.builder().put(IndexMetaData.INDEX_ROUTING_INCLUDE_GROUP_SETTING.getKey() + "tag", "nowhere").put("index.number_of_shards", 3)).setWaitForActiveShards(ActiveShardCount.NONE).get();
 
         logger.info("--> snapshot");
         CreateSnapshotResponse createSnapshotResponse = client.admin().cluster().prepareCreateSnapshot("test-repo", "test-snap").setWaitForCompletion(true).setIndices("test-idx").get();

plugins/discovery-ec2/src/main/java/org/elasticsearch/discovery/ec2/AwsEc2Service.java

@@ -115,7 +115,8 @@ interface AwsEc2Service {
      * instances with a tag key set to stage, and a value of dev. Several tags set will require all of those tags to be set for the
      * instance to be included.
      */
-    Setting<Settings> TAG_SETTING = Setting.groupSetting("discovery.ec2.tag.", Property.NodeScope);
+    Setting.AffixSetting<String> TAG_SETTING = Setting.prefixKeySetting("discovery.ec2.tag.",
+        key -> Setting.simpleString(key, Property.NodeScope));
 
     AmazonEC2 client();
 }

plugins/discovery-ec2/src/main/java/org/elasticsearch/discovery/ec2/AwsEc2UnicastHostsProvider.java

@@ -85,7 +85,7 @@ class AwsEc2UnicastHostsProvider extends AbstractComponent implements UnicastHos
         this.groups = new HashSet<>();
         this.groups.addAll(AwsEc2Service.GROUPS_SETTING.get(settings));
 
-        this.tags = AwsEc2Service.TAG_SETTING.get(settings).getAsMap();
+        this.tags = AwsEc2Service.TAG_SETTING.getAsMap(settings);
 
         this.availabilityZones = new HashSet<>();
         availabilityZones.addAll(AwsEc2Service.AVAILABILITY_ZONES_SETTING.get(settings));

test/framework/src/main/java/org/elasticsearch/test/transport/MockTransportService.java

@@ -118,7 +118,7 @@ public final class MockTransportService extends TransportService {
         return new MockTransportService(settings, transport, threadPool, TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress ->
                 new DiscoveryNode(Node.NODE_NAME_SETTING.get(settings), UUIDs.randomBase64UUID(), boundAddress.publishAddress(),
-                    Node.NODE_ATTRIBUTES.get(settings).getAsMap(), DiscoveryNode.getRolesFromSettings(settings), version),
+                    Node.NODE_ATTRIBUTES.getAsMap(settings), DiscoveryNode.getRolesFromSettings(settings), version),
             clusterSettings);
     }