Improve role cache efficiency for API key roles

libs/x-content/src/main/java/org/elasticsearch/common/xcontent/AbstractObjectParser.java

@@ -210,6 +210,12 @@ public void declareLong(BiConsumer<Value, Long> consumer, ParseField field) {
         declareField(consumer, p -> p.longValue(), field, ValueType.LONG);
     }
 
+    public void declareLongOrNull(BiConsumer<Value, Long> consumer, long nullValue, ParseField field) {
+        // Using a method reference here angers some compilers
+        declareField(consumer, p -> p.currentToken() == XContentParser.Token.VALUE_NULL ? nullValue : p.longValue(),
+            field, ValueType.LONG_OR_NULL);
+    }
+
     public void declareInt(BiConsumer<Value, Integer> consumer, ParseField field) {
         // Using a method reference here angers some compilers
         declareField(consumer, p -> p.intValue(), field, ValueType.INT);

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/SecurityContext.java

@@ -10,9 +10,12 @@
 import org.elasticsearch.ElasticsearchSecurityException;
 import org.elasticsearch.Version;
 import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.ThreadContext;
 import org.elasticsearch.common.util.concurrent.ThreadContext.StoredContext;
+import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.node.Node;
 import org.elasticsearch.xpack.core.security.authc.Authentication;
 import org.elasticsearch.xpack.core.security.authc.Authentication.AuthenticationType;
@@ -23,14 +26,22 @@
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Objects;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+import static org.elasticsearch.xpack.core.security.authc.AuthenticationField.API_KEY_LIMITED_ROLE_DESCRIPTORS_KEY;
+import static org.elasticsearch.xpack.core.security.authc.AuthenticationField.API_KEY_ROLE_DESCRIPTORS_KEY;
+
 /**
  * A lightweight utility that can find the current user and authentication information for the local thread.
  */
 public class SecurityContext {
+
+    public static final Version VERSION_API_KEY_ROLES_AS_BYTES = Version.V_7_9_0;
+
     private final Logger logger = LogManager.getLogger(SecurityContext.class);
 
     private final ThreadContext threadContext;
@@ -149,8 +160,27 @@ public void executeAfterRewritingAuthentication(Consumer<StoredContext> consumer
         final Authentication authentication = getAuthentication();
         try (ThreadContext.StoredContext ignore = threadContext.stashContext()) {
             setAuthentication(new Authentication(authentication.getUser(), authentication.getAuthenticatedBy(),
-                authentication.getLookedUpBy(), version, authentication.getAuthenticationType(), authentication.getMetadata()));
+                authentication.getLookedUpBy(), version, authentication.getAuthenticationType(),
+                rewriteMetadataForApiKeyRoleDescriptors(version, authentication)));
             consumer.accept(original);
         }
     }
+
+    private Map<String, Object> rewriteMetadataForApiKeyRoleDescriptors(Version streamVersion, Authentication authentication) {
+        Map<String, Object> metadata = authentication.getMetadata();
+        if (authentication.getAuthenticationType() == AuthenticationType.API_KEY
+            && authentication.getVersion().onOrAfter(VERSION_API_KEY_ROLES_AS_BYTES)
+            && streamVersion.before(VERSION_API_KEY_ROLES_AS_BYTES)) {
+            metadata = new HashMap<>(metadata);
+            metadata.put(
+                API_KEY_ROLE_DESCRIPTORS_KEY,
+                XContentHelper.convertToMap(
+                    (BytesReference) metadata.get(API_KEY_ROLE_DESCRIPTORS_KEY), false, XContentType.JSON).v2());
+            metadata.put(
+                API_KEY_LIMITED_ROLE_DESCRIPTORS_KEY,
+                XContentHelper.convertToMap(
+                    (BytesReference) metadata.get(API_KEY_LIMITED_ROLE_DESCRIPTORS_KEY), false, XContentType.JSON).v2());
+        }
+        return metadata;
+    }
 }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/authc/AuthenticationField.java

@@ -8,6 +8,8 @@
 public final class AuthenticationField {
 
     public static final String AUTHENTICATION_KEY = "_xpack_security_authentication";
+    public static final String API_KEY_ROLE_DESCRIPTORS_KEY = "_security_api_key_role_descriptors";
+    public static final String API_KEY_LIMITED_ROLE_DESCRIPTORS_KEY = "_security_api_key_limited_by_role_descriptors";
 
     private AuthenticationField() {}
 }