Calculate changed roles on roles.yml reload (#33525)

In order to optimize the use of the role cache, when the roles.yml file
is reloaded we now calculate the names of removed, changed, and added
roles so that they may be passed to any listeners. This allows a
listener to selectively clear cache for only the roles that have been
modified. The CompositeRolesStore has been adapted to do exactly that
so that we limit the need to reload roles from sources such as the
native roles stores or external role providers.

See #33205

Author: jaymode

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authz/store/CompositeRolesStore.java

@@ -97,9 +97,7 @@ public CompositeRolesStore(Settings settings, FileRolesStore fileRolesStore, Nat
                                ThreadContext threadContext, XPackLicenseState licenseState) {
         super(settings);
         this.fileRolesStore = fileRolesStore;
-        // invalidating all on a file based role update is heavy handed to say the least, but in general this should be infrequent so the
-        // impact isn't really worth the added complexity of only clearing the changed values
-        fileRolesStore.addListener(this::invalidateAll);
+        fileRolesStore.addListener(this::invalidate);
         this.nativeRolesStore = nativeRolesStore;
         this.reservedRolesStore = reservedRolesStore;
         this.privilegeStore = privilegeStore;
@@ -356,6 +354,23 @@ public void invalidate(String role) {
         negativeLookupCache.remove(role);
     }
 
+    public void invalidate(Set<String> roles) {
+        numInvalidation.incrementAndGet();
+
+        // the cache cannot be modified while doing this operation per the terms of the cache iterator
+        try (ReleasableLock ignored = writeLock.acquire()) {
+            Iterator<Set<String>> keyIter = roleCache.keys().iterator();
+            while (keyIter.hasNext()) {
+                Set<String> key = keyIter.next();
+                if (Sets.haveEmptyIntersection(key, roles) == false) {
+                    keyIter.remove();
+                }
+            }
+        }
+
+        negativeLookupCache.removeAll(roles);
+    }
+
     public void usageStats(ActionListener<Map<String, Object>> listener) {
         final Map<String, Object> usage = new HashMap<>(2);
         usage.put("file", fileRolesStore.usageStats());

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authz/store/FileRolesStore.java

@@ -12,6 +12,7 @@
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.component.AbstractComponent;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.common.xcontent.LoggingDeprecationHandler;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentParser;
@@ -34,13 +35,16 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.function.Consumer;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
@@ -52,16 +56,16 @@ public class FileRolesStore extends AbstractComponent {
 
     private final Path file;
     private final XPackLicenseState licenseState;
-    private final List<Runnable> listeners = new ArrayList<>();
+    private final List<Consumer<Set<String>>> listeners = new ArrayList<>();
 
     private volatile Map<String, RoleDescriptor> permissions;
 
     public FileRolesStore(Settings settings, Environment env, ResourceWatcherService watcherService, XPackLicenseState licenseState)
             throws IOException {
-        this(settings, env, watcherService, () -> {}, licenseState);
+        this(settings, env, watcherService, null, licenseState);
     }
 
-    FileRolesStore(Settings settings, Environment env, ResourceWatcherService watcherService, Runnable listener,
+    FileRolesStore(Settings settings, Environment env, ResourceWatcherService watcherService, Consumer<Set<String>> listener,
                    XPackLicenseState licenseState) throws IOException {
         super(settings);
         this.file = resolveFile(env);
@@ -76,9 +80,10 @@ public FileRolesStore(Settings settings, Environment env, ResourceWatcherService
     }
 
     public Set<RoleDescriptor> roleDescriptors(Set<String> roleNames) {
+        final Map<String, RoleDescriptor> localPermissions = permissions;
         Set<RoleDescriptor> descriptors = new HashSet<>();
         roleNames.forEach((name) -> {
-            RoleDescriptor descriptor = permissions.get(name);
+            RoleDescriptor descriptor = localPermissions.get(name);
             if (descriptor != null) {
                 descriptors.add(descriptor);
             }
@@ -87,12 +92,13 @@ public Set<RoleDescriptor> roleDescriptors(Set<String> roleNames) {
     }
 
     public Map<String, Object> usageStats() {
+        final Map<String, RoleDescriptor> localPermissions = permissions;
         Map<String, Object> usageStats = new HashMap<>(3);
-        usageStats.put("size", permissions.size());
+        usageStats.put("size", localPermissions.size());
 
         boolean dls = false;
         boolean fls = false;
-        for (RoleDescriptor descriptor : permissions.values()) {
+        for (RoleDescriptor descriptor : localPermissions.values()) {
             for (IndicesPrivileges indicesPrivileges : descriptor.getIndicesPrivileges()) {
                 fls = fls || indicesPrivileges.getGrantedFields() != null || indicesPrivileges.getDeniedFields() != null;
                 dls = dls || indicesPrivileges.getQuery() != null;
@@ -107,17 +113,22 @@ public Map<String, Object> usageStats() {
         return usageStats;
     }
 
-    public void addListener(Runnable runnable) {
-        Objects.requireNonNull(runnable);
+    public void addListener(Consumer<Set<String>> consumer) {
+        Objects.requireNonNull(consumer);
         synchronized (this) {
-            listeners.add(runnable);
+            listeners.add(consumer);
         }
     }
 
     public Path getFile() {
         return file;
     }
 
+    // package private for testing
+    Set<String> getAllRoleNames() {
+        return permissions.keySet();
+    }
+
     public static Path resolveFile(Environment env) {
         return XPackPlugin.resolveConfigFile(env, "roles.yml");
     }
@@ -319,21 +330,27 @@ public void onFileDeleted(Path file) {
         }
 
         @Override
-        public void onFileChanged(Path file) {
+        public synchronized void onFileChanged(Path file) {
             if (file.equals(FileRolesStore.this.file)) {
+                final Map<String, RoleDescriptor> previousPermissions = permissions;
                 try {
                     permissions = parseFile(file, logger, settings, licenseState);
-                    logger.info("updated roles (roles file [{}] {})", file.toAbsolutePath(), Files.exists(file) ? "changed" : "removed");
+                    logger.info("updated roles (roles file [{}] {})", file.toAbsolutePath(),
+                        Files.exists(file) ? "changed" : "removed");
                 } catch (Exception e) {
                     logger.error(
                             (Supplier<?>) () -> new ParameterizedMessage(
                                     "could not reload roles file [{}]. Current roles remain unmodified", file.toAbsolutePath()), e);
                     return;
                 }
 
-                synchronized (FileRolesStore.this) {
-                    listeners.forEach(Runnable::run);
-                }
+                final Set<String> changedOrMissingRoles = Sets.difference(previousPermissions.entrySet(), permissions.entrySet())
+                        .stream()
+                        .map(Map.Entry::getKey)
+                        .collect(Collectors.toSet());
+                final Set<String> addedRoles = Sets.difference(permissions.keySet(), previousPermissions.keySet());
+                final Set<String> changedRoles = Collections.unmodifiableSet(Sets.union(changedOrMissingRoles, addedRoles));
+                listeners.forEach(c -> c.accept(changedRoles));
             }
         }
     }

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authz/store/CompositeRolesStoreTests.java

@@ -53,6 +53,7 @@
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
@@ -213,7 +214,7 @@ public void testNegativeLookupsAreCached() {
                 new CompositeRolesStore(SECURITY_ENABLED_SETTINGS, fileRolesStore, nativeRolesStore, reservedRolesStore,
                         mock(NativePrivilegeStore.class), Collections.emptyList(), new ThreadContext(SECURITY_ENABLED_SETTINGS),
                         new XPackLicenseState(SECURITY_ENABLED_SETTINGS));
-        verify(fileRolesStore).addListener(any(Runnable.class)); // adds a listener in ctor
+        verify(fileRolesStore).addListener(any(Consumer.class)); // adds a listener in ctor
 
         final String roleName = randomAlphaOfLengthBetween(1, 10);
         PlainActionFuture<Role> future = new PlainActionFuture<>();

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authz/store/FileRolesStoreTests.java

@@ -37,6 +37,7 @@
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -319,8 +320,11 @@ public void testAutoReload() throws Exception {
             threadPool = new TestThreadPool("test");
             watcherService = new ResourceWatcherService(settings, threadPool);
             final CountDownLatch latch = new CountDownLatch(1);
-            FileRolesStore store = new FileRolesStore(settings, env, watcherService, latch::countDown,
-                    new XPackLicenseState(Settings.EMPTY));
+            final Set<String> modifiedRoles = new HashSet<>();
+            FileRolesStore store = new FileRolesStore(settings, env, watcherService, roleSet -> {
+                    modifiedRoles.addAll(roleSet);
+                    latch.countDown();
+                }, new XPackLicenseState(Settings.EMPTY));
 
             Set<RoleDescriptor> descriptors = store.roleDescriptors(Collections.singleton("role1"));
             assertThat(descriptors, notNullValue());
@@ -344,6 +348,8 @@ public void testAutoReload() throws Exception {
                 fail("Waited too long for the updated file to be picked up");
             }
 
+            assertEquals(1, modifiedRoles.size());
+            assertTrue(modifiedRoles.contains("role5"));
             final TransportRequest request = mock(TransportRequest.class);
             descriptors = store.roleDescriptors(Collections.singleton("role5"));
             assertThat(descriptors, notNullValue());
@@ -354,6 +360,49 @@ public void testAutoReload() throws Exception {
             assertThat(role.cluster().check("cluster:monitor/foo/bar", request), is(true));
             assertThat(role.cluster().check("cluster:admin/foo/bar", request), is(false));
 
+            // truncate to remove some
+            final Set<String> truncatedFileRolesModified = new HashSet<>();
+            final CountDownLatch truncateLatch = new CountDownLatch(1);
+            store = new FileRolesStore(settings, env, watcherService, roleSet -> {
+                truncatedFileRolesModified.addAll(roleSet);
+                truncateLatch.countDown();
+            }, new XPackLicenseState(Settings.EMPTY));
+
+            final Set<String> allRolesPreTruncate = store.getAllRoleNames();
+            try (BufferedWriter writer = Files.newBufferedWriter(tmp, StandardCharsets.UTF_8, StandardOpenOption.TRUNCATE_EXISTING)) {
+                writer.append("role5:").append(System.lineSeparator());
+                writer.append("  cluster:").append(System.lineSeparator());
+                writer.append("    - 'MONITOR'");
+            }
+
+            truncateLatch.await();
+            assertEquals(allRolesPreTruncate.size() - 1, truncatedFileRolesModified.size());
+            assertTrue(allRolesPreTruncate.contains("role5"));
+            assertFalse(truncatedFileRolesModified.contains("role5"));
+            descriptors = store.roleDescriptors(Collections.singleton("role5"));
+            assertThat(descriptors, notNullValue());
+            assertEquals(1, descriptors.size());
+
+            // modify
+            final Set<String> modifiedFileRolesModified = new HashSet<>();
+            final CountDownLatch modifyLatch = new CountDownLatch(1);
+            store = new FileRolesStore(settings, env, watcherService, roleSet -> {
+                modifiedFileRolesModified.addAll(roleSet);
+                modifyLatch.countDown();
+            }, new XPackLicenseState(Settings.EMPTY));
+
+            try (BufferedWriter writer = Files.newBufferedWriter(tmp, StandardCharsets.UTF_8, StandardOpenOption.TRUNCATE_EXISTING)) {
+                writer.append("role5:").append(System.lineSeparator());
+                writer.append("  cluster:").append(System.lineSeparator());
+                writer.append("    - 'ALL'");
+            }
+
+            modifyLatch.await();
+            assertEquals(1, modifiedFileRolesModified.size());
+            assertTrue(modifiedFileRolesModified.contains("role5"));
+            descriptors = store.roleDescriptors(Collections.singleton("role5"));
+            assertThat(descriptors, notNullValue());
+            assertEquals(1, descriptors.size());
         } finally {
             if (watcherService != null) {
                 watcherService.stop();