Improve detection of index for "rep:ACL" nodes

Rely on EXPLAIN MEASURE and evaluate the estimated cost.

This closes #714

accesscontroltool-bundle/src/main/java/biz/netcentric/cq/tools/actool/helper/QueryHelper.java

@@ -10,6 +10,7 @@
 
 import static biz.netcentric.cq.tools.actool.history.impl.PersistableInstallationLogger.msHumanReadable;
 
+import java.io.IOException;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -29,6 +30,7 @@
 import javax.jcr.query.InvalidQueryException;
 import javax.jcr.query.Query;
 import javax.jcr.query.QueryResult;
+import javax.jcr.query.Row;
 import javax.jcr.security.AccessControlList;
 import javax.jcr.security.AccessControlManager;
 import javax.jcr.security.AccessControlPolicy;
@@ -40,13 +42,18 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
 public class QueryHelper {
     public static final Logger LOG = LoggerFactory.getLogger(QueryHelper.class);
 
     private static final String ROOT_REP_POLICY_NODE = "/rep:policy";
     private static final String ROOT_REPO_POLICY_NODE = "/" + Constants.REPO_POLICY_NODE;
     private static final String HOME_REP_POLICY = "/home/rep:policy";
-    private static final String OAK_INDEX_PATH_REP_ACL = "/oak:index/repACL-custom-1";
+
+    /** every query cost below that threshold means a dedicated index exists, above that threshold means: fallback to traversal */
+    private static final double COST_THRESHOLD_FOR_QUERY_INDEX = 100d;
 
     /** Method that returns a set containing all rep:policy nodes from repository excluding those contained in paths which are excluded from
      * search
@@ -98,7 +105,12 @@ public static Set<String> getRepPolicyNodePaths(final Session session,
                 paths.add(HOME_REP_POLICY);
             }
 
-            boolean indexForRepACLExists = session.nodeExists(OAK_INDEX_PATH_REP_ACL);
+            boolean indexForRepACLExists = false;
+            try {
+                indexForRepACLExists = hasQueryIndexForACLs(session);
+            } catch(IOException|RepositoryException e) {
+                LOG.warn("Cannot figure out if query index for rep:ACL nodes exist", e);
+            }
             LOG.debug("Index for repACL exists: {}",indexForRepACLExists);
             String queryForAClNodes = indexForRepACLExists ? 
                     "SELECT * FROM [rep:ACL] WHERE ISDESCENDANTNODE([%s])" : 
@@ -125,10 +137,32 @@ public static Set<String> getRepPolicyNodePaths(final Session session,
         return paths;
     }
 
+    static boolean hasQueryIndexForACLs(final Session session) throws RepositoryException, IOException {
+        Query query = session.getWorkspace().getQueryManager().createQuery("EXPLAIN MEASURE SELECT * FROM [rep:ACL] AS s WHERE ISDESCENDANTNODE([/])", Query.JCR_SQL2);
+        QueryResult queryResult = query.execute();
+        Row row = queryResult.getRows().nextRow();
+        // inspired by https://github.com/apache/jackrabbit-oak/blob/cc8adb42d89bc4625138a62ab074e7794a4d39ab/oak-jcr/src/test/java/org/apache/jackrabbit/oak/jcr/query/QueryTest.java#L1092
+        String plan = row.getValue("plan").getString();
+        String costJson = plan.substring(plan.lastIndexOf('{'));
+
+        // use jackson for JSON parsing
+        ObjectMapper mapper = new ObjectMapper();
+
+        // read the json strings and convert it into JsonNode
+        JsonNode node = mapper.readTree(costJson);
+        double cost = node.get("s").asDouble(Double.MAX_VALUE);
+        // look at https://jackrabbit.apache.org/oak/docs/query/query-engine.html#cost-calculation for the threshold
+        // https://github.com/apache/jackrabbit-oak/blob/cc8adb42d89bc4625138a62ab074e7794a4d39ab/oak-core/src/main/java/org/apache/jackrabbit/oak/query/index/TraversingIndex.java#L75
+
+        // for traversing cost = estimation of node count
+        // for property index = between 2 and 100
+        LOG.debug("Cost for rep:ACL query is estimated with {}", cost);
+        return cost <= COST_THRESHOLD_FOR_QUERY_INDEX;
+    }
+
     /** Get Nodes with XPATH Query. */
     public static Set<String> getNodePathsFromQuery(final Session session,
-            final String xpathQuery) throws InvalidQueryException,
-            RepositoryException {
+            final String xpathQuery) throws RepositoryException {
         return getNodePathsFromQuery(session, xpathQuery, Query.XPATH);
     }
 

accesscontroltool-bundle/src/test/java/biz/netcentric/cq/tools/actool/extensions/OakRepository.java

@@ -15,8 +15,10 @@
 import java.nio.file.Paths;
 import java.util.Comparator;
 import java.util.Properties;
+import java.util.function.Consumer;
 import java.util.stream.Stream;
 
+import javax.jcr.LoginException;
 import javax.jcr.Repository;
 import javax.jcr.RepositoryException;
 import javax.jcr.Session;
@@ -77,19 +79,39 @@ public class OakRepository implements BeforeAllCallback, BeforeEachCallback, Aft
 
     private static final Logger LOGGER = LoggerFactory.getLogger(OakRepository.class);
 
+    /**
+     * Optionally uses a dedicated BlobStore with Oak, otherwise just in memory
+     */
+    private final boolean useFileStore; 
+
+    private final Consumer<Jcr> jcrInitCallback;
+
+    public OakRepository() {
+        this(true);
+    }
+
+    public OakRepository(boolean useFileStore) {
+        this(useFileStore, null);
+    }
+
+    public OakRepository(boolean useFileStore, Consumer<Jcr> jcrInitCallback) {
+        this.useFileStore = useFileStore;
+        this.jcrInitCallback = jcrInitCallback;
+    }
+
     @Override
     public void afterAll(ExtensionContext context) throws Exception {
         shutdownRepository();
     }
 
     @Override
     public void beforeAll(ExtensionContext context) throws Exception {
-        initRepository(true);
+        initRepository();
     }
 
     @Override
     public void beforeEach(ExtensionContext context) throws Exception {
-        admin = repository.login(new SimpleCredentials("admin", "admin".toCharArray()));
+        admin = createAdminSession();
     }
 
     @Override
@@ -110,11 +132,11 @@ public Object resolveParameter(ParameterContext parameterContext, ExtensionConte
     }
 
     /** 
-     * @param useFileStore only evaluated for Oak. Optionally uses a dedicated BlobStore with Oak
+     * @param useFileStore only evaluated for Oak. O
      * @throws RepositoryException
      * @throws IOException
      * @throws InvalidFileStoreVersionException */
-    private void initRepository(boolean useFileStore) throws RepositoryException, IOException, InvalidFileStoreVersionException {
+    private void initRepository() throws RepositoryException, IOException, InvalidFileStoreVersionException {
         Jcr jcr;
         if (useFileStore) {
             BlobStore blobStore = createBlobStore();
@@ -128,7 +150,9 @@ private void initRepository(boolean useFileStore) throws RepositoryException, IO
             // in-memory repo
             jcr = new Jcr();
         }
-
+        if (jcrInitCallback != null) {
+            jcrInitCallback.accept(jcr);
+        }
         repository = jcr
                 .with(createSecurityProvider())
                 .withAtomicCounter()
@@ -151,8 +175,8 @@ private void shutdownRepository() throws IOException {
             if (fileStore != null) {
                 fileStore.close();
                 fileStore = null;
+                deleteDirectory(DIR_OAK_REPO_HOME);
             }
-            deleteDirectory(DIR_OAK_REPO_HOME);
         }
         repository = null;
     }
@@ -206,4 +230,8 @@ public static ConfigurationParameters getSecurityConfigurationParameters() {
                 UserConfiguration.NAME, ConfigurationParameters.of(userProps),
                 AuthorizationConfiguration.NAME, ConfigurationParameters.of(authzProps));
     }
+
+    public Session createAdminSession() throws RepositoryException {
+        return repository.login(new SimpleCredentials("admin", "admin".toCharArray()));
+    }
 }

accesscontroltool-bundle/src/test/java/biz/netcentric/cq/tools/actool/helper/QueryHelperIT.java

@@ -0,0 +1,50 @@
+/*
+ * (C) Copyright 2023 Cognizant Netcentric.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package biz.netcentric.cq.tools.actool.helper;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.IOException;
+
+import javax.jcr.Node;
+import javax.jcr.PropertyType;
+import javax.jcr.RepositoryException;
+import javax.jcr.Session;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import biz.netcentric.cq.tools.actool.extensions.OakRepository;
+
+class QueryHelperIT {
+
+    @RegisterExtension
+    static final OakRepository repository = new OakRepository(false);
+
+    @Test
+    void testHasQueryIndexForACLsWithoutIndex(Session session) throws RepositoryException, IOException {
+        // adjust nodetype index definition (at /oak:index/nodetype) to reflect what is configured in AEM
+        Node ntIndexDefNode = session.getNode("/oak:index/nodetype");
+        ntIndexDefNode.setProperty("declaringNodeTypes", new String[] { "oak:QueryIndexDefinition", "rep:User", "rep:Authorizable" }, PropertyType.NAME);
+        session.save();
+        assertFalse(QueryHelper.hasQueryIndexForACLs(session));
+    }
+
+    @Test
+    void testHasQueryIndexForACLsWithIndex(Session session) throws RepositoryException, IOException {
+        // adjust nodetype index definition (at /oak:index/nodetype) to include rep:ACL
+        // this is a different type than shipped with ACTool (Lucene), but lucene based index providers are hard to set up in an IT
+        Node ntIndexDefNode = session.getNode("/oak:index/nodetype");
+        ntIndexDefNode.setProperty("declaringNodeTypes", new String[] { "oak:QueryIndexDefinition", "rep:User", "rep:Authorizable", "rep:ACL" }, PropertyType.NAME);
+        session.save();
+        assertTrue(QueryHelper.hasQueryIndexForACLs(session));
+    }
+
+}