CDAP-21270: Enable JEXL expressions allowlisting in Wrangler Directives

pom.xml

@@ -77,7 +77,7 @@
     <commons.validator.version>1.6</commons.validator.version>
     <commons-io.version>2.16.1</commons-io.version>
     <commons-csv.version>1.4</commons-csv.version>
-    <commons-jexl.version>3.0</commons-jexl.version>
+    <commons-jexl.version>3.1</commons-jexl.version>
     <commons-lang.version>2.6</commons-lang.version>
     <commons-lang3.version>3.5</commons-lang3.version>
     <commons-math3.version>3.6.1</commons-math3.version>

wrangler-api/pom.xml

@@ -39,6 +39,10 @@
       <version>${cdap.version}</version>
       <scope>provided</scope>
     </dependency>
-
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>${guava.version}</version>
+    </dependency>
   </dependencies>
 </project>

wrangler-api/src/main/java/io/cdap/wrangler/api/DefaultJexlAllowlist.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2026 Cask Data, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package io.cdap.wrangler.api;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+/**
+ * Defines the set of classes allowed in the JEXL Sandbox by default.
+ */
+public final class DefaultJexlAllowlist {
+
+  private static final List<String> DEFAULT_CLASSES = Arrays.asList(
+      // Data types
+      "java.lang.Boolean", "java.lang.Byte", "java.lang.Character", "java.lang.Double", "java.lang.Float",
+      "java.lang.Integer", "java.lang.Long", "java.lang.Short",
+
+      // Strings
+      "java.lang.String", "java.lang.StringBuilder", "java.util.StringJoiner",
+
+      // Math
+      "java.lang.Math", "java.math.BigDecimal", "java.math.BigInteger",
+
+      // Time
+      "java.time.ZonedDateTime", "java.time.LocalDate", "java.time.LocalDateTime", "java.time.Instant",
+      "java.time.Duration", "java.time.format.DateTimeFormatter",
+
+      // Utilities
+      "java.util.Arrays", "java.util.Collections", "java.util.UUID", "java.util.Base64");
+
+  private static final List<JexlAllowlist> ALLOWLIST = Collections.unmodifiableList(
+      DEFAULT_CLASSES.stream()
+          .map(className -> {
+            return new JexlAllowlist(
+                Objects.requireNonNull(className),
+                Collections.singletonList(JexlAllowlist.INCLUDE_ALL_WILDCARD),
+                Collections.singletonList(JexlAllowlist.INCLUDE_ALL_WILDCARD));
+          })
+          .collect(Collectors.toList()));
+
+  private DefaultJexlAllowlist() {
+  }
+
+  /**
+   * @return the list of default allowed classes.
+   */
+  public static List<JexlAllowlist> get() {
+    return ALLOWLIST;
+  }
+}

wrangler-api/src/main/java/io/cdap/wrangler/api/DirectiveConfig.java

@@ -16,19 +16,29 @@
 
 package io.cdap.wrangler.api;
 
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.gson.Gson;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.google.gson.reflect.TypeToken;
 
+import java.lang.reflect.Type;
 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.Set;
+import javax.annotation.Nullable;
 
 /**
- * This class {@link DirectiveConfig} defines the configuration for the Wrangler.
+ * This class {@link DirectiveConfig} defines the configuration for the
+ * Wrangler.
  * It specifies the directive exclusions -- meaning directives that should
  * not be accessible to the users and as well as directive aliases.
  *
@@ -42,18 +52,69 @@
  *  "aliases" : {
  *      "json-parser" : "parse-as-json",
  *      "js-parser" : "parse-as-json"
+ *   },
+ *   "jexlAllowlist" : [
+ *     {
+ *       "className": "java.lang.Runtime",
+ *       "methods": ["*"],
+ *       "properties": ["*"]
  *   }
+ *   ]
  *  }
  */
 @Deprecated
 public final class DirectiveConfig {
-  public static final DirectiveConfig EMPTY = new DirectiveConfig();
-  // RecipeParser to be excluded or made non-accessible.
-  private final Set<String> exclusions = new HashSet<>();
+  public static final DirectiveConfig EMPTY = new DirectiveConfig(null, null, Collections.emptyList());
+  public static final String EXCLUSIONS_KEY = "exclusions";
+  public static final String ALIASES_KEY = "aliases";
+  public static final String JEXL_ALLOWLIST_KEY = "jexlAllowlist";
 
-  // RecipeParser to be aliased.
-  private final Map<String, String> aliases = new HashMap<>();
+  private final ImmutableSet<String> exclusions;
+  private final ImmutableMap<String, String> aliases;
+  @Nullable private final ImmutableList<JexlAllowlist> jexlAllowlist;
 
+  private DirectiveConfig(
+      @Nullable Set<String> exclusions,
+      @Nullable Map<String, String> aliases,
+      @Nullable List<JexlAllowlist> jexlAllowlist) {
+    this.exclusions = exclusions != null ? ImmutableSet.copyOf(exclusions) : ImmutableSet.of();
+    this.aliases = aliases != null ? ImmutableMap.copyOf(aliases) : ImmutableMap.of();
+    this.jexlAllowlist = jexlAllowlist != null ? ImmutableList.copyOf(jexlAllowlist) : null;
+  }
+
+  /** Custom GSON adapter for {@link DirectiveConfig}. */
+  public static final class DirectiveConfigDeserializer implements JsonDeserializer<DirectiveConfig> {
+
+    @Override
+    public DirectiveConfig deserialize(JsonElement configJson, Type typeOfT, JsonDeserializationContext ctx)
+        throws JsonParseException {
+      JsonObject configJsonObj = configJson.getAsJsonObject();
+
+      return new DirectiveConfig(
+          deserializeProperty(configJsonObj, EXCLUSIONS_KEY, new TypeToken<Set<String>>() {
+          }.getType(), ctx),
+          deserializeProperty(configJsonObj, ALIASES_KEY, new TypeToken<Map<String, String>>() {
+          }.getType(), ctx),
+          deserializeProperty(configJsonObj, JEXL_ALLOWLIST_KEY, new TypeToken<List<JexlAllowlist>>() {
+          }.getType(), ctx));
+    }
+
+    @Nullable
+    private static <T> T deserializeProperty(JsonObject obj, String key, Type type, JsonDeserializationContext ctx) {
+      JsonElement element = obj.get(key);
+      return (element != null && !element.isJsonNull()) ? ctx.deserialize(element, type) : null;
+    }
+  }
+
+  /**
+   * Gets the list of JEXL inclusions.
+   *
+   * @return the list of JEXL inclusions
+   */
+  @Nullable
+  public List<JexlAllowlist> getJexlAllowlist() {
+    return jexlAllowlist == null ? null : Collections.unmodifiableList(jexlAllowlist);
+  }
 
   /**
    * Checks if a directive is aliased.
@@ -108,8 +169,9 @@ public boolean isExcluded(String directive) {
   public JsonElement toJson() {
     Gson gson = new Gson();
     JsonObject object = new JsonObject();
-    object.add("exclusions", gson.toJsonTree(exclusions));
-    object.add("aliases", gson.toJsonTree(aliases));
+    object.add(EXCLUSIONS_KEY, gson.toJsonTree(exclusions));
+    object.add(ALIASES_KEY, gson.toJsonTree(aliases));
+    object.add(JEXL_ALLOWLIST_KEY, gson.toJsonTree(jexlAllowlist));
     return object;
   }
 }

wrangler-api/src/main/java/io/cdap/wrangler/api/DirectiveContext.java

@@ -20,5 +20,5 @@
  * {@link DirectiveContext} provides the context object to the processing of
  * directives.
  */
-public interface DirectiveContext extends DirectiveEnforcer, DirectiveAlias {
+public interface DirectiveContext extends DirectiveEnforcer, DirectiveAlias, DirectiveJexlAllowlist {
 }

wrangler-api/src/main/java/io/cdap/wrangler/api/DirectiveJexlAllowlist.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright © 2026 Cask Data, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package io.cdap.wrangler.api;
+
+import java.util.List;
+
+/**
+ * This interface {@link DirectiveJexlAllowlist} provides a way to get JEXL
+ * configuration.
+ */
+public interface DirectiveJexlAllowlist {
+
+  /**
+   * Gets the list of JEXL inclusions.
+   *
+   * @return the list of JEXL inclusions
+   */
+  List<JexlAllowlist> getJexlAllowlist();
+
+  /**
+   * Checks if JEXL allowlisting is enabled.
+   *
+   * @return true if JEXL allowlisting is enabled, false otherwise.
+   */
+  boolean isJexlAllowlistEnabled();
+}