feat(#2312): replace Nashorn with GraalVM JS Engine

this is required for JDK 15+ compatibility
(Nashorn was removed in JDK 15)

Author: BlasiusSecundus

core/build.gradle

@@ -41,6 +41,9 @@ dependencies {
 
     implementation "com.github.ben-manes.caffeine:caffeine"
 
+    implementation "org.graalvm.js:js:${revGraalVM}"
+    implementation "org.graalvm.js:js-scriptengine:${revGraalVM}"
+
     // JAXB is not bundled with Java 11, dependencies added explicitly
     // These are needed by Apache BVAL
     implementation "jakarta.xml.bind:jakarta.xml.bind-api:${revJAXB}"

core/src/main/java/com/netflix/conductor/core/events/ScriptEvaluator.java

@@ -19,7 +19,12 @@
 
 public class ScriptEvaluator {
 
-    private static final ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
+    private static final ScriptEngine engine =
+            new ScriptEngineManager().getEngineByName("graal.js");
+
+    static {
+        engine.put("polyglot.js.allowHostAccess", true);
+    }
 
     private ScriptEvaluator() {}
 

core/src/main/java/com/netflix/conductor/core/execution/tasks/DoWhile.java

@@ -261,7 +261,7 @@ boolean evaluateCondition(WorkflowModel workflow, TaskModel task) throws ScriptE
         boolean result = false;
         if (condition != null) {
             LOGGER.debug("Condition: {} is being evaluated", condition);
-            // Evaluate the expression by using the Nashorn based script evaluator
+            // Evaluate the expression by using the GraalVM based script evaluator
             result = ScriptEvaluator.evalBool(condition, conditionInput);
         }
         return result;

dependencies.gradle

@@ -53,4 +53,5 @@ ext {
     revSpock = '1.3-groovy-2.5'
     revSpotifyCompletableFutures = '0.3.3'
     revTestContainer = '1.15.3'
+    revGraalVM = '22.3.3'
 }

docs/docs/reference-docs/do-while-task.md

@@ -30,10 +30,10 @@ Branching inside loopOver task is supported.
 
 ### Input Parameters:
 
-| name          | type       | description                                                                                                                                                                                                             |
-|---------------|------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| loopCondition | String     | Condition to be evaluated after every iteration. This is a Javascript expression, evaluated using the Nashorn engine. If an exception occurs during evaluation, the DO_WHILE task is set to FAILED_WITH_TERMINAL_ERROR. |
-| loopOver      | List[Task] | List of tasks that needs to be executed as long as the condition is true.                                                                                                                                               |
+| name          | type       | description                                                                                                                                                                                                                |
+|---------------|------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| loopCondition | String     | Condition to be evaluated after every iteration. This is a Javascript expression, evaluated using the GraalVM JS engine. If an exception occurs during evaluation, the DO_WHILE task is set to FAILED_WITH_TERMINAL_ERROR. |
+| loopOver      | List[Task] | List of tasks that needs to be executed as long as the condition is true.                                                                                                                                                  |
 
 ### Output Parameters
 

java-sdk/build.gradle

@@ -12,6 +12,9 @@ dependencies {
     implementation "javax.ws.rs:javax.ws.rs-api:${revJAXRS}"
     implementation "org.glassfish.jersey.core:jersey-common:${revJerseyCommon}"
 
+    implementation "org.graalvm.js:js:${revGraalVM}"
+    implementation "org.graalvm.js:js-scriptengine:${revGraalVM}"
+
     testImplementation "org.springframework:spring-web"
     testImplementation "org.spockframework:spock-core:${revSpock}"
     testImplementation "org.spockframework:spock-spring:${revSpock}"

java-sdk/src/main/java/com/netflix/conductor/sdk/workflow/def/tasks/Javascript.java

@@ -12,24 +12,21 @@
  */
 package com.netflix.conductor.sdk.workflow.def.tasks;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.HashMap;
-import java.util.Map;
+import com.google.common.base.Strings;
+import com.netflix.conductor.common.metadata.tasks.TaskType;
+import com.netflix.conductor.common.metadata.workflow.WorkflowTask;
+import com.netflix.conductor.sdk.workflow.def.ValidationError;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import javax.script.Bindings;
 import javax.script.ScriptEngine;
 import javax.script.ScriptEngineManager;
 import javax.script.ScriptException;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import com.netflix.conductor.common.metadata.tasks.TaskType;
-import com.netflix.conductor.common.metadata.workflow.WorkflowTask;
-import com.netflix.conductor.sdk.workflow.def.ValidationError;
-
-import com.google.common.base.Strings;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * JQ Transformation task See https://stedolan.github.io/jq/ for how to form the queries to parse
@@ -43,7 +40,9 @@ public class Javascript extends Task<Javascript> {
 
     private static final String EVALUATOR_TYPE_PARAMETER = "evaluatorType";
 
-    private static final String ENGINE = "nashorn";
+    private static final String ENGINE = "graal.js";
+
+    private static final String POLYGLOT_JS_ALLOW_HOST_ACCESS = "polyglot.js.allowHostAccess";
 
     /**
      * Javascript tasks are executed on the Conductor server without having to write worker code
@@ -105,6 +104,7 @@ public Javascript validate() {
             LOGGER.error("missing " + ENGINE + " engine.  Ensure you are running supported JVM");
             return this;
         }
+        scriptEngine.put(POLYGLOT_JS_ALLOW_HOST_ACCESS, true);
 
         try {
 
@@ -133,6 +133,7 @@ public Object test(Map<String, Object> input) {
             LOGGER.error("missing " + ENGINE + " engine.  Ensure you are running supported JVM");
             return this;
         }
+        scriptEngine.put(POLYGLOT_JS_ALLOW_HOST_ACCESS, true);
 
         try {