feat(JS): evaluate JS on GraalVM

README.md

@@ -6,6 +6,12 @@
 
 [![Compatible with: Camunda Platform 8](https://img.shields.io/badge/Compatible%20with-Camunda%20Platform%208-0072Ce)](https://github.com/camunda-community-hub/community/blob/main/extension-lifecycle.md#compatiblilty)
 
+Available script languages:
+* [javascript](https://www.graalvm.org/) (GraalVM JS)
+* [groovy](http://groovy-lang.org/)
+* [feel](https://github.com/camunda/feel-scala)
+
+_This is a community project meant for playing around with Zeebe. It is not officially supported by the Zeebe Team (i.e. no gurantees). Everybody is invited to contribute!_
 A Zeebe worker to evaluate scripts (i.e. script tasks). Scripts are useful for prototyping, to do (simple) calculations, or creating/modifying variables.
 
 ## Usage

pom.xml

@@ -1,4 +1,6 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 
     <modelVersion>4.0.0</modelVersion>
     <name>Zeebe Script Worker</name>
@@ -29,6 +31,7 @@
 
         <maven.compiler.source>${java.version}</maven.compiler.source>
         <maven.compiler.target>${java.version}</maven.compiler.target>
+		<version.graalvm>1.0.0-rc9</version.graalvm>
 
         <!-- release parent settings -->
         <nexus.snapshot.repository>https://artifacts.camunda.com/artifactory/zeebe-io-snapshots/
@@ -114,6 +117,18 @@
             <version>${version.feel}</version>
         </dependency>
 
+		<dependency>
+			<groupId>org.graalvm.sdk</groupId>
+			<artifactId>graal-sdk</artifactId>
+			<version>${version.graalvm}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.graalvm.js</groupId>
+			<artifactId>js</artifactId>
+			<version>${version.graalvm}</version>
+		</dependency>
+
         <dependency>
             <groupId>org.jetbrains.kotlin</groupId>
             <artifactId>kotlin-scripting-jsr223</artifactId>
@@ -241,9 +256,9 @@
                             </gpgArguments>
                         </configuration>
                     </plugin>
-                </plugins>
-            </build>
-        </profile>
+		</plugins>
+	</build>
+</profile>
     </profiles>
 
     <repositories>

src/main/java/io/zeebe/script/GraalEvaluator.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright © 2017 camunda services GmbH ([email protected])
+ *
+ * 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.zeebe.script;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.LongStream;
+import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.PolyglotException;
+import org.graalvm.polyglot.Value;
+
+public class GraalEvaluator {
+
+  private static final String LANGUAGE_ID_JS = "js";
+
+  public static final List<String> SUPPORTED_LANGUAGES = Arrays.asList("js", "javascript");
+
+  public Object evaluate(String language, String script, Map<String, Object> variables)
+      throws PolyglotException, IllegalArgumentException, IllegalStateException {
+
+    // this throws a FileSystemNotFoundException
+    final Context context = Context.create(LANGUAGE_ID_JS);
+
+    final Value bindings = context.getBindings(LANGUAGE_ID_JS);
+    variables.forEach((key, value) -> bindings.putMember(key, value));
+
+    final Value result = context.eval(LANGUAGE_ID_JS, script);
+
+    return mapValueToObject(result);
+  }
+
+  private Object mapValueToObject(final Value value) {
+    if (value.isNull()) {
+      return null;
+
+    } else if (value.isBoolean()) {
+      return value.asBoolean();
+
+    } else if (value.isString()) {
+      return value.asString();
+
+    } else if (value.isNumber()) {
+      if (value.fitsInInt()) {
+        return value.asInt();
+      } else if (value.fitsInLong()) {
+        return value.asLong();
+      } else if (value.fitsInFloat()) {
+        return value.asFloat();
+      } else {
+        return value.asDouble();
+      }
+
+    } else if (value.hasArrayElements()) {
+      return LongStream.range(0, value.getArraySize())
+          .mapToObj(i -> mapValueToObject(value.getArrayElement(i)))
+          .collect(Collectors.toList());
+
+    } else if (value.hasMembers()) {
+      return value
+          .getMemberKeys()
+          .stream()
+          .collect(
+              Collectors.toMap(Function.identity(), key -> mapValueToObject(value.getMember(key))));
+    }
+
+    return "unknown: " + value.toString();
+  }
+}

src/main/java/io/zeebe/script/ScriptEngineEvaluator.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright © 2017 camunda services GmbH ([email protected])
+ *
+ * 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.zeebe.script;
+
+import java.util.HashMap;
+import java.util.Map;
+import javax.script.Bindings;
+import javax.script.ScriptContext;
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineManager;
+import javax.script.ScriptException;
+
+public class ScriptEngineEvaluator {
+
+  private final ScriptEngineManager scriptEngineManager = new ScriptEngineManager();
+
+  private final Map<String, ScriptEngine> cachedScriptEngines = new HashMap<>();
+
+  public Object evaluate(String language, String script, Map<String, Object> variables)
+      throws ScriptException {
+
+    final ScriptEngine scriptEngine =
+        cachedScriptEngines.computeIfAbsent(language, scriptEngineManager::getEngineByName);
+
+    if (scriptEngine == null) {
+      final String msg = String.format("No script engine found with name '%s'", language);
+      throw new RuntimeException(msg);
+    }
+
+    final ScriptContext context = scriptEngine.getContext();
+    final Bindings bindings = context.getBindings(ScriptContext.ENGINE_SCOPE);
+    bindings.putAll(variables);
+
+    return scriptEngine.eval(script, context);
+  }
+}

src/main/java/io/zeebe/script/ScriptEvaluator.java

@@ -22,7 +22,10 @@
 import javax.script.ScriptException;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Map;
+import org.springframework.stereotype.Component;
 
+@Component
 public class ScriptEvaluator {
 
   private final ScriptEngineManager scriptEngineManager = new ScriptEngineManager();
@@ -31,6 +34,8 @@ public class ScriptEvaluator {
       Map.of("mustache", new MustacheEvaluator());
 
   private final Map<String, ScriptEngine> cachedScriptEngines = new HashMap<>();
+  private final GraalEvaluator graalEvaluator = new GraalEvaluator();
+  private final ScriptEngineEvaluator scriptEngineEvaluator = new ScriptEngineEvaluator();
 
   public Object evaluate(String language, String script, Map<String, Object> variables) {
 
@@ -55,7 +60,14 @@ private Object evalWithScriptEngine(
     try {
       return eval(scriptEngine, script, variables);
 
-    } catch (ScriptException e) {
+      if (GraalEvaluator.SUPPORTED_LANGUAGES.contains(language)) {
+        return graalEvaluator.evaluate(language, script, variables);
+
+      } else {
+        return scriptEngineEvaluator.evaluate(language, script, variables);
+      }
+
+    } catch (Exception e) {
       final String msg = String.format("Failed to evaluate script '%s' (%s)", script, language);
       throw new RuntimeException(msg, e);
     }

src/test/java/io/zeebe/script/EvaluationJavaScriptTest.java

@@ -19,8 +19,8 @@
 import static org.assertj.core.api.Assertions.entry;
 
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
-
 import org.junit.jupiter.api.Test;
 
 public class EvaluationJavaScriptTest {
@@ -33,7 +33,7 @@ public void shouldReturnNumber() {
     final Object result =
         scriptEvaluator.evaluate("javascript", "x * 2", Collections.singletonMap("x", 2));
 
-    assertThat(result).isEqualTo(4.0);
+    assertThat(result).isEqualTo(4);
   }
 
   @Test
@@ -67,10 +67,19 @@ public void shouldReturnInlineObject() {
     final Map<String, Object> result =
         (Map<String, Object>)
             scriptEvaluator.evaluate(
-                "javascript",
-                "result = {'foo':foo,'bar':'bar'}",
-                Collections.singletonMap("foo", 123));
+                "javascript", "({'foo':foo,'bar':'bar'})", Collections.singletonMap("foo", 123));
 
     assertThat(result).hasSize(2).contains(entry("bar", "bar"), entry("foo", 123));
   }
+
+  @Test
+  public void shouldReturnArray() {
+
+    @SuppressWarnings("unchecked")
+    final List<String> result =
+        (List<String>)
+            scriptEvaluator.evaluate("javascript", "['foo','bar']", Collections.emptyMap());
+
+    assertThat(result).hasSize(2).contains("foo", "bar");
+  }
 }

src/test/java/io/zeebe/script/ScriptEvaluatorTest.java

@@ -89,7 +89,7 @@ public void shouldEvaluateKotlinWithVariables() {
   @Test
   public void shouldThrowExceptionIfScriptEngineNotFound() {
     assertThatThrownBy(() -> scriptEvaluator.evaluate("foobar", "", Collections.emptyMap()))
-        .hasMessage("No script engine found with name 'foobar'");
+        .hasCause(new RuntimeException("No script engine found with name 'foobar'"));
   }
 
   @Test