Github user markap14 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/185#discussion_r50850518
--- Diff:
nifi-nar-bundles/nifi-scripting-bundle/nifi-scripting-processors/src/main/java/org/apache/nifi/processors/script/ExecuteScript.java
---
@@ -0,0 +1,585 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.nifi.processors.script;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.nifi.annotation.behavior.DynamicProperty;
+import org.apache.nifi.components.AllowableValue;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.Validator;
+import org.apache.nifi.expression.AttributeExpression;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.logging.ProcessorLog;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.ProcessorInitializationContext;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.util.StandardValidators;
+import org.apache.nifi.stream.io.ByteArrayInputStream;
+import org.apache.nifi.util.StopWatch;
+import org.apache.nifi.util.file.monitor.LastModifiedMonitor;
+import org.apache.nifi.util.file.monitor.SynchronousFileWatcher;
+
+import javax.script.Bindings;
+import javax.script.Compilable;
+import javax.script.CompiledScript;
+import javax.script.ScriptContext;
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineFactory;
+import javax.script.ScriptEngineManager;
+import javax.script.ScriptException;
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.ServiceLoader;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+@Tags({"script", "execute", "groovy", "python", "jython", "jruby", "ruby",
"javascript", "js", "lua", "luaj", "scala"})
+@CapabilityDescription("Executes a script given the flow file and a
process session. The script is responsible for "
+ + "handling the incoming flow file (transfer to SUCCESS or remove,
e.g.) as well as any flow files created by "
+ + "the script. If the handling is incomplete or incorrect, the
session will be rolled back.")
+@DynamicProperty(
+ name = "A script engine property to update",
+ value = "The value to set it to",
+ supportsExpressionLanguage = true,
+ description = "Updates a script engine property specified by the
Dynamic Property's key with the value "
+ + "specified by the Dynamic Property's value")
+public class ExecuteScript extends AbstractProcessor {
+
+ public static final Relationship REL_SUCCESS = new
Relationship.Builder()
+ .name("success")
+ .description("FlowFiles that were successfully processed")
+ .build();
+
+ public static final Relationship REL_FAILURE = new
Relationship.Builder()
+ .name("failure")
+ .description("FlowFiles that were failed to process")
+ .build();
+
+ public static PropertyDescriptor SCRIPT_ENGINE;
+
+ public static final PropertyDescriptor SCRIPT_FILE = new
PropertyDescriptor.Builder()
+ .name("Script File")
+ .required(false)
+ .description("Path to script file to execute. Use either file
or body not both")
+ .addValidator(new StandardValidators.FileExistsValidator(true))
+ .expressionLanguageSupported(true)
+ .build();
+
+ public static final PropertyDescriptor SCRIPT_BODY = new
PropertyDescriptor.Builder()
+ .name("Script Body")
+ .required(false)
+ .description("Body to script to execute. Use either file or
body not both")
+ .addValidator(Validator.VALID)
+ .expressionLanguageSupported(true)
+ .build();
+
+ public static final PropertyDescriptor SCRIPT_ARGS = new
PropertyDescriptor.Builder()
+ .name("Arguments")
+ .required(false)
+ .description("Arguments to pass to scripting engine")
+ .addValidator(Validator.VALID)
+ .expressionLanguageSupported(true)
+ .defaultValue("")
+ .build();
+
+ public static final PropertyDescriptor MODULES = new
PropertyDescriptor.Builder()
+ .name("Module Directory")
+ .description("Path to a directory which contains modules
required by the script script.")
+ .required(false)
+ .expressionLanguageSupported(true)
+ .addValidator(new
StandardValidators.DirectoryExistsValidator(true, false))
+ .build();
+
+ // A map from engine name to a custom configurator for that engine
+ private final Map<String, ScriptEngineConfigurator>
scriptEngineConfiguratorMap = new ConcurrentHashMap<>();
+
+ private final AtomicBoolean isInitialized = new AtomicBoolean(false);
+ private final Lock lock = new ReentrantLock();
+ private SynchronousFileWatcher scriptWatcher;
+
+ private Map<String, ScriptEngineFactory> scriptEngineFactoryMap;
+ private ScriptEngine scriptEngine;
+ private String scriptEngineName;
+ private String scriptPath;
+ private String scriptBody;
+ private String modulePath;
+ private CompiledScript compiledScript;
+ private final AtomicBoolean scriptNeedsReload = new
AtomicBoolean(true);
+ private ScheduledExecutorService reloadService;
+ private List<PropertyDescriptor> descriptors;
+
+
+ /**
+ * Initializes this processor. A reload service is defined and
scheduled, for the purpose of watching for
+ * script file changes, which indicates a reload is necessary
+ *
+ * @param context in which to perform initialization
+ */
+ @Override
+ protected void init(final ProcessorInitializationContext context) {
+ }
+
+
+ protected void createResources() {
+
+ // Set up script file reloader service. This checks to see if the
script file has changed, and if so, marks
+ // the script file as needing a reload before evaluation
+ if (reloadService == null) {
+ reloadService = Executors.newScheduledThreadPool(1);
+
+ // monitor the script if configured for changes
+ reloadService.scheduleWithFixedDelay(new Runnable() {
+ @Override
+ public void run() {
+ try {
+ final boolean hasLock = lock.tryLock();
+
+ // if a property is changing we don't need to
reload this iteration
+ if (hasLock) {
+ try {
+ if (scriptWatcher != null &&
scriptWatcher.checkAndReset()) {
+ if (isFile(scriptPath)) {
+ scriptNeedsReload.set(true);
+ }
+ }
+ } finally {
+ lock.unlock();
+ }
+ }
+ } catch (final Throwable t) {
+ final ProcessorLog logger = getLogger();
+ final String message = "Unable to reload
configured script Processor: " + t;
+
+ logger.error(message);
+ if (logger.isDebugEnabled()) {
+ logger.error(message, t);
+ }
+ }
+ }
+ }, 30, 10, TimeUnit.SECONDS);
+ }
+
+ descriptors = new ArrayList<>();
+
+ // The following is required for JRuby, should be transparent to
everything else.
+ // Note this is not done in a ScriptEngineConfigurator, as it is
too early in the lifecycle. The
+ // setting must be there before the factories/engines are loaded.
+ System.setProperty("org.jruby.embed.localvariable.behavior",
"persistent");
+
+ // Create list of available engines
+ ScriptEngineManager scriptEngineManager = new
ScriptEngineManager();
+ List<ScriptEngineFactory> scriptEngineFactories =
scriptEngineManager.getEngineFactories();
+ if (scriptEngineFactories != null) {
+ scriptEngineFactoryMap = new
HashMap<>(scriptEngineFactories.size());
+ List<AllowableValue> engineList = new LinkedList<>();
+ for (ScriptEngineFactory factory : scriptEngineFactories) {
+ engineList.add(new
AllowableValue(factory.getLanguageName()));
+ scriptEngineFactoryMap.put(factory.getLanguageName(),
factory);
+ }
+
+ // Sort the list by name so the list always looks the same.
+ Collections.sort(engineList, new Comparator<AllowableValue>() {
+ @Override
+ public int compare(AllowableValue o1, AllowableValue o2) {
+ if (o1 == null) {
+ return o2 == null ? 0 : 1;
+ }
+ if (o2 == null) {
+ return -1;
+ }
+ return o1.getValue().compareTo(o2.getValue());
+ }
+ });
+
+ AllowableValue[] engines = engineList.toArray(new
AllowableValue[engineList.size()]);
+
+ SCRIPT_ENGINE = new PropertyDescriptor.Builder()
+ .name("Script Engine")
+ .required(true)
+ .description("The engine to execute scripts")
+ .allowableValues(engines)
+ .defaultValue(engines[0].getValue())
+ .required(true)
+ .expressionLanguageSupported(false)
+ .build();
+ descriptors.add(SCRIPT_ENGINE);
+ }
+
+ descriptors.add(SCRIPT_FILE);
+ descriptors.add(SCRIPT_BODY);
+ descriptors.add(SCRIPT_ARGS);
+ descriptors.add(MODULES);
+
+ isInitialized.set(true);
+ }
+
+ /**
+ * Returns the valid relationships for this processor.
+ *
+ * @return a Set of Relationships supported by this processor
+ */
+ @Override
+ public Set<Relationship> getRelationships() {
+ final Set<Relationship> relationships = new HashSet<>();
+ relationships.add(REL_SUCCESS);
+ relationships.add(REL_FAILURE);
+ return Collections.unmodifiableSet(relationships);
+ }
+
+ /**
+ * Returns a list of property descriptors supported by this processor.
The list always includes properties such as
+ * script engine name, script file name, script body name, script
arguments, and an external module path. If the
+ * scripted processor also defines supported properties, those are
added to the list as well.
+ *
+ * @return a List of PropertyDescriptor objects supported by this
processor
+ */
+ @Override
+ protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+ synchronized (isInitialized) {
+ if (!isInitialized.get()) {
+ createResources();
+ }
+ }
+
+ return Collections.unmodifiableList(descriptors);
+ }
+
+ /**
+ * Returns a PropertyDescriptor for the given name. This is for the
user to be able to define their own properties
+ * which will be available as variables in the script
+ *
+ * @param propertyDescriptorName used to lookup if any property
descriptors exist for that name
+ * @return a PropertyDescriptor object corresponding to the specified
dynamic property name
+ */
+ @Override
+ protected PropertyDescriptor
getSupportedDynamicPropertyDescriptor(final String propertyDescriptorName) {
+ return new PropertyDescriptor.Builder()
+ .name(propertyDescriptorName)
+ .required(false)
+
.addValidator(StandardValidators.createAttributeExpressionLanguageValidator(AttributeExpression.ResultType.STRING,
true))
+
.addValidator(StandardValidators.ATTRIBUTE_KEY_PROPERTY_NAME_VALIDATOR)
+ .expressionLanguageSupported(true)
+ .dynamic(true)
+ .build();
+ }
+
+ /**
+ * Determines whether the given path refers to a valid file
+ *
+ * @param path a path to a file
+ * @return true if the path refers to a valid file, false otherwise
+ */
+ private boolean isFile(final String path) {
+ return path != null && Files.isRegularFile(Paths.get(path));
+ }
+
+ /**
+ * Performs setup operations when the processor is scheduled to run.
This includes evaluating the processor's
+ * properties, as well as reloading the script (from file or the
"Script Body" property)
+ *
+ * @param context the context in which to perform the setup operations
+ */
+ @OnScheduled
+ public void setup(final ProcessContext context) {
+ scriptEngineName = context.getProperty(SCRIPT_ENGINE).getValue();
+ scriptPath = context.getProperty(SCRIPT_FILE).getValue();
+ scriptBody = context.getProperty(SCRIPT_BODY).getValue();
+ modulePath = context.getProperty(MODULES).getValue();
+ setupEngine();
+ }
+
+ /**
+ * Configures the specified script engine. First, the engine is loaded
and instantiated using the JSR-223
+ * javax.script APIs. Then, if any script configurators have been
defined for this engine, their init() method is
+ * called, and the configurator is saved for future calls.
+ *
+ * @see org.apache.nifi.processors.script.ScriptEngineConfigurator
+ */
+ private void setupEngine() {
+ ClassLoader originalContextClassLoader =
Thread.currentThread().getContextClassLoader();
+ try {
+ ProcessorLog log = getLogger();
+
+ // Need the right classloader when the engine is created. This
ensures the NAR's execution class loader
+ // (plus the module path) becomes the parent for the script
engine
+ ClassLoader scriptEngineModuleClassLoader =
createScriptEngineModuleClassLoader(modulePath);
+ if (scriptEngineModuleClassLoader != null) {
+
Thread.currentThread().setContextClassLoader(scriptEngineModuleClassLoader);
+ }
+ scriptEngine = getScriptEngine();
+ ServiceLoader<ScriptEngineConfigurator>
configuratorServiceLoader =
+ ServiceLoader.load(ScriptEngineConfigurator.class);
+ for (ScriptEngineConfigurator configurator :
configuratorServiceLoader) {
+ String configuratorScriptEngineName =
configurator.getScriptEngineName();
+ try {
+ if (configuratorScriptEngineName != null
+ &&
configuratorScriptEngineName.equals(scriptEngineName)) {
+ configurator.init(scriptEngine, modulePath);
+
scriptEngineConfiguratorMap.put(configurator.getScriptEngineName(),
configurator);
+ }
+ } catch (ScriptException se) {
+ log.error("Error initializing script engine
configurator {}",
+ new Object[]{configuratorScriptEngineName});
+ if (log.isDebugEnabled()) {
+ log.error("Error initializing script engine
configurator", se);
+ }
+ }
+ }
+ } finally {
+ // Restore original context class loader
+
Thread.currentThread().setContextClassLoader(originalContextClassLoader);
+ }
+ }
+
+
+ /**
+ * Provides a ScriptEngine corresponding to the currently selected
script engine name.
+ * ScriptEngineManager.getEngineByName() doesn't use find
ScriptEngineFactory.getName(), which
+ * is what we used to populate the list. So just search the list of
factories until a match is
+ * found, then create and return a script engine.
+ *
+ * @return a Script Engine corresponding to the currently specified
name, or null if none is found.
+ */
+ private ScriptEngine getScriptEngine() {
+ //
+ ScriptEngineFactory factory =
scriptEngineFactoryMap.get(scriptEngineName);
+ if (factory == null) {
+ return null;
+ }
+ return factory.getScriptEngine();
+ }
+
+ /**
+ * Handles changes to this processor's properties. If changes are made
to script- or engine-related properties,
+ * the script will be reloaded.
+ *
+ * @param descriptor of the modified property
+ * @param oldValue non-null property value (previous)
+ * @param newValue the new property value or if null indicates the
property
+ */
+ @Override
+ public void onPropertyModified(final PropertyDescriptor descriptor,
final String oldValue, final String newValue) {
+ final ProcessorLog logger = getLogger();
+
+ if (SCRIPT_FILE.equals(descriptor)
+ || SCRIPT_BODY.equals(descriptor)
+ || MODULES.equals(descriptor)
+ || SCRIPT_ENGINE.equals(descriptor)) {
+ lock.lock();
+ try {
+ // if the script is changing we'll want to reload the
instance
+ if (SCRIPT_FILE.equals(descriptor)) {
+ if (isFile(newValue)) {
+ scriptNeedsReload.set(true);
+
+ // we're attempted to load the script so we need
to watch for updates
+ scriptWatcher = new
SynchronousFileWatcher(Paths.get(newValue), new LastModifiedMonitor());
+ } else {
+ // the doesn't appear to be a file
+ scriptWatcher = null;
+ }
+
+ // always want to record the configured value
+ scriptPath = newValue;
+ } else if (SCRIPT_BODY.equals(descriptor)) {
+
+ scriptNeedsReload.set(true);
+ scriptBody = newValue;
+
+ } else if (MODULES.equals(descriptor)) {
+
+ // temporarily set new value (will be restored to
oldValue if something goes wrong)
+ modulePath = newValue;
+ try {
+ setupEngine();
+
+ // we only want to reload during a module change
if the script is already loaded
+ if (isFile(scriptPath)) {
+ scriptNeedsReload.set(true);
+ }
+ } catch (Throwable t) {
+ modulePath = oldValue;
+ logger.error(t.getLocalizedMessage(), t);
+ }
+
+ } else if (SCRIPT_ENGINE.equals(descriptor)) {
+ // The script engine has changed, so we need to set up
a new instance for the selected
+ // engine name
+ scriptEngineName = newValue;
+ setupEngine();
+ }
+ } finally {
+ lock.unlock();
+ }
+ }
+ }
+
+ /**
+ * Creates a classloader to be used by the selected script engine and
the provided script file. This
+ * classloader has the ExecuteScript's classloader as a parent (versus
the current thread's context
+ * classloader) and also adds the specified module directory to the
classpath. This enables scripts
+ * to use other scripts, modules, etc. without having to build them
into the ExecuteScript NAR.
+ * If the parameter is null or empty, ExecuteScript's classloader is
returned
+ *
+ * @param modulePath The path to a directory containing modules to be
used by the script(s)
+ */
+ private ClassLoader createScriptEngineModuleClassLoader(String
modulePath) {
+ URLClassLoader newModuleClassLoader = null;
+ if (StringUtils.isEmpty(modulePath)) {
+ return ExecuteScript.class.getClassLoader();
+ }
+ try {
+ newModuleClassLoader =
+ new URLClassLoader(
+ new URL[]{new
File(modulePath).toURI().toURL()}, ExecuteScript.class.getClassLoader());
+ } catch (MalformedURLException mue) {
+ getLogger().error("Couldn't find modules directory at " +
modulePath, mue);
+ }
+ return newModuleClassLoader;
+ }
+
+ /**
+ * Evaluates the given script body (or file) using the current
session, context, and flowfile. The script
+ * evaluation expects a FlowFile to be returned, in which case it will
route the FlowFile to success. If a script
+ * error occurs, the original FlowFile will be routed to failure. If
the script succeeds but does not return a
+ * FlowFile, the original FlowFile will be routed to no-flowfile
+ *
+ * @param context the current process context
+ * @param session the current process session
+ * @throws ProcessException if any error occurs during script
evaluation
+ */
+ @Override
+ public void onTrigger(ProcessContext context, ProcessSession session)
throws ProcessException {
+ synchronized (isInitialized) {
+ if (!isInitialized.get()) {
+ createResources();
+ }
+ }
+ ProcessorLog log = getLogger();
+ FlowFile flowFile = session.get();
+ if (flowFile == null) {
+ return;
+ }
+
+ String[] args =
context.getProperty(SCRIPT_ARGS).evaluateAttributeExpressions().getValue().split(";");
--- End diff --
should probably be calling evaluateAttributeExpressions(flowFile) here
instead of just evaluateAttributeExpressions() - as-is, it will not evaluate
FlowFile Attributes.
Also, rather than splitting by semi-colon, consider splitting by spaces and
allow double-quotes to be used to encapsulate spaces. This is a much more
natural way of specifying arguments, as this is how it works on command-line.
Code exists already in the standard-processors module for this -
org.apache.nifi.processors.standard.util.ArgumentUtils - perhaps that could be
pulled out into the processor-utils module?
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