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/*
* 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.pig.scripting;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
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 java.util.regex.Pattern;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.impl.PigContext;
import org.apache.pig.tools.pigstats.PigStats;
/**
* Base class for various scripting implementations
*/
public abstract class ScriptEngine {
public static enum SupportedScriptLang {
// possibly jruby in the future
//jruby(new String[]{}, new String[]{}, "org.apache.pig.scripting.jruby.JrubyScriptEngine"),
jython(new String[]{"python", "jython"}, new String[]{"py"}, "org.apache.pig.scripting.jython.JythonScriptEngine"),
javascript(new String[]{}, new String[]{"js"}, "org.apache.pig.scripting.js.JsScriptEngine");
private static Set supportedScriptLangs;
static {
supportedScriptLangs = new HashSet();
for (SupportedScriptLang value : SupportedScriptLang.values()) {
supportedScriptLangs.add(value.name());
}
supportedScriptLangs = Collections.unmodifiableSet(supportedScriptLangs);
}
public static boolean contains(String supportedScriptLang) {
return supportedScriptLangs.contains(supportedScriptLang);
}
private String[] shebangs;
private String[] extensions;
/** Class implementing the engine. As a string as dependencies are possibly not on the class path*/
private String engineClassName;
private SupportedScriptLang(String[] shebangs, String[] extensions, String engineClassName) {
this.shebangs = shebangs;
this.extensions = extensions;
this.engineClassName = engineClassName;
}
/**
* If other discovery mechanisms come up they can also override accepts()
* @param file the path of the file
* @param firstLine The first line of the file (possibly containing #!...)
*/
public boolean accepts(String file, String firstLine) {
if( firstLine == null )
return false;
for (String shebang : shebangs) {
Pattern p = Pattern.compile("^#!.*/" + shebang + "\\s*$");
if (p.matcher(firstLine).matches()) {
return true;
}
}
for (String ext : extensions) {
if (file.endsWith("."+ext)) {
return true;
}
}
return false;
}
public String getEngineClassName() {
return engineClassName;
}
}
private static final Pattern shebangPattern = Pattern.compile("^#!.+");
private static boolean declaresShebang(String firstLine) {
if( firstLine == null )
return false;
return shebangPattern.matcher(firstLine).matches();
}
/**
* open a stream load a script locally or in the classpath
* @param scriptPath the path of the script
* @return a stream (it is the responsibility of the caller to close it)
* @throws IllegalStateException if we could not open a stream
*/
protected static InputStream getScriptAsStream(String scriptPath) {
InputStream is = null;
File file = new File(scriptPath);
if (file.exists()) {
try {
is = new FileInputStream(file);
} catch (FileNotFoundException e) {
throw new IllegalStateException("could not find existing file "+scriptPath, e);
}
} else {
if (file.isAbsolute()) {
is = ScriptEngine.class.getResourceAsStream(scriptPath);
} else {
is = ScriptEngine.class.getResourceAsStream("/" + scriptPath);
}
}
// TODO: discuss if we want to add logic here to load a script from HDFS
if (is == null) {
throw new IllegalStateException(
"Could not initialize interpreter (from file system or classpath) with " + scriptPath);
}
return is;
}
public static final String NAMESPACE_SEPARATOR = ".";
/**
* @param file the file to inspect
* @return the Supported Script Lang if this is a supported script language
* @throws IOException if there was an error reading the file or if the file defines explicitly an unknown #!
*/
public static SupportedScriptLang getSupportedScriptLang(String file) throws IOException {
BufferedReader br = new BufferedReader(new FileReader(file));
String firstLine;
try {
firstLine = br.readLine();
} finally {
br.close();
}
for (SupportedScriptLang supportedScriptLang : SupportedScriptLang.values()) {
if (supportedScriptLang.accepts(file, firstLine)) {
return supportedScriptLang;
}
}
if (declaresShebang(firstLine)) {
throw new IOException("Unsupported script type is specified: " + firstLine);
}
return null;
}
private Map> statsMap = new HashMap>();
/**
* Registers scripting language functions as Pig functions with given namespace
*
* @param path path of the script
* @param namespace namespace for the functions
* @param pigContext pigcontext to register functions to pig in the given namespace
* @throws IOException
*/
public abstract void registerFunctions(String path, String namespace,
PigContext pigContext) throws IOException;
/**
* Actually runs the script file. This method will be implemented by
* individual script engines.
*
* @param context {@link ScriptPigContext} to run the script file
* @param scriptFile the file
* @throws IOException
*/
protected abstract Map> main(
PigContext context, String scriptFile) throws IOException;
// Not needed as a general abstraction so far
// /**
// * Loads the script in the interpreter.
// * @param script
// */
// protected abstract void load(InputStream script) throws IOException;
/**
* Gets ScriptEngine classname or keyword for the scripting language
*/
protected abstract String getScriptingLang();
/**
* Returns a map from local variable names to their values
* @throws IOException
*/
protected abstract Map getParamsFromVariables()
throws IOException;
/**
* Figures out the jar location from the class
* @param clazz class in the jar file
* @return the jar file location, null if the class was not loaded from a jar
* @throws FileNotFoundException
*/
public static String getJarPath(Class clazz)
throws FileNotFoundException {
URL resource = clazz.getClassLoader().getResource(
clazz.getCanonicalName().replace(".", "/") + ".class");
if (resource.getProtocol().equals("jar")) {
return resource.getPath().substring(
resource.getPath().indexOf(':') + 1,
resource.getPath().indexOf('!'));
}
throw new FileNotFoundException("Jar for " + clazz.getName()
+ " class is not found");
}
/**
* Gets instance of the scriptEngine for the given scripting language
*
* @param scriptingLang ScriptEngine classname or keyword for the scriptingLang
* @return scriptengine for the given scripting language
* @throws IOException
*/
public static ScriptEngine getInstance(String scriptingLang)
throws IOException {
String scriptingEngine = scriptingLang;
try {
if (SupportedScriptLang.contains(scriptingLang)) {
SupportedScriptLang supportedScriptLang = SupportedScriptLang.valueOf(scriptingLang);
scriptingEngine = supportedScriptLang.getEngineClassName();
}
return (ScriptEngine) Class.forName(scriptingEngine).newInstance();
} catch (Exception e) {
throw new IOException("Could not load ScriptEngine: "
+ scriptingEngine + " for "+scriptingLang+" (Supported langs: "+SupportedScriptLang.supportedScriptLangs+") : " + e, e);
}
}
/**
* Runs a script file.
* @param pigContext {@link PigContext} to run the script file
* @param scriptFile the file
* @return a collection of {@link PigStats} objects. One for each runtime
* instance of {@link Pig} in the script. For named pipelines, the
* map key is the name of the pipeline. For unnamed pipeline, the map key
* is the script id associated with the instance.
* @throws ExecException
* @throws IOException
*/
public Map> run(PigContext pigContext, String scriptFile)
throws ExecException, IOException {
ScriptPigContext.set(pigContext, this);
return main(pigContext, scriptFile);
}
/**
* Gets the collection of {@link PigStats} after the script is run.
*/
protected Map> getPigStatsMap() {
return statsMap;
}
void setPigStats(String key, PigStats stats) {
List lst = statsMap.get(key);
if (lst == null) {
lst = new ArrayList();
statsMap.put(key, lst);
}
lst.add(stats);
}
void setPigStats(String key, List stats) {
statsMap.put(key, stats);
}
}
