/**
* 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.hadoop.ant;
import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.LinkedList;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FsShell;
import org.apache.tools.ant.AntClassLoader;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;
import org.apache.hadoop.util.ToolRunner;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hdfs.HdfsConfiguration;
/**
* {@link org.apache.hadoop.fs.FsShell FsShell} wrapper for ant Task.
*/
@InterfaceAudience.Private
public class DfsTask extends Task {
/**
* Default sink for {@link java.lang.System.out System.out}
* and {@link java.lang.System.err System.err}.
*/
private static final OutputStream nullOut = new OutputStream() {
public void write(int b) { /* ignore */ }
public String toString() { return ""; }
};
private static final FsShell shell = new FsShell();
protected AntClassLoader confloader;
protected OutputStream out = nullOut;
protected OutputStream err = nullOut;
// set by ant
protected String cmd;
protected final LinkedList<String> argv = new LinkedList<String>();
protected String outprop;
protected String errprop;
protected boolean failonerror = true;
// saved ant context
private PrintStream antOut;
private PrintStream antErr;
/**
* Sets the command to run in {@link org.apache.hadoop.fs.FsShell FsShell}.
* @param cmd A valid command to FsShell, sans "-".
*/
public void setCmd(String cmd) {
this.cmd = "-" + cmd.trim();
}
/**
* Sets the argument list from a String of comma-separated values.
* @param args A String of comma-separated arguments to FsShell.
*/
public void setArgs(String args) {
for (String s : args.trim().split("\\s*,\\s*"))
argv.add(s);
}
/**
* Sets the property into which System.out will be written.
* @param outprop The name of the property into which System.out is written.
* If the property is defined before this task is executed, it will not be updated.
*/
public void setOut(String outprop) {
this.outprop = outprop;
out = new ByteArrayOutputStream();
if (outprop.equals(errprop))
err = out;
}
/**
* Sets the property into which System.err will be written. If this property
* has the same name as the property for System.out, the two will be interlaced.
* @param errprop The name of the property into which System.err is written.
* If the property is defined before this task is executed, it will not be updated.
*/
public void setErr(String errprop) {
this.errprop = errprop;
err = (errprop.equals(outprop)) ? err = out : new ByteArrayOutputStream();
}
/**
* Sets the path for the parent-last ClassLoader, intended to be used for
* {@link org.apache.hadoop.conf.Configuration Configuration}.
* @param confpath The path to search for resources, classes, etc. before
* parent ClassLoaders.
*/
public void setConf(String confpath) {
confloader = new AntClassLoader(getClass().getClassLoader(), false);
confloader.setProject(getProject());
if (null != confpath)
confloader.addPathElement(confpath);
}
/**
* Sets a property controlling whether or not a
* {@link org.apache.tools.ant.BuildException BuildException} will be thrown
* if the command returns a value less than zero or throws an exception.
* @param failonerror If true, throw a BuildException on error.
*/
public void setFailonerror(boolean failonerror) {
this.failonerror = failonerror;
}
/**
* Save the current values of System.out, System.err and configure output
* streams for FsShell.
*/
protected void pushContext() {
antOut = System.out;
antErr = System.err;
System.setOut(new PrintStream(out));
System.setErr(out == err ? System.out : new PrintStream(err));
}
/**
* Create the appropriate output properties with their respective output,
* restore System.out, System.err and release any resources from created
* ClassLoaders to aid garbage collection.
*/
protected void popContext() {
// write output to property, if applicable
if (outprop != null && !System.out.checkError())
getProject().setNewProperty(outprop, out.toString());
if (out != err && errprop != null && !System.err.checkError())
getProject().setNewProperty(errprop, err.toString());
System.setErr(antErr);
System.setOut(antOut);
confloader.cleanup();
confloader.setParent(null);
}
// in case DfsTask is overridden
protected int postCmd(int exit_code) {
if ("-test".equals(cmd) && exit_code != 0)
outprop = null;
return exit_code;
}
/**
* Invoke {@link org.apache.hadoop.fs.FsShell#doMain FsShell.doMain} after a
* few cursory checks of the configuration.
*/
public void execute() throws BuildException {
if (null == cmd)
throw new BuildException("Missing command (cmd) argument");
argv.add(0, cmd);
if (null == confloader) {
setConf(getProject().getProperty("hadoop.conf.dir"));
}
int exit_code = 0;
try {
pushContext();
Configuration conf = new HdfsConfiguration();
conf.setClassLoader(confloader);
exit_code = ToolRunner.run(conf, shell,
argv.toArray(new String[argv.size()]));
exit_code = postCmd(exit_code);
if (0 > exit_code) {
StringBuilder msg = new StringBuilder();
for (String s : argv)
msg.append(s + " ");
msg.append("failed: " + exit_code);
throw new Exception(msg.toString());
}
} catch (Exception e) {
if (failonerror)
throw new BuildException(e);
} finally {
popContext();
}
}
}