AbstractJettyMojo

//
//  ========================================================================
//  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.maven.plugin;


import java.io.File;
import java.io.FileInputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.Set;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.project.MavenProject;
import org.codehaus.plexus.util.FileUtils;
import org.eclipse.jetty.security.LoginService;
import org.eclipse.jetty.server.Connector;
import org.eclipse.jetty.server.RequestLog;
import org.eclipse.jetty.server.ShutdownMonitor;
import org.eclipse.jetty.server.handler.ContextHandler;
import org.eclipse.jetty.server.handler.ContextHandlerCollection;
import org.eclipse.jetty.server.handler.HandlerCollection;
import org.eclipse.jetty.util.Scanner;
import org.eclipse.jetty.util.resource.Resource;
import org.eclipse.jetty.xml.XmlConfiguration;


/**
 * AbstractJettyMojo
 *
 * Common base class for most jetty mojos.
 *
 *
 */
public abstract class AbstractJettyMojo extends AbstractMojo
{
    /**
     *
     */
    public String PORT_SYSPROPERTY = "jetty.port";


    /**
     * Whether or not to include dependencies on the plugin's classpath with &lt;scope&gt;provided&lt;/scope&gt;
     * Use WITH CAUTION as you may wind up with duplicate jars/classes.
     *
     * @since jetty-7.5.2
     * @parameter  default-value="false"
     */
    protected boolean useProvidedScope;


    /**
     * List of goals that are NOT to be used
     *
     * @since jetty-7.5.2
     * @parameter
     */
    protected String[] excludedGoals;


    /**
     * List of other contexts to set up. Consider using instead
     * the &lt;jettyXml&gt; element to specify external jetty xml config file.
     * Optional.
     *
     *
     * @parameter
     */
    protected ContextHandler[] contextHandlers;


    /**
     * List of security realms to set up. Consider using instead
     * the &lt;jettyXml&gt; element to specify external jetty xml config file.
     * Optional.
     *
     *
     * @parameter
     */
    protected LoginService[] loginServices;


    /**
     * A RequestLog implementation to use for the webapp at runtime.
     * Consider using instead the &lt;jettyXml&gt; element to specify external jetty xml config file.
     * Optional.
     *
     *
     * @parameter
     */
    protected RequestLog requestLog;


    /**
     * An instance of org.eclipse.jetty.webapp.WebAppContext that represents the webapp.
     * Use any of its setters to configure the webapp. This is the preferred and most
     * flexible method of configuration, rather than using the (deprecated) individual
     * parameters like "tmpDirectory", "contextPath" etc.
     *
     * @parameter alias="webAppConfig"
     */
    protected JettyWebAppContext webApp;


    /**
     * The interval in seconds to scan the webapp for changes
     * and restart the context if necessary. Ignored if reload
     * is enabled. Disabled by default.
     *
     * @parameter expression="${jetty.scanIntervalSeconds}" default-value="0"
     * @required
     */
    protected int scanIntervalSeconds;


    /**
     * reload can be set to either 'automatic' or 'manual'
     *
     * if 'manual' then the context can be reloaded by a linefeed in the console
     * if 'automatic' then traditional reloading on changed files is enabled.
     *
     * @parameter expression="${jetty.reload}" default-value="automatic"
     */
    protected String reload;


    /**
     * File containing system properties to be set before execution
     *
     * Note that these properties will NOT override System properties
     * that have been set on the command line, by the JVM, or directly
     * in the POM via systemProperties. Optional.
     *
     * @parameter expression="${jetty.systemPropertiesFile}"
     */
    protected File systemPropertiesFile;


    /**
     * System properties to set before execution.
     * Note that these properties will NOT override System properties
     * that have been set on the command line or by the JVM. They WILL
     * override System properties that have been set via systemPropertiesFile.
     * Optional.
     * @parameter
     */
    protected SystemProperties systemProperties;


    /**
     * Comma separated list of a jetty xml configuration files whose contents
     * will be applied before any plugin configuration. Optional.
     *
     *
     * @parameter alias="jettyConfig"
     */
    protected String jettyXml;


    /**
     * Port to listen to stop jetty on executing -DSTOP.PORT=&lt;stopPort&gt;
     * -DSTOP.KEY=&lt;stopKey&gt; -jar start.jar --stop
     *
     * @parameter
     */
    protected int stopPort;


    /**
     * Key to provide when stopping jetty on executing java -DSTOP.KEY=&lt;stopKey&gt;
     * -DSTOP.PORT=&lt;stopPort&gt; -jar start.jar --stop
     *
     * @parameter
     */
    protected String stopKey;


    /**
     * <p>
     * Determines whether or not the server blocks when started. The default
     * behavior (daemon = false) will cause the server to pause other processes
     * while it continues to handle web requests. This is useful when starting the
     * server with the intent to work with it interactively.
     * </p><p>
     * Often, it is desirable to let the server start and continue running subsequent
     * processes in an automated build environment. This can be facilitated by setting
     * daemon to true.
     * </p>
     *
     * @parameter expression="${jetty.daemon}" default-value="false"
     */
    protected boolean daemon;


    /**
     * Skip this mojo execution.
     *
     * @parameter expression="${jetty.skip}" default-value="false"
     */
    protected boolean skip;


    /**
     * Location of a context xml configuration file whose contents
     * will be applied to the webapp AFTER anything in &lt;webApp&gt;.Optional.
     *
     *
     * @parameter alias="webAppXml"
     */
    protected String contextXml;


    /**
     * The maven project.
     *
     * @parameter expression="${project}"
     * @readonly
     */
    protected MavenProject project;


    /**
     * The artifacts for the project.
     *
     * @parameter expression="${project.artifacts}"
     * @readonly
     */
    protected Set projectArtifacts;


    /**
     * @parameter expression="${mojoExecution}"
     * @readonly
     */
    protected org.apache.maven.plugin.MojoExecution execution;


    /**
     * The artifacts for the plugin itself.
     *
     * @parameter expression="${plugin.artifacts}"
     * @readonly
     */
    protected List pluginArtifacts;


    /**
     * A ServerConnector to use.
     *
     * @parameter
     */
    protected MavenServerConnector httpConnector;


    /**
     * A wrapper for the Server object
     */
    protected JettyServer server = JettyServer.getInstance();


    /**
     * A scanner to check for changes to the webapp
     */
    protected Scanner scanner;


    /**
     *  List of files and directories to scan
     */
    protected ArrayList<File> scanList;


    /**
     * List of Listeners for the scanner
     */
    protected ArrayList<Scanner.BulkListener> scannerListeners;


    /**
     * A scanner to check ENTER hits on the console
     */
    protected Thread consoleScanner;


    public abstract void restartWebApp(boolean reconfigureScanner) throws Exception;


    public abstract void checkPomConfiguration() throws MojoExecutionException;


    public abstract void configureScanner () throws MojoExecutionException;


    /**
     * @see org.apache.maven.plugin.Mojo#execute()
     */
    public void execute() throws MojoExecutionException, MojoFailureException
    {
        getLog().info("Configuring Jetty for project: " + this.project.getName());
        if (skip)
        {
            getLog().info("Skipping Jetty start: jetty.skip==true");
            return;
        }

        if (isExcluded(execution.getMojoDescriptor().getGoal()))
        {
            getLog().info("The goal \""+execution.getMojoDescriptor().getFullGoalName()+
                          "\" has been made unavailable for this web application by an <excludedGoal> configuration.");
            return;
        }

        configurePluginClasspath();
        PluginLog.setLog(getLog());
        checkPomConfiguration();
        startJetty();
    }


    /**
     * @throws MojoExecutionException
     */
    public void configurePluginClasspath() throws MojoExecutionException
    {
        //if we are configured to include the provided dependencies on the plugin's classpath
        //(which mimics being on jetty's classpath vs being on the webapp's classpath), we first
        //try and filter out ones that will clash with jars that are plugin dependencies, then
        //create a new classloader that we setup in the parent chain.
        if (useProvidedScope)
        {
            try
            {
                List<URL> provided = new ArrayList<URL>();
                URL[] urls = null;

                for ( Iterator<Artifact> iter = projectArtifacts.iterator(); iter.hasNext(); )
                {
                    Artifact artifact = iter.next();
                    if (Artifact.SCOPE_PROVIDED.equals(artifact.getScope()) && !isPluginArtifact(artifact))
                    {
                        provided.add(artifact.getFile().toURI().toURL());
                        if (getLog().isDebugEnabled()) { getLog().debug("Adding provided artifact: "+artifact);}
                    }
                }

                if (!provided.isEmpty())
                {
                    urls = new URL[provided.size()];
                    provided.toArray(urls);
                    URLClassLoader loader  = new URLClassLoader(urls, getClass().getClassLoader());
                    Thread.currentThread().setContextClassLoader(loader);
                    getLog().info("Plugin classpath augmented with <scope>provided</scope> dependencies: "+Arrays.toString(urls));
                }
            }
            catch (MalformedURLException e)
            {
                throw new MojoExecutionException("Invalid url", e);
            }
        }
    }


    /**
     * @param artifact
     * @return
     */
    public boolean isPluginArtifact(Artifact artifact)
    {
        if (pluginArtifacts == null || pluginArtifacts.isEmpty())
            return false;

        boolean isPluginArtifact = false;
        for (Iterator<Artifact> iter = pluginArtifacts.iterator(); iter.hasNext() && !isPluginArtifact; )
        {
            Artifact pluginArtifact = iter.next();
            if (getLog().isDebugEnabled()) { getLog().debug("Checking "+pluginArtifact);}
            if (pluginArtifact.getGroupId().equals(artifact.getGroupId()) && pluginArtifact.getArtifactId().equals(artifact.getArtifactId()))
                isPluginArtifact = true;
        }

        return isPluginArtifact;
    }


    /**
     * @throws Exception
     */
    public void finishConfigurationBeforeStart() throws Exception
    {
        HandlerCollection contexts = (HandlerCollection)server.getChildHandlerByClass(ContextHandlerCollection.class);
        if (contexts==null)
            contexts = (HandlerCollection)server.getChildHandlerByClass(HandlerCollection.class);

        for (int i=0; (this.contextHandlers != null) && (i < this.contextHandlers.length); i++)
        {
            contexts.addHandler(this.contextHandlers[i]);
        }
    }


    /**
     * @throws Exception
     */
    public void applyJettyXml() throws Exception
    {
        if (getJettyXmlFiles() == null)
            return;

        for ( File xmlFile : getJettyXmlFiles() )
        {
            getLog().info( "Configuring Jetty from xml configuration file = " + xmlFile.getCanonicalPath() );
            XmlConfiguration xmlConfiguration = new XmlConfiguration(Resource.toURL(xmlFile));
            xmlConfiguration.configure(this.server);
        }
    }


    /**
     * @throws MojoExecutionException
     */
    public void startJetty () throws MojoExecutionException
    {
        try
        {
            getLog().debug("Starting Jetty Server ...");

            if(stopPort>0 && stopKey!=null)
            {
                ShutdownMonitor monitor = ShutdownMonitor.getInstance();
                monitor.setPort(stopPort);
                monitor.setKey(stopKey);
                monitor.setExitVm(!daemon);
            }

            printSystemProperties();

            //apply any config from a jetty.xml file first which is able to
            //be overwritten by config in the pom.xml
            applyJettyXml ();

            // if a <httpConnector> was specified in the pom, use it
            if (httpConnector != null)
            {
                // check that its port was set
                if (httpConnector.getPort() <= 0)
                {
                    //use any jetty.port settings provided
                    String tmp = System.getProperty(PORT_SYSPROPERTY, MavenServerConnector.DEFAULT_PORT_STR);
                    httpConnector.setPort(Integer.parseInt(tmp.trim()));
                }
                this.server.addConnector(httpConnector);
            }

            // if the user hasn't configured the connectors in a jetty.xml file so use a default one
            Connector[] connectors = this.server.getConnectors();
            if (connectors == null|| connectors.length == 0)
            {
                //if <httpConnector> not configured in the pom, create one
                if (httpConnector == null)
                {
                    httpConnector = new MavenServerConnector();
                    //use any jetty.port settings provided
                    String tmp = System.getProperty(PORT_SYSPROPERTY, MavenServerConnector.DEFAULT_PORT_STR);
                    httpConnector.setPort(Integer.parseInt(tmp.trim()));
                }

                this.server.setConnectors(new Connector[] {httpConnector});
            }

            //set up a RequestLog if one is provided
            if (this.requestLog != null)
                this.server.setRequestLog(this.requestLog);

            //set up the webapp and any context provided
            this.server.configureHandlers();
            configureWebApplication();
            this.server.addWebApplication(webApp);

            // set up security realms
            for (int i = 0; (this.loginServices != null) && i < this.loginServices.length; i++)
            {
                getLog().debug(this.loginServices[i].getClass().getName() + ": "+ this.loginServices[i].toString());
                this.server.addBean(this.loginServices[i]);
            }

            //do any other configuration required by the
            //particular Jetty version
            finishConfigurationBeforeStart();

            // start Jetty
            this.server.start();

            getLog().info("Started Jetty Server");


            // start the scanner thread (if necessary) on the main webapp
            configureScanner ();
            startScanner();

            // start the new line scanner thread if necessary
            startConsoleScanner();

            // keep the thread going if not in daemon mode
            if (!daemon )
            {
                server.join();
            }
        }
        catch (Exception e)
        {
            throw new MojoExecutionException("Failure", e);
        }
        finally
        {
            if (!daemon )
            {
                getLog().info("Jetty server exiting.");
            }
        }
    }


    /**
     * Subclasses should invoke this to setup basic info
     * on the webapp
     *
     * @throws MojoExecutionException
     */
    public void configureWebApplication () throws Exception
    {
        //As of jetty-7, you must use a <webApp> element
        if (webApp == null)
            webApp = new JettyWebAppContext();

        //Apply any context xml file to set up the webapp
        //CAUTION: if you've defined a <webApp> element then the
        //context xml file can OVERRIDE those settings
        if (contextXml != null)
        {
            File file = FileUtils.getFile(contextXml);
            XmlConfiguration xmlConfiguration = new XmlConfiguration(Resource.toURL(file));
            getLog().info("Applying context xml file "+contextXml);
            xmlConfiguration.configure(webApp);
        }

        //If no contextPath was specified, go with default of project artifactid
        String cp = webApp.getContextPath();
        if (cp == null || "".equals(cp))
        {
            cp = "/"+project.getArtifactId();
            webApp.setContextPath(cp);
        }

        //If no tmp directory was specified, and we have one, use it
        if (webApp.getTempDirectory() == null)
        {
            File target = new File(project.getBuild().getDirectory());
            File tmp = new File(target,"tmp");
            if (!tmp.exists())
                tmp.mkdirs();
            webApp.setTempDirectory(tmp);
        }

        getLog().info("Context path = " + webApp.getContextPath());
        getLog().info("Tmp directory = "+ (webApp.getTempDirectory()== null? " determined at runtime": webApp.getTempDirectory()));
        getLog().info("Web defaults = "+(webApp.getDefaultsDescriptor()==null?" jetty default":webApp.getDefaultsDescriptor()));
        getLog().info("Web overrides = "+(webApp.getOverrideDescriptor()==null?" none":webApp.getOverrideDescriptor()));
    }


    /**
     * Run a scanner thread on the given list of files and directories, calling
     * stop/start on the given list of LifeCycle objects if any of the watched
     * files change.
     *
     */
    private void startScanner() throws Exception
    {
        // check if scanning is enabled
        if (scanIntervalSeconds <= 0) return;

        // check if reload is manual. It disables file scanning
        if ( "manual".equalsIgnoreCase( reload ) )
        {
            // issue a warning if both scanIntervalSeconds and reload
            // are enabled
            getLog().warn("scanIntervalSeconds is set to " + scanIntervalSeconds + " but will be IGNORED due to manual reloading");
            return;
        }

        scanner = new Scanner();
        scanner.setReportExistingFilesOnStartup(false);
        scanner.setScanInterval(scanIntervalSeconds);
        scanner.setScanDirs(scanList);
        scanner.setRecursive(true);
        Iterator itor = (this.scannerListeners==null?null:this.scannerListeners.iterator());
        while (itor!=null && itor.hasNext())
            scanner.addListener((Scanner.Listener)itor.next());
        getLog().info("Starting scanner at interval of " + scanIntervalSeconds + " seconds.");
        scanner.start();
    }


    /**
     * Run a thread that monitors the console input to detect ENTER hits.
     */
    protected void startConsoleScanner() throws Exception
    {
        if ( "manual".equalsIgnoreCase( reload ) )
        {
            getLog().info("Console reloading is ENABLED. Hit ENTER on the console to restart the context.");
            consoleScanner = new ConsoleScanner(this);
            consoleScanner.start();
        }
    }


    /**
     *
     */
    private void printSystemProperties ()
    {
        // print out which system properties were set up
        if (getLog().isDebugEnabled())
        {
            if (systemProperties != null)
            {
                Iterator itor = systemProperties.getSystemProperties().iterator();
                while (itor.hasNext())
                {
                    SystemProperty prop = (SystemProperty)itor.next();
                    getLog().debug("Property "+prop.getName()+"="+prop.getValue()+" was "+ (prop.isSet() ? "set" : "skipped"));
                }
            }
        }
    }


    /**
     * Try and find a jetty-web.xml file, using some
     * historical naming conventions if necessary.
     * @param webInfDir
     * @return the jetty web xml file
     */
    public File findJettyWebXmlFile (File webInfDir)
    {
        if (webInfDir == null)
            return null;
        if (!webInfDir.exists())
            return null;

        File f = new File (webInfDir, "jetty-web.xml");
        if (f.exists())
            return f;

        //try some historical alternatives
        f = new File (webInfDir, "web-jetty.xml");
        if (f.exists())
            return f;

        return null;
    }


    /**
     * @param file
     * @throws Exception
     */
    public void setSystemPropertiesFile(File file) throws Exception
    {
        this.systemPropertiesFile = file;
        FileInputStream propFile = new FileInputStream(systemPropertiesFile);
        Properties properties = new Properties();
        properties.load(propFile);

        if (this.systemProperties == null )
            this.systemProperties = new SystemProperties();

        for (Enumeration keys = properties.keys(); keys.hasMoreElements();  )
        {
            String key = (String)keys.nextElement();
            if ( ! systemProperties.containsSystemProperty(key) )
            {
                SystemProperty prop = new SystemProperty();
                prop.setKey(key);
                prop.setValue(properties.getProperty(key));

                this.systemProperties.setSystemProperty(prop);
            }
        }
    }


    /**
     * @param systemProperties
     */
    public void setSystemProperties(SystemProperties systemProperties)
    {
        if (this.systemProperties == null)
            this.systemProperties = systemProperties;
        else
        {
            Iterator itor = systemProperties.getSystemProperties().iterator();
            while (itor.hasNext())
            {
                SystemProperty prop = (SystemProperty)itor.next();
                this.systemProperties.setSystemProperty(prop);
            }
        }
    }


    /**
     * @return
     */
    public List<File> getJettyXmlFiles()
    {
        if ( this.jettyXml == null )
        {
            return null;
        }

        List<File> jettyXmlFiles = new ArrayList<File>();

        if ( this.jettyXml.indexOf(',') == -1 )
        {
            jettyXmlFiles.add( new File( this.jettyXml ) );
        }
        else
        {
            String[] files = this.jettyXml.split(",");

            for ( String file : files )
            {
                jettyXmlFiles.add( new File(file) );
            }
        }

        return jettyXmlFiles;
    }


    /**
     * @param goal
     * @return
     */
    public boolean isExcluded (String goal)
    {
        if (excludedGoals == null || goal == null)
            return false;

        goal = goal.trim();
        if ("".equals(goal))
            return false;

        boolean excluded = false;
        for (int i=0; i<excludedGoals.length && !excluded; i++)
        {
            if (excludedGoals[i].equalsIgnoreCase(goal))
                excluded = true;
        }

        return excluded;
    }
}