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From t...@apache.org
Subject svn commit: r1212060 [3/8] - in /hadoop/common/trunk/hadoop-hdfs-project: ./ hadoop-hdfs-httpfs/ hadoop-hdfs-httpfs/src/ hadoop-hdfs-httpfs/src/main/ hadoop-hdfs-httpfs/src/main/conf/ hadoop-hdfs-httpfs/src/main/java/ hadoop-hdfs-httpfs/src/main/java/o...
Date Thu, 08 Dec 2011 19:25:33 GMT
Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/BaseService.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/BaseService.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/BaseService.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/BaseService.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,178 @@
+/**
+ * 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.lib.server;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.lib.util.ConfigurationUtils;
+
+import java.util.Map;
+
+/**
+ * Convenience class implementing the {@link Service} interface.
+ */
+public abstract class BaseService implements Service {
+  private String prefix;
+  private Server server;
+  private Configuration serviceConfig;
+
+  /**
+   * Service constructor.
+   *
+   * @param prefix service prefix.
+   */
+  public BaseService(String prefix) {
+    this.prefix = prefix;
+  }
+
+  /**
+   * Initializes the service.
+   * <p/>
+   * It collects all service properties (properties having the
+   * <code>#SERVER#.#SERVICE#.</code> prefix). The property names are then
+   * trimmed from the <code>#SERVER#.#SERVICE#.</code> prefix.
+   * <p/>
+   * After collecting  the service properties it delegates to the
+   * {@link #init()} method.
+   *
+   * @param server the server initializing the service, give access to the
+   * server context.
+   *
+   * @throws ServiceException thrown if the service could not be initialized.
+   */
+  @Override
+  public final void init(Server server) throws ServiceException {
+    this.server = server;
+    String servicePrefix = getPrefixedName("");
+    serviceConfig = new Configuration(false);
+    for (Map.Entry<String, String> entry : ConfigurationUtils.resolve(server.getConfig())) {
+      String key = entry.getKey();
+      if (key.startsWith(servicePrefix)) {
+        serviceConfig.set(key.substring(servicePrefix.length()), entry.getValue());
+      }
+    }
+    init();
+  }
+
+
+  /**
+   * Post initializes the service. This method is called by the
+   * {@link Server} after all services of the server have been initialized.
+   * <p/>
+   * This method does a NOP.
+   *
+   * @throws ServiceException thrown if the service could not be
+   * post-initialized.
+   */
+  @Override
+  public void postInit() throws ServiceException {
+  }
+
+  /**
+   * Destroy the services.  This method is called once, when the
+   * {@link Server} owning the service is being destroyed.
+   * <p/>
+   * This method does a NOP.
+   */
+  @Override
+  public void destroy() {
+  }
+
+  /**
+   * Returns the service dependencies of this service. The service will be
+   * instantiated only if all the service dependencies are already initialized.
+   * <p/>
+   * This method returns an empty array (size 0)
+   *
+   * @return an empty array (size 0).
+   */
+  @Override
+  public Class[] getServiceDependencies() {
+    return new Class[0];
+  }
+
+  /**
+   * Notification callback when the server changes its status.
+   * <p/>
+   * This method returns an empty array (size 0)
+   *
+   * @param oldStatus old server status.
+   * @param newStatus new server status.
+   *
+   * @throws ServiceException thrown if the service could not process the status change.
+   */
+  @Override
+  public void serverStatusChange(Server.Status oldStatus, Server.Status newStatus) throws ServiceException {
+  }
+
+  /**
+   * Returns the service prefix.
+   *
+   * @return the service prefix.
+   */
+  protected String getPrefix() {
+    return prefix;
+  }
+
+  /**
+   * Returns the server owning the service.
+   *
+   * @return the server owning the service.
+   */
+  protected Server getServer() {
+    return server;
+  }
+
+  /**
+   * Returns the full prefixed name of a service property.
+   *
+   * @param name of the property.
+   *
+   * @return prefixed name of the property.
+   */
+  protected String getPrefixedName(String name) {
+    return server.getPrefixedName(prefix + "." + name);
+  }
+
+  /**
+   * Returns the service configuration properties. Property
+   * names are trimmed off from its prefix.
+   * <p/>
+   * The sevice configuration properties are all properties
+   * with names starting with <code>#SERVER#.#SERVICE#.</code>
+   * in the server configuration.
+   *
+   * @return the service configuration properties with names
+   *         trimmed off from their <code>#SERVER#.#SERVICE#.</code>
+   *         prefix.
+   */
+  protected Configuration getServiceConfig() {
+    return serviceConfig;
+  }
+
+  /**
+   * Initializes the server.
+   * <p/>
+   * This method is called by {@link #init(Server)} after all service properties
+   * (properties prefixed with
+   *
+   * @throws ServiceException thrown if the service could not be initialized.
+   */
+  protected abstract void init() throws ServiceException;
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Server.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Server.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Server.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Server.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,766 @@
+/**
+ * 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.lib.server;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.lib.util.Check;
+import org.apache.hadoop.lib.util.ConfigurationUtils;
+import org.apache.log4j.LogManager;
+import org.apache.log4j.PropertyConfigurator;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.MessageFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+
+/**
+ * A Server class provides standard configuration, logging and {@link Service}
+ * lifecyle management.
+ * <p/>
+ * A Server normally has a home directory, a configuration directory, a temp
+ * directory and logs directory.
+ * <p/>
+ * The Server configuration is loaded from 2 overlapped files,
+ * <code>#SERVER#-default.xml</code> and <code>#SERVER#-site.xml</code>. The
+ * default file is loaded from the classpath, the site file is laoded from the
+ * configuration directory.
+ * <p/>
+ * The Server collects all configuration properties prefixed with
+ * <code>#SERVER#</code>. The property names are then trimmed from the
+ * <code>#SERVER#</code> prefix.
+ * <p/>
+ * The Server log configuration is loaded from the
+ * <code>#SERVICE#-log4j.properties</code> file in the configuration directory.
+ * <p/>
+ * The lifecycle of server is defined in by {@link Server.Status} enum.
+ * When a server is create, its status is UNDEF, when being initialized it is
+ * BOOTING, once initialization is complete by default transitions to NORMAL.
+ * The <code>#SERVER#.startup.status</code> configuration property can be used
+ * to specify a different startup status (NORMAL, ADMIN or HALTED).
+ * <p/>
+ * Services classes are defined in the <code>#SERVER#.services</code> and
+ * <code>#SERVER#.services.ext</code> properties. They are loaded in order
+ * (services first, then services.ext).
+ * <p/>
+ * Before initializing the services, they are traversed and duplicate service
+ * interface are removed from the service list. The last service using a given
+ * interface wins (this enables a simple override mechanism).
+ * <p/>
+ * After the services have been resoloved by interface de-duplication they are
+ * initialized in order. Once all services are initialized they are
+ * post-initialized (this enables late/conditional service bindings).
+ * <p/>
+ */
+public class Server {
+  private Logger log;
+
+  /**
+   * Server property name that defines the service classes.
+   */
+  public static final String CONF_SERVICES = "services";
+
+  /**
+   * Server property name that defines the service extension classes.
+   */
+  public static final String CONF_SERVICES_EXT = "services.ext";
+
+  /**
+   * Server property name that defines server startup status.
+   */
+  public static final String CONF_STARTUP_STATUS = "startup.status";
+
+  /**
+   * Enumeration that defines the server status.
+   */
+  public enum Status {
+    UNDEF(false, false),
+    BOOTING(false, true),
+    HALTED(true, true),
+    ADMIN(true, true),
+    NORMAL(true, true),
+    SHUTTING_DOWN(false, true),
+    SHUTDOWN(false, false);
+
+    private boolean settable;
+    private boolean operational;
+
+    /**
+     * Status constructor.
+     *
+     * @param settable indicates if the status is settable.
+     * @param operational indicates if the server is operational
+     * when in this status.
+     */
+    private Status(boolean settable, boolean operational) {
+      this.settable = settable;
+      this.operational = operational;
+    }
+
+    /**
+     * Returns if this server status is operational.
+     *
+     * @return if this server status is operational.
+     */
+    public boolean isOperational() {
+      return operational;
+    }
+  }
+
+  /**
+   * Name of the log4j configuration file the Server will load from the
+   * classpath if the <code>#SERVER#-log4j.properties</code> is not defined
+   * in the server configuration directory.
+   */
+  public static final String DEFAULT_LOG4J_PROPERTIES = "default-log4j.properties";
+
+  private Status status;
+  private String name;
+  private String homeDir;
+  private String configDir;
+  private String logDir;
+  private String tempDir;
+  private Configuration config;
+  private Map<Class, Service> services = new LinkedHashMap<Class, Service>();
+
+  /**
+   * Creates a server instance.
+   * <p/>
+   * The config, log and temp directories are all under the specified home directory.
+   *
+   * @param name server name.
+   * @param homeDir server home directory.
+   */
+  public Server(String name, String homeDir) {
+    this(name, homeDir, null);
+  }
+
+  /**
+   * Creates a server instance.
+   *
+   * @param name server name.
+   * @param homeDir server home directory.
+   * @param configDir config directory.
+   * @param logDir log directory.
+   * @param tempDir temp directory.
+   */
+  public Server(String name, String homeDir, String configDir, String logDir, String tempDir) {
+    this(name, homeDir, configDir, logDir, tempDir, null);
+  }
+
+  /**
+   * Creates a server instance.
+   * <p/>
+   * The config, log and temp directories are all under the specified home directory.
+   * <p/>
+   * It uses the provided configuration instead loading it from the config dir.
+   *
+   * @param name server name.
+   * @param homeDir server home directory.
+   * @param config server configuration.
+   */
+  public Server(String name, String homeDir, Configuration config) {
+    this(name, homeDir, homeDir + "/conf", homeDir + "/log", homeDir + "/temp", config);
+  }
+
+  /**
+   * Creates a server instance.
+   * <p/>
+   * It uses the provided configuration instead loading it from the config dir.
+   *
+   * @param name server name.
+   * @param homeDir server home directory.
+   * @param configDir config directory.
+   * @param logDir log directory.
+   * @param tempDir temp directory.
+   * @param config server configuration.
+   */
+  public Server(String name, String homeDir, String configDir, String logDir, String tempDir, Configuration config) {
+    this.name = Check.notEmpty(name, "name").trim().toLowerCase();
+    this.homeDir = Check.notEmpty(homeDir, "homeDir");
+    this.configDir = Check.notEmpty(configDir, "configDir");
+    this.logDir = Check.notEmpty(logDir, "logDir");
+    this.tempDir = Check.notEmpty(tempDir, "tempDir");
+    checkAbsolutePath(homeDir, "homeDir");
+    checkAbsolutePath(configDir, "configDir");
+    checkAbsolutePath(logDir, "logDir");
+    checkAbsolutePath(tempDir, "tempDir");
+    if (config != null) {
+      this.config = new Configuration(false);
+      ConfigurationUtils.copy(config, this.config);
+    }
+    status = Status.UNDEF;
+  }
+
+  /**
+   * Validates that the specified value is an absolute path (starts with '/').
+   *
+   * @param value value to verify it is an absolute path.
+   * @param name name to use in the exception if the value is not an absolute
+   * path.
+   *
+   * @return the value.
+   *
+   * @throws IllegalArgumentException thrown if the value is not an absolute
+   * path.
+   */
+  private String checkAbsolutePath(String value, String name) {
+    if (!value.startsWith("/")) {
+      throw new IllegalArgumentException(
+        MessageFormat.format("[{0}] must be an absolute path [{1}]", name, value));
+    }
+    return value;
+  }
+
+  /**
+   * Returns the current server status.
+   *
+   * @return the current server status.
+   */
+  public Status getStatus() {
+    return status;
+  }
+
+  /**
+   * Sets a new server status.
+   * <p/>
+   * The status must be settable.
+   * <p/>
+   * All services will be notified o the status change via the
+   * {@link Service#serverStatusChange(Status, Status)} method. If a service
+   * throws an exception during the notification, the server will be destroyed.
+   *
+   * @param status status to set.
+   *
+   * @throws ServerException thrown if the service has been destroy because of
+   * a failed notification to a service.
+   */
+  public void setStatus(Status status) throws ServerException {
+    Check.notNull(status, "status");
+    if (status.settable) {
+      if (status != this.status) {
+        Status oldStatus = this.status;
+        this.status = status;
+        for (Service service : services.values()) {
+          try {
+            service.serverStatusChange(oldStatus, status);
+          } catch (Exception ex) {
+            log.error("Service [{}] exception during status change to [{}] -server shutting down-,  {}",
+                      new Object[]{service.getInterface().getSimpleName(), status, ex.getMessage(), ex});
+            destroy();
+            throw new ServerException(ServerException.ERROR.S11, service.getInterface().getSimpleName(),
+                                      status, ex.getMessage(), ex);
+          }
+        }
+      }
+    } else {
+      throw new IllegalArgumentException("Status [" + status + " is not settable");
+    }
+  }
+
+  /**
+   * Verifies the server is operational.
+   *
+   * @throws IllegalStateException thrown if the server is not operational.
+   */
+  protected void ensureOperational() {
+    if (!getStatus().isOperational()) {
+      throw new IllegalStateException("Server is not running");
+    }
+  }
+
+  /**
+   * Convenience method that returns a resource as inputstream from the
+   * classpath.
+   * <p/>
+   * It first attempts to use the Thread's context classloader and if not
+   * set it uses the <code>ClassUtils</code> classloader.
+   *
+   * @param name resource to retrieve.
+   *
+   * @return inputstream with the resource, NULL if the resource does not
+   *         exist.
+   */
+  static InputStream getResource(String name) {
+    Check.notEmpty(name, "name");
+    ClassLoader cl = Thread.currentThread().getContextClassLoader();
+    if (cl == null) {
+      cl = Server.class.getClassLoader();
+    }
+    return cl.getResourceAsStream(name);
+  }
+
+  /**
+   * Initializes the Server.
+   * <p/>
+   * The initialization steps are:
+   * <ul>
+   * <li>It verifies the service home and temp directories exist</li>
+   * <li>Loads the Server <code>#SERVER#-default.xml</code>
+   * configuration file from the classpath</li>
+   * <li>Initializes log4j logging. If the
+   * <code>#SERVER#-log4j.properties</code> file does not exist in the config
+   * directory it load <code>default-log4j.properties</code> from the classpath
+   * </li>
+   * <li>Loads the <code>#SERVER#-site.xml</code> file from the server config
+   * directory and merges it with the default configuration.</li>
+   * <li>Loads the services</li>
+   * <li>Initializes the services</li>
+   * <li>Post-initializes the services</li>
+   * <li>Sets the server startup status</li>
+   *
+   * @throws ServerException thrown if the server could not be initialized.
+   */
+  public void init() throws ServerException {
+    if (status != Status.UNDEF) {
+      throw new IllegalStateException("Server already initialized");
+    }
+    status = Status.BOOTING;
+    verifyDir(homeDir);
+    verifyDir(tempDir);
+    Properties serverInfo = new Properties();
+    try {
+      InputStream is = getResource(name + ".properties");
+      serverInfo.load(is);
+      is.close();
+    } catch (IOException ex) {
+      throw new RuntimeException("Could not load server information file: " + name + ".properties");
+    }
+    initLog();
+    log.info("++++++++++++++++++++++++++++++++++++++++++++++++++++++");
+    log.info("Server [{}] starting", name);
+    log.info("  Built information:");
+    log.info("    Version           : {}", serverInfo.getProperty(name + ".version", "undef"));
+    log.info("    Source Repository : {}", serverInfo.getProperty(name + ".source.repository", "undef"));
+    log.info("    Source Revision   : {}", serverInfo.getProperty(name + ".source.revision", "undef"));
+    log.info("    Built by          : {}", serverInfo.getProperty(name + ".build.username", "undef"));
+    log.info("    Built timestamp   : {}", serverInfo.getProperty(name + ".build.timestamp", "undef"));
+    log.info("  Runtime information:");
+    log.info("    Home   dir: {}", homeDir);
+    log.info("    Config dir: {}", (config == null) ? configDir : "-");
+    log.info("    Log    dir: {}", logDir);
+    log.info("    Temp   dir: {}", tempDir);
+    initConfig();
+    log.debug("Loading services");
+    List<Service> list = loadServices();
+    try {
+      log.debug("Initializing services");
+      initServices(list);
+      log.info("Services initialized");
+    } catch (ServerException ex) {
+      log.error("Services initialization failure, destroying initialized services");
+      destroyServices();
+      throw ex;
+    }
+    Status status = Status.valueOf(getConfig().get(getPrefixedName(CONF_STARTUP_STATUS), Status.NORMAL.toString()));
+    setStatus(status);
+    log.info("Server [{}] started!, status [{}]", name, status);
+  }
+
+  /**
+   * Verifies the specified directory exists.
+   *
+   * @param dir directory to verify it exists.
+   *
+   * @throws ServerException thrown if the directory does not exist or it the
+   * path it is not a directory.
+   */
+  private void verifyDir(String dir) throws ServerException {
+    File file = new File(dir);
+    if (!file.exists()) {
+      throw new ServerException(ServerException.ERROR.S01, dir);
+    }
+    if (!file.isDirectory()) {
+      throw new ServerException(ServerException.ERROR.S02, dir);
+    }
+  }
+
+  /**
+   * Initializes Log4j logging.
+   *
+   * @throws ServerException thrown if Log4j could not be initialized.
+   */
+  protected void initLog() throws ServerException {
+    verifyDir(logDir);
+    LogManager.resetConfiguration();
+    File log4jFile = new File(configDir, name + "-log4j.properties");
+    if (log4jFile.exists()) {
+      PropertyConfigurator.configureAndWatch(log4jFile.toString(), 10 * 1000); //every 10 secs
+      log = LoggerFactory.getLogger(Server.class);
+    } else {
+      Properties props = new Properties();
+      try {
+        InputStream is = getResource(DEFAULT_LOG4J_PROPERTIES);
+        props.load(is);
+      } catch (IOException ex) {
+        throw new ServerException(ServerException.ERROR.S03, DEFAULT_LOG4J_PROPERTIES, ex.getMessage(), ex);
+      }
+      PropertyConfigurator.configure(props);
+      log = LoggerFactory.getLogger(Server.class);
+      log.warn("Log4j [{}] configuration file not found, using default configuration from classpath", log4jFile);
+    }
+  }
+
+  /**
+   * Loads and inializes the server configuration.
+   *
+   * @throws ServerException thrown if the configuration could not be loaded/initialized.
+   */
+  protected void initConfig() throws ServerException {
+    verifyDir(configDir);
+    File file = new File(configDir);
+    Configuration defaultConf;
+    String defaultConfig = name + "-default.xml";
+    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+    InputStream inputStream = classLoader.getResourceAsStream(defaultConfig);
+    if (inputStream == null) {
+      log.warn("Default configuration file not available in classpath [{}]", defaultConfig);
+      defaultConf = new Configuration(false);
+    } else {
+      try {
+        defaultConf = new Configuration(false);
+        ConfigurationUtils.load(defaultConf, inputStream);
+      } catch (Exception ex) {
+        throw new ServerException(ServerException.ERROR.S03, defaultConfig, ex.getMessage(), ex);
+      }
+    }
+
+    if (config == null) {
+      Configuration siteConf;
+      File siteFile = new File(file, name + "-site.xml");
+      if (!siteFile.exists()) {
+        log.warn("Site configuration file [{}] not found in config directory", siteFile);
+        siteConf = new Configuration(false);
+      } else {
+        if (!siteFile.isFile()) {
+          throw new ServerException(ServerException.ERROR.S05, siteFile.getAbsolutePath());
+        }
+        try {
+          log.debug("Loading site configuration from [{}]", siteFile);
+          inputStream = new FileInputStream(siteFile);
+          siteConf = new Configuration(false);
+          ConfigurationUtils.load(siteConf, inputStream);
+        } catch (IOException ex) {
+          throw new ServerException(ServerException.ERROR.S06, siteFile, ex.getMessage(), ex);
+        }
+      }
+
+      config = new Configuration(false);
+      ConfigurationUtils.copy(siteConf, config);
+    }
+
+    ConfigurationUtils.injectDefaults(defaultConf, config);
+
+    for (String name : System.getProperties().stringPropertyNames()) {
+      String value = System.getProperty(name);
+      if (name.startsWith(getPrefix() + ".")) {
+        config.set(name, value);
+        if (name.endsWith(".password") || name.endsWith(".secret")) {
+          value = "*MASKED*";
+        }
+        log.info("System property sets  {}: {}", name, value);
+      }
+    }
+
+    log.debug("Loaded Configuration:");
+    log.debug("------------------------------------------------------");
+    for (Map.Entry<String, String> entry : config) {
+      String name = entry.getKey();
+      String value = config.get(entry.getKey());
+      if (name.endsWith(".password") || name.endsWith(".secret")) {
+        value = "*MASKED*";
+      }
+      log.debug("  {}: {}", entry.getKey(), value);
+    }
+    log.debug("------------------------------------------------------");
+  }
+
+  /**
+   * Loads the specified services.
+   *
+   * @param classes services classes to load.
+   * @param list list of loaded service in order of appearance in the
+   * configuration.
+   *
+   * @throws ServerException thrown if a service class could not be loaded.
+   */
+  private void loadServices(Class[] classes, List<Service> list) throws ServerException {
+    for (Class klass : classes) {
+      try {
+        Service service = (Service) klass.newInstance();
+        log.debug("Loading service [{}] implementation [{}]", service.getInterface(),
+                  service.getClass());
+        if (!service.getInterface().isInstance(service)) {
+          throw new ServerException(ServerException.ERROR.S04, klass, service.getInterface().getName());
+        }
+        list.add(service);
+      } catch (ServerException ex) {
+        throw ex;
+      } catch (Exception ex) {
+        throw new ServerException(ServerException.ERROR.S07, klass, ex.getMessage(), ex);
+      }
+    }
+  }
+
+  /**
+   * Loads services defined in <code>services</code> and
+   * <code>services.ext</code> and de-dups them.
+   *
+   * @return List of final services to initialize.
+   *
+   * @throws ServerException throw if the services could not be loaded.
+   */
+  protected List<Service> loadServices() throws ServerException {
+    try {
+      Map<Class, Service> map = new LinkedHashMap<Class, Service>();
+      Class[] classes = getConfig().getClasses(getPrefixedName(CONF_SERVICES));
+      Class[] classesExt = getConfig().getClasses(getPrefixedName(CONF_SERVICES_EXT));
+      List<Service> list = new ArrayList<Service>();
+      loadServices(classes, list);
+      loadServices(classesExt, list);
+
+      //removing duplicate services, strategy: last one wins
+      for (Service service : list) {
+        if (map.containsKey(service.getInterface())) {
+          log.debug("Replacing service [{}] implementation [{}]", service.getInterface(),
+                    service.getClass());
+        }
+        map.put(service.getInterface(), service);
+      }
+      list = new ArrayList<Service>();
+      for (Map.Entry<Class, Service> entry : map.entrySet()) {
+        list.add(entry.getValue());
+      }
+      return list;
+    } catch (RuntimeException ex) {
+      throw new ServerException(ServerException.ERROR.S08, ex.getMessage(), ex);
+    }
+  }
+
+  /**
+   * Initializes the list of services.
+   *
+   * @param services services to initialized, it must be a de-dupped list of
+   * services.
+   *
+   * @throws ServerException thrown if the services could not be initialized.
+   */
+  protected void initServices(List<Service> services) throws ServerException {
+    for (Service service : services) {
+      log.debug("Initializing service [{}]", service.getInterface());
+      checkServiceDependencies(service);
+      service.init(this);
+      this.services.put(service.getInterface(), service);
+    }
+    for (Service service : services) {
+      service.postInit();
+    }
+  }
+
+  /**
+   * Checks if all service dependencies of a service are available.
+   *
+   * @param service service to check if all its dependencies are available.
+   *
+   * @throws ServerException thrown if a service dependency is missing.
+   */
+  protected void checkServiceDependencies(Service service) throws ServerException {
+    if (service.getServiceDependencies() != null) {
+      for (Class dependency : service.getServiceDependencies()) {
+        if (services.get(dependency) == null) {
+          throw new ServerException(ServerException.ERROR.S10, service.getClass(), dependency);
+        }
+      }
+    }
+  }
+
+  /**
+   * Destroys the server services.
+   */
+  protected void destroyServices() {
+    List<Service> list = new ArrayList<Service>(services.values());
+    Collections.reverse(list);
+    for (Service service : list) {
+      try {
+        log.debug("Destroying service [{}]", service.getInterface());
+        service.destroy();
+      } catch (Throwable ex) {
+        log.error("Could not destroy service [{}], {}",
+                  new Object[]{service.getInterface(), ex.getMessage(), ex});
+      }
+    }
+    log.info("Services destroyed");
+  }
+
+  /**
+   * Destroys the server.
+   * <p/>
+   * All services are destroyed in reverse order of initialization, then the
+   * Log4j framework is shutdown.
+   */
+  public void destroy() {
+    ensureOperational();
+    destroyServices();
+    log.info("Server [{}] shutdown!", name);
+    log.info("======================================================");
+    if (!Boolean.getBoolean("test.circus")) {
+      LogManager.shutdown();
+    }
+    status = Status.SHUTDOWN;
+  }
+
+  /**
+   * Returns the name of the server.
+   *
+   * @return the server name.
+   */
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Returns the server prefix for server configuration properties.
+   * <p/>
+   * By default it is the server name.
+   *
+   * @return the prefix for server configuration properties.
+   */
+  public String getPrefix() {
+    return getName();
+  }
+
+  /**
+   * Returns the prefixed name of a server property.
+   *
+   * @param name of the property.
+   *
+   * @return prefixed name of the property.
+   */
+  public String getPrefixedName(String name) {
+    return getPrefix() + "." + Check.notEmpty(name, "name");
+  }
+
+  /**
+   * Returns the server home dir.
+   *
+   * @return the server home dir.
+   */
+  public String getHomeDir() {
+    return homeDir;
+  }
+
+  /**
+   * Returns the server config dir.
+   *
+   * @return the server config dir.
+   */
+  public String getConfigDir() {
+    return configDir;
+  }
+
+  /**
+   * Returns the server log dir.
+   *
+   * @return the server log dir.
+   */
+  public String getLogDir() {
+    return logDir;
+  }
+
+  /**
+   * Returns the server temp dir.
+   *
+   * @return the server temp dir.
+   */
+  public String getTempDir() {
+    return tempDir;
+  }
+
+  /**
+   * Returns the server configuration.
+   *
+   * @return
+   */
+  public Configuration getConfig() {
+    return config;
+
+  }
+
+  /**
+   * Returns the {@link Service} associated to the specified interface.
+   *
+   * @param serviceKlass service interface.
+   *
+   * @return the service implementation.
+   */
+  @SuppressWarnings("unchecked")
+  public <T> T get(Class<T> serviceKlass) {
+    ensureOperational();
+    Check.notNull(serviceKlass, "serviceKlass");
+    return (T) services.get(serviceKlass);
+  }
+
+  /**
+   * Adds a service programmatically.
+   * <p/>
+   * If a service with the same interface exists, it will be destroyed and
+   * removed before the given one is initialized and added.
+   * <p/>
+   * If an exception is thrown the server is destroyed.
+   *
+   * @param klass service class to add.
+   *
+   * @throws ServerException throw if the service could not initialized/added
+   * to the server.
+   */
+  public void setService(Class<? extends Service> klass) throws ServerException {
+    ensureOperational();
+    Check.notNull(klass, "serviceKlass");
+    if (getStatus() == Status.SHUTTING_DOWN) {
+      throw new IllegalStateException("Server shutting down");
+    }
+    try {
+      Service newService = klass.newInstance();
+      Service oldService = services.get(newService.getInterface());
+      if (oldService != null) {
+        try {
+          oldService.destroy();
+        } catch (Throwable ex) {
+          log.error("Could not destroy service [{}], {}",
+                    new Object[]{oldService.getInterface(), ex.getMessage(), ex});
+        }
+      }
+      newService.init(this);
+      services.put(newService.getInterface(), newService);
+    } catch (Exception ex) {
+      log.error("Could not set service [{}] programmatically -server shutting down-, {}", klass, ex);
+      destroy();
+      throw new ServerException(ServerException.ERROR.S09, klass, ex.getMessage(), ex);
+    }
+  }
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServerException.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServerException.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServerException.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServerException.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,90 @@
+/**
+ * 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.lib.server;
+
+import org.apache.hadoop.lib.lang.XException;
+
+/**
+ * Exception thrown by the {@link Server} class.
+ */
+public class ServerException extends XException {
+
+  /**
+   * Error codes use by the {@link Server} class.
+   */
+  public static enum ERROR implements XException.ERROR {
+    S01("Dir [{0}] does not exist"),
+    S02("[{0}] is not a directory"),
+    S03("Could not load file from classpath [{0}], {1}"),
+    S04("Service [{0}] does not implement declared interface [{1}]"),
+    S05("[{0}] is not a file"),
+    S06("Could not load file [{0}], {1}"),
+    S07("Could not instanciate service class [{0}], {1}"),
+    S08("Could not load service classes, {0}"),
+    S09("Could not set service [{0}] programmatically -server shutting down-, {1}"),
+    S10("Service [{0}] requires service [{1}]"),
+    S11("Service [{0}] exception during status change to [{1}] -server shutting down-, {2}");
+
+    private String msg;
+
+    /**
+     * Constructor for the error code enum.
+     *
+     * @param msg message template.
+     */
+    private ERROR(String msg) {
+      this.msg = msg;
+    }
+
+    /**
+     * Returns the message template for the error code.
+     *
+     * @return the message template for the error code.
+     */
+    @Override
+    public String getTemplate() {
+      return msg;
+    }
+  }
+
+  /**
+   * Constructor for sub-classes.
+   *
+   * @param error error code for the XException.
+   * @param params parameters to use when creating the error message
+   * with the error code template.
+   */
+  protected ServerException(XException.ERROR error, Object... params) {
+    super(error, params);
+  }
+
+  /**
+   * Creates an server exception using the specified error code.
+   * The exception message is resolved using the error code template
+   * and the passed parameters.
+   *
+   * @param error error code for the XException.
+   * @param params parameters to use when creating the error message
+   * with the error code template.
+   */
+  public ServerException(ERROR error, Object... params) {
+    super(error, params);
+  }
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Service.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Service.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Service.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/Service.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,79 @@
+/**
+ * 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.lib.server;
+
+/**
+ * Service interface for components to be managed by the {@link Server} class.
+ */
+public interface Service {
+
+  /**
+   * Initializes the service. This method is called once, when the
+   * {@link Server} owning the service is being initialized.
+   *
+   * @param server the server initializing the service, give access to the
+   * server context.
+   *
+   * @throws ServiceException thrown if the service could not be initialized.
+   */
+  public void init(Server server) throws ServiceException;
+
+  /**
+   * Post initializes the service. This method is called by the
+   * {@link Server} after all services of the server have been initialized.
+   *
+   * @throws ServiceException thrown if the service could not be
+   * post-initialized.
+   */
+  public void postInit() throws ServiceException;
+
+  /**
+   * Destroy the services.  This method is called once, when the
+   * {@link Server} owning the service is being destroyed.
+   */
+  public void destroy();
+
+  /**
+   * Returns the service dependencies of this service. The service will be
+   * instantiated only if all the service dependencies are already initialized.
+   *
+   * @return the service dependencies.
+   */
+  public Class[] getServiceDependencies();
+
+  /**
+   * Returns the interface implemented by this service. This interface is used
+   * the {@link Server} when the {@link Server#get(Class)} method is used to
+   * retrieve a service.
+   *
+   * @return the interface that identifies the service.
+   */
+  public Class getInterface();
+
+  /**
+   * Notification callback when the server changes its status.
+   *
+   * @param oldStatus old server status.
+   * @param newStatus new server status.
+   *
+   * @throws ServiceException thrown if the service could not process the status change.
+   */
+  public void serverStatusChange(Server.Status oldStatus, Server.Status newStatus) throws ServiceException;
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServiceException.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServiceException.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServiceException.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/server/ServiceException.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,41 @@
+/**
+ * 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.lib.server;
+
+import org.apache.hadoop.lib.lang.XException;
+
+/**
+ * Exception thrown by {@link Service} implementations.
+ */
+public class ServiceException extends ServerException {
+
+  /**
+   * Creates an service exception using the specified error code.
+   * The exception message is resolved using the error code template
+   * and the passed parameters.
+   *
+   * @param error error code for the XException.
+   * @param params parameters to use when creating the error message
+   * with the error code template.
+   */
+  public ServiceException(XException.ERROR error, Object... params) {
+    super(error, params);
+  }
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccess.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccess.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccess.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccess.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,42 @@
+/**
+ * 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.lib.service;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+
+import java.io.IOException;
+
+public interface FileSystemAccess {
+
+  public interface FileSystemExecutor<T> {
+
+    public T execute(FileSystem fs) throws IOException;
+  }
+
+  public <T> T execute(String user, Configuration conf, FileSystemExecutor<T> executor) throws
+    FileSystemAccessException;
+
+  public FileSystem createFileSystem(String user, Configuration conf) throws IOException, FileSystemAccessException;
+
+  public void releaseFileSystem(FileSystem fs) throws IOException;
+
+  public Configuration getDefaultConfiguration();
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccessException.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccessException.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccessException.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/FileSystemAccessException.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,52 @@
+/**
+ * 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.lib.service;
+
+import org.apache.hadoop.lib.lang.XException;
+
+public class FileSystemAccessException extends XException {
+
+  public enum ERROR implements XException.ERROR {
+    H01("Service property [{0}] not defined"),
+    H02("Kerberos initialization failed, {0}"),
+    H03("FileSystemExecutor error, {0}"),
+    H04("JobClientExecutor error, {0}"),
+    H05("[{0}] validation failed, {1}"),
+    H06("Property [{0}] not defined in configuration object"),
+    H07("[{0}] not healthy, {1}"),
+    H08(""),
+    H09("Invalid FileSystemAccess security mode [{0}]");
+
+    private String template;
+
+    ERROR(String template) {
+      this.template = template;
+    }
+
+    @Override
+    public String getTemplate() {
+      return template;
+    }
+  }
+
+  public FileSystemAccessException(ERROR error, Object... params) {
+    super(error, params);
+  }
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Groups.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Groups.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Groups.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Groups.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,28 @@
+/**
+ * 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.lib.service;
+
+import java.io.IOException;
+import java.util.List;
+
+public interface Groups {
+
+  public List<String> getGroups(String user) throws IOException;
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Instrumentation.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Instrumentation.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Instrumentation.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Instrumentation.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,50 @@
+/**
+ * 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.lib.service;
+
+import java.util.Map;
+
+public interface Instrumentation {
+
+  public interface Cron {
+
+    public Cron start();
+
+    public Cron stop();
+  }
+
+  public interface Variable<T> {
+
+    T getValue();
+  }
+
+  public Cron createCron();
+
+  public void incr(String group, String name, long count);
+
+  public void addCron(String group, String name, Cron cron);
+
+  public void addVariable(String group, String name, Variable<?> variable);
+
+  //sampling happens once a second
+  public void addSampler(String group, String name, int samplingSize, Variable<Long> variable);
+
+  public Map<String, Map<String, ?>> getSnapshot();
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/ProxyUser.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/ProxyUser.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/ProxyUser.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/ProxyUser.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,28 @@
+/**
+ * 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.lib.service;
+
+import java.io.IOException;
+import java.security.AccessControlException;
+
+public interface ProxyUser {
+
+  public void validate(String proxyUser, String proxyHost, String doAsUser) throws IOException, AccessControlException;
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Scheduler.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Scheduler.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Scheduler.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/Scheduler.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,30 @@
+/**
+ * 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.lib.service;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.TimeUnit;
+
+public interface Scheduler {
+
+  public abstract void schedule(Callable<?> callable, long delay, long interval, TimeUnit unit);
+
+  public abstract void schedule(Runnable runnable, long delay, long interval, TimeUnit unit);
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/hadoop/FileSystemAccessService.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/hadoop/FileSystemAccessService.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/hadoop/FileSystemAccessService.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/hadoop/FileSystemAccessService.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,278 @@
+/**
+ * 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.lib.service.hadoop;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.lib.server.BaseService;
+import org.apache.hadoop.lib.server.ServiceException;
+import org.apache.hadoop.lib.service.FileSystemAccess;
+import org.apache.hadoop.lib.service.FileSystemAccessException;
+import org.apache.hadoop.lib.service.Instrumentation;
+import org.apache.hadoop.lib.util.Check;
+import org.apache.hadoop.lib.util.ConfigurationUtils;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.util.VersionInfo;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.URI;
+import java.security.PrivilegedExceptionAction;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class FileSystemAccessService extends BaseService implements FileSystemAccess {
+  private static final Logger LOG = LoggerFactory.getLogger(FileSystemAccessService.class);
+
+  public static final String PREFIX = "hadoop";
+
+  private static final String INSTRUMENTATION_GROUP = "hadoop";
+
+  public static final String AUTHENTICATION_TYPE = "authentication.type";
+  public static final String KERBEROS_KEYTAB = "authentication.kerberos.keytab";
+  public static final String KERBEROS_PRINCIPAL = "authentication.kerberos.principal";
+
+  public static final String NAME_NODE_WHITELIST = "name.node.whitelist";
+
+  private static final String HADOOP_CONF_PREFIX = "conf:";
+
+  private static final String NAME_NODE_PROPERTY = "fs.default.name";
+
+  public FileSystemAccessService() {
+    super(PREFIX);
+  }
+
+  private Collection<String> nameNodeWhitelist;
+
+  Configuration serviceHadoopConf;
+
+  private AtomicInteger unmanagedFileSystems = new AtomicInteger();
+
+  @Override
+  protected void init() throws ServiceException {
+    LOG.info("Using FileSystemAccess JARs version [{}]", VersionInfo.getVersion());
+    String security = getServiceConfig().get(AUTHENTICATION_TYPE, "simple").trim();
+    if (security.equals("kerberos")) {
+      String defaultName = getServer().getName();
+      String keytab = System.getProperty("user.home") + "/" + defaultName + ".keytab";
+      keytab = getServiceConfig().get(KERBEROS_KEYTAB, keytab).trim();
+      if (keytab.length() == 0) {
+        throw new ServiceException(FileSystemAccessException.ERROR.H01, KERBEROS_KEYTAB);
+      }
+      String principal = defaultName + "/localhost@LOCALHOST";
+      principal = getServiceConfig().get(KERBEROS_PRINCIPAL, principal).trim();
+      if (principal.length() == 0) {
+        throw new ServiceException(FileSystemAccessException.ERROR.H01, KERBEROS_PRINCIPAL);
+      }
+      Configuration conf = new Configuration();
+      conf.set("hadoop.security.authentication", "kerberos");
+      UserGroupInformation.setConfiguration(conf);
+      try {
+        UserGroupInformation.loginUserFromKeytab(principal, keytab);
+      } catch (IOException ex) {
+        throw new ServiceException(FileSystemAccessException.ERROR.H02, ex.getMessage(), ex);
+      }
+      LOG.info("Using FileSystemAccess Kerberos authentication, principal [{}] keytab [{}]", principal, keytab);
+    } else if (security.equals("simple")) {
+      Configuration conf = new Configuration();
+      conf.set("hadoop.security.authentication", "simple");
+      UserGroupInformation.setConfiguration(conf);
+      LOG.info("Using FileSystemAccess simple/pseudo authentication, principal [{}]", System.getProperty("user.name"));
+    } else {
+      throw new ServiceException(FileSystemAccessException.ERROR.H09, security);
+    }
+
+    serviceHadoopConf = new Configuration(false);
+    for (Map.Entry entry : getServiceConfig()) {
+      String name = (String) entry.getKey();
+      if (name.startsWith(HADOOP_CONF_PREFIX)) {
+        name = name.substring(HADOOP_CONF_PREFIX.length());
+        String value = (String) entry.getValue();
+        serviceHadoopConf.set(name, value);
+
+      }
+    }
+    setRequiredServiceHadoopConf(serviceHadoopConf);
+
+    LOG.debug("FileSystemAccess default configuration:");
+    for (Map.Entry entry : serviceHadoopConf) {
+      LOG.debug("  {} = {}", entry.getKey(), entry.getValue());
+    }
+
+    nameNodeWhitelist = toLowerCase(getServiceConfig().getTrimmedStringCollection(NAME_NODE_WHITELIST));
+  }
+
+  @Override
+  public void postInit() throws ServiceException {
+    super.postInit();
+    Instrumentation instrumentation = getServer().get(Instrumentation.class);
+    instrumentation.addVariable(INSTRUMENTATION_GROUP, "unmanaged.fs", new Instrumentation.Variable<Integer>() {
+      @Override
+      public Integer getValue() {
+        return unmanagedFileSystems.get();
+      }
+    });
+    instrumentation.addSampler(INSTRUMENTATION_GROUP, "unmanaged.fs", 60, new Instrumentation.Variable<Long>() {
+      @Override
+      public Long getValue() {
+        return (long) unmanagedFileSystems.get();
+      }
+    });
+  }
+
+  private Set<String> toLowerCase(Collection<String> collection) {
+    Set<String> set = new HashSet<String>();
+    for (String value : collection) {
+      set.add(value.toLowerCase());
+    }
+    return set;
+  }
+
+  @Override
+  public Class getInterface() {
+    return FileSystemAccess.class;
+  }
+
+  @Override
+  public Class[] getServiceDependencies() {
+    return new Class[]{Instrumentation.class};
+  }
+
+  protected UserGroupInformation getUGI(String user) throws IOException {
+    return UserGroupInformation.createProxyUser(user, UserGroupInformation.getLoginUser());
+  }
+
+  protected void setRequiredServiceHadoopConf(Configuration conf) {
+    conf.set("fs.hdfs.impl.disable.cache", "true");
+  }
+
+  protected Configuration createHadoopConf(Configuration conf) {
+    Configuration hadoopConf = new Configuration();
+    ConfigurationUtils.copy(serviceHadoopConf, hadoopConf);
+    ConfigurationUtils.copy(conf, hadoopConf);
+    return hadoopConf;
+  }
+
+  protected Configuration createNameNodeConf(Configuration conf) {
+    return createHadoopConf(conf);
+  }
+
+  protected FileSystem createFileSystem(Configuration namenodeConf) throws IOException {
+    return FileSystem.get(namenodeConf);
+  }
+
+  protected void closeFileSystem(FileSystem fs) throws IOException {
+    fs.close();
+  }
+
+  protected void validateNamenode(String namenode) throws FileSystemAccessException {
+    if (nameNodeWhitelist.size() > 0 && !nameNodeWhitelist.contains("*")) {
+      if (!nameNodeWhitelist.contains(namenode.toLowerCase())) {
+        throw new FileSystemAccessException(FileSystemAccessException.ERROR.H05, namenode, "not in whitelist");
+      }
+    }
+  }
+
+  protected void checkNameNodeHealth(FileSystem fileSystem) throws FileSystemAccessException {
+  }
+
+  @Override
+  public <T> T execute(String user, final Configuration conf, final FileSystemExecutor<T> executor)
+    throws FileSystemAccessException {
+    Check.notEmpty(user, "user");
+    Check.notNull(conf, "conf");
+    Check.notNull(executor, "executor");
+    if (conf.get(NAME_NODE_PROPERTY) == null || conf.getTrimmed(NAME_NODE_PROPERTY).length() == 0) {
+      throw new FileSystemAccessException(FileSystemAccessException.ERROR.H06, NAME_NODE_PROPERTY);
+    }
+    try {
+      validateNamenode(new URI(conf.get(NAME_NODE_PROPERTY)).getAuthority());
+      UserGroupInformation ugi = getUGI(user);
+      return ugi.doAs(new PrivilegedExceptionAction<T>() {
+        public T run() throws Exception {
+          Configuration namenodeConf = createNameNodeConf(conf);
+          FileSystem fs = createFileSystem(namenodeConf);
+          Instrumentation instrumentation = getServer().get(Instrumentation.class);
+          Instrumentation.Cron cron = instrumentation.createCron();
+          try {
+            checkNameNodeHealth(fs);
+            cron.start();
+            return executor.execute(fs);
+          } finally {
+            cron.stop();
+            instrumentation.addCron(INSTRUMENTATION_GROUP, executor.getClass().getSimpleName(), cron);
+            closeFileSystem(fs);
+          }
+        }
+      });
+    } catch (FileSystemAccessException ex) {
+      throw ex;
+    } catch (Exception ex) {
+      throw new FileSystemAccessException(FileSystemAccessException.ERROR.H03, ex);
+    }
+  }
+
+  public FileSystem createFileSystemInternal(String user, final Configuration conf)
+    throws IOException, FileSystemAccessException {
+    Check.notEmpty(user, "user");
+    Check.notNull(conf, "conf");
+    try {
+      validateNamenode(new URI(conf.get(NAME_NODE_PROPERTY)).getAuthority());
+      UserGroupInformation ugi = getUGI(user);
+      return ugi.doAs(new PrivilegedExceptionAction<FileSystem>() {
+        public FileSystem run() throws Exception {
+          Configuration namenodeConf = createNameNodeConf(conf);
+          return createFileSystem(namenodeConf);
+        }
+      });
+    } catch (IOException ex) {
+      throw ex;
+    } catch (FileSystemAccessException ex) {
+      throw ex;
+    } catch (Exception ex) {
+      throw new FileSystemAccessException(FileSystemAccessException.ERROR.H08, ex.getMessage(), ex);
+    }
+  }
+
+  @Override
+  public FileSystem createFileSystem(String user, final Configuration conf) throws IOException,
+    FileSystemAccessException {
+    unmanagedFileSystems.incrementAndGet();
+    return createFileSystemInternal(user, conf);
+  }
+
+  @Override
+  public void releaseFileSystem(FileSystem fs) throws IOException {
+    unmanagedFileSystems.decrementAndGet();
+    closeFileSystem(fs);
+  }
+
+
+  @Override
+  public Configuration getDefaultConfiguration() {
+    Configuration conf = new Configuration(false);
+    ConfigurationUtils.copy(serviceHadoopConf, conf);
+    return conf;
+  }
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/instrumentation/InstrumentationService.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/instrumentation/InstrumentationService.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/instrumentation/InstrumentationService.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/instrumentation/InstrumentationService.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,403 @@
+/**
+ * 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.lib.service.instrumentation;
+
+import org.apache.hadoop.lib.server.BaseService;
+import org.apache.hadoop.lib.server.ServiceException;
+import org.apache.hadoop.lib.service.Instrumentation;
+import org.apache.hadoop.lib.service.Scheduler;
+import org.json.simple.JSONAware;
+import org.json.simple.JSONObject;
+import org.json.simple.JSONStreamAware;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+public class InstrumentationService extends BaseService implements Instrumentation {
+  public static final String PREFIX = "instrumentation";
+  public static final String CONF_TIMERS_SIZE = "timers.size";
+
+  private int timersSize;
+  private Lock counterLock;
+  private Lock timerLock;
+  private Lock variableLock;
+  private Lock samplerLock;
+  private Map<String, Map<String, AtomicLong>> counters;
+  private Map<String, Map<String, Timer>> timers;
+  private Map<String, Map<String, VariableHolder>> variables;
+  private Map<String, Map<String, Sampler>> samplers;
+  private List<Sampler> samplersList;
+  private Map<String, Map<String, ?>> all;
+
+  public InstrumentationService() {
+    super(PREFIX);
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public void init() throws ServiceException {
+    timersSize = getServiceConfig().getInt(CONF_TIMERS_SIZE, 10);
+    counterLock = new ReentrantLock();
+    timerLock = new ReentrantLock();
+    variableLock = new ReentrantLock();
+    samplerLock = new ReentrantLock();
+    Map<String, VariableHolder> jvmVariables = new ConcurrentHashMap<String, VariableHolder>();
+    counters = new ConcurrentHashMap<String, Map<String, AtomicLong>>();
+    timers = new ConcurrentHashMap<String, Map<String, Timer>>();
+    variables = new ConcurrentHashMap<String, Map<String, VariableHolder>>();
+    samplers = new ConcurrentHashMap<String, Map<String, Sampler>>();
+    samplersList = new ArrayList<Sampler>();
+    all = new LinkedHashMap<String, Map<String, ?>>();
+    all.put("os-env", System.getenv());
+    all.put("sys-props", (Map<String, ?>) (Map) System.getProperties());
+    all.put("jvm", jvmVariables);
+    all.put("counters", (Map) counters);
+    all.put("timers", (Map) timers);
+    all.put("variables", (Map) variables);
+    all.put("samplers", (Map) samplers);
+
+    jvmVariables.put("free.memory", new VariableHolder<Long>(new Instrumentation.Variable<Long>() {
+      public Long getValue() {
+        return Runtime.getRuntime().freeMemory();
+      }
+    }));
+    jvmVariables.put("max.memory", new VariableHolder<Long>(new Instrumentation.Variable<Long>() {
+      public Long getValue() {
+        return Runtime.getRuntime().maxMemory();
+      }
+    }));
+    jvmVariables.put("total.memory", new VariableHolder<Long>(new Instrumentation.Variable<Long>() {
+      public Long getValue() {
+        return Runtime.getRuntime().totalMemory();
+      }
+    }));
+  }
+
+  @Override
+  public void postInit() throws ServiceException {
+    Scheduler scheduler = getServer().get(Scheduler.class);
+    if (scheduler != null) {
+      scheduler.schedule(new SamplersRunnable(), 0, 1, TimeUnit.SECONDS);
+    }
+  }
+
+  @Override
+  public Class getInterface() {
+    return Instrumentation.class;
+  }
+
+  @SuppressWarnings("unchecked")
+  private <T> T getToAdd(String group, String name, Class<T> klass, Lock lock, Map<String, Map<String, T>> map) {
+    boolean locked = false;
+    try {
+      Map<String, T> groupMap = map.get(group);
+      if (groupMap == null) {
+        lock.lock();
+        locked = true;
+        groupMap = map.get(group);
+        if (groupMap == null) {
+          groupMap = new ConcurrentHashMap<String, T>();
+          map.put(group, groupMap);
+        }
+      }
+      T element = groupMap.get(name);
+      if (element == null) {
+        if (!locked) {
+          lock.lock();
+          locked = true;
+        }
+        element = groupMap.get(name);
+        if (element == null) {
+          try {
+            if (klass == Timer.class) {
+              element = (T) new Timer(timersSize);
+            } else {
+              element = klass.newInstance();
+            }
+          } catch (Exception ex) {
+            throw new RuntimeException(ex);
+          }
+          groupMap.put(name, element);
+        }
+      }
+      return element;
+    } finally {
+      if (locked) {
+        lock.unlock();
+      }
+    }
+  }
+
+  static class Cron implements Instrumentation.Cron {
+    long start;
+    long lapStart;
+    long own;
+    long total;
+
+    public Cron start() {
+      if (total != 0) {
+        throw new IllegalStateException("Cron already used");
+      }
+      if (start == 0) {
+        start = System.currentTimeMillis();
+        lapStart = start;
+      } else if (lapStart == 0) {
+        lapStart = System.currentTimeMillis();
+      }
+      return this;
+    }
+
+    public Cron stop() {
+      if (total != 0) {
+        throw new IllegalStateException("Cron already used");
+      }
+      if (lapStart > 0) {
+        own += System.currentTimeMillis() - lapStart;
+        lapStart = 0;
+      }
+      return this;
+    }
+
+    void end() {
+      stop();
+      total = System.currentTimeMillis() - start;
+    }
+
+  }
+
+  static class Timer implements JSONAware, JSONStreamAware {
+    static final int LAST_TOTAL = 0;
+    static final int LAST_OWN = 1;
+    static final int AVG_TOTAL = 2;
+    static final int AVG_OWN = 3;
+
+    Lock lock = new ReentrantLock();
+    private long[] own;
+    private long[] total;
+    private int last;
+    private boolean full;
+    private int size;
+
+    public Timer(int size) {
+      this.size = size;
+      own = new long[size];
+      total = new long[size];
+      for (int i = 0; i < size; i++) {
+        own[i] = -1;
+        total[i] = -1;
+      }
+      last = -1;
+    }
+
+    long[] getValues() {
+      lock.lock();
+      try {
+        long[] values = new long[4];
+        values[LAST_TOTAL] = total[last];
+        values[LAST_OWN] = own[last];
+        int limit = (full) ? size : (last + 1);
+        for (int i = 0; i < limit; i++) {
+          values[AVG_TOTAL] += total[i];
+          values[AVG_OWN] += own[i];
+        }
+        values[AVG_TOTAL] = values[AVG_TOTAL] / limit;
+        values[AVG_OWN] = values[AVG_OWN] / limit;
+        return values;
+      } finally {
+        lock.unlock();
+      }
+    }
+
+    void addCron(Cron cron) {
+      cron.end();
+      lock.lock();
+      try {
+        last = (last + 1) % size;
+        full = full || last == (size - 1);
+        total[last] = cron.total;
+        own[last] = cron.own;
+      } finally {
+        lock.unlock();
+      }
+    }
+
+    @SuppressWarnings("unchecked")
+    private JSONObject getJSON() {
+      long[] values = getValues();
+      JSONObject json = new JSONObject();
+      json.put("lastTotal", values[0]);
+      json.put("lastOwn", values[1]);
+      json.put("avgTotal", values[2]);
+      json.put("avgOwn", values[3]);
+      return json;
+    }
+
+    @Override
+    public String toJSONString() {
+      return getJSON().toJSONString();
+    }
+
+    @Override
+    public void writeJSONString(Writer out) throws IOException {
+      getJSON().writeJSONString(out);
+    }
+
+  }
+
+  @Override
+  public Cron createCron() {
+    return new Cron();
+  }
+
+  @Override
+  public void incr(String group, String name, long count) {
+    AtomicLong counter = getToAdd(group, name, AtomicLong.class, counterLock, counters);
+    counter.addAndGet(count);
+  }
+
+  @Override
+  public void addCron(String group, String name, Instrumentation.Cron cron) {
+    Timer timer = getToAdd(group, name, Timer.class, timerLock, timers);
+    timer.addCron((Cron) cron);
+  }
+
+  static class VariableHolder<E> implements JSONAware, JSONStreamAware {
+    Variable<E> var;
+
+    public VariableHolder() {
+    }
+
+    public VariableHolder(Variable<E> var) {
+      this.var = var;
+    }
+
+    @SuppressWarnings("unchecked")
+    private JSONObject getJSON() {
+      JSONObject json = new JSONObject();
+      json.put("value", var.getValue());
+      return json;
+    }
+
+    @Override
+    public String toJSONString() {
+      return getJSON().toJSONString();
+    }
+
+    @Override
+    public void writeJSONString(Writer out) throws IOException {
+      out.write(toJSONString());
+    }
+
+  }
+
+  @Override
+  public void addVariable(String group, String name, Variable<?> variable) {
+    VariableHolder holder = getToAdd(group, name, VariableHolder.class, variableLock, variables);
+    holder.var = variable;
+  }
+
+  static class Sampler implements JSONAware, JSONStreamAware {
+    Variable<Long> variable;
+    long[] values;
+    private AtomicLong sum;
+    private int last;
+    private boolean full;
+
+    void init(int size, Variable<Long> variable) {
+      this.variable = variable;
+      values = new long[size];
+      sum = new AtomicLong();
+      last = 0;
+    }
+
+    void sample() {
+      int index = last;
+      long valueGoingOut = values[last];
+      full = full || last == (values.length - 1);
+      last = (last + 1) % values.length;
+      values[index] = variable.getValue();
+      sum.addAndGet(-valueGoingOut + values[index]);
+    }
+
+    double getRate() {
+      return ((double) sum.get()) / ((full) ? values.length : ((last == 0) ? 1 : last));
+    }
+
+    @SuppressWarnings("unchecked")
+    private JSONObject getJSON() {
+      JSONObject json = new JSONObject();
+      json.put("sampler", getRate());
+      json.put("size", (full) ? values.length : last);
+      return json;
+    }
+
+    @Override
+    public String toJSONString() {
+      return getJSON().toJSONString();
+    }
+
+    @Override
+    public void writeJSONString(Writer out) throws IOException {
+      out.write(toJSONString());
+    }
+  }
+
+  @Override
+  public void addSampler(String group, String name, int samplingSize, Variable<Long> variable) {
+    Sampler sampler = getToAdd(group, name, Sampler.class, samplerLock, samplers);
+    samplerLock.lock();
+    try {
+      sampler.init(samplingSize, variable);
+      samplersList.add(sampler);
+    } finally {
+      samplerLock.unlock();
+    }
+  }
+
+  class SamplersRunnable implements Runnable {
+
+    @Override
+    public void run() {
+      samplerLock.lock();
+      try {
+        for (Sampler sampler : samplersList) {
+          sampler.sample();
+        }
+      } finally {
+        samplerLock.unlock();
+      }
+    }
+  }
+
+  @Override
+  public Map<String, Map<String, ?>> getSnapshot() {
+    return all;
+  }
+
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/scheduler/SchedulerService.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/scheduler/SchedulerService.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/scheduler/SchedulerService.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/scheduler/SchedulerService.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,129 @@
+/**
+ * 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.lib.service.scheduler;
+
+import org.apache.hadoop.lib.lang.RunnableCallable;
+import org.apache.hadoop.lib.server.BaseService;
+import org.apache.hadoop.lib.server.Server;
+import org.apache.hadoop.lib.server.ServiceException;
+import org.apache.hadoop.lib.service.Instrumentation;
+import org.apache.hadoop.lib.service.Scheduler;
+import org.apache.hadoop.lib.util.Check;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.text.MessageFormat;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+public class SchedulerService extends BaseService implements Scheduler {
+  private static final Logger LOG = LoggerFactory.getLogger(SchedulerService.class);
+
+  private static final String INST_GROUP = "scheduler";
+
+  public static final String PREFIX = "scheduler";
+
+  public static final String CONF_THREADS = "threads";
+
+  private ScheduledExecutorService scheduler;
+
+  public SchedulerService() {
+    super(PREFIX);
+  }
+
+  @Override
+  public void init() throws ServiceException {
+    int threads = getServiceConfig().getInt(CONF_THREADS, 5);
+    scheduler = new ScheduledThreadPoolExecutor(threads);
+    LOG.debug("Scheduler started");
+  }
+
+  @Override
+  public void destroy() {
+    try {
+      long limit = System.currentTimeMillis() + 30 * 1000;
+      scheduler.shutdownNow();
+      while (!scheduler.awaitTermination(1000, TimeUnit.MILLISECONDS)) {
+        LOG.debug("Waiting for scheduler to shutdown");
+        if (System.currentTimeMillis() > limit) {
+          LOG.warn("Gave up waiting for scheduler to shutdown");
+          break;
+        }
+      }
+      if (scheduler.isTerminated()) {
+        LOG.debug("Scheduler shutdown");
+      }
+    } catch (InterruptedException ex) {
+      LOG.warn(ex.getMessage(), ex);
+    }
+  }
+
+  @Override
+  public Class[] getServiceDependencies() {
+    return new Class[]{Instrumentation.class};
+  }
+
+  @Override
+  public Class getInterface() {
+    return Scheduler.class;
+  }
+
+  @Override
+  public void schedule(final Callable<?> callable, long delay, long interval, TimeUnit unit) {
+    Check.notNull(callable, "callable");
+    if (!scheduler.isShutdown()) {
+      LOG.debug("Scheduling callable [{}], interval [{}] seconds, delay [{}] in [{}]",
+                new Object[]{callable, delay, interval, unit});
+      Runnable r = new Runnable() {
+        public void run() {
+          String instrName = callable.getClass().getSimpleName();
+          Instrumentation instr = getServer().get(Instrumentation.class);
+          if (getServer().getStatus() == Server.Status.HALTED) {
+            LOG.debug("Skipping [{}], server status [{}]", callable, getServer().getStatus());
+            instr.incr(INST_GROUP, instrName + ".skips", 1);
+          } else {
+            LOG.debug("Executing [{}]", callable);
+            instr.incr(INST_GROUP, instrName + ".execs", 1);
+            Instrumentation.Cron cron = instr.createCron().start();
+            try {
+              callable.call();
+            } catch (Exception ex) {
+              instr.incr(INST_GROUP, instrName + ".fails", 1);
+              LOG.error("Error executing [{}], {}", new Object[]{callable, ex.getMessage(), ex});
+            } finally {
+              instr.addCron(INST_GROUP, instrName, cron.stop());
+            }
+          }
+        }
+      };
+      scheduler.scheduleWithFixedDelay(r, delay, interval, unit);
+    } else {
+      throw new IllegalStateException(
+        MessageFormat.format("Scheduler shutting down, ignoring scheduling of [{}]", callable));
+    }
+  }
+
+  @Override
+  public void schedule(Runnable runnable, long delay, long interval, TimeUnit unit) {
+    schedule((Callable<?>) new RunnableCallable(runnable), delay, interval, unit);
+  }
+
+}

Added: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/security/GroupsService.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/security/GroupsService.java?rev=1212060&view=auto
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/security/GroupsService.java (added)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/service/security/GroupsService.java Thu Dec  8 19:25:28 2011
@@ -0,0 +1,56 @@
+/**
+ * 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.lib.service.security;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.lib.server.BaseService;
+import org.apache.hadoop.lib.server.ServiceException;
+import org.apache.hadoop.lib.service.Groups;
+import org.apache.hadoop.lib.util.ConfigurationUtils;
+
+import java.io.IOException;
+import java.util.List;
+
+public class GroupsService extends BaseService implements Groups {
+  private static final String PREFIX = "groups";
+
+  private org.apache.hadoop.security.Groups hGroups;
+
+  public GroupsService() {
+    super(PREFIX);
+  }
+
+  @Override
+  protected void init() throws ServiceException {
+    Configuration hConf = new Configuration(false);
+    ConfigurationUtils.copy(getServiceConfig(), hConf);
+    hGroups = new org.apache.hadoop.security.Groups(hConf);
+  }
+
+  @Override
+  public Class getInterface() {
+    return Groups.class;
+  }
+
+  @Override
+  public List<String> getGroups(String user) throws IOException {
+    return hGroups.getGroups(user);
+  }
+
+}



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