webapp/wmservices/src/main/java/org/apache/oodt/cas/wmservices/servlets/WmServicesServlet.java

/*
 * 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.oodt.cas.wmservices.servlets;

import org.apache.cxf.jaxrs.servlet.CXFNonSpringJaxrsServlet;
import org.apache.oodt.cas.metadata.util.PathUtils;
import org.apache.oodt.cas.workflow.system.WorkflowManagerClient;
import org.apache.oodt.cas.workflow.system.rpc.RpcCommunicationFactory;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Initialize workflow manager services servlet
 *
 * <p>Set the following Parameters in context.xml for the webapp:
 *
 * <ul>
 *   <li>workflow.url
 *   <li>packagedRepo.dir.path
 * </ul>
 *
 * @author vratnakar
 */
public class WmServicesServlet extends CXFNonSpringJaxrsServlet {

  private static Logger logger = LoggerFactory.getLogger(WmServicesServlet.class);

  /**
   * The name of the servlet context attribute that holds a client for the workflow manager, a
   * {@link WorkflowManagerClient} object.
   */
  public static final String ATTR_NAME_CLIENT = "client";
  /**
   * The name of the servlet context attribute that holds the workflow manager's packaged repository
   * directory: a {@link File} object.
   */
  public static final String ATTR_NAME_PKG_REPO_DIR = "pkgRepoFilesDir";

  // Auto-generated ID for serialization.
  private static final long serialVersionUID = -7830210280506307805L;
  // Default URL for the workflow manager
  private static final String DEFAULT_WM_URL = "http://localhost:9001";
  // Servlet context parameter names.
  private static final String PARAM_NAME_URL = "workflow.url";
  private static final String PARAM_NAME_PKGREPO_DIR = "packagedRepo.dir.path"; // For Packaged Repo
  private WorkflowManagerClient client;

  @Override
  public void init(ServletConfig configuration) throws ServletException {
    super.init(configuration);
    ServletContext context = configuration.getServletContext();
    initializeClient(context);
    initializeWorkingDir(context);

    /*

      Refactored below code to separate methods

    // Initialize the workflow manager client.
    try {
      URL url = null;
      String urlParameter = context.getInitParameter(PARAM_NAME_URL);
      if (urlParameter != null) {
        // Get the workflow manager URL from the context parameter.
        url = new URL(PathUtils.replaceEnvVariables(urlParameter));
      } else {
        // Try the default URL for the workflow manager.
        LOGGER.log(Level.WARNING,
            "Unable to find the servlet context parameter" + " (\""
                + PARAM_NAME_URL + "\") for the workflow manager's URL.");
        url = new URL(DEFAULT_WM_URL);
      }
      // Attempt to connect the client to the workflow manager and if successful
      // store the client as a context attribute for other objects to access.
      client = RpcCommunicationFactory.createClient(url);
      context.setAttribute(ATTR_NAME_CLIENT, client);
    } catch (MalformedURLException e) {
      LOGGER.log(Level.SEVERE, "Encountered a malformed URL for the workflow manager.", e);
      throw new ServletException(e);
    }

    // Initialize the repository directory
    String pkgRepoDirPath = context.getInitParameter(PARAM_NAME_PKGREPO_DIR);
    if (pkgRepoDirPath != null) {
      pkgRepoDirPath = PathUtils.replaceEnvVariables(pkgRepoDirPath);
      File workflowDir = new File(pkgRepoDirPath);
      if (workflowDir.exists() && workflowDir.isDirectory()) {
        context.setAttribute(ATTR_NAME_PKG_REPO_DIR, workflowDir);
      } else {
        LOGGER.log(Level.SEVERE,
            "Unable to locate the Packaged repository directory ("
                + workflowDir.getAbsolutePath());
      }
    }

    */
  }

  /**
   * Initializes the Workflow manager client and stores it as a "client" context attribute by
   * retrieving a value for the workflow manager URL from the servlet context.
   *
   * @param context the servlet context
   * @throws ServletException if the servlet context parameter for the workflow manager working
   *     directory path cannot be found
   */
  private void initializeClient(ServletContext context) throws ServletException {
    String message;
    try {
      URL url;
      String urlParameter = context.getInitParameter(PARAM_NAME_URL);

      /* Get the workflow manager URL from the context parameter. */
      if (urlParameter != null) {
        url = new URL(PathUtils.replaceEnvVariables(urlParameter));
      } else {
        message = "Unable to find a servlet context parameter for the workflow manager URL.";
        /* Try the default URL for the Workflow manager. */
        logger.debug("WARNING Exception Thrown: {}", message);
        url = new URL(DEFAULT_WM_URL);
      }

      // Attempt to connect the client to the workflow manager and if successful
      // store the client as a context attribute for other objects to access.
      client = RpcCommunicationFactory.createClient(url);
      context.setAttribute("client", client);
    } catch (MalformedURLException e) {
      message = "Encountered a malformed URL for the workflow manager.";
      logger.debug("Exception thrown: {}", message, e);
      throw new ServletException(message);
    }
  }

  /**
   * Initializes the workflow manager working directory path and stores it as a "workingDir" context
   * attribute by retrieving a value from the servlet context.
   *
   * @param context the servlet context
   * @throws ServletException if the servlet context parameter for the workflow manager working
   *     directory path cannot be found
   */
  private void initializeWorkingDir(ServletContext context) throws ServletException {
    String workingDirPath = context.getInitParameter(PARAM_NAME_PKGREPO_DIR);
    String message;
    if (workingDirPath != null) {
      /* Validate the path. */
      File workingDir = new File(PathUtils.replaceEnvVariables(workingDirPath));
      if (workingDir.exists() && workingDir.isDirectory()) {
        context.setAttribute(ATTR_NAME_PKG_REPO_DIR, workingDir);
        message =
            "The workflow manager's working directory has been "
                + "set up as "
                + workingDir.getAbsolutePath();
        logger.debug("Exception thrown: {}", message);
      } else {
        message = "Unable to locate the working directory for " + "the workflow manager.";
        logger.debug("SEVERE Exception thrown: {}", message);
      }
    } else {
      message =
          "Unable to find a servlet context parameter for the workflow"
              + " manager working directory path.";
      logger.debug("SEVERE Exception thrown: {}", message);
      throw new ServletException(message);
    }
  }

  @Override
  public void destroy() {
    if (client != null) {
      try {
        client.close();
        client = null;
      } catch (IOException e) {
        String message = "Unable to close WM Client: " + e.getMessage();
        logger.debug("SEVERE Exception thrown: {}", message);
      }
    }

    super.destroy();
  }
}