java/src/main/com/google/apphosting/utils/config/EarHelper.java

   1 package com.google.apphosting.utils.config;
   2
   3 import com.google.common.base.Preconditions;
   4 import com.google.common.collect.ImmutableList;
   5
   6 import org.xml.sax.SAXException;
   7
   8 import java.io.File;
   9 import java.io.FileInputStream;
  10 import java.io.FileNotFoundException;
  11 import java.io.IOException;
  12 import java.io.InputStream;
  13 import java.util.logging.Logger;
  14
  15 import javax.annotation.Nullable;
  16 import javax.xml.XMLConstants;
  17 import javax.xml.transform.stream.StreamSource;
  18 import javax.xml.validation.SchemaFactory;
  19
  20 /**
  21  * Utility for server discovery within an EAR directory.
  22  *
  23  */
  24 public class EarHelper {
  25   private static final Logger LOGGER = Logger.getLogger(EarHelper.class.getName());
  26   private static final AppEngineApplicationXmlReader APP_ENGINE_APPLICATION_XML_READER =
  27       new AppEngineApplicationXmlReader();
  28   private static final ApplicationXmlReader APPLICATION_XML_READER = new ApplicationXmlReader();
  29
  30   private static final String META_INF = "META-INF";
  31   private static final String APPENGINE_APPLICATION_XML_NAME = "appengine-application.xml";
  32   private static final String APPLICATION_XML_NAME = "application.xml";
  33
  34   /**
  35    * Returns true if passed a path for an EAR directory.
  36    * <p>
  37    * This is a convenience fuction that simply calls
  38    * {@link #isEar(String, boolean)} for {@code directory} with {@code logWhyNot}
  39    * set to true.
  40    */
  41   public static boolean isEar(String dir) {
  42     return isEar(dir, true);
  43   }
  44
  45   /**
  46    * Returns true if {@code directory} contains a {@link #META_INF} sub-directory
  47    * with the required {@link #APPENGINE_APPLICATION_XML_NAME} and
  48    * {@link #APPLICATION_XML_NAME} files.
  49    * <p>
  50    * Note this test is a spot check to distinguish an EAR directory as
  51    * opposed to a WAR directory. Passing this test does not guarantee that a
  52    * directory is a fully valid EAR directory.
  53
  54    * @param directory The path for the directory to check or null
  55    * @param logWhyNot true means to log the reason this returns false if
  56    *     it does so.
  57    */
  58   public static boolean isEar(String directory, boolean logWhyNot) {
  59     if (directory == null) {
  60       if (logWhyNot) {
  61         LOGGER.fine("Directory 'null' is not an EAR directory. ");
  62       }
  63       return false;
  64     }
  65
  66     File metaInf = new File(directory, META_INF);
  67     if (!hasFile(metaInf, APPENGINE_APPLICATION_XML_NAME)) {
  68       logNotAnEar(directory.toString(), APPENGINE_APPLICATION_XML_NAME, logWhyNot);
  69       return false;
  70     }
  71
  72     if (!hasFile(metaInf, APPLICATION_XML_NAME)) {
  73       logNotAnEar(directory.toString(), APPLICATION_XML_NAME, logWhyNot);
  74       return false;
  75     }
  76
  77     return true;
  78   }
  79
  80   private static void logNotAnEar(String dir, String missingFile,
  81       boolean withLogging) {
  82     if (withLogging) {
  83       LOGGER.fine("Directory '" + dir + "' is not an EAR directory. File "
  84           + new File(dir, missingFile) + " not detected.");
  85     }
  86   }
  87
  88   private static void reportConfigException(String message) {
  89     LOGGER.info(message);
  90     throw new AppEngineConfigException(message);
  91   }
  92
  93   /**
  94    * Reads an {@link EarInfo from} the provided EAR directory.
  95    * Validation is done via the xsd schemaFile.
  96    * @throws AppEngineConfigException if the provided EAR directory is invalid.
  97    */
  98   public static EarInfo readEarInfo(String earDirectoryPath, File schemaFile)
  99       throws AppEngineConfigException {
 100     if (!isEar(earDirectoryPath)) {
 101       throw new IllegalArgumentException("earDir '" + earDirectoryPath
 102           + "' is not a valid EAR directory.");
 103     }
 104     File earDirectory = new File(earDirectoryPath).getAbsoluteFile();
 105     File metaInf = new File(earDirectory, META_INF);
 106     validateXml(new File(metaInf, APPENGINE_APPLICATION_XML_NAME), schemaFile);
 107     AppEngineApplicationXml appEngineApplicationXml = APP_ENGINE_APPLICATION_XML_READER.processXml(
 108         getInputStream(metaInf, APPENGINE_APPLICATION_XML_NAME));
 109     ApplicationXml applicationXml = APPLICATION_XML_READER.processXml(
 110         getInputStream(metaInf, APPLICATION_XML_NAME));
 111     String applicationId = appEngineApplicationXml.getApplicationId();
 112     ImmutableList.Builder<WebModule> moduleListBuilder = ImmutableList.builder();
 113     for (ApplicationXml.Modules.Web web : applicationXml.getModules().getWeb()) {
 114       File applicationDirectory = getApplicationDirectory(earDirectory, web.getWebUri());
 115       WebModule webModule = readWebModule(web.getContextRoot(), applicationDirectory,
 116           null, null, "");
 117       if (!applicationId.equals(webModule.getAppEngineWebXml().getAppId())) {
 118         LOGGER.info("Application id '" + appEngineApplicationXml.getApplicationId() + "' from '"
 119             + new File(metaInf, APPENGINE_APPLICATION_XML_NAME) + "' is overriding "
 120             + " application id '" + webModule.getAppEngineWebXml().getAppId() + "' from '"
 121             + new File(applicationDirectory, AppEngineWebXmlReader.DEFAULT_RELATIVE_FILENAME)
 122             + "'");
 123         webModule.getAppEngineWebXml().setAppId(applicationId);
 124       }
 125       moduleListBuilder.add(webModule);
 126     }
 127     ImmutableList<WebModule> webModules = moduleListBuilder.build();
 128     if (webModules.size() == 0) {
 129       reportConfigException("At least one web module is required in '"
 130           + new File(metaInf, APPLICATION_XML_NAME) + "'");
 131     }
 132     return new EarInfo(earDirectory, appEngineApplicationXml, applicationXml, webModules);
 133   }
 134
 135   /**
 136    * Reads a {@link WebModule} from the provided application directory.
 137    * <p>
 138    * If the application directory contains a WEB-INF/app.yaml file this will call
 139    * {@link AppYamlProcessor#convert} to generate WEB-INF/appengine-web.xml and
 140    * WEB-INF/web.xml files.
 141    *
 142    * @param contextRoot if this web module is part of an EAR supply the
 143    * context-root element from the web module's specification in
 144    * ear/META-INF/application.xml otherwise supply null to indicate the web
 145    * module has no context root.
 146    * @param applicationDirectory the application directory.
 147    * @param appengineWebXmlFile the appengine-web.xml to read or null to use the default.
 148    * @param webXmlFile the web.xml to read or null to use the default.
 149    * @param appIdPrefix a string to prepend to the app id read from appengine-web.xml. May be
 150    *     empty but not null.
 151    * @throws AppEngineConfigException if applicationDirectory is not correct.
 152    */
 153   public static WebModule readWebModule(
 154       @Nullable String contextRoot, File applicationDirectory, @Nullable File appengineWebXmlFile,
 155       @Nullable File webXmlFile, String appIdPrefix) throws AppEngineConfigException {
 156     Preconditions.checkNotNull(appIdPrefix);
 157     AppEngineWebXmlReader appEngineWebXmlReader =
 158         newAppEngineWebXmlReader(applicationDirectory, appengineWebXmlFile);
 159     WebXmlReader webXmlReader = newWebXmlReader(applicationDirectory, webXmlFile);
 160
 161     AppYamlProcessor.convert(new File(applicationDirectory, "WEB-INF"),
 162         appEngineWebXmlReader.getFilename(), webXmlReader.getFilename());
 163
 164     AppEngineWebXml appEngineWebXml;
 165     try {
 166       appEngineWebXml = appEngineWebXmlReader.readAppEngineWebXml();
 167     } catch (AppEngineConfigException aece) {
 168       throw new AppEngineConfigException(String.format("Invalid appengine-web.xml(%s) - %s",
 169           appEngineWebXmlReader.getFilename(), aece.getMessage()));
 170     }
 171     String appId = appEngineWebXml.getAppId();
 172     if (appId != null) {
 173       appEngineWebXml.setAppId(appIdPrefix + appEngineWebXml.getAppId());
 174     }
 175
 176     WebXml webXml = webXmlReader.readWebXml();
 177
 178     WebModule webModule =
 179         new WebModule(applicationDirectory, appEngineWebXml,
 180             new File(appEngineWebXmlReader.getFilename()), webXml,
 181             new File(webXmlReader.getFilename()), contextRoot);
 182     return webModule;
 183   }
 184
 185   private static File getApplicationDirectory(File earDirectory, String contextRoot) {
 186     File applicationDirectory = new File(earDirectory, contextRoot);
 187     if (!applicationDirectory.exists() || !applicationDirectory.isDirectory()) {
 188       reportConfigException("Application directory '" + applicationDirectory
 189           + "' must exist and be a directory.");
 190     }
 191     return applicationDirectory;
 192   }
 193
 194   private static AppEngineWebXmlReader newAppEngineWebXmlReader(File applicationDirectory,
 195       File appEngineWebXmlFile) {
 196     return appEngineWebXmlFile == null ?
 197         new AppEngineWebXmlReader(applicationDirectory.getAbsolutePath()) :
 198           new AppEngineWebXmlReader(appEngineWebXmlFile.getParent(),
 199               appEngineWebXmlFile.getName());
 200   }
 201
 202   private static WebXmlReader newWebXmlReader(File applicationDirectory, File webXmlFile) {
 203     return webXmlFile == null ?
 204         new WebXmlReader(applicationDirectory.getAbsolutePath()) :
 205           new WebXmlReader(webXmlFile.getParent(), webXmlFile.getName());
 206   }
 207
 208   /**
 209    * Returns an input stream for an existing file.
 210    */
 211   private static InputStream getInputStream(File parent, String fileName) {
 212     File file = new File(parent, fileName);
 213     try {
 214       return new FileInputStream(file);
 215     } catch (FileNotFoundException fnfe) {
 216       throw new IllegalStateException("File should exist - '" + file + "'");
 217     }
 218   }
 219
 220   private static boolean hasFile(File parent, String child) {
 221       File file = new File(parent, child);
 222       if (!file.isFile()) {
 223         return false;
 224       }
 225
 226       return true;
 227   }
 228
 229    /**
 230    * Validates a given XML document against a given schema.
 231    *
 232    * @param xml file with XML document
 233    * @param schema XSD schema to validate with
 234    *
 235    * @throws AppEngineConfigException for malformed XML, or IO errors
 236    */
 237   private static void validateXml(File xml, File schema) {
 238     if (!xml.exists()) {
 239       return;
 240     }
 241     StreamSource ss = null;
 242     try {
 243       SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
 244       try {
 245         ss = new StreamSource(new FileInputStream(xml));
 246         factory.newSchema(schema).newValidator().validate(ss);
 247       } catch (SAXException ex) {
 248         throw new AppEngineConfigException("XML error validating " +
 249             xml.getPath() + " against " + schema.getPath(), ex);
 250       }
 251     } catch (IOException ex) {
 252       throw new AppEngineConfigException("IO error validating " +
 253           xml.getPath() + " against " + schema.getPath(), ex);
 254     } finally {
 255       if (ss != null) {
 256         try {
 257           ss.getInputStream().close();
 258         } catch (IOException e) {
 259         }
 260       }
 261
 262     }
 263   }
 264
 265 }