HADOOP-7171. Support UGI in FileContext API. Contributed by jitendra.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1092832 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -20,6 +20,8 @@ Trunk (unreleased changes)
 
     HADOOP-6994. Api to get delegation token in AbstractFileSystem. (jitendra)
 
+    HADOOP-7171. Support UGI in FileContext API. (jitendra)
+
   IMPROVEMENTS
 
     HADOOP-7042. Updates to test-patch.sh to include failed test names and

src/java/org/apache/hadoop/fs/FileContext.java

@@ -22,6 +22,7 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URI;
+import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.EnumSet;
@@ -50,6 +51,7 @@
 import org.apache.hadoop.ipc.UnexpectedServerException;
 import org.apache.hadoop.fs.InvalidPathException;
 import org.apache.hadoop.security.AccessControlException;
+import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.security.token.Token;
 
 /**
@@ -196,12 +198,20 @@ public boolean accept(final Path file) {
   private Path workingDir;          // Fully qualified
   private FsPermission umask;
   private final Configuration conf;
+  private final UserGroupInformation ugi;
 
   private FileContext(final AbstractFileSystem defFs,
     final FsPermission theUmask, final Configuration aConf) {
     defaultFS = defFs;
     umask = FsPermission.getUMask(aConf);
     conf = aConf;
+    try {
+      ugi = UserGroupInformation.getCurrentUser();
+    } catch (IOException e) {
+      LOG.error("Exception in getCurrentUser: ",e);
+      throw new RuntimeException("Failed to get the current user " +
+      		"while creating a FileContext", e);
+    }
     /*
      * Init the wd.
      * WorkingDir is implemented at the FileContext layer 
@@ -276,9 +286,11 @@ private static void checkNotSchemeWithRelative(final Path path) {
    * 
    * @throws UnsupportedFileSystemException If the file system for
    *           <code>absOrFqPath</code> is not supported.
+   * @throws IOExcepton If the file system for <code>absOrFqPath</code> could
+   *         not be instantiated.
    */
   private AbstractFileSystem getFSofPath(final Path absOrFqPath)
-      throws UnsupportedFileSystemException {
+      throws UnsupportedFileSystemException, IOException {
     checkNotSchemeWithRelative(absOrFqPath);
     if (!absOrFqPath.isAbsolute() && absOrFqPath.toUri().getScheme() == null) {
       throw new HadoopIllegalArgumentException(
@@ -290,10 +302,25 @@ private AbstractFileSystem getFSofPath(final Path absOrFqPath)
       defaultFS.checkPath(absOrFqPath);
       return defaultFS;
     } catch (Exception e) { // it is different FileSystem
-      return AbstractFileSystem.get(absOrFqPath.toUri(), conf);
+      return getAbstractFileSystem(ugi, absOrFqPath.toUri(), conf);
     }
   }
   
+  private static AbstractFileSystem getAbstractFileSystem(
+      UserGroupInformation user, final URI uri, final Configuration conf)
+      throws UnsupportedFileSystemException, IOException {
+    try {
+      return user.doAs(new PrivilegedExceptionAction<AbstractFileSystem>() {
+        public AbstractFileSystem run() throws UnsupportedFileSystemException {
+          return AbstractFileSystem.get(uri, conf);
+        }
+      });
+    } catch (InterruptedException ex) {
+      LOG.error(ex);
+      throw new IOException("Failed to get the AbstractFileSystem for path: "
+          + uri, ex);
+    }
+  }
   
   /**
    * Protected Static Factory methods for getting a FileContexts
@@ -390,10 +417,23 @@ public static FileContext getFileContext(final URI defaultFsUri)
    * @return new FileContext for specified uri
    * @throws UnsupportedFileSystemException If the file system with specified is
    *           not supported
+   * @throws RuntimeException If the file system specified is supported but
+   *         could not be instantiated, or if login fails.
    */
   public static FileContext getFileContext(final URI defaultFsUri,
       final Configuration aConf) throws UnsupportedFileSystemException {
-    return getFileContext(AbstractFileSystem.get(defaultFsUri,  aConf), aConf);
+    UserGroupInformation currentUser = null;
+    AbstractFileSystem defaultAfs = null;
+    try {
+      currentUser = UserGroupInformation.getCurrentUser();
+      defaultAfs = getAbstractFileSystem(currentUser, defaultFsUri, aConf);
+    } catch (UnsupportedFileSystemException ex) {
+      throw ex;
+    } catch (IOException ex) {
+      LOG.error(ex);
+      throw new RuntimeException(ex);
+    }
+    return getFileContext(defaultAfs, aConf);
   }
 
   /**
@@ -477,6 +517,14 @@ public Path getWorkingDirectory() {
     return workingDir;
   }
   
+  /**
+   * Gets the ugi in the file-context
+   * @return UserGroupInformation
+   */
+  public UserGroupInformation getUgi() {
+    return ugi;
+  }
+  
   /**
    * 
    * @return the umask of this FileContext

src/test/core/org/apache/hadoop/fs/FileContextPermissionBase.java

@@ -18,6 +18,7 @@
 package org.apache.hadoop.fs;
 
 import java.io.IOException;
+import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.StringTokenizer;
@@ -25,6 +26,7 @@
 import junit.framework.Assert;
 
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.util.Shell;
 import org.apache.hadoop.util.StringUtils;
 import org.junit.After;
@@ -32,6 +34,7 @@
 import org.junit.Test;
 
 import static org.apache.hadoop.fs.FileContextTestHelper.*;
+import static org.junit.Assert.assertEquals;
 
 /**
  * <p>
@@ -163,6 +166,22 @@ public void testSetOwner() throws IOException {
     finally {cleanupFile(fc, f);}
   }
   
+  @Test
+  public void testUgi() throws IOException, InterruptedException {
+    
+    UserGroupInformation otherUser = UserGroupInformation
+        .createRemoteUser("otherUser");
+    FileContext newFc = otherUser.doAs(new PrivilegedExceptionAction<FileContext>() {
+
+      public FileContext run() throws Exception {
+        FileContext newFc = FileContext.getFileContext();
+        return newFc;
+      }
+      
+    });
+    assertEquals("otherUser",newFc.getUgi().getUserName());
+  }
+
   static List<String> getGroups() throws IOException {
     List<String> a = new ArrayList<String>();
     String s = Shell.execCommand(Shell.getGroupsCommand());