HADOOP-14788. Credentials readTokenStorageFile to stop wrapping IOEs in IOEs.

Contributed by Ajay Kumar.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/IOUtils.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.io;
 
 import java.io.*;
+import java.lang.reflect.Constructor;
 import java.net.Socket;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
@@ -35,6 +36,7 @@ import org.apache.commons.logging.Log;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.PathIOException;
 import org.apache.hadoop.util.Shell;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -450,4 +452,58 @@ public class IOUtils {
       throw ioe;
     }
   }
+
+  /**
+   * Takes an IOException, file/directory path, and method name and returns an
+   * IOException with the input exception as the cause and also include the
+   * file,method details. The new exception provides the stack trace of the
+   * place where the exception is thrown and some extra diagnostics
+   * information.
+   *
+   * Return instance of same exception if exception class has a public string
+   * constructor; Otherwise return an PathIOException.
+   * InterruptedIOException and PathIOException are returned unwrapped.
+   *
+   * @param path file/directory path
+   * @param methodName method name
+   * @param exception the caught exception.
+   * @return an exception to throw
+   */
+  public static IOException wrapException(final String path,
+      final String methodName, final IOException exception) {
+
+    if (exception instanceof InterruptedIOException
+        || exception instanceof PathIOException) {
+      return exception;
+    } else {
+      String msg = String
+          .format("Failed with %s while processing file/directory :[%s] in "
+                  + "method:[%s]",
+              exception.getClass().getName(), path, methodName);
+      try {
+        return wrapWithMessage(exception, msg);
+      } catch (Exception ex) {
+        // For subclasses which have no (String) constructor throw IOException
+        // with wrapped message
+
+        return new PathIOException(path, exception);
+      }
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  private static <T extends IOException> T wrapWithMessage(
+      final T exception, final String msg) throws T {
+    Class<? extends Throwable> clazz = exception.getClass();
+    try {
+      Constructor<? extends Throwable> ctor = clazz
+          .getConstructor(String.class);
+      Throwable t = ctor.newInstance(msg);
+      return (T) (t.initCause(exception));
+    } catch (Throwable e) {
+      LOG.warn("Unable to wrap exception of type " +
+          clazz + ": it has no (String) constructor", e);
+      throw exception;
+    }
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/Credentials.java

@@ -207,7 +207,8 @@ public class Credentials implements Writable {
       in.close();
       return credentials;
     } catch(IOException ioe) {
-      throw new IOException("Exception reading " + filename, ioe);
+      throw IOUtils.wrapException(filename.toString(), "Credentials"
+          + ".readTokenStorageFile", ioe);
     } finally {
       IOUtils.cleanupWithLogger(LOG, in);
     }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/TestIOUtils.java

@@ -33,13 +33,16 @@ import java.io.OutputStream;
 import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
+import java.nio.charset.CharacterCodingException;
 import java.nio.file.Files;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
-import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.FileUtils;;
+import org.apache.hadoop.fs.PathIOException;
 import org.apache.hadoop.test.GenericTestUtils;
+import org.apache.hadoop.test.LambdaTestUtils;
 import org.junit.Assert;
 import org.junit.Test;
 import org.mockito.Mockito;
@@ -328,4 +331,24 @@ public class TestIOUtils {
     }
 
   }
+
+  @Test
+  public void testWrapException() throws Exception {
+    // Test for IOException with valid (String) constructor
+    LambdaTestUtils.intercept(EOFException.class,
+        "Failed with java.io.EOFException while processing file/directory "
+            + ":[/tmp/abc.txt] in method:[testWrapException]", () -> {
+          throw IOUtils.wrapException("/tmp/abc.txt", "testWrapException",
+              new EOFException("EOFException "));
+        });
+
+    // Test for IOException with  no (String) constructor
+    PathIOException returnedEx = LambdaTestUtils
+        .intercept(PathIOException.class, "Input/output error:",
+            () -> {
+              throw IOUtils.wrapException("/tmp/abc.txt", "testWrapEx",
+                  new CharacterCodingException());
+            });
+    assertEquals("/tmp/abc.txt", returnedEx.getPath().toString());
+  }
 }