HADOOP-9150. Avoid unnecessary DNS resolution attempts for logical URIs. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1462303 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -538,6 +538,9 @@ Release 2.0.5-beta - UNRELEASED
 
   OPTIMIZATIONS
 
+    HADOOP-9150. Avoid unnecessary DNS resolution attempts for logical URIs
+    (todd)
+
   BUG FIXES
 
     HADOOP-9294. GetGroupsTestBase fails on Windows. (Chris Nauroth via suresh)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java

@@ -21,6 +21,7 @@ import java.io.Closeable;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.net.URI;
+import java.net.URISyntaxException;
 import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -211,12 +212,46 @@ public abstract class FileSystem extends Configured implements Closeable {
   public abstract URI getUri();
   
   /**
-   * Resolve the uri's hostname and add the default port if not in the uri
+   * Return a canonicalized form of this FileSystem's URI.
+   * 
+   * The default implementation simply calls {@link #canonicalizeUri(URI)}
+   * on the filesystem's own URI, so subclasses typically only need to
+   * implement that method.
+   *
+   * @see #canonicalizeUri(URI)
+   */
+  protected URI getCanonicalUri() {
+    return canonicalizeUri(getUri());
+  }
+  
+  /**
+   * Canonicalize the given URI.
+   * 
+   * This is filesystem-dependent, but may for example consist of
+   * canonicalizing the hostname using DNS and adding the default
+   * port if not specified.
+   * 
+   * The default implementation simply fills in the default port if
+   * not specified and if the filesystem has a default port.
+   *
    * @return URI
    * @see NetUtils#getCanonicalUri(URI, int)
    */
-  protected URI getCanonicalUri() {
+  protected URI canonicalizeUri(URI uri) {
-    return NetUtils.getCanonicalUri(getUri(), getDefaultPort());
+    if (uri.getPort() == -1 && getDefaultPort() > 0) {
+      // reconstruct the uri with the default port set
+      try {
+        uri = new URI(uri.getScheme(), uri.getUserInfo(),
+            uri.getHost(), getDefaultPort(),
+            uri.getPath(), uri.getQuery(), uri.getFragment());
+      } catch (URISyntaxException e) {
+        // Should never happen!
+        throw new AssertionError("Valid URI became unparseable: " +
+            uri);
+      }
+    }
+    
+    return uri;
   }
   
   /**
@@ -581,7 +616,7 @@ public abstract class FileSystem extends Configured implements Closeable {
       }
       if (uri != null) {
         // canonicalize uri before comparing with this fs
-        uri = NetUtils.getCanonicalUri(uri, getDefaultPort());
+        uri = canonicalizeUri(uri);
         thatAuthority = uri.getAuthority();
         if (thisAuthority == thatAuthority ||       // authorities match
             (thisAuthority != null &&

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FilterFileSystem.java

@@ -96,15 +96,17 @@ public class FilterFileSystem extends FileSystem {
     return fs.getUri();
   }
   
-  /**
+  
-   * Returns a qualified URI whose scheme and authority identify this
-   * FileSystem.
-   */
   @Override
   protected URI getCanonicalUri() {
     return fs.getCanonicalUri();
   }
 
+  @Override
+  protected URI canonicalizeUri(URI uri) {
+    return fs.canonicalizeUri(uri);
+  }
+
   /** Make sure that a path specifies a FileSystem. */
   @Override
   public Path makeQualified(Path path) {

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemCanonicalization.java

@@ -26,6 +26,7 @@ import java.net.URI;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.net.NetUtils;
 import org.apache.hadoop.security.NetUtilsTestResolver;
 import org.apache.hadoop.util.Progressable;
 import org.junit.BeforeClass;
@@ -312,6 +313,11 @@ public class TestFileSystemCanonicalization {
       return defaultPort;
     }
     
+    @Override
+    protected URI canonicalizeUri(URI uri) {
+      return NetUtils.getCanonicalUri(uri, getDefaultPort());
+    }
+
     @Override
     public FSDataInputStream open(Path f, int bufferSize) throws IOException {
       throw new IOException("not supposed to be here");

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/test/GenericTestUtils.java

@@ -20,6 +20,7 @@ package org.apache.hadoop.test;
 import java.io.File;
 import java.io.IOException;
 import java.io.StringWriter;
+import java.lang.reflect.InvocationTargetException;
 import java.util.Arrays;
 import java.util.Random;
 import java.util.Set;
@@ -266,15 +267,29 @@ public abstract class GenericTestUtils {
    */
   public static class DelegateAnswer implements Answer<Object> { 
     private final Object delegate;
+    private final Log log;
     
     public DelegateAnswer(Object delegate) {
+      this(null, delegate);
+    }
+    
+    public DelegateAnswer(Log log, Object delegate) {
+      this.log = log;
       this.delegate = delegate;
     }
 
     @Override
     public Object answer(InvocationOnMock invocation) throws Throwable {
+      try {
+        if (log != null) {
+          log.info("Call to " + invocation + " on " + delegate,
+              new Exception("TRACE"));
+        }
         return invocation.getMethod().invoke(
             delegate, invocation.getArguments());
+      } catch (InvocationTargetException ite) {
+        throw ite.getCause();
+      }
     }
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -62,6 +62,7 @@ import org.apache.hadoop.hdfs.security.token.block.InvalidBlockTokenException;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.io.Text;
+import org.apache.hadoop.net.NetUtils;
 import org.apache.hadoop.security.AccessControlException;
 import org.apache.hadoop.security.token.SecretManager.InvalidToken;
 import org.apache.hadoop.security.token.Token;
@@ -894,6 +895,17 @@ public class DistributedFileSystem extends FileSystem {
     return dfs.getCanonicalServiceName();
   }
   
+  @Override
+  protected URI canonicalizeUri(URI uri) {
+    if (HAUtil.isLogicalUri(getConf(), uri)) {
+      // Don't try to DNS-resolve logical URIs, since the 'authority'
+      // portion isn't a proper hostname
+      return uri;
+    } else {
+      return NetUtils.getCanonicalUri(uri, getDefaultPort());
+    }
+  }
+
   /**
    * Utility function that returns if the NameNode is in safemode or not. In HA
    * mode, this API will return only ActiveNN's safemode status.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/HftpFileSystem.java

@@ -162,6 +162,11 @@ public class HftpFileSystem extends FileSystem
     return SecurityUtil.buildTokenService(nnSecureUri).toString();
   }
   
+  @Override
+  protected URI canonicalizeUri(URI uri) {
+    return NetUtils.getCanonicalUri(uri, getDefaultPort());
+  }
+
   /**
    * Return the protocol scheme for the FileSystem.
    * <p/>

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java

@@ -239,6 +239,11 @@ public class WebHdfsFileSystem extends FileSystem
     return this.uri;
   }
   
+  @Override
+  protected URI canonicalizeUri(URI uri) {
+    return NetUtils.getCanonicalUri(uri, getDefaultPort());
+  }
+
   /** @return the home directory. */
   public static String getHomeDirectoryString(final UserGroupInformation ugi) {
     return "/user/" + ugi.getShortUserName();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSClientFailover.java

@@ -26,8 +26,11 @@ import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.net.Socket;
 import java.net.SocketAddress;
+import java.lang.reflect.Field;
+import java.net.InetAddress;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.List;
 
 import javax.net.SocketFactory;
 
@@ -35,6 +38,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
+import org.apache.hadoop.fs.FileContext;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
@@ -48,10 +52,13 @@ import org.apache.hadoop.util.StringUtils;
 import org.hamcrest.BaseMatcher;
 import org.hamcrest.Description;
 import org.junit.After;
+import org.junit.Assume;
 import org.junit.Before;
 import org.junit.Test;
 import org.mockito.Mockito;
 
+import sun.net.spi.nameservice.NameService;
+
 public class TestDFSClientFailover {
   
   private static final Log LOG = LogFactory.getLog(TestDFSClientFailover.class);
@@ -201,4 +208,74 @@ public class TestDFSClientFailover {
           "Could not find any configured addresses for URI " + uri));
     }
   }
+
+  /**
+   * Spy on the Java DNS infrastructure.
+   * This likely only works on Sun-derived JDKs, but uses JUnit's
+   * Assume functionality so that any tests using it are skipped on
+   * incompatible JDKs.
+   */
+  private NameService spyOnNameService() {
+    try {
+      Field f = InetAddress.class.getDeclaredField("nameServices");
+      f.setAccessible(true);
+      Assume.assumeNotNull(f);
+      @SuppressWarnings("unchecked")
+      List<NameService> nsList = (List<NameService>) f.get(null);
+
+      NameService ns = nsList.get(0);
+      Log log = LogFactory.getLog("NameServiceSpy");
+      
+      ns = Mockito.mock(NameService.class,
+          new GenericTestUtils.DelegateAnswer(log, ns));
+      nsList.set(0, ns);
+      return ns;
+    } catch (Throwable t) {
+      LOG.info("Unable to spy on DNS. Skipping test.", t);
+      // In case the JDK we're testing on doesn't work like Sun's, just
+      // skip the test.
+      Assume.assumeNoException(t);
+      throw new RuntimeException(t);
+    }
+  }
+  
+  /**
+   * Test that the client doesn't ever try to DNS-resolve the logical URI.
+   * Regression test for HADOOP-9150.
+   */
+  @Test
+  public void testDoesntDnsResolveLogicalURI() throws Exception {
+    NameService spyNS = spyOnNameService();
+    
+    FileSystem fs = HATestUtil.configureFailoverFs(cluster, conf);
+    String logicalHost = fs.getUri().getHost();
+    Path qualifiedRoot = fs.makeQualified(new Path("/"));
+    
+    // Make a few calls against the filesystem.
+    fs.getCanonicalServiceName();
+    fs.listStatus(qualifiedRoot);
+    
+    // Ensure that the logical hostname was never resolved.
+    Mockito.verify(spyNS, Mockito.never()).lookupAllHostAddr(Mockito.eq(logicalHost));
+  }
+  
+  /**
+   * Same test as above, but for FileContext.
+   */
+  @Test
+  public void testFileContextDoesntDnsResolveLogicalURI() throws Exception {
+    NameService spyNS = spyOnNameService();
+    FileSystem fs = HATestUtil.configureFailoverFs(cluster, conf);
+    String logicalHost = fs.getUri().getHost();
+    Configuration haClientConf = fs.getConf();
+    
+    FileContext fc = FileContext.getFileContext(haClientConf);
+    Path root = new Path("/");
+    fc.listStatus(root);
+    fc.listStatus(fc.makeQualified(root));
+    fc.getDefaultFileSystem().getCanonicalServiceName();
+
+    // Ensure that the logical hostname was never resolved.
+    Mockito.verify(spyNS, Mockito.never()).lookupAllHostAddr(Mockito.eq(logicalHost));
+  }
 }