HDFS-7597. DelegationTokenIdentifier should cache the TokenIdentifier to UGI mapping. Contributed by Daryn Sharp, Bob Hansen, and Xiao Chen.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/security/token/delegation/DelegationTokenIdentifier.java

@@ -21,13 +21,20 @@
 import java.io.ByteArrayInputStream;
 import java.io.DataInputStream;
 import java.io.IOException;
+import java.util.Collections;
+import java.util.Map;
 
+import org.apache.commons.collections.map.LRUMap;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hdfs.web.WebHdfsConstants;
 import org.apache.hadoop.io.Text;
+import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.security.token.Token;
+import org.apache.hadoop.security.token.TokenIdentifier;
 import org.apache.hadoop.security.token.delegation.AbstractDelegationTokenIdentifier;
 
+import com.google.common.annotations.VisibleForTesting;
+
 /**
  * A delegation token identifier that is specific to HDFS.
  */
@@ -37,6 +44,15 @@ public class DelegationTokenIdentifier
   public static final Text HDFS_DELEGATION_KIND =
       new Text("HDFS_DELEGATION_TOKEN");
 
+  @SuppressWarnings("unchecked")
+  private static Map<TokenIdentifier, UserGroupInformation> ugiCache =
+      Collections.synchronizedMap(new LRUMap(64));
+
+  @VisibleForTesting
+  public void clearCache() {
+    ugiCache.clear();
+  }
+
   /**
    * Create an empty delegation token identifier for reading into.
    */
@@ -58,6 +74,16 @@ public Text getKind() {
     return HDFS_DELEGATION_KIND;
   }
 
+  @Override
+  public UserGroupInformation getUser() {
+    UserGroupInformation ugi = ugiCache.get(this);
+    if (ugi == null) {
+      ugi = super.getUser();
+      ugiCache.put(this, ugi);
+    }
+    return ugi;
+  }
+
   @Override
   public String toString() {
     StringBuilder sbld = new StringBuilder();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/DataNodeUGIProvider.java

@@ -61,6 +61,13 @@ public static synchronized void init(Configuration conf) {
     }
   }
 
+  @VisibleForTesting
+  void clearCache() throws IOException {
+    if (UserGroupInformation.isSecurityEnabled()) {
+      params.delegationToken().decodeIdentifier().clearCache();
+    }
+  }
+
   UserGroupInformation ugi() throws IOException {
     UserGroupInformation ugi;
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/security/TestDelegationToken.java

@@ -239,7 +239,36 @@ public Object run() throws IOException {
       }
     });
   }
-  
+
+  @Test
+  public void testDelegationTokenUgi() throws Exception {
+    final DistributedFileSystem dfs = cluster.getFileSystem();
+    Token<?>[] tokens = dfs.addDelegationTokens("renewer", null);
+    Assert.assertEquals(1, tokens.length);
+    Token<?> token1 = tokens[0];
+    DelegationTokenIdentifier ident =
+        (DelegationTokenIdentifier) token1.decodeIdentifier();
+    UserGroupInformation expectedUgi = ident.getUser();
+
+    // get 2 new instances (clones) of the identifier, query their ugi
+    // twice each, all ugi instances should be equivalent
+    for (int i=0; i<2; i++) {
+      DelegationTokenIdentifier identClone =
+          (DelegationTokenIdentifier)token1.decodeIdentifier();
+      Assert.assertEquals(ident, identClone);
+      Assert.assertNotSame(ident, identClone);
+      Assert.assertSame(expectedUgi, identClone.getUser());
+      Assert.assertSame(expectedUgi, identClone.getUser());
+    }
+
+    // a new token must decode to a different ugi instance than the first token
+    tokens = dfs.addDelegationTokens("renewer", null);
+    Assert.assertEquals(1, tokens.length);
+    Token<?> token2 = tokens[0];
+    Assert.assertNotEquals(token1, token2);
+    Assert.assertNotSame(expectedUgi, token2.decodeIdentifier().getUser());
+  }
+
   /**
    * Test that the delegation token secret manager only runs when the
    * NN is out of safe mode. This is because the secret manager

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/common/TestJspHelper.java

@@ -109,6 +109,7 @@ public void testGetUgi() throws IOException {
     
     //Test attribute name.node.address 
     //Set the nnaddr url parameter to null.
+    token.decodeIdentifier().clearCache();
     when(request.getParameter(JspHelper.NAMENODE_ADDRESS)).thenReturn(null);
     InetSocketAddress addr = new InetSocketAddress("localhost", 2222);
     when(context.getAttribute(NameNodeHttpServer.NAMENODE_ADDRESS_ATTRIBUTE_KEY))
@@ -116,7 +117,12 @@ public void testGetUgi() throws IOException {
     verifyServiceInToken(context, request, addr.getAddress().getHostAddress()
         + ":2222");
     
-    //Test service already set in the token
+    //Test service already set in the token and DN doesn't change service
+    //when it doesn't know the NN service addr
+    userText = new Text(user+"2");
+    dtId = new DelegationTokenIdentifier(userText, userText, null);
+    token = new Token<DelegationTokenIdentifier>(
+        dtId, new DummySecretManager(0, 0, 0, 0));
     token.setService(new Text("3.3.3.3:3333"));
     tokenString = token.encodeToUrlString();
     //Set the name.node.address attribute in Servlet context to null

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/TestDataNodeUGIProvider.java

@@ -121,6 +121,7 @@ public void testUGICacheSecure() throws Exception {
         "With UGI cache, two UGIs for the different token should not be same",
         ugi11, url22);
 
+    ugiProvider2.clearCache();
     awaitCacheEmptyDueToExpiration();
     ugi12 = ugiProvider1.ugi();
     url22 = ugiProvider2.ugi();