HDFS-8213. DFSClient should use hdfs.client.htrace HTrace configuration prefix rather than hadoop.htrace (cmccabe)

(cherry picked from commit b82567d45507c50d2f28eff4bbdf3b1a69d4bf1b)
(cherry picked from commit 9edea9507db2566cf465a77953320b1349859486)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/tracing/SpanReceiverHost.java

@@ -25,6 +25,7 @@ import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
@@ -52,41 +53,36 @@ import org.apache.htrace.Trace;
  */
 @InterfaceAudience.Private
 public class SpanReceiverHost implements TraceAdminProtocol {
-  public static final String SPAN_RECEIVERS_CONF_KEY =
-    "hadoop.htrace.spanreceiver.classes";
+  public static final String SPAN_RECEIVERS_CONF_SUFFIX =
+    "spanreceiver.classes";
   private static final Log LOG = LogFactory.getLog(SpanReceiverHost.class);
+  private static final HashMap<String, SpanReceiverHost> hosts =
+      new HashMap<String, SpanReceiverHost>(1);
   private final TreeMap<Long, SpanReceiver> receivers =
       new TreeMap<Long, SpanReceiver>();
+  private final String confPrefix;
   private Configuration config;
   private boolean closed = false;
   private long highestId = 1;
 
-  private final static String LOCAL_FILE_SPAN_RECEIVER_PATH =
-      "hadoop.htrace.local-file-span-receiver.path";
+  private final static String LOCAL_FILE_SPAN_RECEIVER_PATH_SUFFIX =
+      "local-file-span-receiver.path";
 
-  private static enum SingletonHolder {
-    INSTANCE;
-    Object lock = new Object();
-    SpanReceiverHost host = null;
-  }
-
-  public static SpanReceiverHost getInstance(Configuration conf) {
-    if (SingletonHolder.INSTANCE.host != null) {
-      return SingletonHolder.INSTANCE.host;
-    }
-    synchronized (SingletonHolder.INSTANCE.lock) {
-      if (SingletonHolder.INSTANCE.host != null) {
-        return SingletonHolder.INSTANCE.host;
+  public static SpanReceiverHost get(Configuration conf, String confPrefix) {
+    synchronized (SpanReceiverHost.class) {
+      SpanReceiverHost host = hosts.get(confPrefix);
+      if (host != null) {
+        return host;
       }
-      SpanReceiverHost host = new SpanReceiverHost();
-      host.loadSpanReceivers(conf);
-      SingletonHolder.INSTANCE.host = host;
+      final SpanReceiverHost newHost = new SpanReceiverHost(confPrefix);
+      newHost.loadSpanReceivers(conf);
       ShutdownHookManager.get().addShutdownHook(new Runnable() {
           public void run() {
-            SingletonHolder.INSTANCE.host.closeReceivers();
+            newHost.closeReceivers();
           }
         }, 0);
-      return SingletonHolder.INSTANCE.host;
+      hosts.put(confPrefix, newHost);
+      return newHost;
     }
   }
 
@@ -119,6 +115,10 @@ public class SpanReceiverHost implements TraceAdminProtocol {
     return new File(tmp, nonce).getAbsolutePath();
   }
 
+  private SpanReceiverHost(String confPrefix) {
+    this.confPrefix = confPrefix;
+  }
+
   /**
    * Reads the names of classes specified in the
    * "hadoop.htrace.spanreceiver.classes" property and instantiates and registers
@@ -131,22 +131,22 @@ public class SpanReceiverHost implements TraceAdminProtocol {
    */
   public synchronized void loadSpanReceivers(Configuration conf) {
     config = new Configuration(conf);
-    String[] receiverNames =
-        config.getTrimmedStrings(SPAN_RECEIVERS_CONF_KEY);
+    String receiverKey = confPrefix + SPAN_RECEIVERS_CONF_SUFFIX;
+    String[] receiverNames = config.getTrimmedStrings(receiverKey);
     if (receiverNames == null || receiverNames.length == 0) {
       if (LOG.isTraceEnabled()) {
-        LOG.trace("No span receiver names found in " +
-                  SPAN_RECEIVERS_CONF_KEY + ".");
+        LOG.trace("No span receiver names found in " + receiverKey + ".");
       }
       return;
     }
     // It's convenient to have each daemon log to a random trace file when
     // testing.
-    if (config.get(LOCAL_FILE_SPAN_RECEIVER_PATH) == null) {
+    String pathKey = confPrefix + LOCAL_FILE_SPAN_RECEIVER_PATH_SUFFIX;
+    if (config.get(pathKey) == null) {
       String uniqueFile = getUniqueLocalTraceFileName();
-      config.set(LOCAL_FILE_SPAN_RECEIVER_PATH, uniqueFile);
+      config.set(pathKey, uniqueFile);
       if (LOG.isTraceEnabled()) {
-        LOG.trace("Set " + LOCAL_FILE_SPAN_RECEIVER_PATH + " to " +  uniqueFile);
+        LOG.trace("Set " + pathKey + " to " + uniqueFile);
       }
     }
     for (String className : receiverNames) {
@@ -164,7 +164,8 @@ public class SpanReceiverHost implements TraceAdminProtocol {
   private synchronized SpanReceiver loadInstance(String className,
       List<ConfigurationPair> extraConfig) throws IOException {
     SpanReceiverBuilder builder =
-        new SpanReceiverBuilder(TraceUtils.wrapHadoopConf(config, extraConfig));
+        new SpanReceiverBuilder(TraceUtils.
+            wrapHadoopConf(confPrefix, config, extraConfig));
     SpanReceiver rcvr = builder.spanReceiverClass(className.trim()).build();
     if (rcvr == null) {
       throw new IOException("Failed to load SpanReceiver " + className);

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/tracing/TraceUtils.java

@@ -31,15 +31,15 @@ import org.apache.htrace.HTraceConfiguration;
  */
 @InterfaceAudience.Private
 public class TraceUtils {
-  public static final String HTRACE_CONF_PREFIX = "hadoop.htrace.";
   private static List<ConfigurationPair> EMPTY = Collections.emptyList();
 
-  public static HTraceConfiguration wrapHadoopConf(final Configuration conf) {
-    return wrapHadoopConf(conf, EMPTY);
+  public static HTraceConfiguration wrapHadoopConf(final String prefix,
+        final Configuration conf) {
+    return wrapHadoopConf(prefix, conf, EMPTY);
   }
 
-  public static HTraceConfiguration wrapHadoopConf(final Configuration conf,
-          List<ConfigurationPair> extraConfig) {
+  public static HTraceConfiguration wrapHadoopConf(final String prefix,
+        final Configuration conf, List<ConfigurationPair> extraConfig) {
     final HashMap<String, String> extraMap = new HashMap<String, String>();
     for (ConfigurationPair pair : extraConfig) {
       extraMap.put(pair.getKey(), pair.getValue());
@@ -50,7 +50,7 @@ public class TraceUtils {
         if (extraMap.containsKey(key)) {
           return extraMap.get(key);
         }
-        return conf.get(HTRACE_CONF_PREFIX + key, "");
+        return conf.get(prefix + key, "");
       }
 
       @Override
@@ -58,7 +58,7 @@ public class TraceUtils {
         if (extraMap.containsKey(key)) {
           return extraMap.get(key);
         }
-        return conf.get(HTRACE_CONF_PREFIX + key, defaultValue);
+        return conf.get(prefix + key, defaultValue);
       }
     };
   }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/tracing/TestTraceUtils.java

@@ -25,13 +25,15 @@ import org.apache.htrace.HTraceConfiguration;
 import org.junit.Test;
 
 public class TestTraceUtils {
+  private static String TEST_PREFIX = "test.prefix.htrace.";
+
   @Test
   public void testWrappedHadoopConf() {
     String key = "sampler";
     String value = "ProbabilitySampler";
     Configuration conf = new Configuration();
-    conf.set(TraceUtils.HTRACE_CONF_PREFIX + key, value);
-    HTraceConfiguration wrapped = TraceUtils.wrapHadoopConf(conf);
+    conf.set(TEST_PREFIX + key, value);
+    HTraceConfiguration wrapped = TraceUtils.wrapHadoopConf(TEST_PREFIX, conf);
     assertEquals(value, wrapped.get(key));
   }
 
@@ -41,11 +43,11 @@ public class TestTraceUtils {
     String oldValue = "old value";
     String newValue = "new value";
     Configuration conf = new Configuration();
-    conf.set(TraceUtils.HTRACE_CONF_PREFIX + key, oldValue);
+    conf.set(TEST_PREFIX + key, oldValue);
     LinkedList<ConfigurationPair> extraConfig =
         new LinkedList<ConfigurationPair>();
     extraConfig.add(new ConfigurationPair(key, newValue));
-    HTraceConfiguration wrapped = TraceUtils.wrapHadoopConf(conf, extraConfig);
+    HTraceConfiguration wrapped = TraceUtils.wrapHadoopConf(TEST_PREFIX, conf, extraConfig);
     assertEquals(newValue, wrapped.get(key));
   }
 }

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -19,6 +19,9 @@ Release 2.7.1 - UNRELEASED
     HDFS-7770. Need document for storage type label of data node storage
     locations under dfs.data.dir. (Xiaoyu Yao via aajisaka)
 
+    HDFS-8213. DFSClient should use hdfs.client.htrace HTrace configuration
+    prefix rather than hadoop.htrace (cmccabe)
+
   OPTIMIZATIONS
 
   BUG FIXES

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

@@ -631,8 +631,9 @@ public class DFSClient implements java.io.Closeable, RemotePeerFactory,
   public DFSClient(URI nameNodeUri, ClientProtocol rpcNamenode,
       Configuration conf, FileSystem.Statistics stats)
     throws IOException {
-    SpanReceiverHost.getInstance(conf);
-    traceSampler = new SamplerBuilder(TraceUtils.wrapHadoopConf(conf)).build();
+    SpanReceiverHost.get(conf, DFSConfigKeys.DFS_CLIENT_HTRACE_PREFIX);
+    traceSampler = new SamplerBuilder(TraceUtils.
+        wrapHadoopConf(DFSConfigKeys.DFS_CLIENT_HTRACE_PREFIX, conf)).build();
     // Copy only the required DFSClient configuration
     this.dfsClientConf = new Conf(conf);
     if (this.dfsClientConf.useLegacyBlockReaderLocal) {

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

@@ -101,6 +101,13 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String DFS_WEBHDFS_ACL_PERMISSION_PATTERN_DEFAULT =
       "^(default:)?(user|group|mask|other):[[A-Za-z_][A-Za-z0-9._-]]*:([rwx-]{3})?(,(default:)?(user|group|mask|other):[[A-Za-z_][A-Za-z0-9._-]]*:([rwx-]{3})?)*$";
 
+  // HDFS HTrace configuration is controlled by dfs.htrace.spanreceiver.classes,
+  // etc.
+  public static final String  DFS_SERVER_HTRACE_PREFIX = "dfs.htrace.";
+
+  // HDFS client HTrace configuration.
+  public static final String  DFS_CLIENT_HTRACE_PREFIX = "dfs.client.htrace.";
+
   // HA related configuration
   public static final String  DFS_CLIENT_FAILOVER_PROXY_PROVIDER_KEY_PREFIX = "dfs.client.failover.proxy.provider";
   public static final String  DFS_CLIENT_FAILOVER_MAX_ATTEMPTS_KEY = "dfs.client.failover.max.attempts";

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -1099,7 +1099,8 @@ public class DataNode extends ReconfigurableBase
     this.dnConf = new DNConf(conf);
     checkSecureConfig(dnConf, conf, resources);
 
-    this.spanReceiverHost = SpanReceiverHost.getInstance(conf);
+    this.spanReceiverHost =
+      SpanReceiverHost.get(conf, DFSConfigKeys.DFS_SERVER_HTRACE_PREFIX);
 
     if (dnConf.maxLockedMemory > 0) {
       if (!NativeIO.POSIX.getCacheManipulator().verifyCanMlock()) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java

@@ -638,7 +638,8 @@ public class NameNode implements NameNodeStatusMXBean {
       startHttpServer(conf);
     }
 
-    this.spanReceiverHost = SpanReceiverHost.getInstance(conf);
+    this.spanReceiverHost =
+      SpanReceiverHost.get(conf, DFSConfigKeys.DFS_SERVER_HTRACE_PREFIX);
 
     loadNamesystem(conf);
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/tracing/TestTraceAdmin.java

@@ -18,6 +18,7 @@
 package org.apache.hadoop.tracing;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.net.unix.TemporarySocketDirectory;
 import org.junit.Assert;
@@ -57,7 +58,8 @@ public class TestTraceAdmin {
   public void testCreateAndDestroySpanReceiver() throws Exception {
     Configuration conf = new Configuration();
     conf = new Configuration();
-    conf.set(SpanReceiverHost.SPAN_RECEIVERS_CONF_KEY, "");
+    conf.set(DFSConfigKeys.DFS_SERVER_HTRACE_PREFIX  +
+        SpanReceiverHost.SPAN_RECEIVERS_CONF_SUFFIX, "");
     MiniDFSCluster cluster =
         new MiniDFSCluster.Builder(conf).numDataNodes(3).build();
     cluster.waitActive();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/tracing/TestTracing.java

@@ -22,6 +22,7 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.test.GenericTestUtils;
@@ -53,14 +54,9 @@ public class TestTracing {
   private static Configuration conf;
   private static MiniDFSCluster cluster;
   private static DistributedFileSystem dfs;
-  private static SpanReceiverHost spanReceiverHost;
 
   @Test
   public void testTracing() throws Exception {
-    // getting instance already loaded.
-    Assert.assertEquals(spanReceiverHost,
-        SpanReceiverHost.getInstance(new Configuration()));
-
     // write and read without tracing started
     String fileName = "testTracingDisabled.dat";
     writeTestFile(fileName);
@@ -196,9 +192,9 @@ public class TestTracing {
   public static void setup() throws IOException {
     conf = new Configuration();
     conf.setLong("dfs.blocksize", 100 * 1024);
-    conf.set(SpanReceiverHost.SPAN_RECEIVERS_CONF_KEY,
+    conf.set(DFSConfigKeys.DFS_CLIENT_HTRACE_PREFIX +
+        SpanReceiverHost.SPAN_RECEIVERS_CONF_SUFFIX,
         SetSpanReceiver.class.getName());
-    spanReceiverHost = SpanReceiverHost.getInstance(conf);
   }
 
   @Before

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/tracing/TestTracingShortCircuitLocalRead.java

@@ -64,7 +64,8 @@ public class TestTracingShortCircuitLocalRead {
   public void testShortCircuitTraceHooks() throws IOException {
     assumeTrue(NativeCodeLoader.isNativeCodeLoaded() && !Path.WINDOWS);
     conf = new Configuration();
-    conf.set(SpanReceiverHost.SPAN_RECEIVERS_CONF_KEY,
+    conf.set(DFSConfigKeys.DFS_CLIENT_HTRACE_PREFIX +
+        SpanReceiverHost.SPAN_RECEIVERS_CONF_SUFFIX,
         TestTracing.SetSpanReceiver.class.getName());
     conf.setLong("dfs.blocksize", 100 * 1024);
     conf.setBoolean(DFSConfigKeys.DFS_CLIENT_READ_SHORTCIRCUIT_KEY, true);
@@ -78,7 +79,6 @@ public class TestTracingShortCircuitLocalRead {
     dfs = cluster.getFileSystem();
 
     try {
-      spanReceiverHost = SpanReceiverHost.getInstance(conf);
       DFSTestUtil.createFile(dfs, TEST_PATH, TEST_LENGTH, (short)1, 5678L);
 
       TraceScope ts = Trace.startSpan("testShortCircuitTraceHooks", Sampler.ALWAYS);