Merge pull request #224 from metamx/task-announcement

Task announcement

indexing-service/src/main/java/com/metamx/druid/indexing/common/TaskStatus.java

@@ -27,8 +27,8 @@ import com.google.common.base.Preconditions;
 import com.metamx.druid.indexing.common.task.TaskResource;
 
 /**
- * Represents the status of a task. The task may be ongoing ({@link #isComplete()} false) or it may be
+ * Represents the status of a task from the perspective of the coordinator. The task may be ongoing
- * complete ({@link #isComplete()} true).
+ * ({@link #isComplete()} false) or it may be complete ({@link #isComplete()} true).
  * <p/>
  * TaskStatus objects are immutable.
  */
@@ -43,36 +43,38 @@ public class TaskStatus
 
   public static TaskStatus running(String taskId)
   {
-    return new TaskStatus(taskId, Status.RUNNING, -1, null);
+    return new TaskStatus(taskId, Status.RUNNING, -1);
   }
 
   public static TaskStatus success(String taskId)
   {
-    return new TaskStatus(taskId, Status.SUCCESS, -1, null);
+    return new TaskStatus(taskId, Status.SUCCESS, -1);
   }
 
   public static TaskStatus failure(String taskId)
   {
-    return new TaskStatus(taskId, Status.FAILED, -1, null);
+    return new TaskStatus(taskId, Status.FAILED, -1);
+  }
+
+  public static TaskStatus fromCode(String taskId, Status code)
+  {
+    return new TaskStatus(taskId, code, -1);
   }
 
   private final String id;
   private final Status status;
   private final long duration;
-  private final TaskResource resource;
 
   @JsonCreator
   private TaskStatus(
       @JsonProperty("id") String id,
       @JsonProperty("status") Status status,
-      @JsonProperty("duration") long duration,
+      @JsonProperty("duration") long duration
-      @JsonProperty("resource") TaskResource resource
   )
   {
     this.id = id;
     this.status = status;
     this.duration = duration;
-    this.resource = resource == null ? new TaskResource(id, 1) : resource;
 
     // Check class invariants.
     Preconditions.checkNotNull(id, "id");
@@ -97,12 +99,6 @@ public class TaskStatus
     return duration;
   }
 
-  @JsonProperty("resource")
-  public TaskResource getResource()
-  {
-    return resource;
-  }
-
   /**
    * Signals that a task is not yet complete, and is still runnable on a worker. Exactly one of isRunnable,
    * isSuccess, or isFailure will be true at any one time.
@@ -144,7 +140,7 @@ public class TaskStatus
 
   public TaskStatus withDuration(long _duration)
   {
-    return new TaskStatus(id, status, _duration, resource);
+    return new TaskStatus(id, status, _duration);
   }
 
   @Override
@@ -154,7 +150,6 @@ public class TaskStatus
                   .add("id", id)
                   .add("status", status)
                   .add("duration", duration)
-                  .add("resource", resource)
                   .toString();
   }
 }

indexing-service/src/main/java/com/metamx/druid/indexing/coordinator/ForkingTaskRunner.java

@@ -26,12 +26,10 @@ import com.google.common.base.Optional;
 import com.google.common.base.Splitter;
 import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.io.ByteStreams;
-import com.google.common.io.Closeables;
 import com.google.common.io.Closer;
 import com.google.common.io.Files;
 import com.google.common.io.InputSupplier;
@@ -49,7 +47,6 @@ import com.metamx.druid.indexing.worker.executor.ExecutorMain;
 import com.metamx.emitter.EmittingLogger;
 import org.apache.commons.io.FileUtils;
 
-import java.io.Closeable;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -63,7 +60,6 @@ import java.util.Properties;
 import java.util.UUID;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * Runs tasks in separate processes using {@link ExecutorMain}.
@@ -79,7 +75,7 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
   private final ListeningExecutorService exec;
   private final ObjectMapper jsonMapper;
 
-  private final Map<String, TaskInfo> tasks = Maps.newHashMap();
+  private final Map<String, ForkingTaskRunnerWorkItem> tasks = Maps.newHashMap();
 
   public ForkingTaskRunner(
       ForkingTaskRunnerConfig config,
@@ -109,7 +105,8 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
       if (!tasks.containsKey(task.getId())) {
         tasks.put(
             task.getId(),
-            new TaskInfo(
+            new ForkingTaskRunnerWorkItem(
+                task,
                 exec.submit(
                     new Callable<TaskStatus>()
                     {
@@ -135,17 +132,17 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
 
                             // time to adjust process holders
                             synchronized (tasks) {
-                              final TaskInfo taskInfo = tasks.get(task.getId());
+                              final ForkingTaskRunnerWorkItem taskWorkItem = tasks.get(task.getId());
 
-                              if (taskInfo.shutdown) {
+                              if (taskWorkItem.shutdown) {
                                 throw new IllegalStateException("Task has been shut down!");
                               }
 
-                              if (taskInfo == null) {
+                              if (taskWorkItem == null) {
                                 throw new ISE("WTF?! TaskInfo disappeared for task: %s", task.getId());
                               }
 
-                              if (taskInfo.processHolder != null) {
+                              if (taskWorkItem.processHolder != null) {
                                 throw new ISE("WTF?! TaskInfo already has a process holder for task: %s", task.getId());
                               }
 
@@ -206,13 +203,13 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
                               jsonMapper.writeValue(taskFile, task);
 
                               log.info("Running command: %s", Joiner.on(" ").join(command));
-                              taskInfo.processHolder = new ProcessHolder(
+                              taskWorkItem.processHolder = new ProcessHolder(
                                   new ProcessBuilder(ImmutableList.copyOf(command)).redirectErrorStream(true).start(),
                                   logFile,
                                   childPort
                               );
 
-                              processHolder = taskInfo.processHolder;
+                              processHolder = taskWorkItem.processHolder;
                               processHolder.registerWithCloser(closer);
                             }
 
@@ -261,9 +258,9 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
                         finally {
                           try {
                             synchronized (tasks) {
-                              final TaskInfo taskInfo = tasks.remove(task.getId());
+                              final ForkingTaskRunnerWorkItem taskWorkItem = tasks.remove(task.getId());
-                              if (taskInfo != null && taskInfo.processHolder != null) {
+                              if (taskWorkItem != null && taskWorkItem.processHolder != null) {
-                                taskInfo.processHolder.process.destroy();
+                                taskWorkItem.processHolder.process.destroy();
                               }
                             }
 
@@ -281,7 +278,7 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
         );
       }
 
-      return tasks.get(task.getId()).statusFuture;
+      return tasks.get(task.getId()).getResult();
     }
   }
 
@@ -291,10 +288,10 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
     synchronized (tasks) {
       exec.shutdown();
 
-      for (TaskInfo taskInfo : tasks.values()) {
+      for (ForkingTaskRunnerWorkItem taskWorkItem : tasks.values()) {
-        if (taskInfo.processHolder != null) {
+        if (taskWorkItem.processHolder != null) {
-          log.info("Destroying process: %s", taskInfo.processHolder.process);
+          log.info("Destroying process: %s", taskWorkItem.processHolder.process);
-          taskInfo.processHolder.process.destroy();
+          taskWorkItem.processHolder.process.destroy();
         }
       }
     }
@@ -303,7 +300,7 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
   @Override
   public void shutdown(final String taskid)
   {
-    final TaskInfo taskInfo;
+    final ForkingTaskRunnerWorkItem taskInfo;
 
     synchronized (tasks) {
       taskInfo = tasks.get(taskid);
@@ -326,13 +323,29 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
   @Override
   public Collection<TaskRunnerWorkItem> getRunningTasks()
   {
-    return ImmutableList.of();
+    synchronized (tasks) {
+      final List<TaskRunnerWorkItem> ret = Lists.newArrayList();
+      for (final ForkingTaskRunnerWorkItem taskWorkItem : tasks.values()) {
+        if (taskWorkItem.processHolder != null) {
+          ret.add(taskWorkItem);
+        }
+      }
+      return ret;
+    }
   }
 
   @Override
   public Collection<TaskRunnerWorkItem> getPendingTasks()
   {
-    return ImmutableList.of();
+    synchronized (tasks) {
+      final List<TaskRunnerWorkItem> ret = Lists.newArrayList();
+      for (final ForkingTaskRunnerWorkItem taskWorkItem : tasks.values()) {
+        if (taskWorkItem.processHolder == null) {
+          ret.add(taskWorkItem);
+        }
+      }
+      return ret;
+    }
   }
 
   @Override
@@ -347,9 +360,9 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
     final ProcessHolder processHolder;
 
     synchronized (tasks) {
-      final TaskInfo taskInfo = tasks.get(taskid);
+      final ForkingTaskRunnerWorkItem taskWorkItem = tasks.get(taskid);
-      if (taskInfo != null && taskInfo.processHolder != null) {
+      if (taskWorkItem != null && taskWorkItem.processHolder != null) {
-        processHolder = taskInfo.processHolder;
+        processHolder = taskWorkItem.processHolder;
       } else {
         return Optional.absent();
       }
@@ -380,13 +393,13 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
       int port = config.getStartPort();
       int maxPortSoFar = -1;
 
-      for (TaskInfo taskInfo : tasks.values()) {
+      for (ForkingTaskRunnerWorkItem taskWorkItem : tasks.values()) {
-        if (taskInfo.processHolder != null) {
+        if (taskWorkItem.processHolder != null) {
-          if (taskInfo.processHolder.port > maxPortSoFar) {
+          if (taskWorkItem.processHolder.port > maxPortSoFar) {
-            maxPortSoFar = taskInfo.processHolder.port;
+            maxPortSoFar = taskWorkItem.processHolder.port;
           }
 
-          if (taskInfo.processHolder.port == port) {
+          if (taskWorkItem.processHolder.port == port) {
             port = maxPortSoFar + 1;
           }
         }
@@ -396,15 +409,17 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogProvider
     }
   }
 
-  private static class TaskInfo
+  private static class ForkingTaskRunnerWorkItem extends TaskRunnerWorkItem
   {
-    private final ListenableFuture<TaskStatus> statusFuture;
     private volatile boolean shutdown = false;
     private volatile ProcessHolder processHolder = null;
 
-    private TaskInfo(ListenableFuture<TaskStatus> statusFuture)
+    private ForkingTaskRunnerWorkItem(
+        Task task,
+        ListenableFuture<TaskStatus> statusFuture
+    )
     {
-      this.statusFuture = statusFuture;
+      super(task, statusFuture);
     }
   }
 

indexing-service/src/main/java/com/metamx/druid/indexing/coordinator/RemoteTaskRunner.java

@@ -41,6 +41,7 @@ import com.metamx.druid.indexing.common.task.Task;
 import com.metamx.druid.indexing.common.tasklogs.TaskLogProvider;
 import com.metamx.druid.indexing.coordinator.config.RemoteTaskRunnerConfig;
 import com.metamx.druid.indexing.coordinator.setup.WorkerSetupData;
+import com.metamx.druid.indexing.worker.TaskAnnouncement;
 import com.metamx.druid.indexing.worker.Worker;
 import com.metamx.emitter.EmittingLogger;
 import com.metamx.http.client.HttpClient;
@@ -291,9 +292,9 @@ public class RemoteTaskRunner implements TaskRunner, TaskLogProvider
         runningTasks.remove(task.getId());
       } else {
         log.info("Task[%s] already running on %s.", task.getId(), zkWorker.getWorker().getHost());
-        TaskStatus status = zkWorker.getRunningTasks().get(task.getId());
+        TaskAnnouncement announcement = zkWorker.getRunningTasks().get(task.getId());
-        if (status.isComplete()) {
+        if (announcement.getTaskStatus().isComplete()) {
-          taskComplete(runningTask, zkWorker, task.getId(), status);
+          taskComplete(runningTask, zkWorker, task.getId(), announcement.getTaskStatus());
         }
         return runningTask.getResult();
       }

indexing-service/src/main/java/com/metamx/druid/indexing/coordinator/TaskRunnerWorkItem.java

@@ -35,8 +35,7 @@ public class TaskRunnerWorkItem implements Comparable<TaskRunnerWorkItem>
   private final Task task;
   private final ListenableFuture<TaskStatus> result;
   private final DateTime createdTime;
-
+  private final DateTime queueInsertionTime;
-  private volatile DateTime queueInsertionTime;
 
   public TaskRunnerWorkItem(
       Task task,

indexing-service/src/main/java/com/metamx/druid/indexing/coordinator/ZkWorker.java

@@ -28,6 +28,7 @@ import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 import com.metamx.druid.indexing.common.TaskStatus;
 import com.metamx.druid.indexing.common.task.Task;
+import com.metamx.druid.indexing.worker.TaskAnnouncement;
 import com.metamx.druid.indexing.worker.Worker;
 import org.apache.curator.framework.recipes.cache.ChildData;
 import org.apache.curator.framework.recipes.cache.PathChildrenCache;
@@ -48,7 +49,7 @@ public class ZkWorker implements Closeable
 {
   private final Worker worker;
   private final PathChildrenCache statusCache;
-  private final Function<ChildData, TaskStatus> cacheConverter;
+  private final Function<ChildData, TaskAnnouncement> cacheConverter;
 
   private AtomicReference<DateTime> lastCompletedTaskTime = new AtomicReference<DateTime>(new DateTime());
 
@@ -56,13 +57,13 @@ public class ZkWorker implements Closeable
   {
     this.worker = worker;
     this.statusCache = statusCache;
-    this.cacheConverter = new Function<ChildData, TaskStatus>()
+    this.cacheConverter = new Function<ChildData, TaskAnnouncement>()
     {
       @Override
-      public TaskStatus apply(ChildData input)
+      public TaskAnnouncement apply(ChildData input)
       {
         try {
-          return jsonMapper.readValue(input.getData(), TaskStatus.class);
+          return jsonMapper.readValue(input.getData(), TaskAnnouncement.class);
         }
         catch (Exception e) {
           throw Throwables.propagate(e);
@@ -93,14 +94,14 @@ public class ZkWorker implements Closeable
     return getRunningTasks().keySet();
   }
 
-  public Map<String, TaskStatus> getRunningTasks()
+  public Map<String, TaskAnnouncement> getRunningTasks()
   {
-    Map<String, TaskStatus> retVal = Maps.newHashMap();
+    Map<String, TaskAnnouncement> retVal = Maps.newHashMap();
-    for (TaskStatus taskStatus : Lists.transform(
+    for (TaskAnnouncement taskAnnouncement : Lists.transform(
         statusCache.getCurrentData(),
         cacheConverter
     )) {
-      retVal.put(taskStatus.getId(), taskStatus);
+      retVal.put(taskAnnouncement.getTaskStatus().getId(), taskAnnouncement);
     }
 
     return retVal;
@@ -110,8 +111,8 @@ public class ZkWorker implements Closeable
   public int getCurrCapacityUsed()
   {
     int currCapacity = 0;
-    for (TaskStatus taskStatus : getRunningTasks().values()) {
+    for (TaskAnnouncement taskAnnouncement : getRunningTasks().values()) {
-      currCapacity += taskStatus.getResource().getRequiredCapacity();
+      currCapacity += taskAnnouncement.getTaskResource().getRequiredCapacity();
     }
     return currCapacity;
   }
@@ -120,8 +121,8 @@ public class ZkWorker implements Closeable
   public Set<String> getAvailabilityGroups()
   {
     Set<String> retVal = Sets.newHashSet();
-    for (TaskStatus taskStatus : getRunningTasks().values()) {
+    for (TaskAnnouncement taskAnnouncement : getRunningTasks().values()) {
-      retVal.add(taskStatus.getResource().getAvailabilityGroup());
+      retVal.add(taskAnnouncement.getTaskResource().getAvailabilityGroup());
     }
     return retVal;
   }

indexing-service/src/main/java/com/metamx/druid/indexing/worker/TaskAnnouncement.java

@@ -0,0 +1,87 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package com.metamx.druid.indexing.worker;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.base.Preconditions;
+import com.metamx.druid.indexing.common.TaskStatus;
+import com.metamx.druid.indexing.common.task.Task;
+import com.metamx.druid.indexing.common.task.TaskResource;
+
+/**
+ * Used by workers to announce the status of tasks they are currently running. This class is immutable.
+ */
+public class TaskAnnouncement
+{
+  private final TaskStatus taskStatus;
+  private final TaskResource taskResource;
+
+  public static TaskAnnouncement create(Task task, TaskStatus status)
+  {
+    Preconditions.checkArgument(status.getId().equals(task.getId()), "task id == status id");
+    return new TaskAnnouncement(null, null, status, task.getTaskResource());
+  }
+
+  @JsonCreator
+  private TaskAnnouncement(
+      @JsonProperty("id") String taskId,
+      @JsonProperty("status") TaskStatus.Status status,
+      @JsonProperty("taskStatus") TaskStatus taskStatus,
+      @JsonProperty("taskResource") TaskResource taskResource
+  )
+  {
+    if (taskStatus != null) {
+      this.taskStatus = taskStatus;
+    } else {
+      // Can be removed when backwards compat is no longer needed
+      this.taskStatus = TaskStatus.fromCode(taskId, status);
+    }
+    this.taskResource = taskResource == null ? new TaskResource(this.taskStatus.getId(), 1) : taskResource;
+  }
+
+  // Can be removed when backwards compat is no longer needed
+  @JsonProperty("id")
+  @Deprecated
+  public String getTaskId()
+  {
+    return taskStatus.getId();
+  }
+
+  // Can be removed when backwards compat is no longer needed
+  @JsonProperty("status")
+  @Deprecated
+  public TaskStatus.Status getStatus()
+  {
+    return taskStatus.getStatusCode();
+  }
+
+  @JsonProperty("taskStatus")
+  public TaskStatus getTaskStatus()
+  {
+    return taskStatus;
+  }
+
+  @JsonProperty("taskResource")
+  public TaskResource getTaskResource()
+  {
+    return taskResource;
+  }
+}

indexing-service/src/main/java/com/metamx/druid/indexing/worker/WorkerCuratorCoordinator.java

@@ -180,7 +180,7 @@ public class WorkerCuratorCoordinator
     }
   }
 
-  public void announceStatus(TaskStatus status)
+  public void announceTask(TaskAnnouncement announcement)
   {
     synchronized (lock) {
       if (!started) {
@@ -188,7 +188,7 @@ public class WorkerCuratorCoordinator
       }
 
       try {
-        byte[] rawBytes = jsonMapper.writeValueAsBytes(status);
+        byte[] rawBytes = jsonMapper.writeValueAsBytes(announcement);
         if (rawBytes.length > config.getMaxNumBytes()) {
           throw new ISE("Length of raw bytes for task too large[%,d > %,d]", rawBytes.length, config.getMaxNumBytes());
         }
@@ -196,7 +196,7 @@ public class WorkerCuratorCoordinator
         curatorFramework.create()
                         .withMode(CreateMode.EPHEMERAL)
                         .forPath(
-                            getStatusPathForId(status.getId()), rawBytes
+                            getStatusPathForId(announcement.getTaskStatus().getId()), rawBytes
                         );
       }
       catch (Exception e) {
@@ -205,7 +205,7 @@ public class WorkerCuratorCoordinator
     }
   }
 
-  public void updateStatus(TaskStatus status)
+  public void updateAnnouncement(TaskAnnouncement announcement)
   {
     synchronized (lock) {
       if (!started) {
@@ -213,18 +213,18 @@ public class WorkerCuratorCoordinator
       }
 
       try {
-        if (curatorFramework.checkExists().forPath(getStatusPathForId(status.getId())) == null) {
+        if (curatorFramework.checkExists().forPath(getStatusPathForId(announcement.getTaskStatus().getId())) == null) {
-          announceStatus(status);
+          announceTask(announcement);
           return;
         }
-        byte[] rawBytes = jsonMapper.writeValueAsBytes(status);
+        byte[] rawBytes = jsonMapper.writeValueAsBytes(announcement);
         if (rawBytes.length > config.getMaxNumBytes()) {
           throw new ISE("Length of raw bytes for task too large[%,d > %,d]", rawBytes.length, config.getMaxNumBytes());
         }
 
         curatorFramework.setData()
                         .forPath(
-                            getStatusPathForId(status.getId()), rawBytes
+                            getStatusPathForId(announcement.getTaskStatus().getId()), rawBytes
                         );
       }
       catch (Exception e) {

indexing-service/src/main/java/com/metamx/druid/indexing/worker/WorkerTaskMonitor.java

@@ -118,7 +118,12 @@ public class WorkerTaskMonitor
                         TaskStatus taskStatus;
                         try {
                           workerCuratorCoordinator.unannounceTask(task.getId());
-                          workerCuratorCoordinator.announceStatus(TaskStatus.running(task.getId()));
+                          workerCuratorCoordinator.announceTask(
+                              TaskAnnouncement.create(
+                                  task,
+                                  TaskStatus.running(task.getId())
+                              )
+                          );
                           taskStatus = taskRunner.run(task).get();
                         }
                         catch (Exception e) {
@@ -134,7 +139,7 @@ public class WorkerTaskMonitor
                         taskStatus = taskStatus.withDuration(System.currentTimeMillis() - startTime);
 
                         try {
-                          workerCuratorCoordinator.updateStatus(taskStatus);
+                          workerCuratorCoordinator.updateAnnouncement(TaskAnnouncement.create(task, taskStatus));
                           log.info(
                               "Job's finished. Completed [%s] with status [%s]",
                               task.getId(),

indexing-service/src/test/java/com/metamx/druid/indexing/coordinator/scaling/SimpleResourceManagementStrategyTest.java

@@ -31,6 +31,7 @@ import com.metamx.druid.indexing.common.task.Task;
 import com.metamx.druid.indexing.coordinator.RemoteTaskRunnerWorkItem;
 import com.metamx.druid.indexing.coordinator.ZkWorker;
 import com.metamx.druid.indexing.coordinator.setup.WorkerSetupData;
+import com.metamx.druid.indexing.worker.TaskAnnouncement;
 import com.metamx.druid.indexing.worker.Worker;
 import com.metamx.druid.jackson.DefaultObjectMapper;
 import com.metamx.emitter.EmittingLogger;
@@ -351,12 +352,12 @@ public class SimpleResourceManagementStrategyTest
     }
 
     @Override
-    public Map<String, TaskStatus> getRunningTasks()
+    public Map<String, TaskAnnouncement> getRunningTasks()
     {
       if (testTask == null) {
         return Maps.newHashMap();
       }
-      return ImmutableMap.of(testTask.getId(), TaskStatus.running(testTask.getId()));
+      return ImmutableMap.of(testTask.getId(), TaskAnnouncement.create(testTask, TaskStatus.running(testTask.getId())));
     }
   }
 }

indexing-service/src/test/java/com/metamx/druid/indexing/worker/TaskAnnouncementTest.java

@@ -0,0 +1,59 @@
+package com.metamx.druid.indexing.worker;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.metamx.druid.QueryGranularity;
+import com.metamx.druid.aggregation.AggregatorFactory;
+import com.metamx.druid.index.v1.IndexGranularity;
+import com.metamx.druid.indexing.common.TaskStatus;
+import com.metamx.druid.indexing.common.task.RealtimeIndexTask;
+import com.metamx.druid.indexing.common.task.Task;
+import com.metamx.druid.indexing.common.task.TaskResource;
+import com.metamx.druid.jackson.DefaultObjectMapper;
+import com.metamx.druid.realtime.Schema;
+import com.metamx.druid.shard.NoneShardSpec;
+import junit.framework.Assert;
+import org.joda.time.Period;
+import org.junit.Test;
+
+public class TaskAnnouncementTest
+{
+  @Test
+  public void testBackwardsCompatibleSerde() throws Exception
+  {
+    final Task task = new RealtimeIndexTask(
+        "theid",
+        new TaskResource("rofl", 2),
+        new Schema("foo", null, new AggregatorFactory[0], QueryGranularity.NONE, new NoneShardSpec()),
+        null,
+        null,
+        new Period("PT10M"),
+        IndexGranularity.HOUR,
+        null
+    );
+    final TaskStatus status = TaskStatus.running(task.getId());
+    final TaskAnnouncement announcement = TaskAnnouncement.create(task, status);
+
+    final ObjectMapper jsonMapper = new DefaultObjectMapper();
+    final String statusJson = jsonMapper.writeValueAsString(status);
+    final String announcementJson = jsonMapper.writeValueAsString(announcement);
+
+    final TaskStatus statusFromStatus = jsonMapper.readValue(statusJson, TaskStatus.class);
+    final TaskStatus statusFromAnnouncement = jsonMapper.readValue(announcementJson, TaskStatus.class);
+    final TaskAnnouncement announcementFromStatus = jsonMapper.readValue(statusJson, TaskAnnouncement.class);
+    final TaskAnnouncement announcementFromAnnouncement = jsonMapper.readValue(
+        announcementJson,
+        TaskAnnouncement.class
+    );
+
+    Assert.assertEquals("theid", statusFromStatus.getId());
+    Assert.assertEquals("theid", statusFromAnnouncement.getId());
+    Assert.assertEquals("theid", announcementFromStatus.getTaskStatus().getId());
+    Assert.assertEquals("theid", announcementFromAnnouncement.getTaskStatus().getId());
+
+    Assert.assertEquals("theid", announcementFromStatus.getTaskResource().getAvailabilityGroup());
+    Assert.assertEquals("rofl", announcementFromAnnouncement.getTaskResource().getAvailabilityGroup());
+
+    Assert.assertEquals(1, announcementFromStatus.getTaskResource().getRequiredCapacity());
+    Assert.assertEquals(2, announcementFromAnnouncement.getTaskResource().getRequiredCapacity());
+  }
+}