[Java] Add runtime context (#4194)

java/api/src/main/java/org/ray/api/Ray.java

@@ -120,4 +120,11 @@ public final class Ray extends RayCall {
   public static RayRuntime internal() {
     return runtime;
   }
+
+  /**
+   * Get the runtime context.
+   */
+  public static RuntimeContext getRuntimeContext() {
+    return runtime.getRuntimeContext();
+  }
 }

java/api/src/main/java/org/ray/api/RuntimeContext.java

@@ -0,0 +1,46 @@
+package org.ray.api;
+
+import org.ray.api.id.UniqueId;
+
+/**
+ * A class used for getting information of Ray runtime.
+ */
+public interface RuntimeContext {
+
+  /**
+   * Get the current Driver ID.
+   *
+   * If called in a driver, this returns the driver ID. If called in a worker, this returns the ID
+   * of the associated driver.
+   */
+  UniqueId getCurrentDriverId();
+
+  /**
+   * Get the current actor ID.
+   *
+   * Note, this can only be called in actors.
+   */
+  UniqueId getCurrentActorId();
+
+  /**
+   * Returns true if the current actor was reconstructed, false if it's created for the first time.
+   *
+   * Note, this method should only be called from an actor creation task.
+   */
+  boolean wasCurrentActorReconstructed();
+
+  /**
+   * Get the raylet socket name.
+   */
+  String getRayletSocketName();
+
+  /**
+   * Get the object store socket name.
+   */
+  String getObjectStoreSocketName();
+
+  /**
+   * Return true if Ray is running in single-process mode, false if Ray is running in cluster mode.
+   */
+  boolean isSingleProcess();
+}

java/api/src/main/java/org/ray/api/runtime/RayRuntime.java

@@ -3,6 +3,7 @@ package org.ray.api.runtime;
 import java.util.List;
 import org.ray.api.RayActor;
 import org.ray.api.RayObject;
+import org.ray.api.RuntimeContext;
 import org.ray.api.WaitResult;
 import org.ray.api.function.RayFunc;
 import org.ray.api.id.UniqueId;
@@ -93,4 +94,6 @@ public interface RayRuntime {
    */
   <T> RayActor<T> createActor(RayFunc actorFactoryFunc, Object[] args,
       ActorCreationOptions options);
+
+  RuntimeContext getRuntimeContext();
 }

java/runtime/src/main/java/org/ray/runtime/AbstractRayRuntime.java

@@ -10,6 +10,7 @@ import java.util.Map;
 import java.util.stream.Collectors;
 import org.ray.api.RayActor;
 import org.ray.api.RayObject;
+import org.ray.api.RuntimeContext;
 import org.ray.api.WaitResult;
 import org.ray.api.exception.RayException;
 import org.ray.api.function.RayFunc;
@@ -61,6 +62,7 @@ public abstract class AbstractRayRuntime implements RayRuntime {
   protected RayletClient rayletClient;
   protected ObjectStoreProxy objectStoreProxy;
   protected FunctionManager functionManager;
+  protected RuntimeContext runtimeContext;
 
   public AbstractRayRuntime(RayConfig rayConfig) {
     this.rayConfig = rayConfig;
@@ -68,6 +70,7 @@ public abstract class AbstractRayRuntime implements RayRuntime {
     worker = new Worker(this);
     workerContext = new WorkerContext(rayConfig.workerMode,
             rayConfig.driverId, rayConfig.runMode);
+    runtimeContext = new RuntimeContextImpl(this);
   }
 
   /**
@@ -346,4 +349,9 @@ public abstract class AbstractRayRuntime implements RayRuntime {
   public RayConfig getRayConfig() {
     return rayConfig;
   }
+
+  public RuntimeContext getRuntimeContext() {
+    return runtimeContext;
+  }
+
 }

java/runtime/src/main/java/org/ray/runtime/RayNativeRuntime.java

@@ -173,4 +173,22 @@ public final class RayNativeRuntime extends AbstractRayRuntime {
     checkpoints.sort((x, y) -> Long.compare(y.timestamp, x.timestamp));
     return checkpoints;
   }
+
+
+  /**
+   * Query whether the actor exists in Gcs.
+   */
+  boolean actorExistsInGcs(UniqueId actorId) {
+    byte[] key = ArrayUtils.addAll("ACTOR".getBytes(), actorId.getBytes());
+
+    // TODO(qwang): refactor this with `GlobalState` after this issue
+    // getting finished. https://github.com/ray-project/ray/issues/3933
+    for (RedisClient client : redisClients) {
+      if (client.exists(key)) {
+        return true;
+      }
+    }
+
+    return false;
+  }
 }

java/runtime/src/main/java/org/ray/runtime/RuntimeContextImpl.java

@@ -0,0 +1,56 @@
+package org.ray.runtime;
+
+import com.google.common.base.Preconditions;
+import org.ray.api.RuntimeContext;
+import org.ray.api.id.UniqueId;
+import org.ray.runtime.config.RunMode;
+import org.ray.runtime.config.WorkerMode;
+import org.ray.runtime.task.TaskSpec;
+
+public class RuntimeContextImpl implements RuntimeContext {
+
+  private AbstractRayRuntime runtime;
+
+  public RuntimeContextImpl(AbstractRayRuntime runtime) {
+    this.runtime = runtime;
+  }
+
+  @Override
+  public UniqueId getCurrentDriverId() {
+    return runtime.getWorkerContext().getCurrentDriverId();
+  }
+
+  @Override
+  public UniqueId getCurrentActorId() {
+    Preconditions.checkState(runtime.rayConfig.workerMode == WorkerMode.WORKER);
+    return runtime.getWorker().getCurrentActorId();
+  }
+
+  @Override
+  public boolean wasCurrentActorReconstructed() {
+    TaskSpec currentTask = runtime.getWorkerContext().getCurrentTask();
+    Preconditions.checkState(currentTask != null && currentTask.isActorCreationTask(),
+        "This method can only be called from an actor creation task.");
+    if (isSingleProcess()) {
+      return false;
+    }
+
+    return ((RayNativeRuntime) runtime).actorExistsInGcs(getCurrentActorId());
+  }
+
+  @Override
+  public String getRayletSocketName() {
+    return runtime.getRayConfig().rayletSocketName;
+  }
+
+  @Override
+  public String getObjectStoreSocketName() {
+    return runtime.getRayConfig().objectStoreSocketName;
+  }
+
+  @Override
+  public boolean isSingleProcess() {
+    return RunMode.SINGLE_PROCESS == runtime.getRayConfig().runMode;
+  }
+
+}

java/runtime/src/main/java/org/ray/runtime/Worker.java

@@ -63,6 +63,10 @@ public class Worker {
     this.runtime = runtime;
   }
 
+  public UniqueId getCurrentActorId() {
+    return currentActorId;
+  }
+
   public void loop() {
     while (true) {
       LOGGER.info("Fetching new task in thread {}.", Thread.currentThread().getName());
@@ -86,6 +90,11 @@ public class Worker {
       // Set context
       runtime.getWorkerContext().setCurrentTask(spec, rayFunction.classLoader);
       Thread.currentThread().setContextClassLoader(rayFunction.classLoader);
+
+      if (spec.isActorCreationTask()) {
+        currentActorId = returnId;
+      }
+
       // Get local actor object and arguments.
       Object actor = null;
       if (spec.isActorTask()) {
@@ -94,6 +103,7 @@ public class Worker {
           throw actorCreationException;
         }
         actor = currentActor;
+
       }
       Object[] args = ArgumentsBuilder.unwrap(spec, rayFunction.classLoader);
       // Execute the task.
@@ -112,7 +122,6 @@ public class Worker {
       } else {
         maybeLoadCheckpoint(result, returnId);
         currentActor = result;
-        currentActorId = returnId;
       }
       LOGGER.info("Finished executing task {}", spec.taskId);
     } catch (Exception e) {
@@ -121,7 +130,6 @@ public class Worker {
         runtime.put(returnId, new RayTaskException("Error executing task " + spec, e));
       } else {
         actorCreationException = e;
-        currentActorId = returnId;
       }
     } finally {
       Thread.currentThread().setContextClassLoader(oldLoader);

java/runtime/src/main/java/org/ray/runtime/WorkerContext.java

@@ -26,6 +26,8 @@ public class WorkerContext {
    */
   private ThreadLocal<Integer> taskIndex;
 
+  private ThreadLocal<TaskSpec> currentTask;
+
   private UniqueId currentDriverId;
 
   private ClassLoader currentClassLoader;
@@ -46,6 +48,7 @@ public class WorkerContext {
     putIndex = ThreadLocal.withInitial(() -> 0);
     currentTaskId = ThreadLocal.withInitial(UniqueId::randomId);
     this.runMode = runMode;
+    currentTask = ThreadLocal.withInitial(() -> null);
     currentClassLoader = null;
     if (workerMode == WorkerMode.DRIVER) {
       workerId = driverId;
@@ -83,6 +86,7 @@ public class WorkerContext {
     this.currentDriverId = task.driverId;
     taskIndex.set(0);
     putIndex.set(0);
+    this.currentTask.set(task);
     currentClassLoader = classLoader;
   }
 
@@ -124,4 +128,10 @@ public class WorkerContext {
     return currentClassLoader;
   }
 
+  /**
+   * Get the current task.
+   */
+  public TaskSpec getCurrentTask() {
+    return this.currentTask.get();
+  }
 }

java/runtime/src/main/java/org/ray/runtime/gcs/RedisClient.java

@@ -85,4 +85,14 @@ public class RedisClient {
       return jedis.lrange(key, start, end);
     }
   }
+
+  /**
+   * Whether the key exists in Redis.
+   */
+  public boolean exists(byte[] key) {
+    try (Jedis jedis = jedisPool.getResource()) {
+      return jedis.exists(key);
+    }
+  }
+
 }

java/runtime/src/main/java/org/ray/runtime/runner/RunManager.java

@@ -268,6 +268,10 @@ public class RunManager {
       cmd.add("-Dray.logging.file.path=" + logFile);
     }
 
+    // socket names
+    cmd.add("-Dray.raylet.socket-name=" + rayConfig.rayletSocketName);
+    cmd.add("-Dray.object-store.socket-name=" + rayConfig.objectStoreSocketName);
+
     // Config overwrite
     cmd.add("-Dray.redis.address=" + rayConfig.getRedisAddress());
 

java/test/src/main/java/org/ray/api/test/ActorReconstructionTest.java

@@ -24,6 +24,16 @@ public class ActorReconstructionTest extends BaseTest {
 
     protected int value = 0;
 
+    private boolean wasCurrentActorReconstructed = false;
+
+    public Counter() {
+      wasCurrentActorReconstructed = Ray.getRuntimeContext().wasCurrentActorReconstructed();
+    }
+
+    public boolean wasCurrentActorReconstructed() {
+      return wasCurrentActorReconstructed;
+    }
+
     public int increase() {
       value += 1;
       return value;
@@ -48,6 +58,8 @@ public class ActorReconstructionTest extends BaseTest {
       Ray.call(Counter::increase, actor).get();
     }
 
+    Assert.assertFalse(Ray.call(Counter::wasCurrentActorReconstructed, actor).get());
+
     // Kill the actor process.
     int pid = Ray.call(Counter::getPid, actor).get();
     Runtime.getRuntime().exec("kill -9 " + pid);
@@ -58,6 +70,8 @@ public class ActorReconstructionTest extends BaseTest {
     int value = Ray.call(Counter::increase, actor).get();
     Assert.assertEquals(value, 4);
 
+    Assert.assertTrue(Ray.call(Counter::wasCurrentActorReconstructed, actor).get());
+
     // Kill the actor process again.
     pid = Ray.call(Counter::getPid, actor).get();
     Runtime.getRuntime().exec("kill -9 " + pid);

java/test/src/main/java/org/ray/api/test/RuntimeContextTest.java

@@ -0,0 +1,52 @@
+package org.ray.api.test;
+
+import org.ray.api.Ray;
+import org.ray.api.RayActor;
+import org.ray.api.annotation.RayRemote;
+import org.ray.api.id.UniqueId;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class RuntimeContextTest extends BaseTest {
+
+  private static UniqueId DRIVER_ID =
+      UniqueId.fromHexString("0011223344556677889900112233445566778899");
+  private static String RAYLET_SOCKET_NAME = "/tmp/ray/test/raylet_socket";
+  private static String OBJECT_STORE_SOCKET_NAME = "/tmp/ray/test/object_store_socket";
+
+  @Override
+  public void beforeInitRay() {
+    System.setProperty("ray.driver.id", DRIVER_ID.toString());
+    System.setProperty("ray.raylet.socket-name", RAYLET_SOCKET_NAME);
+    System.setProperty("ray.object-store.socket-name", OBJECT_STORE_SOCKET_NAME);
+  }
+
+  @Test
+  public void testRuntimeContextInDriver() {
+    Assert.assertEquals(DRIVER_ID, Ray.getRuntimeContext().getCurrentDriverId());
+    Assert.assertEquals(RAYLET_SOCKET_NAME, Ray.getRuntimeContext().getRayletSocketName());
+    Assert.assertEquals(OBJECT_STORE_SOCKET_NAME,
+        Ray.getRuntimeContext().getObjectStoreSocketName());
+  }
+
+  @RayRemote
+  public static class RuntimeContextTester {
+
+    public String testRuntimeContext(UniqueId actorId) {
+      Assert.assertEquals(DRIVER_ID, Ray.getRuntimeContext().getCurrentDriverId());
+      Assert.assertEquals(actorId, Ray.getRuntimeContext().getCurrentActorId());
+      Assert.assertEquals(RAYLET_SOCKET_NAME, Ray.getRuntimeContext().getRayletSocketName());
+      Assert.assertEquals(OBJECT_STORE_SOCKET_NAME,
+          Ray.getRuntimeContext().getObjectStoreSocketName());
+      return "ok";
+    }
+  }
+
+  @Test
+  public void testRuntimeContextInActor() {
+    RayActor<RuntimeContextTester> actor = Ray.createActor(RuntimeContextTester::new);
+    Assert.assertEquals("ok",
+        Ray.call(RuntimeContextTester::testRuntimeContext, actor, actor.getId()).get());
+  }
+
+}