[FLINK-16439][runtime] Introduce PendingWorkerCounter for counting pe…

…nding workers per WorkerResourceSpec in ActiveResourceManager.

flink-runtime/src/main/java/org/apache/flink/runtime/resourcemanager/ActiveResourceManager.java

@@ -18,6 +18,7 @@
 
 package org.apache.flink.runtime.resourcemanager;
 
+import org.apache.flink.annotation.VisibleForTesting;
 import org.apache.flink.configuration.Configuration;
 import org.apache.flink.configuration.TaskManagerOptions;
 import org.apache.flink.runtime.akka.AkkaUtils;
@@ -35,9 +36,11 @@
 import org.apache.flink.runtime.rpc.FatalErrorHandler;
 import org.apache.flink.runtime.rpc.RpcService;
 import org.apache.flink.util.FlinkException;
+import org.apache.flink.util.Preconditions;
 
 import javax.annotation.Nullable;
 
+import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 
@@ -63,6 +66,8 @@ public abstract class ActiveResourceManager <WorkerType extends ResourceIDRetrie
 	/** Flink configuration uploaded by client. */
 	protected final Configuration flinkClientConfig;
 
+	private final PendingWorkerCounter pendingWorkerCounter;
+
 	public ActiveResourceManager(
 			Configuration flinkConfig,
 			Map<String, String> env,
@@ -101,6 +106,8 @@ public ActiveResourceManager(
 
 		// Load the flink config uploaded by flink client
 		this.flinkClientConfig = loadClientConfiguration();
+
+		pendingWorkerCounter = new PendingWorkerCounter();
 	}
 
 	protected CompletableFuture<Void> getStopTerminationFutureOrCompletedExceptionally(@Nullable Throwable exception) {
@@ -117,4 +124,76 @@ protected CompletableFuture<Void> getStopTerminationFutureOrCompletedExceptional
 	protected abstract Configuration loadClientConfiguration();
 
 	protected abstract double getCpuCores(final Configuration configuration);
+
+	protected int getNumPendingWorkers() {
+		return pendingWorkerCounter.getTotalNum();
+	}
+
+	protected int getNumPendingWorkersFor(WorkerResourceSpec workerResourceSpec) {
+		return pendingWorkerCounter.getNum(workerResourceSpec);
+	}
+
+	/**
+	 * Notify that a worker with the given resource spec has been requested.
+	 * @param workerResourceSpec resource spec of the requested worker
+	 * @return updated number of pending workers for the given resource spec
+	 */
+	protected int notifyNewWorkerRequested(WorkerResourceSpec workerResourceSpec) {
+		return pendingWorkerCounter.increaseAndGet(workerResourceSpec);
+	}
+
+	/**
+	 * Notify that a worker with the given resource spec has been allocated.
+	 * @param workerResourceSpec resource spec of the requested worker
+	 * @return updated number of pending workers for the given resource spec
+	 */
+	protected int notifyNewWorkerAllocated(WorkerResourceSpec workerResourceSpec) {
+		return pendingWorkerCounter.decreaseAndGet(workerResourceSpec);
+	}
+
+	/**
+	 * Notify that allocation of a worker with the given resource spec has failed.
+	 * @param workerResourceSpec resource spec of the requested worker
+	 * @return updated number of pending workers for the given resource spec
+	 */
+	protected int notifyNewWorkerAllocationFailed(WorkerResourceSpec workerResourceSpec) {
+		return pendingWorkerCounter.decreaseAndGet(workerResourceSpec);
+	}
+
+	/**
+	 * Utility class for counting pending workers per {@link WorkerResourceSpec}.
+	 */
+	@VisibleForTesting
+	static class PendingWorkerCounter {
+		private final Map<WorkerResourceSpec, Integer> pendingWorkerNums;
+
+		PendingWorkerCounter() {
+			pendingWorkerNums = new HashMap<>();
+		}
+
+		int getTotalNum() {
+			return pendingWorkerNums.values().stream().reduce(0, Integer::sum);
+		}
+
+		int getNum(final WorkerResourceSpec workerResourceSpec) {
+			return pendingWorkerNums.getOrDefault(Preconditions.checkNotNull(workerResourceSpec), 0);
+		}
+
+		int increaseAndGet(final WorkerResourceSpec workerResourceSpec) {
+			return pendingWorkerNums.compute(
+				Preconditions.checkNotNull(workerResourceSpec),
+				(ignored, num) -> num != null ? num + 1 : 1);
+		}
+
+		int decreaseAndGet(final WorkerResourceSpec workerResourceSpec) {
+			final Integer newValue = pendingWorkerNums.compute(
+				Preconditions.checkNotNull(workerResourceSpec),
+				(ignored, num) -> {
+					Preconditions.checkState(num != null && num > 0,
+						"Cannot decrease, no pending worker of spec %s.", workerResourceSpec);
+					return num == 1 ? null : num - 1;
+				});
+			return newValue != null ? newValue : 0;
+		}
+	}
 }

flink-runtime/src/test/java/org/apache/flink/runtime/resourcemanager/ActiveResourceManagerTest.java

@@ -0,0 +1,75 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.runtime.resourcemanager;
+
+import org.apache.flink.util.TestLogger;
+
+import org.junit.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.core.Is.is;
+
+/**
+ * Tests for {@link ActiveResourceManager}.
+ */
+public class ActiveResourceManagerTest extends TestLogger {
+
+	@Test
+	public void testPendingWorkerCounterIncreaseAndDecrease() {
+		final WorkerResourceSpec spec1 = new WorkerResourceSpec.Builder().setCpuCores(1.0).build();
+		final WorkerResourceSpec spec2 = new WorkerResourceSpec.Builder().setCpuCores(2.0).build();
+
+		final ActiveResourceManager.PendingWorkerCounter counter = new ActiveResourceManager.PendingWorkerCounter();
+		assertThat(counter.getTotalNum(), is(0));
+		assertThat(counter.getNum(spec1), is(0));
+		assertThat(counter.getNum(spec2), is(0));
+
+		assertThat(counter.increaseAndGet(spec1), is(1));
+		assertThat(counter.getTotalNum(), is(1));
+		assertThat(counter.getNum(spec1), is(1));
+		assertThat(counter.getNum(spec2), is(0));
+
+		assertThat(counter.increaseAndGet(spec1), is(2));
+		assertThat(counter.getTotalNum(), is(2));
+		assertThat(counter.getNum(spec1), is(2));
+		assertThat(counter.getNum(spec2), is(0));
+
+		assertThat(counter.increaseAndGet(spec2), is(1));
+		assertThat(counter.getTotalNum(), is(3));
+		assertThat(counter.getNum(spec1), is(2));
+		assertThat(counter.getNum(spec2), is(1));
+
+		assertThat(counter.decreaseAndGet(spec1), is(1));
+		assertThat(counter.getTotalNum(), is(2));
+		assertThat(counter.getNum(spec1), is(1));
+		assertThat(counter.getNum(spec2), is(1));
+
+		assertThat(counter.decreaseAndGet(spec2), is(0));
+		assertThat(counter.getTotalNum(), is(1));
+		assertThat(counter.getNum(spec1), is(1));
+		assertThat(counter.getNum(spec2), is(0));
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void testPendingWorkerCounterDecreaseOnZero() {
+		final WorkerResourceSpec spec = new WorkerResourceSpec.Builder().build();
+		final ActiveResourceManager.PendingWorkerCounter counter = new ActiveResourceManager.PendingWorkerCounter();
+		counter.decreaseAndGet(spec);
+	}
+}