TestRetryCache.java
/**
* 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.hadoop.ipc;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.hadoop.ipc.RPC.RpcKind;
import org.apache.hadoop.ipc.RetryCache.CacheEntryWithPayload;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
/**
* Tests for {@link RetryCache}
*/
public class TestRetryCache {
private static final byte[] CLIENT_ID = ClientId.getClientId();
private static int callId = 100;
private static final Random r = new Random();
private static final TestServer testServer = new TestServer();
@BeforeEach
public void setup() {
testServer.resetCounters();
}
static class TestServer {
AtomicInteger retryCount = new AtomicInteger();
AtomicInteger operationCount = new AtomicInteger();
private final RetryCache retryCache = new RetryCache(
"TestRetryCache", 1, 100 * 1000 * 1000 * 1000L);
/**
* A server method implemented using {@link RetryCache}.
*
* @param input is returned back in echo, if {@code success} is true.
* @param failureOutput returned on failure, if {@code success} is false.
* @param methodTime time taken by the operation. By passing smaller/larger
* value one can simulate an operation that takes short/long time.
* @param success whether this operation completes successfully or not
* @return return the input parameter {@code input}, if {@code success} is
* true, else return {@code failureOutput}.
*/
int echo(int input, int failureOutput, long methodTime, boolean success)
throws InterruptedException {
CacheEntryWithPayload entry = RetryCache.waitForCompletion(retryCache,
null, Server.getClientId(), Server.getCallId());
if (entry != null && entry.isSuccess()) {
System.out.println("retryCount incremented " + retryCount.get());
retryCount.incrementAndGet();
return (Integer) entry.getPayload();
}
try {
operationCount.incrementAndGet();
if (methodTime > 0) {
Thread.sleep(methodTime);
}
} finally {
RetryCache.setState(entry, success, input);
}
return success ? input : failureOutput;
}
void resetCounters() {
retryCount.set(0);
operationCount.set(0);
}
}
public static Server.Call newCall() {
return new Server.Call(++callId, 1, null, null,
RpcKind.RPC_PROTOCOL_BUFFER, CLIENT_ID);
}
/**
* This simlulates a long server retried operations. Multiple threads start an
* operation that takes long time and finally succeeds. The retries in this
* case end up waiting for the current operation to complete. All the retries
* then complete based on the entry in the retry cache.
*/
@Test
public void testLongOperationsSuccessful() throws Exception {
// Test long successful operations
// There is no entry in cache expected when the first operation starts
testOperations(r.nextInt(), 100, 20, true, false, newCall());
}
/**
* This simlulates a long server operation. Multiple threads start an
* operation that takes long time and finally fails. The retries in this case
* end up waiting for the current operation to complete. All the retries end
* up performing the operation again.
*/
@Test
public void testLongOperationsFailure() throws Exception {
// Test long failed operations
// There is no entry in cache expected when the first operation starts
testOperations(r.nextInt(), 100, 20, false, false, newCall());
}
/**
* This simlulates a short server operation. Multiple threads start an
* operation that takes very short time and finally succeeds. The retries in
* this case do not wait long for the current operation to complete. All the
* retries then complete based on the entry in the retry cache.
*/
@Test
public void testShortOperationsSuccess() throws Exception {
// Test long failed operations
// There is no entry in cache expected when the first operation starts
testOperations(r.nextInt(), 25, 0, false, false, newCall());
}
/**
* This simlulates a short server operation. Multiple threads start an
* operation that takes short time and finally fails. The retries in this case
* do not wait for the current operation to complete. All the retries end up
* performing the operation again.
*/
@Test
public void testShortOperationsFailure() throws Exception {
// Test long failed operations
// There is no entry in cache expected when the first operation starts
testOperations(r.nextInt(), 25, 0, false, false, newCall());
}
@Test
public void testRetryAfterSuccess() throws Exception {
// Previous operation successfully completed
Server.Call call = newCall();
int input = r.nextInt();
Server.getCurCall().set(call);
testServer.echo(input, input + 1, 5, true);
testOperations(input, 25, 0, true, true, call);
}
@Test
public void testRetryAfterFailure() throws Exception {
// Previous operation failed
Server.Call call = newCall();
int input = r.nextInt();
Server.getCurCall().set(call);
testServer.echo(input, input + 1, 5, false);
testOperations(input, 25, 0, false, true, call);
}
public void testOperations(final int input, final int numberOfThreads,
final int pause, final boolean success, final boolean attemptedBefore,
final Server.Call call) throws InterruptedException, ExecutionException {
final int failureOutput = input + 1;
ExecutorService executorService = Executors
.newFixedThreadPool(numberOfThreads);
List<Future<Integer>> list = new ArrayList<>();
for (int i = 0; i < numberOfThreads; i++) {
Callable<Integer> worker = () -> {
Server.getCurCall().set(call);
assertEquals(Server.getCurCall().get(), call);
int randomPause = pause == 0 ? pause : r.nextInt(pause);
return testServer.echo(input, failureOutput, randomPause, success);
};
Future<Integer> submit = executorService.submit(worker);
list.add(submit);
}
assertEquals(numberOfThreads, list.size());
for (Future<Integer> future : list) {
if (success) {
assertEquals(input, future.get().intValue());
} else {
assertEquals(failureOutput, future.get().intValue());
}
}
if (success) {
// If the operation was successful, all the subsequent operations
// by other threads should be retries. Operation count should be 1.
int retries = numberOfThreads + (attemptedBefore ? 0 : -1);
assertEquals(1, testServer.operationCount.get());
assertEquals(retries, testServer.retryCount.get());
} else {
// If the operation failed, all the subsequent operations
// should execute once more, hence the retry count should be 0 and
// operation count should be the number of tries
int opCount = numberOfThreads + (attemptedBefore ? 1 : 0);
assertEquals(opCount, testServer.operationCount.get());
assertEquals(0, testServer.retryCount.get());
}
}
}