ratis-test/src/test/java/org/apache/ratis/retry/TestRetryPolicy.java - ratis-hadoop-projects - Git at Google

 /*
  * 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.ratis.retry;

 import org.apache.ratis.BaseTest;
 import org.apache.ratis.client.impl.RaftClientImpl;
 import org.apache.ratis.client.retry.ClientRetryEvent;
 import org.apache.ratis.client.retry.RequestTypeDependentRetryPolicy;
 import org.apache.ratis.proto.RaftProtos.RaftClientRequestProto;
 import org.apache.ratis.proto.RaftProtos.ReplicationLevel;
 import org.apache.ratis.protocol.ClientId;
 import org.apache.ratis.protocol.exceptions.LeaderNotReadyException;
 import org.apache.ratis.protocol.exceptions.NotLeaderException;
 import org.apache.ratis.protocol.RaftClientRequest;
 import org.apache.ratis.protocol.RaftGroupId;
 import org.apache.ratis.protocol.RaftGroupMemberId;
 import org.apache.ratis.protocol.RaftPeerId;
 import org.apache.ratis.protocol.exceptions.TimeoutIOException;
 import org.apache.ratis.protocol.exceptions.ResourceUnavailableException;
 import org.apache.ratis.util.TimeDuration;
 import org.junit.Assert;
 import org.junit.Test;

 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;

 /** Test {@link RetryPolicy}. */
 public class TestRetryPolicy extends BaseTest {
   @Override
   public int getGlobalTimeoutSeconds() {
     return 1;
   }

   @Test
   public void testRetryMultipleTimesWithFixedSleep() {
     final int n = 4;
     final TimeDuration sleepTime = HUNDRED_MILLIS;
     final RetryPolicy policy = RetryPolicies.retryUpToMaximumCountWithFixedSleep(n, sleepTime);
     for(int i = 1; i < 2*n; i++) {
       final int attempt = i;
       final RetryPolicy.Event event = () -> attempt;
       final RetryPolicy.Action action = policy.handleAttemptFailure(event);

       final boolean expected = i < n;
       Assert.assertEquals(expected, action.shouldRetry());
       if (expected) {
         Assert.assertEquals(sleepTime, action.getSleepTime());
       } else {
         Assert.assertEquals(0L, action.getSleepTime().getDuration());
       }
     }
   }

   @Test
   public void testRequestTypeDependentRetry() {
     final RequestTypeDependentRetryPolicy.Builder b = RequestTypeDependentRetryPolicy.newBuilder();
     final int n = 4;
     final TimeDuration writeSleep = HUNDRED_MILLIS;
     final RetryPolicies.RetryLimited writePolicy = RetryPolicies.retryUpToMaximumCountWithFixedSleep(n, writeSleep);
     b.setRetryPolicy(RaftClientRequestProto.TypeCase.WRITE, writePolicy);
     b.setRetryPolicy(RaftClientRequestProto.TypeCase.WATCH, RetryPolicies.noRetry());
     final RetryPolicy policy = b.build();
     LOG.info("policy = {}", policy);

     final RaftClientRequest staleReadRequest = newRaftClientRequest(RaftClientRequest.staleReadRequestType(1));
     final RaftClientRequest readRequest = newRaftClientRequest(RaftClientRequest.readRequestType());
     final RaftClientRequest writeRequest = newRaftClientRequest(RaftClientRequest.writeRequestType());
     final RaftClientRequest watchRequest = newRaftClientRequest(
         RaftClientRequest.watchRequestType(1, ReplicationLevel.MAJORITY));
     for(int i = 1; i < 2*n; i++) {
       { //write
         final ClientRetryEvent event = new ClientRetryEvent(i, writeRequest, null);
         final RetryPolicy.Action action = policy.handleAttemptFailure(event);

         final boolean expected = i < n;
         Assert.assertEquals(expected, action.shouldRetry());
         if (expected) {
           Assert.assertEquals(writeSleep, action.getSleepTime());
         } else {
           Assert.assertEquals(0L, action.getSleepTime().getDuration());
         }
       }

       { //read and stale read are using default
         final ClientRetryEvent event = new ClientRetryEvent(i, readRequest, null);
         final RetryPolicy.Action action = policy.handleAttemptFailure(event);
         Assert.assertTrue(action.shouldRetry());
         Assert.assertEquals(0L, action.getSleepTime().getDuration());
       }

       {
         final ClientRetryEvent event = new ClientRetryEvent(i, staleReadRequest, null);
         final RetryPolicy.Action action = policy.handleAttemptFailure(event);
         Assert.assertTrue(action.shouldRetry());
         Assert.assertEquals(0L, action.getSleepTime().getDuration());
       }

       { //watch has no retry
         final ClientRetryEvent event = new ClientRetryEvent(i, watchRequest, null);
         final RetryPolicy.Action action = policy.handleAttemptFailure(event);
         Assert.assertFalse(action.shouldRetry());
         Assert.assertEquals(0L, action.getSleepTime().getDuration());
       }
     }

   }

   @Test
   public void testRequestTypeDependentRetryWithTimeout()
       throws InterruptedException {
     final RequestTypeDependentRetryPolicy.Builder b = RequestTypeDependentRetryPolicy.newBuilder();
     b.setRetryPolicy(RaftClientRequestProto.TypeCase.WRITE, RetryPolicies.retryForeverNoSleep());
     b.setRetryPolicy(RaftClientRequestProto.TypeCase.WATCH, RetryPolicies.retryForeverNoSleep());
     TimeDuration timeout = TimeDuration.valueOf(10, TimeUnit.MILLISECONDS);
     final RetryPolicy policy = b.setTimeout(RaftClientRequestProto.TypeCase.WRITE, timeout)
             .setTimeout(RaftClientRequestProto.TypeCase.WATCH, timeout).build();
     LOG.info("policy = {}", policy);

     final RaftClientRequest writeRequest = newRaftClientRequest(RaftClientRequest.writeRequestType());
     final RaftClientRequest watchRequest = newRaftClientRequest(
         RaftClientRequest.watchRequestType(1, ReplicationLevel.MAJORITY));

     RaftClientRequest[] requests = new RaftClientRequest[] {writeRequest, watchRequest};
     RaftClientImpl.PendingClientRequest pending = new RaftClientImpl.PendingClientRequest() {
       @Override
       public RaftClientRequest newRequestImpl() {
         return null;
       }
     };

     for (RaftClientRequest request : requests) {
       final ClientRetryEvent event = new ClientRetryEvent(request, new Exception(), pending);
       final RetryPolicy.Action action = policy.handleAttemptFailure(event);
       Assert.assertTrue(action.shouldRetry());
       Assert.assertEquals(0L, action.getSleepTime().getDuration());
     }

     Thread.sleep(timeout.toLong(TimeUnit.MILLISECONDS) * 10);
     for (RaftClientRequest request : requests) {
       final ClientRetryEvent event = new ClientRetryEvent(request, new Exception(), pending);
       final RetryPolicy.Action action = policy.handleAttemptFailure(event);
       Assert.assertFalse(action.shouldRetry());
     }
   }

     @Test
   public void testRequestTypeDependentRetryWithExceptionDependentPolicy() throws Exception {
     final RequestTypeDependentRetryPolicy.Builder retryPolicy =
         RequestTypeDependentRetryPolicy.newBuilder();
     Map<Class<? extends Throwable>, Pair> exceptionPolicyMap = new HashMap<>();
     exceptionPolicyMap.put(NotLeaderException.class, new Pair(10, 1));
     exceptionPolicyMap.put(LeaderNotReadyException.class, new Pair(10, 1));
     exceptionPolicyMap.put(TimeoutIOException.class, new Pair(5, 5));
     exceptionPolicyMap.put(ResourceUnavailableException.class, new Pair(5, 5));
     Pair defaultPolicy = new Pair(10, 2);

       retryPolicy.setRetryPolicy(RaftClientRequestProto.TypeCase.WRITE,
           buildExceptionBasedRetry(exceptionPolicyMap, defaultPolicy));
       retryPolicy.setRetryPolicy(RaftClientRequestProto.TypeCase.WATCH,
           buildExceptionBasedRetry(exceptionPolicyMap, defaultPolicy));

     final RetryPolicy policy = retryPolicy.build();
     LOG.info("policy = {}", policy);

     final RaftClientRequest writeRequest = newRaftClientRequest(RaftClientRequest.writeRequestType());
     final RaftClientRequest watchRequest = newRaftClientRequest(
         RaftClientRequest.watchRequestType(1, ReplicationLevel.MAJORITY));

     List<RaftClientRequest> requests = new ArrayList<>();
     requests.add(writeRequest);
     requests.add(watchRequest);

     for (RaftClientRequest raftClientRequest : requests) {
       for (Map.Entry< Class< ? extends Throwable >, Pair > exceptionPolicy :
           exceptionPolicyMap.entrySet()) {
         Throwable exception = createException(exceptionPolicy.getKey());
         for (int j = 1; j < exceptionPolicy.getValue().retries * 2; j++) {
           checkEvent(j, policy, raftClientRequest, exception,
               exceptionPolicy.getValue());
         }
       }
     }
     // Now try with an exception that is not defined in retry exception map.
     for (RaftClientRequest raftClientRequest : requests) {
       Throwable exception = createException(IOException.class);
       for (int j = 1; j < defaultPolicy.retries * 2; j++) {
         checkEvent(j, policy, raftClientRequest, exception, defaultPolicy);
       }
     }
   }

   /**
    * Check Event with the policy defined.
    * @param exceptionAttemptCount
    * @param retryPolicy
    * @param raftClientRequest
    * @param exception
    * @param exceptionPolicyPair
    */
   private void checkEvent(int exceptionAttemptCount, RetryPolicy retryPolicy, RaftClientRequest raftClientRequest,
       Throwable exception, Pair exceptionPolicyPair) {
     final ClientRetryEvent event =
         new ClientRetryEvent(exceptionAttemptCount, raftClientRequest, exception);
     final RetryPolicy.Action action = retryPolicy.handleAttemptFailure(event);

     final boolean expected = exceptionAttemptCount < exceptionPolicyPair.retries;
     Assert.assertEquals(expected, action.shouldRetry());
     if (expected) {
       Assert.assertEquals(exceptionPolicyPair.sleepTime, action.getSleepTime().getDuration());
     } else {
       Assert.assertEquals(0L, action.getSleepTime().getDuration());
     }
   }

   /**
    * Create exception object based on the exception class,
    * @param exception
    * @return exception object.
    */
   private Throwable createException(Class<? extends Throwable> exception) {
     Throwable ex;
     if (exception.getName().equals(LeaderNotReadyException.class.getName())) {
       ex =
           new LeaderNotReadyException(RaftGroupMemberId.valueOf(RaftPeerId.valueOf("node1"), RaftGroupId.randomId()));
     } else if (exception.getName().equals(NotLeaderException.class.getName())) {
       ex = new NotLeaderException(null, null, null);
     } else if (exception.getName().equals(TimeoutIOException.class.getName())) {
       ex = new TimeoutIOException("time out");
     } else if (exception.getName().equals(ResourceUnavailableException.class.getName())){
       ex = new ResourceUnavailableException("resource unavailable");
     } else {
       ex = new IOException("io exception");
     }
     return ex;
   }

   /**
    * Build {@link ExceptionDependentRetry} object.
    * @param exceptionPolicyMap
    * @param defaultPolicy
    * @return ExceptionDependentRetry
    */
   private ExceptionDependentRetry buildExceptionBasedRetry(Map<Class<?
       extends Throwable>, Pair> exceptionPolicyMap, Pair defaultPolicy) {
     final ExceptionDependentRetry.Builder policy =
         ExceptionDependentRetry.newBuilder();
     exceptionPolicyMap.forEach((k, v) -> {
       policy.setExceptionToPolicy(k,
           RetryPolicies.retryUpToMaximumCountWithFixedSleep(v.retries,
               TimeDuration.valueOf(v.sleepTime, TimeUnit.SECONDS)));
     });

     policy.setDefaultPolicy(RetryPolicies.retryUpToMaximumCountWithFixedSleep(defaultPolicy.retries,
         TimeDuration.valueOf(defaultPolicy.sleepTime, TimeUnit.SECONDS)));

     return policy.build();
   }


   private static RaftClientRequest newRaftClientRequest(RaftClientRequest.Type type) {
     return RaftClientRequest.newBuilder()
         .setClientId(ClientId.randomId())
         .setServerId(RaftPeerId.valueOf("s0"))
         .setGroupId(RaftGroupId.randomId())
         .setCallId(1L)
         .setType(type)
         .build();
   }

   /**
    * Pair class to hold retries and sleep time.
    */
   static class Pair {
     private int retries;
     private long sleepTime;

     Pair(int retries, long sleepTime) {
       this.retries = retries;
       this.sleepTime = sleepTime;
     }
   }
 }
	/*
	* 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.ratis.retry;

	import org.apache.ratis.BaseTest;
	import org.apache.ratis.client.impl.RaftClientImpl;
	import org.apache.ratis.client.retry.ClientRetryEvent;
	import org.apache.ratis.client.retry.RequestTypeDependentRetryPolicy;
	import org.apache.ratis.proto.RaftProtos.RaftClientRequestProto;
	import org.apache.ratis.proto.RaftProtos.ReplicationLevel;
	import org.apache.ratis.protocol.ClientId;
	import org.apache.ratis.protocol.exceptions.LeaderNotReadyException;
	import org.apache.ratis.protocol.exceptions.NotLeaderException;
	import org.apache.ratis.protocol.RaftClientRequest;
	import org.apache.ratis.protocol.RaftGroupId;
	import org.apache.ratis.protocol.RaftGroupMemberId;
	import org.apache.ratis.protocol.RaftPeerId;
	import org.apache.ratis.protocol.exceptions.TimeoutIOException;
	import org.apache.ratis.protocol.exceptions.ResourceUnavailableException;
	import org.apache.ratis.util.TimeDuration;
	import org.junit.Assert;
	import org.junit.Test;

	import java.io.IOException;
	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.concurrent.TimeUnit;

	/** Test {@link RetryPolicy}. */
	public class TestRetryPolicy extends BaseTest {
	@Override
	public int getGlobalTimeoutSeconds() {
	return 1;
	}

	@Test
	public void testRetryMultipleTimesWithFixedSleep() {
	final int n = 4;
	final TimeDuration sleepTime = HUNDRED_MILLIS;
	final RetryPolicy policy = RetryPolicies.retryUpToMaximumCountWithFixedSleep(n, sleepTime);
	for(int i = 1; i < 2*n; i++) {
	final int attempt = i;
	final RetryPolicy.Event event = () -> attempt;
	final RetryPolicy.Action action = policy.handleAttemptFailure(event);

	final boolean expected = i < n;
	Assert.assertEquals(expected, action.shouldRetry());
	if (expected) {
	Assert.assertEquals(sleepTime, action.getSleepTime());
	} else {
	Assert.assertEquals(0L, action.getSleepTime().getDuration());
	}
	}
	}

	@Test
	public void testRequestTypeDependentRetry() {
	final RequestTypeDependentRetryPolicy.Builder b = RequestTypeDependentRetryPolicy.newBuilder();
	final int n = 4;
	final TimeDuration writeSleep = HUNDRED_MILLIS;
	final RetryPolicies.RetryLimited writePolicy = RetryPolicies.retryUpToMaximumCountWithFixedSleep(n, writeSleep);
	b.setRetryPolicy(RaftClientRequestProto.TypeCase.WRITE, writePolicy);
	b.setRetryPolicy(RaftClientRequestProto.TypeCase.WATCH, RetryPolicies.noRetry());
	final RetryPolicy policy = b.build();
	LOG.info("policy = {}", policy);

	final RaftClientRequest staleReadRequest = newRaftClientRequest(RaftClientRequest.staleReadRequestType(1));
	final RaftClientRequest readRequest = newRaftClientRequest(RaftClientRequest.readRequestType());
	final RaftClientRequest writeRequest = newRaftClientRequest(RaftClientRequest.writeRequestType());
	final RaftClientRequest watchRequest = newRaftClientRequest(
	RaftClientRequest.watchRequestType(1, ReplicationLevel.MAJORITY));
	for(int i = 1; i < 2*n; i++) {
	{ //write
	final ClientRetryEvent event = new ClientRetryEvent(i, writeRequest, null);
	final RetryPolicy.Action action = policy.handleAttemptFailure(event);

	final boolean expected = i < n;
	Assert.assertEquals(expected, action.shouldRetry());
	if (expected) {
	Assert.assertEquals(writeSleep, action.getSleepTime());
	} else {
	Assert.assertEquals(0L, action.getSleepTime().getDuration());
	}
	}

	{ //read and stale read are using default
	final ClientRetryEvent event = new ClientRetryEvent(i, readRequest, null);
	final RetryPolicy.Action action = policy.handleAttemptFailure(event);
	Assert.assertTrue(action.shouldRetry());
	Assert.assertEquals(0L, action.getSleepTime().getDuration());
	}

	{
	final ClientRetryEvent event = new ClientRetryEvent(i, staleReadRequest, null);
	final RetryPolicy.Action action = policy.handleAttemptFailure(event);
	Assert.assertTrue(action.shouldRetry());
	Assert.assertEquals(0L, action.getSleepTime().getDuration());
	}

	{ //watch has no retry
	final ClientRetryEvent event = new ClientRetryEvent(i, watchRequest, null);
	final RetryPolicy.Action action = policy.handleAttemptFailure(event);
	Assert.assertFalse(action.shouldRetry());
	Assert.assertEquals(0L, action.getSleepTime().getDuration());
	}
	}

	}

	@Test
	public void testRequestTypeDependentRetryWithTimeout()
	throws InterruptedException {
	final RequestTypeDependentRetryPolicy.Builder b = RequestTypeDependentRetryPolicy.newBuilder();
	b.setRetryPolicy(RaftClientRequestProto.TypeCase.WRITE, RetryPolicies.retryForeverNoSleep());
	b.setRetryPolicy(RaftClientRequestProto.TypeCase.WATCH, RetryPolicies.retryForeverNoSleep());
	TimeDuration timeout = TimeDuration.valueOf(10, TimeUnit.MILLISECONDS);
	final RetryPolicy policy = b.setTimeout(RaftClientRequestProto.TypeCase.WRITE, timeout)
	.setTimeout(RaftClientRequestProto.TypeCase.WATCH, timeout).build();
	LOG.info("policy = {}", policy);

	final RaftClientRequest writeRequest = newRaftClientRequest(RaftClientRequest.writeRequestType());
	final RaftClientRequest watchRequest = newRaftClientRequest(
	RaftClientRequest.watchRequestType(1, ReplicationLevel.MAJORITY));

	RaftClientRequest[] requests = new RaftClientRequest[] {writeRequest, watchRequest};
	RaftClientImpl.PendingClientRequest pending = new RaftClientImpl.PendingClientRequest() {
	@Override
	public RaftClientRequest newRequestImpl() {
	return null;
	}
	};

	for (RaftClientRequest request : requests) {
	final ClientRetryEvent event = new ClientRetryEvent(request, new Exception(), pending);
	final RetryPolicy.Action action = policy.handleAttemptFailure(event);
	Assert.assertTrue(action.shouldRetry());
	Assert.assertEquals(0L, action.getSleepTime().getDuration());
	}

	Thread.sleep(timeout.toLong(TimeUnit.MILLISECONDS) * 10);
	for (RaftClientRequest request : requests) {
	final ClientRetryEvent event = new ClientRetryEvent(request, new Exception(), pending);
	final RetryPolicy.Action action = policy.handleAttemptFailure(event);
	Assert.assertFalse(action.shouldRetry());
	}
	}

	@Test
	public void testRequestTypeDependentRetryWithExceptionDependentPolicy() throws Exception {
	final RequestTypeDependentRetryPolicy.Builder retryPolicy =
	RequestTypeDependentRetryPolicy.newBuilder();
	Map<Class<? extends Throwable>, Pair> exceptionPolicyMap = new HashMap<>();
	exceptionPolicyMap.put(NotLeaderException.class, new Pair(10, 1));
	exceptionPolicyMap.put(LeaderNotReadyException.class, new Pair(10, 1));
	exceptionPolicyMap.put(TimeoutIOException.class, new Pair(5, 5));
	exceptionPolicyMap.put(ResourceUnavailableException.class, new Pair(5, 5));
	Pair defaultPolicy = new Pair(10, 2);

	retryPolicy.setRetryPolicy(RaftClientRequestProto.TypeCase.WRITE,
	buildExceptionBasedRetry(exceptionPolicyMap, defaultPolicy));
	retryPolicy.setRetryPolicy(RaftClientRequestProto.TypeCase.WATCH,
	buildExceptionBasedRetry(exceptionPolicyMap, defaultPolicy));

	final RetryPolicy policy = retryPolicy.build();
	LOG.info("policy = {}", policy);

	final RaftClientRequest writeRequest = newRaftClientRequest(RaftClientRequest.writeRequestType());
	final RaftClientRequest watchRequest = newRaftClientRequest(
	RaftClientRequest.watchRequestType(1, ReplicationLevel.MAJORITY));

	List<RaftClientRequest> requests = new ArrayList<>();
	requests.add(writeRequest);
	requests.add(watchRequest);

	for (RaftClientRequest raftClientRequest : requests) {
	for (Map.Entry< Class< ? extends Throwable >, Pair > exceptionPolicy :
	exceptionPolicyMap.entrySet()) {
	Throwable exception = createException(exceptionPolicy.getKey());
	for (int j = 1; j < exceptionPolicy.getValue().retries * 2; j++) {
	checkEvent(j, policy, raftClientRequest, exception,
	exceptionPolicy.getValue());
	}
	}
	}
	// Now try with an exception that is not defined in retry exception map.
	for (RaftClientRequest raftClientRequest : requests) {
	Throwable exception = createException(IOException.class);
	for (int j = 1; j < defaultPolicy.retries * 2; j++) {
	checkEvent(j, policy, raftClientRequest, exception, defaultPolicy);
	}
	}
	}

	/**
	* Check Event with the policy defined.
	* @param exceptionAttemptCount
	* @param retryPolicy
	* @param raftClientRequest
	* @param exception
	* @param exceptionPolicyPair
	*/
	private void checkEvent(int exceptionAttemptCount, RetryPolicy retryPolicy, RaftClientRequest raftClientRequest,
	Throwable exception, Pair exceptionPolicyPair) {
	final ClientRetryEvent event =
	new ClientRetryEvent(exceptionAttemptCount, raftClientRequest, exception);
	final RetryPolicy.Action action = retryPolicy.handleAttemptFailure(event);

	final boolean expected = exceptionAttemptCount < exceptionPolicyPair.retries;
	Assert.assertEquals(expected, action.shouldRetry());
	if (expected) {
	Assert.assertEquals(exceptionPolicyPair.sleepTime, action.getSleepTime().getDuration());
	} else {
	Assert.assertEquals(0L, action.getSleepTime().getDuration());
	}
	}

	/**
	* Create exception object based on the exception class,
	* @param exception
	* @return exception object.
	*/
	private Throwable createException(Class<? extends Throwable> exception) {
	Throwable ex;
	if (exception.getName().equals(LeaderNotReadyException.class.getName())) {
	ex =
	new LeaderNotReadyException(RaftGroupMemberId.valueOf(RaftPeerId.valueOf("node1"), RaftGroupId.randomId()));
	} else if (exception.getName().equals(NotLeaderException.class.getName())) {
	ex = new NotLeaderException(null, null, null);
	} else if (exception.getName().equals(TimeoutIOException.class.getName())) {
	ex = new TimeoutIOException("time out");
	} else if (exception.getName().equals(ResourceUnavailableException.class.getName())){
	ex = new ResourceUnavailableException("resource unavailable");
	} else {
	ex = new IOException("io exception");
	}
	return ex;
	}

	/**
	* Build {@link ExceptionDependentRetry} object.
	* @param exceptionPolicyMap
	* @param defaultPolicy
	* @return ExceptionDependentRetry
	*/
	private ExceptionDependentRetry buildExceptionBasedRetry(Map<Class<?
	extends Throwable>, Pair> exceptionPolicyMap, Pair defaultPolicy) {
	final ExceptionDependentRetry.Builder policy =
	ExceptionDependentRetry.newBuilder();
	exceptionPolicyMap.forEach((k, v) -> {
	policy.setExceptionToPolicy(k,
	RetryPolicies.retryUpToMaximumCountWithFixedSleep(v.retries,
	TimeDuration.valueOf(v.sleepTime, TimeUnit.SECONDS)));
	});

	policy.setDefaultPolicy(RetryPolicies.retryUpToMaximumCountWithFixedSleep(defaultPolicy.retries,
	TimeDuration.valueOf(defaultPolicy.sleepTime, TimeUnit.SECONDS)));

	return policy.build();
	}


	private static RaftClientRequest newRaftClientRequest(RaftClientRequest.Type type) {
	return RaftClientRequest.newBuilder()
	.setClientId(ClientId.randomId())
	.setServerId(RaftPeerId.valueOf("s0"))
	.setGroupId(RaftGroupId.randomId())
	.setCallId(1L)
	.setType(type)
	.build();
	}

	/**
	* Pair class to hold retries and sleep time.
	*/
	static class Pair {
	private int retries;
	private long sleepTime;

	Pair(int retries, long sleepTime) {
	this.retries = retries;
	this.sleepTime = sleepTime;
	}
	}
	}