com.netflix.astyanax.cql.retrypolicies.ChangeConsistencyLevelRetryPolicy Maven / Gradle / Ivy

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/**
 * Copyright 2013 Netflix, Inc.
 *
 * Licensed 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 com.netflix.astyanax.cql.retrypolicies;

import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.ConsistencyLevel;
import com.datastax.driver.core.Statement;
import com.datastax.driver.core.WriteType;
import com.datastax.driver.core.exceptions.DriverException;
import com.datastax.driver.core.policies.RetryPolicy.RetryDecision;
import com.netflix.astyanax.cql.ConsistencyLevelMapping;

/**
 * Class that encapsulates a RetryPolicy that can be used in a configurable way when doing reties.
 * Users can choose whether to retry on just  reads / writes / unavailable exceptions or just all operations.
 * Users can also decide to change the consistency level on different reties.
 *
 * @author poberai
 *
 */
public class ChangeConsistencyLevelRetryPolicy extends JavaDriverBasedRetryPolicy {

	// Policies for specific conditions
	private boolean retryOnAllConditions = true;
	private boolean retryOnReads = false;
	private boolean retryOnWrites = false;
	private boolean retryOnUnavailable = false;

	// The retry count
	private int retryCount = 0;
	// the next consistency level to use.
	private ConsistencyLevel nextConsistencyLevel;
	// throw when giving up or ignore failures
	private boolean suppressFinalFailure = false;

	public ChangeConsistencyLevelRetryPolicy() {
	}

	public ChangeConsistencyLevelRetryPolicy retryOnAllConditions(boolean condition) {
		retryOnAllConditions = condition;
		return this;
	}

	public ChangeConsistencyLevelRetryPolicy retryOnReadTimeouts(boolean condition) {
		retryOnReads = condition;
		retryOnAllConditions = false;
		return this;
	}

	public ChangeConsistencyLevelRetryPolicy retryOnWriteTimeouts(boolean condition) {
		retryOnWrites = condition;
		retryOnAllConditions = false;
		return this;
	}

	public ChangeConsistencyLevelRetryPolicy retryOnUnavailable(boolean condition) {
		retryOnUnavailable = condition;
		retryOnAllConditions = false;
		return this;
	}

	public ChangeConsistencyLevelRetryPolicy withNumRetries(int retries) {
		retryCount = retries;
		return this;
	}

	public ChangeConsistencyLevelRetryPolicy withNextConsistencyLevel(com.netflix.astyanax.model.ConsistencyLevel cl) {
		nextConsistencyLevel = ConsistencyLevelMapping.getCL(cl);
		return this;
	}

	public ChangeConsistencyLevelRetryPolicy suppressFinalFailure(boolean condition) {
		suppressFinalFailure = condition;
		return this;
	}

	private com.datastax.driver.core.policies.RetryPolicy jdRetry = new com.datastax.driver.core.policies.RetryPolicy() {

		@Override
		public RetryDecision onReadTimeout(Statement query, ConsistencyLevel cl,
										   int requiredResponses, int receivedResponses,
										   boolean dataRetrieved, int nbRetry) {

			boolean shouldRetry = retryOnAllConditions || retryOnReads;
			return checkRetry(query, cl, shouldRetry);
		}

		@Override
		public RetryDecision onWriteTimeout(Statement query, ConsistencyLevel cl,
											WriteType writeType, int requiredAcks, int receivedAcks,
											int nbRetry) {

			boolean shouldRetry = retryOnAllConditions || retryOnWrites;
			return checkRetry(query, cl, shouldRetry);
		}

		@Override
		public RetryDecision onUnavailable(Statement query, ConsistencyLevel cl,
										   int requiredReplica, int aliveReplica, int nbRetry) {

			boolean shouldRetry = retryOnAllConditions || retryOnUnavailable;
			return checkRetry(query, cl, shouldRetry);
		}

		@Override
		public RetryDecision onRequestError(Statement query, ConsistencyLevel cl, DriverException e, int nbRetry) {
			boolean shouldRetry = retryOnAllConditions || retryOnUnavailable;
			return checkRetry(query, cl, shouldRetry);
		}

		@Override
		public void init(Cluster cluster) {
			// Do nothing
		}

		@Override
		public void close() {
			// Do nothing
		}
	};

	@Override
	public com.datastax.driver.core.policies.RetryPolicy getJDRetryPolicy() {
		return jdRetry;
	}

	private RetryDecision checkRetry(Statement query, ConsistencyLevel cl, boolean shouldRetry) {

		if (!shouldRetry || retryCount <= 0) {
			// We are out of retries. 
			if (suppressFinalFailure) {
				return RetryDecision.ignore();
			} else {
				return RetryDecision.rethrow();
			}
		}

		// Ok we should retry and have some tries left.
		retryCount--;    // Note this retry

		// Check if the consistency level needs to be changed
		if (nextConsistencyLevel != null) {
			return RetryDecision.retry(nextConsistencyLevel);
		} else {
			return RetryDecision.retry(cl);
		}
	}
}