HystrixFaultToleranceFactory.java

/*
 * Copyright 2014 Avanza Bank AB
 *
 * 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.avanza.astrix.ft.hystrix;

import java.util.concurrent.atomic.AtomicInteger;

import com.avanza.astrix.beans.config.AstrixConfig;
import com.avanza.astrix.beans.core.AstrixBeanKey;
import com.avanza.astrix.beans.ft.BeanFaultTolerance;
import com.avanza.astrix.beans.ft.BeanFaultToleranceFactorySpi;
import com.avanza.astrix.beans.ft.HystrixCommandNamingStrategy;
import com.avanza.astrix.beans.ft.MonitorableFaultToleranceSpi;
import com.avanza.hystrix.multiconfig.MultiConfigId;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandKey;
import com.netflix.hystrix.HystrixThreadPoolKey;
/**
 * 
 * @author Elias Lindholm (elilin)
 *
 */
final class HystrixFaultToleranceFactory implements BeanFaultToleranceFactorySpi, MonitorableFaultToleranceSpi {

	/*
	 * Astrix allows multiple AstrixContext within the same JVM, although
	 * more than one AstrixContext within a single JVM is most often only used during unit testing. However,
	 * since Astrix allows multiple AstrixContext's we want those to be isolated from each other. Hystrix only 
	 * allows registering a global strategy for each exposed SPI. Therefore Astrix registers a global "dispatcher"
	 * strategy (see HystrixPluginDispatcher) that dispatches each invocation to a HystrixPlugin to
	 * the HystrixPlugin instance associated with a given AstrixContext.
	 * 
	 * The "id" property is used by the dispatcher to identify the HystrixPlugin instances associated with a given
	 * AstrixContext.
	 */
	
	private static final AtomicInteger idGenerator = new AtomicInteger(0);
	
	private final BeanMapping beanMapping;
	private final HystrixCommandKeyFactory hystrixCommandKeyFactory;
	private final String id;
	private MultiConfigId multiConfigId = MultiConfigId.create("astrix");
	
	@Override
	public BeanFaultTolerance create(AstrixBeanKey<?> beanKey) {
		return new HystrixBeanFaultTolerance(getCommandKey(beanKey), getGroupKey(beanKey));
	}
	
	public HystrixFaultToleranceFactory(HystrixCommandNamingStrategy hystrixCommandNamingStrategy,
								 AstrixConcurrencyStrategy concurrencyStrategy,
								 BeanConfigurationPropertiesStrategy propertiesStrategy,
								 BeanMapping beanMapping,
								 AstrixConfig config) {
		this.id = Integer.toString(idGenerator.incrementAndGet()); 
		this.beanMapping = beanMapping;
		HystrixStrategies hystrixStrategies = new HystrixStrategies(propertiesStrategy, 
																	concurrencyStrategy, 
																	new FailedServiceInvocationLogger(beanMapping, config), 
																	id);
		HystrixStrategyDispatcher.registerStrategies(hystrixStrategies);
		this.hystrixCommandKeyFactory = new HystrixCommandKeyFactory(id, hystrixCommandNamingStrategy);
	}
	
	@Override
	public BeanFaultToleranceMetricsMBean createBeanFaultToleranceMetricsMBean(AstrixBeanKey<?> beanKey) {
		return new BeanFaultToleranceMetrics(getCommandKey(beanKey), getThreadPoolKey(beanKey));
	}
	
	HystrixCommandGroupKey getGroupKey(AstrixBeanKey<?> beanKey) {
		HystrixCommandGroupKey result = hystrixCommandKeyFactory.createGroupKey(beanKey);
		this.beanMapping.registerBeanKey(result.name(), beanKey);
		return multiConfigId.encode(result);
	}

	HystrixCommandKey getCommandKey(AstrixBeanKey<?> beanKey) {
		HystrixCommandKey result =  hystrixCommandKeyFactory.createCommandKey(beanKey);
		this.beanMapping.registerBeanKey(result.name(), beanKey);
		return multiConfigId.encode(result);
	}
	
	HystrixThreadPoolKey getThreadPoolKey(AstrixBeanKey<?> beanKey) {
		HystrixThreadPoolKey result =  hystrixCommandKeyFactory.createThreadPoolKey(beanKey);
		this.beanMapping.registerBeanKey(result.name(), beanKey);
		return multiConfigId.encode(result);
	}

}