components/camel-hystrix/src/test/java/org/apache/camel/component/hystrix/processor/HystrixCircuitOpenTest.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.camel.component.hystrix.processor;

import java.io.IOException;

import org.apache.camel.CamelExecutionException;
import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.RoutesBuilder;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.spi.CircuitBreakerConstants;
import org.apache.camel.test.junit4.CamelTestSupport;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class HystrixCircuitOpenTest extends CamelTestSupport {
    public static final Integer REQUEST_VOLUME_THRESHOLD = 4;
    private static final Logger LOG = LoggerFactory.getLogger(HystrixCircuitOpenTest.class);

    private HystrixExceptionRoute route = new HystrixExceptionRoute();

    @Test
    public void testCircuitOpen() throws Exception {
        LOG.info("testCircuitOpen start");
        // failing requests
        route.throwException = true;
        for (int i = 0; i < 2 * REQUEST_VOLUME_THRESHOLD; i++) {
            try {
                template.asyncRequestBody("direct:start", "Request Body");
            } catch (CamelExecutionException e) {
                LOG.info(e.toString());
            }
        }
        Thread.sleep(1500);

        resetMocks();

        // notice this can be flaky due timing when using thread sleeps in unit tests
        getMockEndpoint("mock:result").expectedPropertyReceived(CircuitBreakerConstants.RESPONSE_SHORT_CIRCUITED, true);

        route.throwException = false;
        try {
            template.requestBody("direct:start", "Request Body");
            LOG.info("Instead circuit open expected");
        } catch (CamelExecutionException e) {
            LOG.info("Circuit open expected ", e);
        }

        assertMockEndpointsSatisfied();

        // wait for the circuit to try an other request
        Thread.sleep(500);
        for (int i = 0; i < 2 * REQUEST_VOLUME_THRESHOLD; i++) {
            try {
                template.requestBody("direct:start", "Request Body");
                LOG.info("Circuit has closed");
            } catch (CamelExecutionException e) {
                Thread.sleep(i * 100);
                LOG.info("Circuit will be closed soon " + e.toString());
            }
        }

        resetMocks();

        getMockEndpoint("mock:result").expectedPropertyReceived(CircuitBreakerConstants.RESPONSE_SHORT_CIRCUITED, false);
        getMockEndpoint("mock:result").expectedPropertyReceived(CircuitBreakerConstants.RESPONSE_SUCCESSFUL_EXECUTION, true);

        template.requestBody("direct:start", "Request Body");

        assertMockEndpointsSatisfied();
    }

    @Override
    protected RoutesBuilder createRouteBuilder() throws Exception {
        return route;
    }

    class HystrixExceptionRoute extends RouteBuilder {
        volatile boolean throwException = true;

        @Override
        public void configure() throws Exception {
            from("direct:start")
                .circuitBreaker()
                    .hystrixConfiguration()
                        .executionTimeoutInMilliseconds(100)
                        .circuitBreakerRequestVolumeThreshold(REQUEST_VOLUME_THRESHOLD)
                        .metricsRollingStatisticalWindowInMilliseconds(1000)
                        .circuitBreakerSleepWindowInMilliseconds(2000)
                    .end()
                    .log("Hystrix processing start: ${threadName}")
                    .process(new Processor() {
                        @Override
                        public void process(Exchange exchange) throws Exception {
                            if (throwException) {
                                LOG.info("Will throw exception");
                                throw new IOException("Route has failed");
                            } else {
                                LOG.info("Will NOT throw exception");
                            }
                        }
                    })
                    .log("Hystrix processing end: ${threadName}")
                .end()
                .log(CircuitBreakerConstants.RESPONSE_SHORT_CIRCUITED + " = ${exchangeProperty." + CircuitBreakerConstants.RESPONSE_SHORT_CIRCUITED + "}")
                .to("mock:result");
        }
    }
}