cf.spring.CfComponentConfiguration.java Source code

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Here is the source code for cf.spring.CfComponentConfiguration.java

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/*
 *   Copyright (c) 2014 Intellectual Reserve, Inc.  All rights reserved.
 *
 *   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 cf.spring;

import cf.component.BasicVarzProducer;
import cf.component.VarzAggregator;
import cf.component.VarzProducer;
import cf.component.util.DateTimeUtils;
import cf.nats.CfNats;
import cf.nats.DefaultCfNats;
import cf.nats.Publication;
import cf.nats.PublicationHandler;
import cf.nats.message.ComponentAnnounce;
import cf.nats.message.ComponentDiscover;
import nats.client.Nats;
import nats.client.Subscription;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanCreationException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.BeanExpressionContext;
import org.springframework.beans.factory.config.BeanExpressionResolver;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportAware;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StringUtils;

import java.lang.management.ManagementFactory;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.ThreadLocalRandom;

/**
 * @author Mike Heath <elcapo@gmail.com>
 */
@Configuration
public class CfComponentConfiguration implements InitializingBean, DisposableBean, ImportAware, BeanFactoryAware {

    @Autowired
    private Nats nats;
    @Autowired(required = false)
    private CfNats cfNats;

    private BeanExpressionResolver expressionResolver;
    private BeanExpressionContext expressionContext;

    private String type;
    private int index;
    private String uuid;
    private String host;
    private int port;
    private String username;
    private String password;

    private Subscription componentDiscoverSubscription;

    private final long startTime = ManagementFactory.getRuntimeMXBean().getStartTime();

    @Override
    public void setImportMetadata(AnnotationMetadata importMetadata) {
        final MultiValueMap<String, Object> attributes = importMetadata
                .getAllAnnotationAttributes(CfComponent.class.getName());
        type = evaluate(attributes, "type");
        index = Integer.valueOf(evaluate(attributes, "index"));
        uuid = evaluate(attributes, "uuid");
        if (StringUtils.isEmpty(uuid)) {
            uuid = UUID.randomUUID().toString();
        }
        host = evaluate(attributes, "host");
        port = Integer.valueOf(evaluate(attributes, "port"));
        username = evaluate(attributes, "username");
        password = evaluate(attributes, "password");
        if (StringUtils.isEmpty(password)) {
            password = new BigInteger(256, ThreadLocalRandom.current()).toString(32);
        }
    }

    private String evaluate(MultiValueMap<String, Object> annotationAttributes, String attribute) {
        final String expression = annotationAttributes.getFirst(attribute).toString();
        final Object value = expressionResolver.evaluate(expression, expressionContext);
        return value == null ? null : value.toString();
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        if (cfNats == null) {
            cfNats = new DefaultCfNats(nats);
        }
        componentDiscoverSubscription = cfNats.subscribe(ComponentDiscover.class,
                new PublicationHandler<ComponentDiscover, ComponentAnnounce>() {
                    @Override
                    public void onMessage(Publication<ComponentDiscover, ComponentAnnounce> publication) {
                        publication.reply(buildComponentAnnounceMessage());
                    }
                });
        cfNats.publish(buildComponentAnnounceMessage());
    }

    @Override
    public void destroy() throws Exception {
        componentDiscoverSubscription.close();
    }

    @Bean
    HealthzHandlerMapping healthzHandlerMapping() {
        return new HealthzHandlerMapping();
    }

    @Bean
    VarzHandlerMapping varzHandlerMapping(List<VarzProducer> varzProducers) {
        return new VarzHandlerMapping(new VarzAggregator(varzProducers),
                new HttpBasicAuthenticator("", username, password));
    }

    @Bean
    BasicVarzProducer basicVarz() {
        return new BasicVarzProducer(type, index, uuid);
    }

    public String getType() {
        return type;
    }

    public int getIndex() {
        return index;
    }

    public String getUuid() {
        return uuid;
    }

    public String getHost() {
        return host;
    }

    public int getPort() {
        return port;
    }

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }

    private ComponentAnnounce buildComponentAnnounceMessage() {
        return new ComponentAnnounce(type, index, uuid, host + ":" + port, Arrays.asList(username, password),
                DateTimeUtils.formatDateTime(startTime), DateTimeUtils.formatUptime(startTime));
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        if (beanFactory instanceof ConfigurableBeanFactory) {
            final ConfigurableBeanFactory cbf = (ConfigurableBeanFactory) beanFactory;
            expressionResolver = cbf.getBeanExpressionResolver();
            expressionContext = new BeanExpressionContext(cbf,
                    cbf.getRegisteredScope(ConfigurableBeanFactory.SCOPE_PROTOTYPE));
        } else {
            throw new BeanCreationException(
                    getClass().getName() + " can only be used with a " + ConfigurableBeanFactory.class.getName());
        }
    }
}