org.springframework.bus.runner.adapter.discovery.DiscoveryClientChannelLocator.java Source code

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Here is the source code for org.springframework.bus.runner.adapter.discovery.DiscoveryClientChannelLocator.java

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/*
 * Copyright 2015 the original author or authors.
 *
 * 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 org.springframework.bus.runner.adapter.discovery;

import java.net.URI;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Random;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.bus.runner.adapter.ChannelBinding;
import org.springframework.bus.runner.adapter.ChannelLocator;
import org.springframework.bus.runner.adapter.ChannelsMetadata;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.client.RestOperations;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;

/**
 * @author Dave Syer
 */
public class DiscoveryClientChannelLocator implements ChannelLocator {

    private Log logger = LogFactory.getLog(DiscoveryClientChannelLocator.class);

    private DiscoveryClient discovery;

    private RestOperations restTemplate = new RestTemplate();

    private String serviceId;

    public DiscoveryClientChannelLocator(DiscoveryClient discovery, String serviceId) {
        this.discovery = discovery;
        this.serviceId = serviceId;
    }

    public void setRestTemplate(RestOperations restTemplate) {
        this.restTemplate = restTemplate;
    }

    @Override
    public String locate(String name) {
        List<ServiceInstance> instances = this.discovery.getInstances(this.serviceId);
        if (instances == null || instances.isEmpty()) {
            return null;
        }
        URI uri = pickUrl(instances);
        try {
            ChannelsMetadata channels = this.restTemplate.getForObject(uri, ChannelsMetadata.class);
            Collection<? extends ChannelBinding> bindings = Collections.emptySet();
            if (name.startsWith("input")) {
                name = name.replace("input", "output");
                bindings = channels.getOutputChannels();
            } else if (name.startsWith("output")) {
                name = name.replace("output", "input");
                bindings = channels.getInputChannels();
            }
            for (ChannelBinding binding : bindings) {
                if (name.equals(binding.getLocalName())) {
                    this.logger.debug("Discovered channel for '" + this.serviceId + "' (" + name + "="
                            + binding.getRemoteName() + ")");
                    return binding.getRemoteName();
                }
            }
        } catch (Exception e) {
            this.logger.warn("Could not discover channel for '" + this.serviceId + "' (" + e.getClass() + ": "
                    + e.getMessage() + ")");
            return null;
        }
        this.logger.warn("No channel disccovered for '" + this.serviceId + "' (" + name + ")");
        return null;
    }

    private URI pickUrl(List<ServiceInstance> instances) {
        return UriComponentsBuilder.fromUri(instances.get(new Random().nextInt(instances.size())).getUri())
                .path("channels").build().toUri();
    }

}