package com.netflix.astyanax.contrib.eureka;
import java.util.List;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.base.Supplier;
import com.google.common.collect.Collections2;
import com.google.common.collect.Lists;
import com.netflix.appinfo.AmazonInfo;
import com.netflix.appinfo.AmazonInfo.MetaDataKey;
import com.netflix.appinfo.InstanceInfo;
import com.netflix.appinfo.MyDataCenterInstanceConfig;
import com.netflix.astyanax.connectionpool.Host;
import com.netflix.discovery.DefaultEurekaClientConfig;
import com.netflix.discovery.DiscoveryClient;
import com.netflix.discovery.DiscoveryManager;
import com.netflix.discovery.shared.Application;
/**
* Simple class that implements {@link Supplier}<{@link List}<{@link Host}>>. It provides a List<{@link Host}>
* using the {@link DiscoveryManager} which is the eureka client.
*
* Note that the class needs the eureka application name to discover all instances for that application.
*
* @author poberai
*/
public class EurekaBasedHostSupplier implements Supplier<List<Host>> {
private static final Logger LOG = LoggerFactory.getLogger(EurekaBasedHostSupplier.class);
// The C* cluster name for discovering nodes
private final String applicationName;
public EurekaBasedHostSupplier(String applicationName) {
this.applicationName = applicationName.toUpperCase();
// initialize eureka client. make sure eureka properties are properly configured in config.properties
DiscoveryManager.getInstance().initComponent(new MyDataCenterInstanceConfig(), new DefaultEurekaClientConfig());
}
@Override
public List<Host> get() {
DiscoveryClient discoveryClient = DiscoveryManager.getInstance().getDiscoveryClient();
if (discoveryClient == null) {
LOG.error("Error getting discovery client");
throw new RuntimeException("Failed to create discovery client");
}
Application app = discoveryClient.getApplication(applicationName);
List<Host> hosts = Lists.newArrayList();
if (app == null) {
return hosts;
}
List<InstanceInfo> ins = app.getInstances();
if (ins == null || ins.isEmpty()) {
return hosts;
}
hosts = Lists.newArrayList(Collections2.transform(
Collections2.filter(ins, new Predicate<InstanceInfo>() {
@Override
public boolean apply(InstanceInfo input) {
return input.getStatus() == InstanceInfo.InstanceStatus.UP;
}
}), new Function<InstanceInfo, Host>() {
@Override
public Host apply(InstanceInfo info) {
String[] parts = StringUtils.split(
StringUtils.split(info.getHostName(), ".")[0], '-');
Host host = new Host(info.getHostName(), info.getPort())
.addAlternateIpAddress(
StringUtils.join(new String[] { parts[1], parts[2], parts[3],
parts[4] }, "."))
.addAlternateIpAddress(info.getIPAddr())
.setId(info.getId());
try {
if (info.getDataCenterInfo() instanceof AmazonInfo) {
AmazonInfo amazonInfo = (AmazonInfo)info.getDataCenterInfo();
host.setRack(amazonInfo.get(MetaDataKey.availabilityZone));
}
}
catch (Throwable t) {
LOG.error("Error getting rack for host " + host.getName(), t);
}
return host;
}
}));
return hosts;
}
}