package com.bazaarvoice.ostrich.examples.calculator.user;
import com.bazaarvoice.ostrich.ServiceCallback;
import com.bazaarvoice.ostrich.ServicePool;
import com.bazaarvoice.ostrich.discovery.zookeeper.ZooKeeperHostDiscovery;
import com.bazaarvoice.ostrich.discovery.zookeeper.ZooKeeperHostDiscovery;
import com.bazaarvoice.ostrich.dropwizard.healthcheck.ContainsHealthyEndPointCheck;
import com.bazaarvoice.ostrich.examples.calculator.client.CalculatorService;
import com.bazaarvoice.ostrich.examples.calculator.client.CalculatorServiceFactory;
import com.bazaarvoice.ostrich.examples.calculator.service.ZooKeeperConfiguration;
import com.bazaarvoice.ostrich.exceptions.ServiceException;
import com.bazaarvoice.ostrich.pool.ServiceCachingPolicy;
import com.bazaarvoice.ostrich.pool.ServiceCachingPolicyBuilder;
import com.bazaarvoice.ostrich.pool.ServicePoolBuilder;
import com.bazaarvoice.ostrich.retry.ExponentialBackoffRetry;
import com.google.common.io.Closeables;
import com.netflix.curator.framework.CuratorFramework;
import com.netflix.curator.framework.CuratorFrameworkFactory;
import com.yammer.dropwizard.config.ConfigurationFactory;
import com.yammer.dropwizard.validation.Validator;
import com.yammer.metrics.HealthChecks;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.util.Random;
import java.util.concurrent.TimeUnit;
public class CalculatorUser {
private static final Logger LOG = LoggerFactory.getLogger(CalculatorUser.class);
private final Random _random = new Random();
private final ServicePool<CalculatorService> _calculatorPool;
public CalculatorUser(ServicePool<CalculatorService> calculatorPool) {
_calculatorPool = calculatorPool;
}
public void use() throws InterruptedException {
int i = 0;
while (++i > 0) {
try {
final int a = _random.nextInt(10);
final int b = 1 + _random.nextInt(9);
final int op = _random.nextInt(4);
int result = _calculatorPool.execute(new ExponentialBackoffRetry(5, 50, 1000, TimeUnit.MILLISECONDS),
new ServiceCallback<CalculatorService, Integer>() {
@Override
public Integer call(CalculatorService service) throws ServiceException {
return CalculatorUser.this.call(service, op, a, b);
}
});
LOG.info("i:{}, result:{}", i, result);
} catch (Exception e) {
LOG.warn("i:{}, {}", i, e);
}
Thread.sleep(100);
}
}
private int call(CalculatorService service, int op, int a, int b) {
switch (op) {
case 0: return service.add(a, b);
case 1: return service.sub(a, b);
case 2: return service.mul(a, b);
default: return service.div(a, b);
}
}
public static void main(String[] args) throws Exception {
// Load the config.yaml file specified as the first argument. Or just use defaults if none specified.
CalculatorConfiguration configuration;
if (args.length > 0) {
ConfigurationFactory<CalculatorConfiguration> configFactory = ConfigurationFactory.forClass(
CalculatorConfiguration.class, new Validator());
configuration = configFactory.build(new File(args[0]));
} else {
configuration = new CalculatorConfiguration();
}
CuratorFramework curator = newCurator(configuration.getZooKeeperConfiguration());
// Connection caching is optional, but included here for the sake of demonstration.
ServiceCachingPolicy cachingPolicy = new ServiceCachingPolicyBuilder()
.withMaxNumServiceInstances(10)
.withMaxNumServiceInstancesPerEndPoint(1)
.withMaxServiceInstanceIdleTime(5, TimeUnit.MINUTES)
.build();
ServicePool<CalculatorService> pool = ServicePoolBuilder.create(CalculatorService.class)
.withServiceFactory(new CalculatorServiceFactory(configuration.getHttpClientConfiguration()))
.withHostDiscovery(new ZooKeeperHostDiscovery(curator, "calculator"))
.withCachingPolicy(cachingPolicy)
.build();
// If using Yammer Metrics or running in Dropwizard (which includes Yammer Metrics), you may want a health
// check that pings a service you depend on. This will register a simple check that will confirm the service
// pool contains at least one healthy end point.
HealthChecks.register(new ContainsHealthyEndPointCheck(pool, "calculator-user"));
CalculatorUser user = new CalculatorUser(pool);
user.use();
Closeables.closeQuietly(pool);
Closeables.closeQuietly(curator);
}
private static CuratorFramework newCurator(ZooKeeperConfiguration config) {
CuratorFramework curator = CuratorFrameworkFactory.newClient(config.getConnectString(), config.getRetry());
curator.start();
return curator.usingNamespace(config.getNamespace());
}
}