package com.datasift.dropwizard.curator;
import io.dropwizard.util.Duration;
import com.datasift.dropwizard.curator.ensemble.DropwizardConfiguredEnsembleProvider;
import com.datasift.dropwizard.curator.ensemble.DropwizardConfiguredZooKeeperFactory;
import com.datasift.dropwizard.curator.health.CuratorHealthCheck;
import com.datasift.dropwizard.zookeeper.ZooKeeperFactory;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import io.dropwizard.setup.Environment;
import org.apache.curator.framework.api.CompressionProvider;
import org.apache.curator.framework.imps.GzipCompressionProvider;
import org.apache.curator.retry.ExponentialBackoffRetry;
import javax.validation.Valid;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
/**
* A factory for creating and managing {@link CuratorFramework} instances.
* <p/>
* The resulting {@link CuratorFramework} will have its lifecycle managed by the {@link Environment}
* and will have {@link com.codahale.metrics.health.HealthCheck}s installed for the underlying ZooKeeper
* ensemble.
*
* @see CuratorFramework
*/
public class CuratorFactory {
private static final String DEFAULT_NAME = "curator-default";
/**
* An enumeration of the available compression codecs available for compressed entries.
*
* @see #getCompressionProvider()
* @see CompressionProvider
*/
enum CompressionCodec {
/**
* GZIP compression.
*
* @see GzipCompressionProvider
*/
GZIP(new GzipCompressionProvider());
final private CompressionProvider provider;
CompressionCodec(final CompressionProvider provider) {
this.provider = provider;
}
/**
* Gets the {@link CompressionProvider} for this codec.
*
* @return the provider for this codec.
*/
public CompressionProvider getProvider() {
return provider;
}
}
@Valid
@NotNull
protected ZooKeeperFactory ensemble = new ZooKeeperFactory();
@Min(0)
protected int maxRetries = 1;
@NotNull
protected Duration backOffBaseTime = Duration.seconds(1);
@NotNull
protected CompressionCodec compression = CompressionCodec.GZIP;
/**
* Returns a {@link ZooKeeperFactory} for the ZooKeeper ensemble to connect to.
*
* @return a factory for the ZooKeeper ensemble for the client.
*/
@JsonProperty("ensemble")
public ZooKeeperFactory getZooKeeperFactory() {
return ensemble;
}
/**
* Sets the {@link ZooKeeperFactory} for the ZooKeeper ensemble to connect to.
*
* @param factory the factory for the ZooKeeper ensemble for the client.
*/
@JsonProperty("ensemble")
public void setZooKeeperFactory(final ZooKeeperFactory factory) {
this.ensemble = factory;
}
/**
* Returns the maximum number of retries to attempt to connect to the ensemble.
*
* @return the maximum number of connection attempts.
*/
@JsonProperty
public int getMaxRetries() {
return maxRetries;
}
/**
* Sets the maximum number of retries to attempt to connect to the ensemble.
*
* @param maxRetries the maximum number of connection attempts.
*/
@JsonProperty
public void setMaxRetries(final int maxRetries) {
this.maxRetries = maxRetries;
}
/**
* Returns the initial time to wait before retrying a failed connection.
* <p/>
* Subsequent retries will wait an exponential amount of time more than this.
*
* @return the initial time to wait before trying to connect again.
*/
@JsonProperty
public Duration getBackOffBaseTime() {
return backOffBaseTime;
}
/**
* Sets the initial time to wait before retrying a failed connection.
* <p/>
* Subsequent retries will wait an exponential amount of time more than this.
*
* @param backOffBaseTime the initial time to wait before trying to connect again.
*/
@JsonProperty
public void setBackOffBaseTime(final Duration backOffBaseTime) {
this.backOffBaseTime = backOffBaseTime;
}
/**
* Returns a {@link RetryPolicy} for handling failed connection attempts.
* <p/>
* Always configures an {@link ExponentialBackoffRetry} based on the {@link #getMaxRetries()
* maximum retries} and {@link #getBackOffBaseTime() initial back-off} configured.
*
* @return a {@link RetryPolicy} for handling failed connection attempts.
*
* @see #getMaxRetries()
* @see #getBackOffBaseTime()
*/
public RetryPolicy getRetryPolicy() {
return new ExponentialBackoffRetry((int) backOffBaseTime.toMilliseconds(), maxRetries);
}
/**
* Returns the {@link CompressionCodec} to compress values with.
*
* @return the compression codec to compress values with.
*
* @see CompressionCodec
*/
@JsonProperty("compression")
public CompressionCodec getCompressionCodec() {
return compression;
}
/**
* Sets a {@link CompressionCodec} to compress values with.
*
* @param codec the compression codec to compress values with.
*
* @see CompressionCodec
*/
@JsonProperty("compression")
public void setCompressionCodec(final CompressionCodec codec) {
this.compression = codec;
}
/**
* Returns a {@link CompressionProvider} to compress values with.
*
* @return the compression provider used to compress values.
*
* @see CompressionCodec
*/
public CompressionProvider getCompressionProvider() {
return getCompressionCodec().getProvider();
}
/**
* Builds a default {@link CuratorFramework} for the given {@link Environment}.
*
* @param environment the {@link Environment} to build the {@link CuratorFramework} for.
*
* @return a {@link CuratorFramework} instance, managed and configured.
*/
public CuratorFramework build(final Environment environment) {
return build(environment, DEFAULT_NAME);
}
/**
* Builds a {@link CuratorFramework} instance with the given {@code name} for an {@link
* Environment}.
*
* @param environment the {@link Environment} to build the {@link CuratorFramework} for.
* @param name the name for the {@link CuratorFramework} instance.
*
* @return a {@link CuratorFramework} instance, managed and configured.
*/
public CuratorFramework build(final Environment environment, final String name) {
final ZooKeeperFactory factory = getZooKeeperFactory();
final String namespace = factory.getNamespace();
final CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder()
.zookeeperFactory(new DropwizardConfiguredZooKeeperFactory(environment, name))
.ensembleProvider(new DropwizardConfiguredEnsembleProvider(factory))
.connectionTimeoutMs((int) factory.getConnectionTimeout().toMilliseconds())
.threadFactory(new ThreadFactoryBuilder().setNameFormat(name + "-%d").build())
.sessionTimeoutMs((int) factory.getSessionTimeout().toMilliseconds())
.namespace(namespace.startsWith("/") ? namespace.substring(1) : namespace)
.compressionProvider(getCompressionProvider())
.retryPolicy(getRetryPolicy())
.canBeReadOnly(factory.isReadOnly());
// add optional auth details
final ZooKeeperFactory.Auth auth = factory.getAuth();
if (auth != null) {
builder.authorization(auth.getScheme(), auth.getId().getBytes());
}
final CuratorFramework framework = builder.build();
environment.healthChecks().register(name, new CuratorHealthCheck(framework));
environment.lifecycle().manage(new ManagedCuratorFramework(framework));
return framework;
}
}