Package org.graylog2.lookup.adapters.dnslookup

Class DnsResolverPool

java.lang.Object

org.graylog2.lookup.adapters.dnslookup.DnsResolverPool

public class DnsResolverPool
extends Object

Manages a pool of Netty DnsNameResolverFactory objects.
Since the source port for DNS resolution requests is fixed for the duration of the resolver lifecycle, the pooling capability of this class allows the source address to by varied for each request by choosing a random resolver from the pool for each request.
The resolvers in the pool are periodically refreshed to cycle in new source ports for subsequent requests.
The pool size and refresh interval are configurable globally for all DNS Lookup adapters with the following Graylog server configuration properties (the defaults are indicated below as well).

 dns_lookup_adapter_resolver_pool_size = 10
 dns_lookup_adapter_resolver_pool_refresh_interval = 300s
 

Callers can use the takeLease() method to acquire a lease for a resolver. The DnsResolverPool.ResolverLease.release() method must be called to release a resolver lease after use. These operations are thread-safe.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	DnsResolverPool.ResolverLease

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DnsResolverPool(String dnsServerIps, long queryTimeout, long poolSize, long poolRefreshSeconds)

Method Summary

Modifier and Type	Method	Description
protected void	initialize()
protected boolean	isStopped()
protected int	poolSize()
protected int	randomResolverIndex()	Allows for a random resolver to be returned for each request.
protected void	returnLease(DnsResolverPool.ResolverLease lease)
void	stop()
protected DnsResolverPool.ResolverLease	takeLease()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DnsResolverPool

protected DnsResolverPool(String dnsServerIps,
 long queryTimeout,
 long poolSize,
 long poolRefreshSeconds)

Method Details

initialize

protected void initialize()

takeLease

protected DnsResolverPool.ResolverLease takeLease()

returnLease

protected void returnLease(DnsResolverPool.ResolverLease lease)

stop

public void stop()

isStopped

protected boolean isStopped()

randomResolverIndex

protected int randomResolverIndex()

Allows for a random resolver to be returned for each request.

poolSize

protected int poolSize()