Package com.linecorp.armeria.client

Class DnsResolverGroupBuilder

java.lang.Object

com.linecorp.armeria.client.DnsResolverGroupBuilder

public final class DnsResolverGroupBuilder
extends Object

Builds an AddressResolverGroup which builds AddressResolvers that update DNS caches automatically. Standard DnsNameResolver will only expire a cache entry after TTL, meaning DNS queries after TTL will always take time to resolve. A refreshing AddressResolver on the other hand updates the DNS cache automatically when TTL elapses, meaning DNS queries after TTL will retrieve a refreshed result right away. If refreshing fails, the AddressResolver will retry with refreshBackoff(Backoff).

The refreshing AddressResolver will only start auto refresh for a given hostname on the second access before TTL to avoid auto-refreshing for queries that only happen once (e.g., requests during server startup).

Method Summary

Modifier and Type	Method	Description
DnsResolverGroupBuilder	cacheSpec(String cacheSpec)	Sets the Caffeine specification string of the cache that stores the domain names and their resolved addresses.
DnsResolverGroupBuilder	decodeIdn(boolean decodeIdn)	Sets if the domain and host names should be decoded to unicode when received.
DnsResolverGroupBuilder	dnsQueryLifecycleObserverFactory(DnsQueryLifecycleObserverFactory dnsQueryLifecycleObserverFactory)	Sets DnsQueryLifecycleObserverFactory that is used to generate objects which can observe individual DNS queries.
DnsResolverGroupBuilder	dnsServerAddressStreamProvider(DnsServerAddressStreamProvider dnsServerAddressStreamProvider)	Sets DnsServerAddressStreamProvider which is used to determine which DNS server is used to resolve each hostname.
DnsResolverGroupBuilder	hostsFileEntriesResolver(HostsFileEntriesResolver hostsFileEntriesResolver)	Sets HostsFileEntriesResolver which is used to first check if the hostname is locally aliased.
DnsResolverGroupBuilder	maxPayloadSize(int maxPayloadSize)	Sets the capacity of the datagram packet buffer in bytes.
DnsResolverGroupBuilder	maxQueriesPerResolve(int maxQueriesPerResolve)	Returns the maximum allowed number of DNS queries to send when resolving a host name.
DnsResolverGroupBuilder	ndots(int ndots)	Sets the number of dots which must appear in a name before an initial absolute query is made.
DnsResolverGroupBuilder	negativeTtl(int negativeTtl)	Sets the TTL of the cache for the failed DNS queries in seconds.
DnsResolverGroupBuilder	optResourceEnabled(boolean optResourceEnabled)	Enables the automatic inclusion of a optional records that tries to give the remote DNS server a hint about how much data the resolver can read per response.
DnsResolverGroupBuilder	queryTimeout(Duration queryTimeout)	Sets the timeout of the DNS query performed by this resolver.
DnsResolverGroupBuilder	queryTimeoutMillis(long queryTimeoutMillis)	Sets the timeout of the DNS query performed by this resolver in milliseconds.
DnsResolverGroupBuilder	recursionDesired(boolean recursionDesired)	Sets if this resolver has to send a DNS query with the RD (recursion desired) flag set.
DnsResolverGroupBuilder	refreshBackoff(Backoff refreshBackoff)	Sets Backoff which is used when the DnsNameResolver fails to update the cache.
DnsResolverGroupBuilder	resolvedAddressTypes(ResolvedAddressTypes resolvedAddressTypes)	Sets ResolvedAddressTypes which is the list of the protocol families of the address resolved.
DnsResolverGroupBuilder	searchDomains(Iterable<String> searchDomains)	Sets the list of search domains of the resolver.
DnsResolverGroupBuilder	searchDomains(String... searchDomains)	Sets the search domains of the resolver.
DnsResolverGroupBuilder	traceEnabled(boolean traceEnabled)	Sets if this resolver should generate detailed trace information in exception messages so that it is easier to understand the cause of resolution failure.
DnsResolverGroupBuilder	ttl(int minTtl, int maxTtl)	Sets the minimum and maximum TTL of the cached DNS resource records in seconds.

Methods inherited from class java.lang.Object

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

Method Details

refreshBackoff

public DnsResolverGroupBuilder refreshBackoff(Backoff refreshBackoff)

Sets Backoff which is used when the DnsNameResolver fails to update the cache.

ttl

public DnsResolverGroupBuilder ttl(int minTtl,
int maxTtl)

Sets the minimum and maximum TTL of the cached DNS resource records in seconds. If the TTL of the DNS resource record returned by the DNS server is less than the minimum TTL or greater than the maximum TTL, this resolver will ignore the TTL from the DNS server and use the minimum TTL or the maximum TTL instead respectively. The default value is 1 and Integer.MAX_VALUE, which practically tells this resolver to respect the TTL from the DNS server.

negativeTtl

public DnsResolverGroupBuilder negativeTtl(int negativeTtl)

Sets the TTL of the cache for the failed DNS queries in seconds. The default value is 0 which means that the AddressResolver does not cache when DNS queries are failed.

traceEnabled

public DnsResolverGroupBuilder traceEnabled(boolean traceEnabled)

Sets if this resolver should generate detailed trace information in exception messages so that it is easier to understand the cause of resolution failure. This flag is enabled by default.

queryTimeout

public DnsResolverGroupBuilder queryTimeout(Duration queryTimeout)

Sets the timeout of the DNS query performed by this resolver. 0 disables the timeout.

See Also:

DnsNameResolverBuilder.queryTimeoutMillis(long)

queryTimeoutMillis

public DnsResolverGroupBuilder queryTimeoutMillis(long queryTimeoutMillis)

Sets the timeout of the DNS query performed by this resolver in milliseconds. 0 disables the timeout.

See Also:

DnsNameResolverBuilder.queryTimeoutMillis(long)

resolvedAddressTypes

public DnsResolverGroupBuilder resolvedAddressTypes(ResolvedAddressTypes resolvedAddressTypes)

Sets ResolvedAddressTypes which is the list of the protocol families of the address resolved.

See Also:

DnsNameResolverBuilder.resolvedAddressTypes(ResolvedAddressTypes)

recursionDesired

public DnsResolverGroupBuilder recursionDesired(boolean recursionDesired)

Sets if this resolver has to send a DNS query with the RD (recursion desired) flag set.

See Also:

DnsNameResolverBuilder.recursionDesired(boolean)

maxQueriesPerResolve

public DnsResolverGroupBuilder maxQueriesPerResolve(int maxQueriesPerResolve)

Returns the maximum allowed number of DNS queries to send when resolving a host name.

See Also:

DnsNameResolverBuilder.maxQueriesPerResolve(int)

maxPayloadSize

public DnsResolverGroupBuilder maxPayloadSize(int maxPayloadSize)

Sets the capacity of the datagram packet buffer in bytes.

See Also:

DnsNameResolverBuilder.maxPayloadSize(int)

optResourceEnabled

public DnsResolverGroupBuilder optResourceEnabled(boolean optResourceEnabled)

Enables the automatic inclusion of a optional records that tries to give the remote DNS server a hint about how much data the resolver can read per response. Some DNSServer may not support this and so fail to answer queries.

See Also:

DnsNameResolverBuilder.optResourceEnabled(boolean)

hostsFileEntriesResolver

public DnsResolverGroupBuilder hostsFileEntriesResolver(HostsFileEntriesResolver hostsFileEntriesResolver)

Sets HostsFileEntriesResolver which is used to first check if the hostname is locally aliased.

See Also:

DnsNameResolverBuilder.hostsFileEntriesResolver(HostsFileEntriesResolver)

dnsServerAddressStreamProvider

public DnsResolverGroupBuilder dnsServerAddressStreamProvider(DnsServerAddressStreamProvider dnsServerAddressStreamProvider)

Sets DnsServerAddressStreamProvider which is used to determine which DNS server is used to resolve each hostname.

See Also:

DnsNameResolverBuilder.nameServerProvider(DnsServerAddressStreamProvider)

dnsQueryLifecycleObserverFactory

public DnsResolverGroupBuilder dnsQueryLifecycleObserverFactory(DnsQueryLifecycleObserverFactory dnsQueryLifecycleObserverFactory)

Sets DnsQueryLifecycleObserverFactory that is used to generate objects which can observe individual DNS queries.

See Also:

DnsNameResolverBuilder.dnsQueryLifecycleObserverFactory(DnsQueryLifecycleObserverFactory)

searchDomains

public DnsResolverGroupBuilder searchDomains(Iterable<String> searchDomains)

Sets the list of search domains of the resolver.

See Also:

DnsNameResolverBuilder.searchDomains(Iterable)

searchDomains

public DnsResolverGroupBuilder searchDomains(String... searchDomains)

Sets the search domains of the resolver.

See Also:

DnsNameResolverBuilder.searchDomains(Iterable)

ndots

public DnsResolverGroupBuilder ndots(int ndots)

Sets the number of dots which must appear in a name before an initial absolute query is made.

See Also:

DnsNameResolverBuilder.ndots(int)

decodeIdn

public DnsResolverGroupBuilder decodeIdn(boolean decodeIdn)

Sets if the domain and host names should be decoded to unicode when received. See rfc3492. This flag is enabled by default.

See Also:

DnsNameResolverBuilder.decodeIdn(boolean)

cacheSpec

public DnsResolverGroupBuilder cacheSpec(String cacheSpec)

Sets the Caffeine specification string of the cache that stores the domain names and their resolved addresses. If not set, Flags.dnsCacheSpec() is used by default.