DnsResolverGroupBuilder (filter-service-metrics 1.13 1.13 API)

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

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`DnsResolverGroupBuilder`	`decodeIdn(boolean decodeIdn)` Sets if the domain and host names should be decoded to unicode when received.
`DnsResolverGroupBuilder`	`dnsQueryLifecycleObserverFactory(io.netty.resolver.dns.DnsQueryLifecycleObserverFactory dnsQueryLifecycleObserverFactory)` Sets `DnsQueryLifecycleObserverFactory` that is used to generate objects which can observe individual DNS queries.
`DnsResolverGroupBuilder`	`dnsServerAddressStreamProvider(io.netty.resolver.dns.DnsServerAddressStreamProvider dnsServerAddressStreamProvider)` Sets `DnsServerAddressStreamProvider` which is used to determine which DNS server is used to resolve each hostname.
`DnsResolverGroupBuilder`	`hostsFileEntriesResolver(io.netty.resolver.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 each DNS query performed by this resolver.
`DnsResolverGroupBuilder`	`queryTimeoutMillis(long queryTimeoutMillis)` Sets the timeout of each 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(io.netty.resolver.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 Detail
  - 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 each DNS query performed by this resolver.
    
    See Also:
    
    DnsNameResolverBuilder.queryTimeoutMillis(long)
  - queryTimeoutMillis
```
public DnsResolverGroupBuilder queryTimeoutMillis(long queryTimeoutMillis)
```
    Sets the timeout of each DNS query performed by this resolver in milliseconds.
    
    See Also:
    
    DnsNameResolverBuilder.queryTimeoutMillis(long)
  - resolvedAddressTypes
```
public DnsResolverGroupBuilder resolvedAddressTypes(io.netty.resolver.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(io.netty.resolver.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(io.netty.resolver.dns.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(io.netty.resolver.dns.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)

Class DnsResolverGroupBuilder

Method Summary

Methods inherited from class java.lang.Object

Method Detail

refreshBackoff

ttl

negativeTtl

traceEnabled

queryTimeout

queryTimeoutMillis

resolvedAddressTypes

recursionDesired

maxQueriesPerResolve

maxPayloadSize

optResourceEnabled

hostsFileEntriesResolver

dnsServerAddressStreamProvider

dnsQueryLifecycleObserverFactory

searchDomains

searchDomains

ndots

decodeIdn