Class DnsNameResolver

java.lang.Object

io.grpc.NameResolver

io.grpc.internal.DnsNameResolver

public class DnsNameResolver
extends NameResolver

A DNS-based NameResolver.

Each A or AAAA record emits an EquivalentAddressGroup in the list passed to NameResolver.Listener2.onResult2(ResolutionResult).

See Also:

• DnsNameResolverProvider

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	DnsNameResolver.AddressResolver	AddressResolver resolves a hostname into a list of addresses.
protected static final class	DnsNameResolver.InternalResolutionResult	Used as a DNS-based name resolver's internal representation of resolution result.
static interface	DnsNameResolver.ResourceResolver	DnsNameResolver.ResourceResolver is a Dns ResourceRecord resolver.
static final class	DnsNameResolver.SrvRecord	Describes a parsed SRV record.

Nested classes/interfaces inherited from class NameResolver

NameResolver.Args, NameResolver.ConfigOrError, NameResolver.Factory, NameResolver.Listener, NameResolver.Listener2, NameResolver.ResolutionResult, NameResolver.ResolutionResultAttr, NameResolver.ServiceConfigParser

Field Summary

Fields

Modifier and Type	Field	Description
protected DnsNameResolver.AddressResolver	addressResolver
protected static boolean	enableTxt
protected boolean	resolved

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DnsNameResolver(String nsAuthority, String name, NameResolver.Args args, SharedResourceHolder.Resource<Executor> executorResource, com.google.common.base.Stopwatch stopwatch, boolean isAndroid)

Method Summary

Modifier and Type	Method	Description
protected DnsNameResolver.InternalResolutionResult	doResolve(boolean forceTxt)	Main logic of name resolution.
protected String	getHost()
protected DnsNameResolver.ResourceResolver	getResourceResolver()
String	getServiceAuthority()	Returns the authority used to authenticate connections to servers.
void	refresh()	Re-resolve the name.
protected void	setAddressResolver(DnsNameResolver.AddressResolver addressResolver)
protected void	setResourceResolver(DnsNameResolver.ResourceResolver resourceResolver)
protected static boolean	shouldUseJndi(boolean jndiEnabled, boolean jndiLocalhostEnabled, String target)
void	shutdown()	Stops the resolution.
void	start(NameResolver.Listener2 listener)	Starts the resolution.

Methods inherited from class NameResolver

start

Methods inherited from class Object

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

Field Details

enableTxt

protected static boolean enableTxt

addressResolver

protected volatile DnsNameResolver.AddressResolver addressResolver

resolved

protected boolean resolved

Constructor Details

DnsNameResolver

protected DnsNameResolver(@Nullable
 String nsAuthority,
 String name,
 NameResolver.Args args,
 SharedResourceHolder.Resource<Executor> executorResource,
 com.google.common.base.Stopwatch stopwatch,
 boolean isAndroid)

Method Details

getServiceAuthority

public String getServiceAuthority()

Description copied from class: NameResolver

Returns the authority used to authenticate connections to servers. It must be from a trusted source, because if the authority is tampered with, RPCs may be sent to the attackers which may leak sensitive user data.

An implementation must generate it without blocking, typically in line, and must keep it unchanged. NameResolvers created from the same factory with the same argument must return the same authority.

Specified by:

getServiceAuthority in class NameResolver

getHost

protected String getHost()

start

public void start(NameResolver.Listener2 listener)

Description copied from class: NameResolver

Starts the resolution. The method is not supposed to throw any exceptions. That might cause the Channel that the name resolver is serving to crash. Errors should be propagated through NameResolver.Listener2.onError(Status).

An instance may not be started more than once, by any overload of this method, even after an intervening call to NameResolver.shutdown().

Overrides:

start in class NameResolver

Parameters:

listener - used to receive updates on the target

refresh

public void refresh()

Description copied from class: NameResolver

Re-resolve the name.

Can only be called after NameResolver.start(NameResolver.Listener) has been called.

This is only a hint. Implementation takes it as a signal but may not start resolution immediately. It should never throw.

The default implementation is no-op.

Overrides:

refresh in class NameResolver

doResolve

protected DnsNameResolver.InternalResolutionResult doResolve(boolean forceTxt)

Main logic of name resolution.

shutdown

public void shutdown()

Description copied from class: NameResolver

Stops the resolution. Updates to the Listener will stop.

Specified by:

shutdown in class NameResolver

setAddressResolver

protected void setAddressResolver(DnsNameResolver.AddressResolver addressResolver)

setResourceResolver

protected void setResourceResolver(DnsNameResolver.ResourceResolver resourceResolver)

getResourceResolver

@Nullable
protected DnsNameResolver.ResourceResolver getResourceResolver()

shouldUseJndi

protected static boolean shouldUseJndi(boolean jndiEnabled,
 boolean jndiLocalhostEnabled,
 String target)