org.apache.hadoop.hbase.coprocessor

Interface MasterCoprocessorEnvironment

All Superinterfaces:

CoprocessorEnvironment<MasterCoprocessor>

@InterfaceAudience.LimitedPrivate(value="Coprocesssor")
 @InterfaceStability.Evolving
public interface MasterCoprocessorEnvironment
extends CoprocessorEnvironment<MasterCoprocessor>

Method Summary

Modifier and Type	Method and Description
Connection	getConnection() Be careful RPC'ing from a Coprocessor context.
MetricRegistry	getMetricRegistryForMaster() Returns a MetricRegistry that can be used to track metrics at the master level.
ServerName	getServerName()

Methods inherited from interface org.apache.hadoop.hbase.CoprocessorEnvironment

getClassLoader, getConfiguration, getHBaseVersion, getInstance, getLoadSequence, getPriority, getVersion, shutdown, startup

Method Detail

getServerName

ServerName getServerName()

Returns:

Hosting Server's ServerName

getConnection

Connection getConnection()

Be careful RPC'ing from a Coprocessor context. RPC's will fail, stall, retry, and/or crawl because the remote side is not online, is struggling or it is on the other side of a network partition. Any use of Connection from inside a Coprocessor must be able to handle all such hiccups.

Using a Connection to get at a local resource -- say a Region that is on the local Server or using Admin Interface from a Coprocessor hosted on the Master -- will result in a short-circuit of the RPC framework to make a direct invocation avoiding RPC (and protobuf marshalling/unmarshalling).

Returns:

The host's Connection to the Cluster.

getMetricRegistryForMaster

MetricRegistry getMetricRegistryForMaster()

Returns a MetricRegistry that can be used to track metrics at the master level.

See ExampleMasterObserverWithMetrics class in the hbase-examples modules for examples of how metrics can be instantiated and used.

Returns:

A MetricRegistry for the coprocessor class to track and export metrics.