org.apache.hadoop.hbase.procedure

Class ZKProcedureUtil

java.lang.Object

org.apache.hadoop.hbase.zookeeper.ZKListener

org.apache.hadoop.hbase.procedure.ZKProcedureUtil

All Implemented Interfaces:

Closeable, AutoCloseable

@InterfaceAudience.Private
public abstract class ZKProcedureUtil
extends ZKListener
implements Closeable

This is a shared ZooKeeper-based znode management utils for distributed procedure. All znode operations should go through the provided methods in coordinators and members. Layout of nodes in ZK is /hbase/[op name]/acquired/ [op instance] - op data/ /[nodes that have acquired] /reached/ [op instance]/ /[nodes that have completed] /abort/ [op instance] - failure data NOTE: while acquired and completed are znode dirs, abort is actually just a znode. Assumption here that procedure names are unique

Field Summary

Fields

Modifier and Type	Field and Description
static String	ABORT_ZNODE_DEFAULT
protected String	abortZnode
static String	ACQUIRED_BARRIER_ZNODE_DEFAULT
protected String	acquiredZnode
String	baseZNode
static String	REACHED_BARRIER_ZNODE_DEFAULT
protected String	reachedZnode

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

watcher

Constructor Summary

Constructors

Constructor and Description
ZKProcedureUtil(ZKWatcher watcher, String procDescription) Top-level watcher/controller for procedures across the cluster.

Method Summary

Modifier and Type	Method and Description
void	clearChildZNodes()
void	clearZNodes(String procedureName)
void	close()
static String	getAbortNode(ZKProcedureUtil controller, String opInstanceName) Get the full znode path for the node used by the coordinator or member to trigger an abort of the global barrier acquisition or execution in subprocedures.
String	getAbortZnode()
String	getAbortZNode(String opInstanceName)
static String	getAcquireBarrierNode(ZKProcedureUtil controller, String opInstanceName) Get the full znode path for the node used by the coordinator to trigger a global barrier acquire on each subprocedure.
String	getAcquiredBarrier()
String	getAcquiredBarrierNode(String opInstanceName)
String	getBaseZnode()
String	getReachedBarrierNode(String opInstanceName)
static String	getReachedBarrierNode(ZKProcedureUtil controller, String opInstanceName) Get the full znode path for the node used by the coordinator to trigger a global barrier execution and release on each subprocedure.
ZKWatcher	getWatcher()
boolean	isAbortPathNode(String path) Is this in the procedure barrier abort znode path
protected void	logZKTree(String root, String prefix) Helper method to print the current state of the ZK tree.

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

nodeChildrenChanged, nodeCreated, nodeDataChanged, nodeDeleted

Methods inherited from class java.lang.Object

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

Field Detail

ACQUIRED_BARRIER_ZNODE_DEFAULT

public static final String ACQUIRED_BARRIER_ZNODE_DEFAULT

See Also:

Constant Field Values

REACHED_BARRIER_ZNODE_DEFAULT

public static final String REACHED_BARRIER_ZNODE_DEFAULT

See Also:

Constant Field Values

ABORT_ZNODE_DEFAULT

public static final String ABORT_ZNODE_DEFAULT

See Also:

Constant Field Values

baseZNode

public final String baseZNode

acquiredZnode

protected final String acquiredZnode

reachedZnode

protected final String reachedZnode

abortZnode

protected final String abortZnode

Constructor Detail

ZKProcedureUtil

public ZKProcedureUtil(ZKWatcher watcher,
                       String procDescription)
                throws org.apache.zookeeper.KeeperException

Top-level watcher/controller for procedures across the cluster.

On instantiation, this ensures the procedure znodes exist. This however requires the passed in watcher has been started.

Parameters:

watcher - watcher for the cluster ZK. Owned by this and closed via close()

procDescription - name of the znode describing the procedure to run

Throws:

org.apache.zookeeper.KeeperException - when the procedure znodes cannot be created

Method Detail

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

getAcquiredBarrierNode

public String getAcquiredBarrierNode(String opInstanceName)

getReachedBarrierNode

public String getReachedBarrierNode(String opInstanceName)

getAbortZNode

public String getAbortZNode(String opInstanceName)

getAbortZnode

public String getAbortZnode()

getBaseZnode

public String getBaseZnode()

getAcquiredBarrier

public String getAcquiredBarrier()

getAcquireBarrierNode

public static String getAcquireBarrierNode(ZKProcedureUtil controller,
                                           String opInstanceName)

Get the full znode path for the node used by the coordinator to trigger a global barrier acquire on each subprocedure.

Parameters:

controller - controller running the procedure

opInstanceName - name of the running procedure instance (not the procedure description).

Returns:

full znode path to the prepare barrier/start node

getReachedBarrierNode

public static String getReachedBarrierNode(ZKProcedureUtil controller,
                                           String opInstanceName)

Get the full znode path for the node used by the coordinator to trigger a global barrier execution and release on each subprocedure.

Parameters:

controller - controller running the procedure

opInstanceName - name of the running procedure instance (not the procedure description).

Returns:

full znode path to the commit barrier

getAbortNode

public static String getAbortNode(ZKProcedureUtil controller,
                                  String opInstanceName)

Get the full znode path for the node used by the coordinator or member to trigger an abort of the global barrier acquisition or execution in subprocedures.

Parameters:

controller - controller running the procedure

opInstanceName - name of the running procedure instance (not the procedure description).

Returns:

full znode path to the abort znode

getWatcher

public ZKWatcher getWatcher()

Overrides:

getWatcher in class ZKListener

Returns:

The watcher associated with this listener

isAbortPathNode

public boolean isAbortPathNode(String path)

Is this in the procedure barrier abort znode path

logZKTree

protected void logZKTree(String root,
                         String prefix)
                  throws org.apache.zookeeper.KeeperException

Helper method to print the current state of the ZK tree.

Throws:

org.apache.zookeeper.KeeperException - if an unexpected exception occurs

See Also:

logZKTree(String)

clearChildZNodes

public void clearChildZNodes()
                      throws org.apache.zookeeper.KeeperException

Throws:

org.apache.zookeeper.KeeperException

clearZNodes

public void clearZNodes(String procedureName)
                 throws org.apache.zookeeper.KeeperException

Throws:

org.apache.zookeeper.KeeperException