org.apache.hadoop.hbase.procedure

Class ZKProcedureMemberRpcs

java.lang.Object

org.apache.hadoop.hbase.procedure.ZKProcedureMemberRpcs

All Implemented Interfaces:

Closeable, AutoCloseable, ProcedureMemberRpcs

@InterfaceAudience.Private
public class ZKProcedureMemberRpcs
extends Object
implements ProcedureMemberRpcs

ZooKeeper based controller for a procedure member.

There can only be one ZKProcedureMemberRpcs per procedure type per member, since each procedure type is bound to a single set of znodes. You can have multiple ZKProcedureMemberRpcs on the same server, each serving a different member name, but each individual rpcs is still bound to a single member name (and since they are used to determine global progress, its important to not get this wrong).

To make this slightly more confusing, you can run multiple, concurrent procedures at the same time (as long as they have different types), from the same controller, but the same node name must be used for each procedure (though there is no conflict between the two procedure as long as they have distinct names).

There is no real error recovery with this mechanism currently -- if any the coordinator fails, its re-initialization will delete the znodes and require all in progress subprocedures to start anew.

Field Summary

Fields

Modifier and Type	Field and Description
private static org.slf4j.Logger	LOG
protected ProcedureMember	member
private String	memberName
private ZKProcedureUtil	zkController

Constructor Summary

Constructors

Constructor and Description
ZKProcedureMemberRpcs(ZKWatcher watcher, String procType) Must call start(String, ProcedureMember) before this can be used.

Method Summary

Modifier and Type	Method and Description
protected void	abort(String abortZNode) Pass along the found abort notification to the listener
void	close()
String	getMemberName() Each subprocedure is being executed on a member.
ZKProcedureUtil	getZkController()
private void	receivedReachedGlobalBarrier(String path) Pass along the procedure global barrier notification to any listeners
void	sendMemberAborted(Subprocedure sub, ForeignException ee) This should be called by the member and should write a serialized root cause exception as to the abort znode.
void	sendMemberAcquired(Subprocedure sub) This attempts to create an acquired state znode for the procedure (snapshot name).
void	sendMemberCompleted(Subprocedure sub, byte[] data) This acts as the ack for a completed procedure
void	start(String memberName, ProcedureMember listener) Initialize and start any threads or connections the member needs.
private void	startNewSubprocedure(String path) Kick off a new sub-procedure on the listener with the data stored in the passed znode.
private void	waitForNewProcedures()
private void	watchForAbortedProcedures()

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final org.slf4j.Logger LOG

zkController

private final ZKProcedureUtil zkController

member

protected ProcedureMember member

memberName

private String memberName

Constructor Detail

ZKProcedureMemberRpcs

public ZKProcedureMemberRpcs(ZKWatcher watcher,
                             String procType)
                      throws org.apache.zookeeper.KeeperException

Must call start(String, ProcedureMember) before this can be used.

Parameters:

watcher - ZKWatcher to be owned by this. Closed via close().

procType - name of the znode describing the procedure type

Throws:

org.apache.zookeeper.KeeperException - if we can't reach zookeeper

Method Detail

getZkController

public ZKProcedureUtil getZkController()

getMemberName

public String getMemberName()

Description copied from interface: ProcedureMemberRpcs

Each subprocedure is being executed on a member. This is the identifier for the member.

Specified by:

getMemberName in interface ProcedureMemberRpcs

Returns:

the member name

receivedReachedGlobalBarrier

private void receivedReachedGlobalBarrier(String path)

Pass along the procedure global barrier notification to any listeners

Parameters:

path - full znode path that cause the notification

watchForAbortedProcedures

private void watchForAbortedProcedures()

waitForNewProcedures

private void waitForNewProcedures()

startNewSubprocedure

private void startNewSubprocedure(String path)

Kick off a new sub-procedure on the listener with the data stored in the passed znode.

Will attempt to create the same procedure multiple times if an procedure znode with the same name is created. It is left up the coordinator to ensure this doesn't occur.

Parameters:

path - full path to the znode for the procedure to start

sendMemberAcquired

public void sendMemberAcquired(Subprocedure sub)
                        throws IOException

This attempts to create an acquired state znode for the procedure (snapshot name). It then looks for the reached znode to trigger in-barrier execution. If not present we have a watcher, if present then trigger the in-barrier action.

Specified by:

sendMemberAcquired in interface ProcedureMemberRpcs

Parameters:

sub - the specified Subprocedure

Throws:

IOException - if we can't reach the coordinator

sendMemberCompleted

public void sendMemberCompleted(Subprocedure sub,
                                byte[] data)
                         throws IOException

This acts as the ack for a completed procedure

Specified by:

sendMemberCompleted in interface ProcedureMemberRpcs

Parameters:

sub - the specified Subprocedure

data - the data the member returns to the coordinator along with the notification

Throws:

IOException - if we can't reach the coordinator

sendMemberAborted

public void sendMemberAborted(Subprocedure sub,
                              ForeignException ee)

This should be called by the member and should write a serialized root cause exception as to the abort znode.

Specified by:

sendMemberAborted in interface ProcedureMemberRpcs

Parameters:

sub - the Subprocedure we are aborting

ee - the reason why the member's subprocedure aborted

abort

protected void abort(String abortZNode)

Pass along the found abort notification to the listener

Parameters:

abortZNode - full znode path to the failed procedure information

start

public void start(String memberName,
                  ProcedureMember listener)

Description copied from interface: ProcedureMemberRpcs

Initialize and start any threads or connections the member needs.

Specified by:

start in interface ProcedureMemberRpcs

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException