ZKProcedureUtil (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.zookeeper.ZooKeeperListener
- - org.apache.hadoop.hbase.procedure.ZKProcedureUtil

All Implemented Interfaces:

Closeable, AutoCloseable
```
@InterfaceAudience.Private
public abstract class ZKProcedureUtil
extends ZooKeeperListener
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`
`private static org.apache.commons.logging.Log`	`LOG`
`static String`	`REACHED_BARRIER_ZNODE_DEFAULT`
`protected String`	`reachedZnode`

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperListener
watcher

Constructor Summary

Constructors
Constructor and Description

ZKProcedureUtil(ZooKeeperWatcher watcher, String procDescription)
Top-level watcher/controller for procedures across the cluster.

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

Method Summary

Methods
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.
`ZooKeeperWatcher`	`getWatcher()`
`(package private) boolean`	`isAbortNode(String path)` Is this in the procedure barrier abort znode path
`boolean`	`isAbortPathNode(String path)` Is this in the procedure barrier abort znode path
`(package private) boolean`	`isAcquiredNode(String path)` Is this the exact procedure barrier acquired znode
`(package private) boolean`	`isAcquiredPathNode(String path)` Is this in the procedure barrier acquired znode path
`(package private) boolean`	`isInProcedurePath(String path)` Is this a procedure related znode path? TODO: this is not strict, can return true if had name just starts with same prefix but is different zdir.
`private boolean`	`isMemberNode(String path, String statePath)`
`(package private) boolean`	`isReachedNode(String path)` Is this the exact procedure barrier reached znode
`(package private) boolean`	`isReachedPathNode(String path)` Is this in the procedure barrier reached znode path
`(package private) void`	`logZKTree(String root)` Recursively print the current state of ZK (non-transactional)
`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.ZooKeeperListener
nodeChildrenChanged, nodeCreated, nodeDataChanged, nodeDeleted

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.apache.commons.logging.Log LOG
```
  - 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(ZooKeeperWatcher 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 ZooKeeperWatcher getWatcher()
```
    Overrides:
    
    getWatcher in class ZooKeeperListener
    
    Returns:
    The watcher associated with this listener
  - isInProcedurePath
```
boolean isInProcedurePath(String path)
```
    Is this a procedure related znode path? TODO: this is not strict, can return true if had name just starts with same prefix but is different zdir.
    
    Returns:
    true if starts with baseZnode
  - isAcquiredNode
```
boolean isAcquiredNode(String path)
```
    Is this the exact procedure barrier acquired znode
  - isAcquiredPathNode
```
boolean isAcquiredPathNode(String path)
```
    Is this in the procedure barrier acquired znode path
  - isReachedNode
```
boolean isReachedNode(String path)
```
    Is this the exact procedure barrier reached znode
  - isReachedPathNode
```
boolean isReachedPathNode(String path)
```
    Is this in the procedure barrier reached znode path
  - isMemberNode
```
private boolean isMemberNode(String path,
                   String statePath)
```
  - isAbortNode
```
boolean isAbortNode(String path)
```
    Is this in the procedure barrier abort znode path
  - isAbortPathNode
```
public boolean isAbortPathNode(String path)
```
    Is this in the procedure barrier abort znode path
  - logZKTree
```
void logZKTree(String root)
```
    Recursively print the current state of ZK (non-transactional)
    
    Parameters:
    root - name of the root directory in zk to print
    
    Throws:
    
    org.apache.zookeeper.KeeperException
  - 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

Class ZKProcedureUtil

Field Summary

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

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

LOG

ACQUIRED_BARRIER_ZNODE_DEFAULT

REACHED_BARRIER_ZNODE_DEFAULT

ABORT_ZNODE_DEFAULT

baseZNode

acquiredZnode

reachedZnode

abortZnode

Constructor Detail

ZKProcedureUtil

Method Detail

close

getAcquiredBarrierNode

getReachedBarrierNode

getAbortZNode

getAbortZnode

getBaseZnode

getAcquiredBarrier

getAcquireBarrierNode

getReachedBarrierNode

getAbortNode

getWatcher

isInProcedurePath

isAcquiredNode

isAcquiredPathNode

isReachedNode

isReachedPathNode

isMemberNode

isAbortNode

isAbortPathNode

logZKTree

logZKTree

clearChildZNodes

clearZNodes