io.druid.indexing.overlord

Class TaskLockbox

java.lang.Object

io.druid.indexing.overlord.TaskLockbox

public class TaskLockbox
extends Object

Remembers which activeTasks have locked which intervals. Tasks are permitted to lock an interval if no other task outside their group has locked an overlapping interval for the same datasource. When a task locks an interval, it is assigned a version string that it can use to publish segments.

Constructor Summary

Constructors

Constructor and Description
TaskLockbox(TaskStorage taskStorage)

Method Summary

Modifier and Type	Method and Description
void	add(Task task)
<T> T	doInCriticalSection(Task task, List<org.joda.time.Interval> intervals, CriticalAction<T> action) Perform the given action with a guarantee that the locks of the task are not revoked in the middle of action.
List<TaskLock>	findLocksForTask(Task task) Return the currently-active locks for some task.
Map<String,NavigableMap<org.joda.time.Interval,List<io.druid.indexing.overlord.TaskLockbox.TaskLockPosse>>>	getAllLocks()
LockResult	lock(TaskLockType lockType, Task task, org.joda.time.Interval interval) Acquires a lock on behalf of a task.
LockResult	lock(TaskLockType lockType, Task task, org.joda.time.Interval interval, long timeoutMs) Acquires a lock on behalf of a task, waiting up to the specified wait time if necessary.
void	remove(Task task) Release all locks for a task and remove task from set of active tasks.
void	syncFromStorage() Wipe out our current in-memory state and resync it from our bundled TaskStorage.
LockResult	tryLock(TaskLockType lockType, Task task, org.joda.time.Interval interval) Attempt to acquire a lock for a task, without removing it from the queue.
void	unlock(Task task, org.joda.time.Interval interval) Release lock held for a task on a particular interval.

Methods inherited from class java.lang.Object

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

Constructor Detail

TaskLockbox

@Inject
public TaskLockbox(TaskStorage taskStorage)

Method Detail

syncFromStorage

public void syncFromStorage()

Wipe out our current in-memory state and resync it from our bundled TaskStorage.

lock

public LockResult lock(TaskLockType lockType,
                       Task task,
                       org.joda.time.Interval interval)
                throws InterruptedException

Acquires a lock on behalf of a task. Blocks until the lock is acquired.

Parameters:

lockType - lock type

task - task to acquire lock for

interval - interval to lock

Returns:

LockResult containing a new or an existing lock if succeeded. Otherwise, LockResult with a LockResult.revoked flag.

Throws:

InterruptedException - if the current thread is interrupted

lock

public LockResult lock(TaskLockType lockType,
                       Task task,
                       org.joda.time.Interval interval,
                       long timeoutMs)
                throws InterruptedException

Acquires a lock on behalf of a task, waiting up to the specified wait time if necessary.

Parameters:

lockType - lock type

task - task to acquire a lock for

interval - interval to lock

timeoutMs - maximum time to wait

Returns:

LockResult containing a new or an existing lock if succeeded. Otherwise, LockResult with a LockResult.revoked flag.

Throws:

InterruptedException - if the current thread is interrupted

tryLock

public LockResult tryLock(TaskLockType lockType,
                          Task task,
                          org.joda.time.Interval interval)

Attempt to acquire a lock for a task, without removing it from the queue. Can safely be called multiple times on the same task until the lock is preempted.

Parameters:

lockType - type of lock to be acquired

task - task that wants a lock

interval - interval to lock

Returns:

LockResult containing a new or an existing lock if succeeded. Otherwise, LockResult with a LockResult.revoked flag.

Throws:

IllegalStateException - if the task is not a valid active task

doInCriticalSection

public <T> T doInCriticalSection(Task task,
                                 List<org.joda.time.Interval> intervals,
                                 CriticalAction<T> action)
                          throws Exception

Perform the given action with a guarantee that the locks of the task are not revoked in the middle of action. This method first checks that all locks for the given task and intervals are valid and perform the right action. The given action should be finished as soon as possible because all other methods in this class are blocked until this method is finished.

Parameters:

task - task performing a critical action

intervals - intervals

action - action to be performed inside of the critical section

Throws:

Exception

findLocksForTask

public List<TaskLock> findLocksForTask(Task task)

Return the currently-active locks for some task.

Parameters:

task - task for which to locate locks

Returns:

currently-active locks for the given task

unlock

public void unlock(Task task,
                   org.joda.time.Interval interval)

Release lock held for a task on a particular interval. Does nothing if the task does not currently hold the mentioned lock.

Parameters:

task - task to unlock

interval - interval to unlock

remove

public void remove(Task task)

Release all locks for a task and remove task from set of active tasks. Does nothing if the task is not currently locked or not an active task.

Parameters:

task - task to unlock

add

public void add(Task task)

getAllLocks

public Map<String,NavigableMap<org.joda.time.Interval,List<io.druid.indexing.overlord.TaskLockbox.TaskLockPosse>>> getAllLocks()