io.druid.indexing.overlord

Interface TaskStorage

All Known Implementing Classes:

HeapMemoryTaskStorage, MetadataTaskStorage

public interface TaskStorage

Method Summary

Modifier and Type	Method and Description
<T> void	addAuditLog(Task task, TaskAction<T> taskAction) Add an action taken by a task to the audit log.
void	addLock(String taskid, TaskLock taskLock) Persists lock state in the storage facility.
List<Task>	getActiveTasks() Returns a list of currently running or pending tasks as stored in the storage facility.
List<TaskAction>	getAuditLogs(String taskid) Returns all actions taken by a task.
List<TaskLock>	getLocks(String taskid) Returns a list of locks for a particular task.
List<TaskStatus>	getRecentlyFinishedTaskStatuses() Returns a list of recently finished task statuses as stored in the storage facility.
com.google.common.base.Optional<TaskStatus>	getStatus(String taskid) Returns task status as stored in the storage facility.
com.google.common.base.Optional<Task>	getTask(String taskid) Returns task as stored in the storage facility.
void	insert(Task task, TaskStatus status) Adds a task to the storage facility with a particular status.
void	removeLock(String taskid, TaskLock taskLock) Removes lock state from the storage facility.
void	setStatus(TaskStatus status) Persists task status in the storage facility.

Method Detail

insert

void insert(Task task,
            TaskStatus status)
     throws EntryExistsException

Adds a task to the storage facility with a particular status.

Parameters:

task - task to add

status - task status

Throws:

EntryExistsException - if the task ID already exists

setStatus

void setStatus(TaskStatus status)

Persists task status in the storage facility. This method should throw an exception if the task status lifecycle is not respected (absent -> RUNNING -> SUCCESS/FAILURE).

Parameters:

status - task status

addLock

void addLock(String taskid,
             TaskLock taskLock)

Persists lock state in the storage facility.

Parameters:

taskid - task ID

taskLock - lock state

removeLock

void removeLock(String taskid,
                TaskLock taskLock)

Removes lock state from the storage facility. It is harmless to keep old locks in the storage facility, but this method can help reclaim wasted space.

Parameters:

taskid - task ID

taskLock - lock state

getTask

com.google.common.base.Optional<Task> getTask(String taskid)

Returns task as stored in the storage facility. If the task ID does not exist, this will return an absentee Optional. NOTE: This method really feels like it should be combined with getStatus(java.lang.String). Expect that in the future.

Parameters:

taskid - task ID

Returns:

optional task

getStatus

com.google.common.base.Optional<TaskStatus> getStatus(String taskid)

Returns task status as stored in the storage facility. If the task ID does not exist, this will return an absentee Optional.

Parameters:

taskid - task ID

Returns:

task status

addAuditLog

<T> void addAuditLog(Task task,
                     TaskAction<T> taskAction)

Add an action taken by a task to the audit log.

Type Parameters:

T - task action return type

Parameters:

task - task to record action for

taskAction - task action to record

getAuditLogs

List<TaskAction> getAuditLogs(String taskid)

Returns all actions taken by a task.

Parameters:

taskid - task ID

Returns:

list of task actions

getActiveTasks

List<Task> getActiveTasks()

Returns a list of currently running or pending tasks as stored in the storage facility. No particular order is guaranteed, but implementations are encouraged to return tasks in ascending order of creation.

Returns:

list of active tasks

getRecentlyFinishedTaskStatuses

List<TaskStatus> getRecentlyFinishedTaskStatuses()

Returns a list of recently finished task statuses as stored in the storage facility. No particular order is guaranteed, but implementations are encouraged to return tasks in descending order of creation. No particular standard of "recent" is guaranteed, and in fact, this method is permitted to simply return nothing.

Returns:

list of recently finished tasks

getLocks

List<TaskLock> getLocks(String taskid)

Returns a list of locks for a particular task.

Parameters:

taskid - task ID

Returns:

list of TaskLocks for the given task