Exists

Checks whether a data node object exists.

Note

We recommend that you use system-managed preconditions instead. For more information, see Preconditions.

Example

The following is an example of this object type. The InputData object references this object, Ready, plus another object that you'd define in the same pipeline definition file. CopyPeriod is a Schedule object.

{
  "id" : "InputData",
  "type" : "S3DataNode",
  "schedule" : { "ref" : "CopyPeriod" },
  "filePath" : "s3://amzn-s3-demo-bucket/InputData/#{@scheduledStartTime.format('YYYY-MM-dd-hh:mm')}.csv",
  "precondition" : { "ref" : "Ready" }
},
{
  "id" : "Ready",
  "type" : "Exists"
}

Syntax

Optional Fields	Description	Slot Type
attemptStatus	Most recently reported status from the remote activity.	String
attemptTimeout	Timeout for remote work completion. If set then a remote activity that does not complete within the set time of starting may be retried.	Period
failureAndRerunMode	Describes consumer node behavior when dependencies fail or are rerun.	Enumeration
lateAfterTimeout	The elapsed time after pipeline start within which the object must complete. It is triggered only when the schedule type is not set to ondemand.	Period
maximumRetries	Maximum number attempt retries on failure	Integer
onFail	An action to run when current object fails.	Reference Object, e.g. "onFail":{"ref":"myActionId"}
onLateAction	Actions that should be triggered if an object has not yet been scheduled or still not completed.	Reference Object, e.g. "onLateAction":{"ref":"myActionId"}
onSuccess	An action to run when current object succeeds.	Reference Object, e.g. "onSuccess":{"ref":"myActionId"}
parent	Parent of the current object from which slots will be inherited.	Reference Object, e.g. "parent":{"ref":"myBaseObjectId"}
preconditionTimeout	The period from start after which precondition is marked as failed if still not satisfied	Period
reportProgressTimeout	Timeout for remote work successive calls to reportProgress. If set, then remote activities that do not report progress for the specified period may be considered stalled and so retried.	Period
retryDelay	The timeout duration between two retry attempts.	Period

Runtime Fields	Description	Slot Type
@activeInstances	List of the currently scheduled active instance objects.	Reference Object, e.g. "activeInstances":{"ref":"myRunnableObjectId"}
@actualEndTime	Time when the execution of this object finished.	DateTime
@actualStartTime	Time when the execution of this object started.	DateTime
cancellationReason	The cancellationReason if this object was cancelled.	String
@cascadeFailedOn	Description of the dependency chain the object failed on.	Reference Object, e.g. "cascadeFailedOn":{"ref":"myRunnableObjectId"}
emrStepLog	EMR step logs available only on EMR activity attempts	String
errorId	The errorId if this object failed.	String
errorMessage	The errorMessage if this object failed.	String
errorStackTrace	The error stack trace if this object failed.	String
hadoopJobLog	Hadoop job logs available on attempts for EMR-based activities.	String
hostname	The host name of client that picked up the task attempt.	String
node	The node for which this precondition is being performed.	Reference Object, e.g. "node":{"ref":"myRunnableObjectId"}
reportProgressTime	Most recent time that remote activity reported progress.	DateTime
@scheduledEndTime	Schedule end time for object.	DateTime
@scheduledStartTime	Schedule start time for object.	DateTime
@status	The status of this object.	String
@version	Pipeline version the object was created with.	String
@waitingOn	Description of list of dependencies this object is waiting on.	Reference Object, e.g. "waitingOn":{"ref":"myRunnableObjectId"}

System Fields	Description	Slot Type
@error	Error describing the ill-formed object.	String
@pipelineId	Id of the pipeline to which this object belongs to.	String
@sphere	The sphere of an object denotes its place in the lifecycle: Component Objects give rise to Instance Objects which execute Attempt Objects.	String

See Also

• ShellCommandPrecondition