Used by workers to tell the service that the ActivityTask identified by the taskToken was successfully canceled. Additional details can be optionally provided using the details argument.

These details (if provided) appear in the ActivityTaskCanceled event added to the workflow history.

IMPORTANT: Only use this operation if the canceled flag of a RecordActivityTaskHeartbeat request returns true and if the activity can be safely undone or abandoned.

A task is considered open from the time that it is scheduled until it is closed. Therefore a task is reported as open while a worker is processing it. A task is closed after it has been specified in a call to RespondActivityTaskCompleted, RespondActivityTaskCanceled, RespondActivityTaskFailed, or the task has timed out.

Access Control

You can use IAM policies to control this action's access to Amazon SWF resources as follows:

• Use a Resource element with the domain name to limit the action to only specified domains.
• Use an Action element to allow or deny permission to call this action.
• You cannot use an IAM policy to constrain this action's parameters.

If the caller does not have sufficient permissions to invoke the action, or the parameter values fall outside the specified constraints, the action fails by throwing OperationNotPermitted . For details and example IAM policies, see Using IAM to Manage Access to Amazon SWF Workflows.