Used by deciders to get a DecisionTask from the specified decision
taskList. A decision task may be returned for any open workflow execution that
is using the specified task list. The task includes a paginated view of the history of the
workflow execution. The decider should use the workflow type and the history to determine how
to properly handle the task.
This action initiates a long poll, where the service holds the HTTP connection open and responds as soon a task becomes available. If no decision task is available in the specified task list before the timeout of 60 seconds expires, an empty result is returned. An empty result, in this context, means that a DecisionTask is returned, but that the value of taskToken is an empty string.
Deciders should set their client side socket timeout to at least 70 seconds (10 seconds higher than the timeout).
Because the number of workflow history events for a single workflow execution might
be very large, the result returned might be split up across a number of pages. To retrieve
subsequent pages, make additional calls to
PollForDecisionTask using the
nextPageToken returned by the initial call. Note that you do
GetWorkflowExecutionHistory with this
nextPageToken. Instead, call
You can use IAM policies to control this action's access to Amazon SWF resources as follows:
Resource element with the domain name to limit the action to
only specified domains.
Action element to allow or deny permission to call this
taskList.name parameter by using a
Condition element with the
swf:taskList.name key to allow the
action to access only certain task lists.
If the caller doesn't have sufficient permissions to invoke the action, or the
parameter values fall outside the specified constraints, the action fails. The associated
cause parameter is set to
For details and example IAM policies, see Using IAM to Manage Access to Amazon SWF
Workflows in the Amazon SWF Developer Guide.