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.
swf_poll_for_decision_task(domain, taskList, identity, nextPageToken,
maximumPageSize, reverseOrder)[required] The name of the domain containing the task lists to poll.
[required] Specifies the task list to poll for decision tasks.
The specified string must not start or end with whitespace. It must not
contain a : (colon), / (slash), | (vertical bar), or any control
characters (U+0000`-`U+001f \| U+007f`-`U+009f). Also, it must not be
the literal string arn.
Identity of the decider making the request, which is recorded in the DecisionTaskStarted event in the workflow history. This enables diagnostic tracing when problems arise. The form of this identity is user defined.
If NextPageToken is returned there are more results available. The
value of NextPageToken is a unique pagination token for each page.
Make the call again using the returned token to retrieve the next page.
Keep all other arguments unchanged. Each pagination token expires after
60 seconds. Using an expired pagination token will return a 400 error:
"Specified token has exceeded its maximum lifetime".
The configured maximumPageSize determines how many results can be
returned in a single call.
The nextPageToken returned by this action cannot be used with
GetWorkflowExecutionHistory to get the next page. You must call
PollForDecisionTask again (with the nextPageToken) to retrieve the
next page of history records. Calling PollForDecisionTask with a
nextPageToken doesn't return a new decision task.
The maximum number of results that are returned per call. Use
nextPageToken to obtain further pages of results.
This is an upper limit only; the actual number of results returned per call may be fewer than the specified maximum.
When set to true, returns the events in reverse order. By default the
results are returned in ascending order of the eventTimestamp of the
events.
svc$poll_for_decision_task(
domain = "string",
taskList = list(
name = "string"
),
identity = "string",
nextPageToken = "string",
maximumPageSize = 123,
reverseOrder = TRUE|FALSE
)
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 not call GetWorkflowExecutionHistory
with this nextPageToken. Instead, call PollForDecisionTask again.
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.
Constrain the 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 event attribute's cause parameter is set
to OPERATION_NOT_PERMITTED. For details and example IAM policies, see
Using IAM to Manage Access to Amazon SWF Workflows
in the Amazon SWF Developer Guide.