Safe Haskell | None |
---|---|
Language | Haskell2010 |
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 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 does not 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 will be set to OPERATION_NOT_PERMITTED. For details and example IAM
policies, see Using IAM to Manage Access to Amazon SWF Workflows.
http://docs.aws.amazon.com/amazonswf/latest/apireference/API_PollForDecisionTask.html
- data PollForDecisionTask
- pollForDecisionTask :: Text -> TaskList -> PollForDecisionTask
- pfdtDomain :: Lens' PollForDecisionTask Text
- pfdtIdentity :: Lens' PollForDecisionTask (Maybe Text)
- pfdtMaximumPageSize :: Lens' PollForDecisionTask (Maybe Natural)
- pfdtNextPageToken :: Lens' PollForDecisionTask (Maybe Text)
- pfdtReverseOrder :: Lens' PollForDecisionTask (Maybe Bool)
- pfdtTaskList :: Lens' PollForDecisionTask TaskList
- data PollForDecisionTaskResponse
- pollForDecisionTaskResponse :: Text -> Integer -> WorkflowExecution -> WorkflowType -> PollForDecisionTaskResponse
- pfdtrEvents :: Lens' PollForDecisionTaskResponse [HistoryEvent]
- pfdtrNextPageToken :: Lens' PollForDecisionTaskResponse (Maybe Text)
- pfdtrPreviousStartedEventId :: Lens' PollForDecisionTaskResponse (Maybe Integer)
- pfdtrStartedEventId :: Lens' PollForDecisionTaskResponse Integer
- pfdtrTaskToken :: Lens' PollForDecisionTaskResponse Text
- pfdtrWorkflowExecution :: Lens' PollForDecisionTaskResponse WorkflowExecution
- pfdtrWorkflowType :: Lens' PollForDecisionTaskResponse WorkflowType
Request
data PollForDecisionTask Source
Request constructor
PollForDecisionTask
constructor.
The fields accessible through corresponding lenses are:
Request lenses
pfdtDomain :: Lens' PollForDecisionTask Text Source
The name of the domain containing the task lists to poll.
pfdtIdentity :: Lens' PollForDecisionTask (Maybe Text) Source
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.
pfdtMaximumPageSize :: Lens' PollForDecisionTask (Maybe Natural) Source
The maximum number of results that will be returned per call. nextPageToken
can be used to obtain futher pages of results. The default is 100, which is
the maximum allowed page size. You can, however, specify a page size smaller
than 100.
This is an upper limit only; the actual number of results returned per call may be fewer than the specified maximum.
pfdtNextPageToken :: Lens' PollForDecisionTask (Maybe Text) Source
If a NextPageToken
was returned by a previous call, there are more results
available. To retrieve the next page of results, make the call again using
the returned token in nextPageToken
. Keep all other arguments unchanged.
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
will not return a new decision task..
pfdtReverseOrder :: Lens' PollForDecisionTask (Maybe Bool) Source
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.
pfdtTaskList :: Lens' PollForDecisionTask TaskList Source
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
(u0000-u001f | u007f - u009f). Also, it must not contain the literal
string quotarnquot.
Response
Response constructor
pollForDecisionTaskResponse Source
PollForDecisionTaskResponse
constructor.
The fields accessible through corresponding lenses are:
Response lenses
pfdtrEvents :: Lens' PollForDecisionTaskResponse [HistoryEvent] Source
A paginated list of history events of the workflow execution. The decider uses this during the processing of the decision task.
pfdtrNextPageToken :: Lens' PollForDecisionTaskResponse (Maybe Text) Source
If a NextPageToken
was returned by a previous call, there are more results
available. To retrieve the next page of results, make the call again using
the returned token in nextPageToken
. Keep all other arguments unchanged.
The configured maximumPageSize
determines how many results can be returned
in a single call.
pfdtrPreviousStartedEventId :: Lens' PollForDecisionTaskResponse (Maybe Integer) Source
The id of the DecisionTaskStarted event of the previous decision task of this workflow execution that was processed by the decider. This can be used to determine the events in the history new since the last decision task received by the decider.
pfdtrStartedEventId :: Lens' PollForDecisionTaskResponse Integer Source
The id of the DecisionTaskStarted
event recorded in the history.
pfdtrTaskToken :: Lens' PollForDecisionTaskResponse Text Source
The opaque string used as a handle on the task. This token is used by workers to communicate progress and response information back to the system about the task.
pfdtrWorkflowExecution :: Lens' PollForDecisionTaskResponse WorkflowExecution Source
The workflow execution for which this decision task was created.
pfdtrWorkflowType :: Lens' PollForDecisionTaskResponse WorkflowType Source
The type of the workflow execution for which this decision task was created.