Copyright	(c) 2013-2021 Brendan Hay
License	Mozilla Public License, v. 2.0.
Maintainer	Brendan Hay <brendan.g.hay+amazonka@gmail.com>
Stability	auto-generated
Portability	non-portable (GHC extensions)
Safe Haskell	None

Amazonka.SWF.PollForDecisionTask

Contents

Creating a Request
Request Lenses
Destructuring the Response
Response Lenses

Description

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 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.

This operation returns paginated results.

Synopsis

Creating a Request

data PollForDecisionTask Source #

See: newPollForDecisionTask smart constructor.

Constructors

PollForDecisionTask'

Fields

nextPageToken :: Maybe Text
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.
reverseOrder :: Maybe Bool
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.
maximumPageSize :: Maybe Natural
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.
identity :: Maybe Text
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.
domain :: Text
The name of the domain containing the task lists to poll.
taskList :: TaskList
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 be the literal string arn.

Instances

Instances details

Eq PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods (==) :: PollForDecisionTask -> PollForDecisionTask -> Bool # (/=) :: PollForDecisionTask -> PollForDecisionTask -> Bool #
Read PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods readsPrec :: Int -> ReadS PollForDecisionTask # readList :: ReadS [PollForDecisionTask] # readPrec :: ReadPrec PollForDecisionTask # readListPrec :: ReadPrec [PollForDecisionTask] #
Show PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods showsPrec :: Int -> PollForDecisionTask -> ShowS # show :: PollForDecisionTask -> String # showList :: [PollForDecisionTask] -> ShowS #
Generic PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Associated Types type Rep PollForDecisionTask :: Type -> Type # Methods from :: PollForDecisionTask -> Rep PollForDecisionTask x # to :: Rep PollForDecisionTask x -> PollForDecisionTask #
NFData PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods rnf :: PollForDecisionTask -> () #
Hashable PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods hashWithSalt :: Int -> PollForDecisionTask -> Int # hash :: PollForDecisionTask -> Int #
ToJSON PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods toJSON :: PollForDecisionTask -> Value # toEncoding :: PollForDecisionTask -> Encoding # toJSONList :: [PollForDecisionTask] -> Value # toEncodingList :: [PollForDecisionTask] -> Encoding #
AWSPager PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods page :: PollForDecisionTask -> AWSResponse PollForDecisionTask -> Maybe PollForDecisionTask #
AWSRequest PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Associated Types type AWSResponse PollForDecisionTask # Methods request :: PollForDecisionTask -> Request PollForDecisionTask # response :: MonadResource m => Logger -> Service -> Proxy PollForDecisionTask -> ClientResponse ClientBody -> m (Either Error (ClientResponse (AWSResponse PollForDecisionTask))) #
ToHeaders PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods toHeaders :: PollForDecisionTask -> [Header] #
ToPath PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods toPath :: PollForDecisionTask -> ByteString #
ToQuery PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods toQuery :: PollForDecisionTask -> QueryString #
type Rep PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask type Rep PollForDecisionTask = D1 ('MetaData "PollForDecisionTask" "Amazonka.SWF.PollForDecisionTask" "libZSservicesZSamazonka-swfZSamazonka-swf" 'False) (C1 ('MetaCons "PollForDecisionTask'" 'PrefixI 'True) ((S1 ('MetaSel ('Just "nextPageToken") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Text)) :: (S1 ('MetaSel ('Just "reverseOrder") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Bool)) :: S1 ('MetaSel ('Just "maximumPageSize") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Natural)))) :: (S1 ('MetaSel ('Just "identity") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Text)) :: (S1 ('MetaSel ('Just "domain") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 Text) :*: S1 ('MetaSel ('Just "taskList") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 TaskList)))))
type AWSResponse PollForDecisionTask Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask type AWSResponse PollForDecisionTask = PollForDecisionTaskResponse

newPollForDecisionTask Source #

Arguments

:: Text	`$sel:domain:PollForDecisionTask'`
-> TaskList	`$sel:taskList:PollForDecisionTask'`
-> PollForDecisionTask

Create a value of PollForDecisionTask with all optional fields omitted.

Use generic-lens or optics to modify other optional fields.

The following record fields are available, with the corresponding lenses provided for backwards compatibility:

$sel:nextPageToken:PollForDecisionTask', pollForDecisionTask_nextPageToken - 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.

$sel:reverseOrder:PollForDecisionTask', pollForDecisionTask_reverseOrder - 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.

$sel:maximumPageSize:PollForDecisionTask', pollForDecisionTask_maximumPageSize - 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.

$sel:identity:PollForDecisionTask', pollForDecisionTask_identity - 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.

$sel:domain:PollForDecisionTask', pollForDecisionTask_domain - The name of the domain containing the task lists to poll.

$sel:taskList:PollForDecisionTask', pollForDecisionTask_taskList - 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 be the literal string arn.

Request Lenses

pollForDecisionTask_nextPageToken :: Lens' PollForDecisionTask (Maybe Text) Source #

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.

pollForDecisionTask_reverseOrder :: 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.

pollForDecisionTask_maximumPageSize :: Lens' PollForDecisionTask (Maybe Natural) Source #

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.

pollForDecisionTask_identity :: 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.

pollForDecisionTask_domain :: Lens' PollForDecisionTask Text Source #

The name of the domain containing the task lists to poll.

pollForDecisionTask_taskList :: 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 be the literal string arn.

Destructuring the Response

data PollForDecisionTaskResponse Source #

A structure that represents a decision task. Decision tasks are sent to deciders in order for them to make decisions.

See: newPollForDecisionTaskResponse smart constructor.

Constructors

PollForDecisionTaskResponse'

Fields

nextPageToken :: Maybe Text
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.
workflowType :: Maybe WorkflowType
The type of the workflow execution for which this decision task was created.
previousStartedEventId :: Maybe Integer
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.
events :: Maybe [HistoryEvent]
A paginated list of history events of the workflow execution. The decider uses this during the processing of the decision task.
taskToken :: Maybe Text
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.
workflowExecution :: Maybe WorkflowExecution
The workflow execution for which this decision task was created.
httpStatus :: Int
The response's http status code.
startedEventId :: Integer
The ID of the DecisionTaskStarted event recorded in the history.

Instances

Instances details

Eq PollForDecisionTaskResponse Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods (==) :: PollForDecisionTaskResponse -> PollForDecisionTaskResponse -> Bool # (/=) :: PollForDecisionTaskResponse -> PollForDecisionTaskResponse -> Bool #
Read PollForDecisionTaskResponse Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods readsPrec :: Int -> ReadS PollForDecisionTaskResponse # readList :: ReadS [PollForDecisionTaskResponse] # readPrec :: ReadPrec PollForDecisionTaskResponse # readListPrec :: ReadPrec [PollForDecisionTaskResponse] #
Show PollForDecisionTaskResponse Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods showsPrec :: Int -> PollForDecisionTaskResponse -> ShowS # show :: PollForDecisionTaskResponse -> String # showList :: [PollForDecisionTaskResponse] -> ShowS #
Generic PollForDecisionTaskResponse Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Associated Types type Rep PollForDecisionTaskResponse :: Type -> Type # Methods from :: PollForDecisionTaskResponse -> Rep PollForDecisionTaskResponse x # to :: Rep PollForDecisionTaskResponse x -> PollForDecisionTaskResponse #
NFData PollForDecisionTaskResponse Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask Methods rnf :: PollForDecisionTaskResponse -> () #
type Rep PollForDecisionTaskResponse Source #
Instance details Defined in Amazonka.SWF.PollForDecisionTask type Rep PollForDecisionTaskResponse = D1 ('MetaData "PollForDecisionTaskResponse" "Amazonka.SWF.PollForDecisionTask" "libZSservicesZSamazonka-swfZSamazonka-swf" 'False) (C1 ('MetaCons "PollForDecisionTaskResponse'" 'PrefixI 'True) (((S1 ('MetaSel ('Just "nextPageToken") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Text)) :: S1 ('MetaSel ('Just "workflowType") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe WorkflowType))) :: (S1 ('MetaSel ('Just "previousStartedEventId") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Integer)) :: S1 ('MetaSel ('Just "events") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe [HistoryEvent])))) :: ((S1 ('MetaSel ('Just "taskToken") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Text)) :: S1 ('MetaSel ('Just "workflowExecution") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe WorkflowExecution))) :: (S1 ('MetaSel ('Just "httpStatus") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 Int) :*: S1 ('MetaSel ('Just "startedEventId") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 Integer)))))

newPollForDecisionTaskResponse Source #

Arguments

:: Int	`$sel:httpStatus:PollForDecisionTaskResponse'`
-> Integer	`$sel:startedEventId:PollForDecisionTaskResponse'`
-> PollForDecisionTaskResponse

Create a value of PollForDecisionTaskResponse with all optional fields omitted.

Use generic-lens or optics to modify other optional fields.

The following record fields are available, with the corresponding lenses provided for backwards compatibility:

$sel:nextPageToken:PollForDecisionTask', pollForDecisionTaskResponse_nextPageToken - 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.

$sel:workflowType:PollForDecisionTaskResponse', pollForDecisionTaskResponse_workflowType - The type of the workflow execution for which this decision task was created.

$sel:previousStartedEventId:PollForDecisionTaskResponse', pollForDecisionTaskResponse_previousStartedEventId - 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.

$sel:events:PollForDecisionTaskResponse', pollForDecisionTaskResponse_events - A paginated list of history events of the workflow execution. The decider uses this during the processing of the decision task.

$sel:taskToken:PollForDecisionTaskResponse', pollForDecisionTaskResponse_taskToken - 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.

$sel:workflowExecution:PollForDecisionTaskResponse', pollForDecisionTaskResponse_workflowExecution - The workflow execution for which this decision task was created.

$sel:httpStatus:PollForDecisionTaskResponse', pollForDecisionTaskResponse_httpStatus - The response's http status code.

$sel:startedEventId:PollForDecisionTaskResponse', pollForDecisionTaskResponse_startedEventId - The ID of the DecisionTaskStarted event recorded in the history.

Response Lenses

pollForDecisionTaskResponse_nextPageToken :: 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.

pollForDecisionTaskResponse_workflowType :: Lens' PollForDecisionTaskResponse (Maybe WorkflowType) Source #

The type of the workflow execution for which this decision task was created.

pollForDecisionTaskResponse_previousStartedEventId :: 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.

pollForDecisionTaskResponse_events :: Lens' PollForDecisionTaskResponse (Maybe [HistoryEvent]) Source #

A paginated list of history events of the workflow execution. The decider uses this during the processing of the decision task.

pollForDecisionTaskResponse_taskToken :: Lens' PollForDecisionTaskResponse (Maybe 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.

pollForDecisionTaskResponse_workflowExecution :: Lens' PollForDecisionTaskResponse (Maybe WorkflowExecution) Source #

The workflow execution for which this decision task was created.

pollForDecisionTaskResponse_httpStatus :: Lens' PollForDecisionTaskResponse Int Source #

The response's http status code.

pollForDecisionTaskResponse_startedEventId :: Lens' PollForDecisionTaskResponse Integer Source #

The ID of the DecisionTaskStarted event recorded in the history.