aws swf poll-for-decision-task
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
Options
| Name | Description |
|---|---|
--domain <string> | The name of the domain containing the task lists to poll |
--task-list <structure> | 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 |
--identity <string> | 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 |
--next-page-token <string> | 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 |
--maximum-page-size <integer> | 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 |
--reverse-order | 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 |
--no-reverse-order | 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 |
--cli-input-json <string> | Performs service operation based on the JSON string provided. The JSON string follows the format provided by ``--generate-cli-skeleton``. If other arguments are provided on the command line, the CLI values will override the JSON-provided values. It is not possible to pass arbitrary binary values using a JSON-provided value as the string will be taken literally |
--starting-token <string> | A token to specify where to start paginating. This is the NextToken from a previously truncated response. For usage examples, see Pagination in the AWS Command Line Interface User Guide |
--page-size <integer> | The size of each page to get in the AWS service call. This does not affect the number of items returned in the command's output. Setting a smaller page size results in more calls to the AWS service, retrieving fewer items in each call. This can help prevent the AWS service calls from timing out. For usage examples, see Pagination in the AWS Command Line Interface User Guide |
--max-items <integer> | The total number of items to return in the command's output. If the total number of items available is more than the value specified, a NextToken is provided in the command's output. To resume pagination, provide the NextToken value in the starting-token argument of a subsequent command. Do not use the NextToken response element directly outside of the AWS CLI. For usage examples, see Pagination in the AWS Command Line Interface User Guide |
--generate-cli-skeleton <string> | Prints a JSON skeleton to standard output without sending an API request. If provided with no value or the value ``input``, prints a sample input JSON that can be used as an argument for ``--cli-input-json``. If provided with the value ``output``, it validates the command inputs and returns a sample output JSON for that command |