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Amazon Simple Workflow Service
API Reference (API Version 2012-01-25)

StartWorkflowExecution

Starts an execution of the workflow type in the specified domain using the provided workflowId and input data.

This action returns the newly started workflow execution.

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 following parameters by using a Condition element with the appropriate keys.

    • tagList.member.0: The key is swf:tagList.member.0.

    • tagList.member.1: The key is swf:tagList.member.1.

    • tagList.member.2: The key is swf:tagList.member.2.

    • tagList.member.3: The key is swf:tagList.member.3.

    • tagList.member.4: The key is swf:tagList.member.4.

    • taskList: String constraint. The key is swf:taskList.name.

    • workflowType.name: String constraint. The key is swf:workflowType.name.

    • workflowType.version: String constraint. The key is swf:workflowType.version.

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.

Request Syntax

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{ "childPolicy": "string", "domain": "string", "executionStartToCloseTimeout": "string", "input": "string", "lambdaRole": "string", "tagList": [ "string" ], "taskList": { "name": "string" }, "taskPriority": "string", "taskStartToCloseTimeout": "string", "workflowId": "string", "workflowType": { "name": "string", "version": "string" } }

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

The request accepts the following data in JSON format.

childPolicy

If set, specifies the policy to use for the child workflow executions of this workflow execution if it is terminated, by calling the TerminateWorkflowExecution action explicitly or due to an expired timeout. This policy overrides the default child policy specified when registering the workflow type using RegisterWorkflowType.

The supported child policies are:

  • TERMINATE: the child executions will be terminated.

  • REQUEST_CANCEL: a request to cancel will be attempted for each child execution by recording a WorkflowExecutionCancelRequested event in its history. It is up to the decider to take appropriate actions when it receives an execution history with this event.

  • ABANDON: no action will be taken. The child executions will continue to run.

Note

A child policy for this workflow execution must be specified either as a default for the workflow type or through this parameter. If neither this parameter is set nor a default child policy was specified at registration time then a fault will be returned.

Type: String

Valid Values: TERMINATE | REQUEST_CANCEL | ABANDON

Required: No

domain

The name of the domain in which the workflow execution is created.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 256.

Required: Yes

executionStartToCloseTimeout

The total duration for this workflow execution. This overrides the defaultExecutionStartToCloseTimeout specified when registering the workflow type.

The duration is specified in seconds; an integer greater than or equal to 0. Exceeding this limit will cause the workflow execution to time out. Unlike some of the other timeout parameters in Amazon SWF, you cannot specify a value of "NONE" for this timeout; there is a one-year max limit on the time that a workflow execution can run.

Note

An execution start-to-close timeout must be specified either through this parameter or as a default when the workflow type is registered. If neither this parameter nor a default execution start-to-close timeout is specified, a fault is returned.

Type: String

Length Constraints: Maximum length of 8.

Required: No

input

The input for the workflow execution. This is a free form string which should be meaningful to the workflow you are starting. This input is made available to the new workflow execution in the WorkflowExecutionStarted history event.

Type: String

Length Constraints: Maximum length of 32768.

Required: No

lambdaRole

Type: String

Length Constraints: Minimum length of 1. Maximum length of 1224.

Required: No

tagList

The list of tags to associate with the workflow execution. You can specify a maximum of 5 tags. You can list workflow executions with a specific tag by calling ListOpenWorkflowExecutions or ListClosedWorkflowExecutions and specifying a TagFilter.

Type: Array of strings

Array Members: Maximum number of 5 items.

Length Constraints: Minimum length of 1. Maximum length of 256.

Required: No

taskList

The task list to use for the decision tasks generated for this workflow execution. This overrides the defaultTaskList specified when registering the workflow type.

Note

A task list for this workflow execution must be specified either as a default for the workflow type or through this parameter. If neither this parameter is set nor a default task list was specified at registration time then a fault will be returned.

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 "arn".

Type: TaskList object

Required: No

taskPriority

The task priority to use for this workflow execution. This will override any default priority that was assigned when the workflow type was registered. If not set, then the default task priority for the workflow type will be used. Valid values are integers that range from Java's Integer.MIN_VALUE (-2147483648) to Integer.MAX_VALUE (2147483647). Higher numbers indicate higher priority.

For more information about setting task priority, see Setting Task Priority in the Amazon Simple Workflow Developer Guide.

Type: String

Length Constraints: Maximum length of 11.

Required: No

taskStartToCloseTimeout

Specifies the maximum duration of decision tasks for this workflow execution. This parameter overrides the defaultTaskStartToCloseTimout specified when registering the workflow type using RegisterWorkflowType.

The duration is specified in seconds; an integer greater than or equal to 0. The value "NONE" can be used to specify unlimited duration.

Note

A task start-to-close timeout for this workflow execution must be specified either as a default for the workflow type or through this parameter. If neither this parameter is set nor a default task start-to-close timeout was specified at registration time then a fault will be returned.

Type: String

Length Constraints: Maximum length of 8.

Required: No

workflowId

The user defined identifier associated with the workflow execution. You can use this to associate a custom identifier with the workflow execution. You may specify the same identifier if a workflow execution is logically a restart of a previous execution. You cannot have two open workflow executions with the same workflowId at the same time.

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 "arn".

Type: String

Length Constraints: Minimum length of 1. Maximum length of 256.

Required: Yes

workflowType

The type of the workflow to start.

Type: WorkflowType object

Required: Yes

Response Syntax

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{ "runId": "string" }

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

runId

The runId of a workflow execution. This Id is generated by the service and can be used to uniquely identify the workflow execution within a domain.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 64.

Errors

For information about the errors that are common to all actions, see Common Errors.

DefaultUndefinedFault

HTTP Status Code: 400

LimitExceededFault

Returned by any operation if a system imposed limitation has been reached. To address this fault you should either clean up unused resources or increase the limit by contacting AWS.

HTTP Status Code: 400

OperationNotPermittedFault

Returned when the caller does not have sufficient permissions to invoke the action.

HTTP Status Code: 400

TypeDeprecatedFault

Returned when the specified activity or workflow type was already deprecated.

HTTP Status Code: 400

UnknownResourceFault

Returned when the named resource cannot be found with in the scope of this operation (region or domain). This could happen if the named resource was never created or is no longer available for this operation.

HTTP Status Code: 400

WorkflowExecutionAlreadyStartedFault

Returned by StartWorkflowExecution when an open execution with the same workflowId is already running in the specified domain.

HTTP Status Code: 400

Example

StartWorkflowExecution Example

Sample Request

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POST / HTTP/1.1 Host: swf.us-east-1.amazonaws.com User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.25) Gecko/20111212 Firefox/3.6.25 ( .NET CLR 3.5.30729; .NET4.0E) Accept: application/json, text/javascript, */* Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 115 Connection: keep-alive Content-Type: application/x-amz-json-1.0 X-Requested-With: XMLHttpRequest X-Amz-Date: Sat, 14 Jan 2012 22:45:13 GMT X-Amz-Target: SimpleWorkflowService.StartWorkflowExecution Content-Encoding: amz-1.0 X-Amzn-Authorization: AWS3 AWSAccessKeyId=AKIAIOSFODNN7EXAMPLE,Algorithm=HmacSHA256,SignedHeaders=Host;X-Amz-Date;X-Amz-Target;Content-Encoding,Signature=aYxuqLX+TO91kPVg+jh+aA8PWxQazQRN2+SZUGdOgU0= Referer: http://swf.us-east-1.amazonaws.com/explorer/index.html Content-Length: 417 Pragma: no-cache Cache-Control: no-cache { "domain": "867530901", "taskList": { "name": "specialTaskList" }, "taskPriority": "100", "taskStartToCloseTimeout": "600", "workflowId": "20110927-T-1", "childPolicy": "TERMINATE", "executionStartToCloseTimeout": "1800", "input": "arbitrary-string-that-is-meaningful-to-the-workflow", "workflowType": { "version": "1.0", "name": "customerOrderWorkflow" }, "tagList": [ "music purchase", "digital", "ricoh-the-dog" ] }

Sample Response

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HTTP/1.1 200 OK Content-Length: 48 Content-Type: application/json x-amzn-RequestId: 6c25f6e6-3f01-11e1-9a27-0760db01a4a8 { "runId": "1e536162-f1ea-48b0-85f3-aade88eef2f7" }

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: