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

SignalWorkflowExecution

Records a WorkflowExecutionSignaled event in the workflow execution history and creates a decision task for the workflow execution identified by the given domain, workflowId and runId. The event is recorded with the specified user defined signalName and input (if provided).

Note

If a runId isn't specified, then the WorkflowExecutionSignaled event is recorded in the history of the current open workflow with the matching workflowId in the domain.

Note

If the specified workflow execution isn't open, this method fails with UnknownResource.

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.

  • You cannot use an IAM policy to constrain this action's parameters.

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.

Request Syntax

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{ "domain": "string", "input": "string", "runId": "string", "signalName": "string", "workflowId": "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.

domain

The name of the domain containing the workflow execution to signal.

Type: String

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

Required: Yes

input

Data to attach to the WorkflowExecutionSignaled event in the target workflow execution's history.

Type: String

Length Constraints: Maximum length of 32768.

Required: No

runId

The runId of the workflow execution to signal.

Type: String

Length Constraints: Maximum length of 64.

Required: No

signalName

The name of the signal. This name must be meaningful to the target workflow.

Type: String

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

Required: Yes

workflowId

The workflowId of the workflow execution to signal.

Type: String

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

Required: Yes

Response Elements

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

Errors

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

OperationNotPermittedFault

Returned when the caller doesn't have sufficient permissions to invoke the action.

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

Example

SignalWorkflowExecution 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: Sun, 15 Jan 2012 00:06:18 GMT X-Amz-Target: SimpleWorkflowService.SignalWorkflowExecution Content-Encoding: amz-1.0 X-Amzn-Authorization: AWS3 AWSAccessKeyId=AKIAIOSFODNN7EXAMPLE,Algorithm=HmacSHA256,SignedHeaders=Host;X-Amz-Date;X-Amz-Target;Content-Encoding,Signature=lQpBZezK7JNQrXeWuJE+l7S0ZwjOEONCeRyImoyfX+E= Referer: http://swf.us-east-1.amazonaws.com/explorer/index.html Content-Length: 162 Pragma: no-cache Cache-Control: no-cache {"domain": "867530901", "workflowId": "20110927-T-1", "runId": "f5ebbac6-941c-4342-ad69-dfd2f8be6689", "signalName": "CancelOrder", "input": "order 3553"}

Sample Response

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HTTP/1.1 200 OK Content-Length: 0 Content-Type: application/json x-amzn-RequestId: bf78ae15-3f0c-11e1-9914-a356b6ea8bdf

See Also

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