{ "type": "object", "required": [ "decisionType" ], "properties": { "decisionType": { "allOf": [ { "$ref": "#/components/schemas/DecisionType" }, { "description": "Specifies the type of the decision." } ] }, "scheduleActivityTaskDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/ScheduleActivityTaskDecisionAttributes" }, { "description": "Provides the details of the ScheduleActivityTask decision. It isn't set for other decision types." } ] }, "requestCancelActivityTaskDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/RequestCancelActivityTaskDecisionAttributes" }, { "description": "Provides the details of the RequestCancelActivityTask decision. It isn't set for other decision types." } ] }, "completeWorkflowExecutionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/CompleteWorkflowExecutionDecisionAttributes" }, { "description": "Provides the details of the CompleteWorkflowExecution decision. It isn't set for other decision types." } ] }, "failWorkflowExecutionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/FailWorkflowExecutionDecisionAttributes" }, { "description": "Provides the details of the FailWorkflowExecution decision. It isn't set for other decision types." } ] }, "cancelWorkflowExecutionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/CancelWorkflowExecutionDecisionAttributes" }, { "description": "Provides the details of the CancelWorkflowExecution decision. It isn't set for other decision types." } ] }, "continueAsNewWorkflowExecutionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/ContinueAsNewWorkflowExecutionDecisionAttributes" }, { "description": "Provides the details of the ContinueAsNewWorkflowExecution decision. It isn't set for other decision types." } ] }, "recordMarkerDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/RecordMarkerDecisionAttributes" }, { "description": "Provides the details of the RecordMarker decision. It isn't set for other decision types." } ] }, "startTimerDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/StartTimerDecisionAttributes" }, { "description": "Provides the details of the StartTimer decision. It isn't set for other decision types." } ] }, "cancelTimerDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/CancelTimerDecisionAttributes" }, { "description": "Provides the details of the CancelTimer decision. It isn't set for other decision types." } ] }, "signalExternalWorkflowExecutionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/SignalExternalWorkflowExecutionDecisionAttributes" }, { "description": "Provides the details of the SignalExternalWorkflowExecution decision. It isn't set for other decision types." } ] }, "requestCancelExternalWorkflowExecutionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/RequestCancelExternalWorkflowExecutionDecisionAttributes" }, { "description": "Provides the details of the RequestCancelExternalWorkflowExecution decision. It isn't set for other decision types." } ] }, "startChildWorkflowExecutionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/StartChildWorkflowExecutionDecisionAttributes" }, { "description": "Provides the details of the StartChildWorkflowExecution decision. It isn't set for other decision types." } ] }, "scheduleLambdaFunctionDecisionAttributes": { "allOf": [ { "$ref": "#/components/schemas/ScheduleLambdaFunctionDecisionAttributes" }, { "description": "Provides the details of the ScheduleLambdaFunction decision. It isn't set for other decision types." } ] } }, "description": "

Specifies a decision made by the decider. A decision can be one of these types:

Access Control

If you grant permission to use RespondDecisionTaskCompleted, you can use IAM policies to express permissions for the list of decisions returned by this action as if they were members of the API. Treating decisions as a pseudo API maintains a uniform conceptual model and helps keep policies readable. For details and example IAM policies, see Using IAM to Manage Access to Amazon SWF Workflows in the Amazon SWF Developer Guide.

Decision Failure

Decisions can fail for several reasons

One of the following events might be added to the history to indicate an error. The event attribute's cause parameter indicates the cause. If cause is set to OPERATION_NOT_PERMITTED, the decision failed because it lacked sufficient permissions. For details and example IAM policies, see Using IAM to Manage Access to Amazon SWF Workflows in the Amazon SWF Developer Guide.

The preceding error events might occur due to an error in the decider logic, which might put the workflow execution in an unstable state The cause field in the event structure for the error event indicates the cause of the error.

A workflow execution may be closed by the decider by returning one of the following decisions when completing a decision task: CompleteWorkflowExecution, FailWorkflowExecution, CancelWorkflowExecution and ContinueAsNewWorkflowExecution. An UnhandledDecision fault is returned if a workflow closing decision is specified and a signal or activity event had been added to the history while the decision task was being performed by the decider. Unlike the above situations which are logic issues, this fault is always possible because of race conditions in a distributed system. The right action here is to call RespondDecisionTaskCompleted without any decisions. This would result in another decision task with these new events included in the history. The decider should handle the new events and may decide to close the workflow execution.

How to Code a Decision

You code a decision by first setting the decision type field to one of the above decision values, and then set the corresponding attributes field shown below:

", "$schema": "http://json-schema.org/draft-07/schema#", "title": "Decision" }