How to get the result of an Activity Execution in Go

The ExecuteActivity API call returns an instance of workflow.Future which has the following two methods:

• Get(): Takes an instance of the workflow.Context, that was passed to the Activity Execution, and a pointer as parameters. The variable associated with the pointer is populated with the Activity Execution result. This call blocks until the results are available.
• IsReady(): Returns true when the result of the Activity Execution is ready.

Call the Get() method on the instance of workflow.Future to get the result of the Activity Execution. The type of the result parameter must match the type of the return value declared by the Activity function.

func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (YourWorkflowResponse, error) {
 // ...
 future := workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam)
 var yourActivityResult YourActivityResult
 if err := future.Get(ctx, &yourActivityResult); err != nil {
   // ...
 }
 // ...
}

Use the IsReady() method first to make sure the Get() call doesn't cause the Workflow Execution to wait on the result.

func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (YourWorkflowResponse, error) {
 // ...
 future := workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam)
 // ...
 if(future.IsReady()) {
   var yourActivityResult YourActivityResult
   if err := future.Get(ctx, &yourActivityResult); err != nil {
     // ...
   }
 }
 // ...
}

It is idiomatic to invoke multiple Activity Executions from within a Workflow. Therefore, it is also idiomatic to either block on the results of the Activity Executions or continue on to execute additional logic, checking for the Activity Execution results at a later time.