Activities

An activity is defined as an item on an external queue of work, that a workflow can wait for.

In this example the workflow will wait for activity-1, before proceeding. It also passes the value of data.Value1 to the activity, it then maps the result of the activity to data.Value2.

Then we create a worker to process the queue of activity items. It uses the GetPendingActivity method to get an activity and the data that a workflow is waiting for.

public class ActivityWorkflow : IWorkflow<MyData>
{
    public void Build(IWorkflowBuilder<MyData> builder)
    {
        builder                
            .StartWith<HelloWorld>()
            .Activity("activity-1", (data) => data.Value1)
                .Output(data => data.Value2, step => step.Result)
            .Then<PrintMessage>()
                .Input(step => step.Message, data => data.Value2);
    }

}
...

var activity = host.GetPendingActivity("activity-1", "worker1", TimeSpan.FromMinutes(1)).Result;

if (activity != null)
{
    Console.WriteLine(activity.Parameters);
    host.SubmitActivitySuccess(activity.Token, "Some response data");
}

The JSON representation of this step would look like this

{
    "Id": "activity-step",
    "StepType": "WorkflowCore.Primitives.Activity, WorkflowCore",
    "Inputs": 
    {
        "ActivityName": "\"activity-1\"",
        "Parameters": "data.Value1" 
    },
    "Outputs": { "Value2": "step.Result" }
}

JSON / YAML API

The Activity step can be configured using inputs as follows

Field	Description
CancelCondition	Optional expression to specify a cancel condition
Inputs.ActivityName	Expression to specify the activity name
Inputs.Parameters	Expression to specify the parameters to pass the activity worker
Inputs.EffectiveDate	Optional expression to specify the effective date

{
    "Id": "MyActivityStep",
    "StepType": "WorkflowCore.Primitives.Activity, WorkflowCore",
    "NextStepId": "...",
    "CancelCondition": "...",
    "Inputs": {
        "ActivityName": "\"my-activity\"",
        "Parameters": "data.SomeValue"
    }
}

Id: MyActivityStep
StepType: WorkflowCore.Primitives.Activity, WorkflowCore
NextStepId: "..."
CancelCondition: "..."
Inputs:
  ActivityName: '"my-activity"'
  EventKey: '"Key1"'
  Parameters: data.SomeValue