/// <summary>
/// Two stage workflow execution start.
/// First create and initialise the workflow variables
/// Then schedule the first task
/// If this process is interrupted then the variables
/// </summary>
/// <param name="db"></param>
/// <param name="workflow"></param>
/// <param name="execution"></param>
/// <param name="history"></param>
/// <param name="decisions"></param>
private static void ProcessWorkflowExecutionStartedEvent(Database db, WorkflowObj workflow, Execution execution, History history, List <History> decisions)
{
var evt = WorkflowExecutionStartedEvent.Create(history);
CreateVariables(db, evt, execution, workflow);
// Ensure that the variables are set up for the first task
// This should never fail due to conflict
db.SubmitChanges();
// Scheduling the first task
var startTaskId = workflow.Tasks.Single(t => t.ActivityName == "start").Outflows.Single(o => o.Name == "Out").Target;
var startTask = workflow.Tasks.Single(t => t.TaskId == startTaskId);
CreateTaskScheduledEvent(db, execution, startTask, decisions);
}
/// <summary>
/// Create all workflow variables and initialise them from the workflow input data
/// </summary>
/// <param name="db"></param>
/// <param name="evt"></param>
/// <param name="execution"></param>
/// <param name="workflow"></param>
private static void CreateVariables(Database db, WorkflowExecutionStartedEvent evt, Execution execution, WorkflowObj workflow)
{
foreach (var vdefn in workflow.Variables)
{
// Get the initial value of the variable
JToken value = null;
if (!string.IsNullOrWhiteSpace(vdefn.Value.Path))
{
value = evt.Input.SelectToken(vdefn.Value.Path);
if (value == null) // The path expression failed
{
if (vdefn.Value.Required)
{
throw new ApplicationException("Uninitialised required variable - " + vdefn.Key);
}
}
// Empty default is equivalent to an explicit null
if (IsNullOrUndefined(value) && !string.IsNullOrWhiteSpace(vdefn.Value.Default))
{
value = JToken.Parse(vdefn.Value.Default);
}
}
// Empty literal is equivalent to an explicit null
else if (!string.IsNullOrWhiteSpace(vdefn.Value.Lit))
{
value = JToken.Parse(vdefn.Value.Lit);
}
// TODO: Check datatypes for validity
db.Variables.InsertOnSubmit(new Variable
{
ExecutionId = execution.ExecutionId,
Name = vdefn.Key,
Json = JsonConvert.SerializeObject(value)
});
}
}
