private static bool TryHandleError(this ModelAction action,
JToken error,
StateMachineContext context,
out RetryPolicy?retry)
{
Debug.Assert(action != null);
Debug.Assert(context != null);
retry = null;
if (action.ErrorHandlers != null)
{
foreach (var handler in action.ErrorHandlers)
{
if (handler.Condition?.EvalPredicateExpr(error, context) ?? true)
{
error.Merge(context.Data, handler.ResultHandler, context);
retry = context.Workflow.Retries?.SingleOrDefault(r => r.Name.IsEqualTo(handler.RetryPolicy ?? string.Empty));
return(true);
}
}
}
return(false);
}
public static async Task <JToken> ExecuteAsync(this ModelAction action,
StateMachineContext context,
JToken input)
{
action.CheckArgNull(nameof(action));
context.CheckArgNull(nameof(context));
input.CheckArgNull(nameof(input));
await context.RecordObservableActionAsync(ObservableAction.BeforeAction,
() => new Dictionary <string, object>
{
{ "actionName", action.Name },
{ "actionType", action.GetType().FullName }
});
Func <StateMachineContext, JToken, Task <JToken> > executeFunc = action switch
{
InjectDataAction inject => inject.ExecuteAsync,
ParallelAction parallel => parallel.ExecuteAsync,
SequenceAction sequence => sequence.ExecuteAsync,
SendEventAction send => send.ExecuteAsync,
DelayAction delay => delay.ExecuteAsync,
InvokeSubflowAction subflow => subflow.ExecuteAsync,
InvokeFunctionAction function => function.ExecuteAsync,
ForEachAction forEach => forEach.ExecuteAsync,
_ => throw new NotImplementedException("Action behavior not implemented: " + action.GetType().FullName)
};
Debug.Assert(executeFunc != null);
var attempts = 0;
DateTimeOffset?start = null;
while (true)
{
try
{
var result = await executeFunc(context, input);
await context.RecordObservableActionAsync(ObservableAction.AfterAction,
() => new Dictionary <string, object>
{
{ "actionName", action.Name },
{ "actionType", action.GetType().FullName }
});
return(result);
}
catch (Exception ex)
{
if (action.TryHandleError(JObject.FromObject(ex),
context,
out RetryPolicy? retryPolicy))
{
if (retryPolicy == null)
{
return(JValue.CreateNull());
}
else
{
TimeSpan elapsedDelay;
if (start == null)
{
start = DateTimeOffset.UtcNow;
elapsedDelay = TimeSpan.Zero;
}
else
{
elapsedDelay = DateTimeOffset.UtcNow.Subtract(start.Value);
}
var retry = await retryPolicy.ShouldRetryAsync(context, ++attempts, elapsedDelay);
if (retry)
{
continue;
}
}
}
throw;
}
}
}