TaskOrchestration

核心编程模型之 TaskOrchestration

src\DurableTask.Core\TaskOrchestration.cs

TaskOrchestration.cs 中定义了三个方法：

Execute()
RaiseEvent()
GetStatus()

Execute() 方法

public abstract Task<string> Execute(OrchestrationContext context, string input);

方法实现为：

public override async Task<string> Execute(OrchestrationContext context, string input)
        {
            var parameter = DataConverter.Deserialize<TInput>(input);
            TResult result;
            try
            {
                result = await RunTask(context, parameter);
            }
            catch (Exception e) when (!Utils.IsFatal(e) && !Utils.IsExecutionAborting(e))
            {
                string details = null;
                FailureDetails failureDetails = null;
                if (context.ErrorPropagationMode == ErrorPropagationMode.SerializeExceptions)
                {
                    details = Utils.SerializeCause(e, DataConverter);
                }
                else
                {
                    failureDetails = new FailureDetails(e);
                }

                throw new OrchestrationFailureException(e.Message, details)
                {
                    FailureDetails = failureDetails,
                };
            }

            return DataConverter.Serialize(result);
        }

RunTask() 方法是个抽象方法。

public abstract Task<TResult> RunTask(OrchestrationContext context, TInput input);

默认的 DataConverter 是 json：

    public abstract class TaskOrchestration<TResult, TInput, TEvent, TStatus> : TaskOrchestration
    {
        /// <summary>
        /// Creates a new TaskOrchestration with the default DataConverter
        /// </summary>
        protected TaskOrchestration()
        {
            DataConverter = JsonDataConverter.Default;
        }

        /// <summary>
        /// The DataConverter to use for input and output serialization/deserialization
        /// </summary>
        public DataConverter DataConverter { get; protected set; }

RaiseEvent() 方法

public abstract void RaiseEvent(OrchestrationContext context, string name, string input);

方法实现为：

public override void RaiseEvent(OrchestrationContext context, string name, string input)
{
  var parameter = DataConverter.Deserialize<TEvent>(input);
  OnEvent(context, name, parameter);
}

OnEvent() 是一个空实现。

        public virtual void OnEvent(OrchestrationContext context, string name, TEvent input)
        {
            // do nothing
        }

GetStatus() 方法

public abstract string GetStatus();