如何查询 MailboxProcessor 状态？

Question

我想实现的是有一个代理负责操作项目的地图。那是一个简单的聚会，但现在我想知道如何查询该地图？

看看这段代码：

(* APPLIACATION STATE *)
let rec timeTable = Map.empty<string, TimeTableEntry>

let timeTableAgent = new TimeTableAgent(fun inbox -> 
   (* Internal functions *)
    let validateCronExpr task = 
        try
            task.CronExpr |> CrontabSchedule.Parse |> Success
        with | ex -> Failure "Cron expression is invalid."

    let rec schedule (timeTable : Map<string, TimeTableEntry>) (entry : TimeTableEntry) = 
        match validateCronExpr(entry) with
        | Failure err -> Failure err
        | Success _ -> match timeTable.ContainsKey(entry.Name) with
                       | false ->
                            let timeTable = timeTable.Add(entry.Name, entry)
                            Success "Task has been scheduled."
                       | true -> Failure "Task already exists."


   (* message processing *)
    let rec messageLoop (timeTable : Map<string, TimeTableEntry>) = 
        async {
            let! message = inbox.Receive()

            match message with
            | Command.Schedule (entry, reply) ->
                 let timeTable = timeTable.Add(entry.Name, entry)
                 reply.Reply(schedule timeTable entry)
            | Command.RecalculateOccurance (key, reply) -> reply.Reply(Success("OK"))
            | Command.UnSchedule (key, reply) -> reply.Reply(Success("OK"))

            return! messageLoop timeTable
     }

    // start the loop
    messageLoop timeTable
   )
timeTableAgent.Start()

let task = { Name = ""; CronExpr = "* * * * *"; Job = FileName("");    NextOccurance = DateTime.Now }


let messageAsync = timeTableAgent.PostAndAsyncReply(fun replyChannel -> Command.Schedule(task, replyChannel))

所以现在我想做这样的事情：

printf "%i" timeTable.Count

timeTable |> Map.iter (fun k v -> printf "%s" v.Name)

但项目计数为 0，查询没有 return 任何内容:(

我知道时间表的状态是不可变的，但我记得可以用新实例替换不可变变量....

有人可以帮我解决这个问题吗？

Answer 1

以您上面的示例为例，您可以执行以下操作。

在代理消息处理程序中添加另一个命令

(** Previous match clauses **)
| Command.GetCount(reply) -> 
    reply.Reply(timeTable.Count)

然后您可以使用该命令查询代理状态的视图

let timeTableCount = timeTableAgent.PostandReply(Command.GetCount)

如何查询 MailboxProcessor 状态？

How to query for the MailboxProcessor state?

f#

mailboxprocessor