Akka.Net shutting down doesn't wait for Serilog? - f#

Question

I have the following code and I had to add Threading.Thread.Sleep 5000 to wait for five seconds before shutdown the actor system. Otherwise, some of the Serilog loggings which write to a database will not save. Is there a way to make sure all the logging is done before exit the program?
open System
open Akka.FSharp
open Akka
type CRange = CRange of low: string * high: string
type ErrorMessage = string
type CError =
| LoginFailed of string // Optional reason
| CTimeOut of CRange list // new range
| CException of CRange list * exn
| CMessage of CRange list * ErrorMessage
type CTask =
CTask of
c: string *
username: string *
password: string *
proxyAddress: string *
cycle: DateTime *
issuerRange: CRange list *
filterTable: bool
type DoWork = Map<string, CTask -> Result<int * string, CError>>
type PartKeyCount = PartKeyCount of Key: string * Count: int
type PartGroupCount = PartGroupCount of Group: string list * Count: int
let system = System.create "ASystem" <| Configuration.load ()
let scheduler (actors: Actor.IActorRef list) task (mailbox: Actor<Result<int, CError>>) =
let newTask task range =
let (CTask(c, username, password, proxy, cycle, _, filter)) = task
CTask(c, username, password, proxy, cycle, range, filter)
let rec loop (list: CRange list list) running = actor {
let akkaName = mailbox.Self.Path.Name
printfn "%s scheduler loop (Running: %d Todo:%d)" akkaName running list.Length
let! m = mailbox.Receive ()
let sender = mailbox.Sender ()
printfn "%s received message %A from %A" akkaName m sender
match m with
| Ok _ ->
printfn "finished one"
match list with
| [] ->
if running = 1 then
//Log.Information("....")
Threading.Thread.Sleep 5000 // Wait for 5 seconds
mailbox.Context.System.Terminate() |> ignore
else
return! loop [] (running - 1)
| x :: xs ->
printfn "Finished one. Todo %d, running %d - %A. New task %A to %A" xs.Length running sender x sender
let t = newTask task x
sender.Tell(t, mailbox.Self) // <!
return! loop xs running
| _ -> ()
}
let groups = [(CRange ("A","A"), 1); (CRange ("B","B"), 1); (CRange ("C","C"), 1);
(CRange ("D","D"), 1); (CRange ("zzz","zzz"), 1)]
let n = if actors.Length < groups.Length then actors.Length else groups.Length
[0..n-1] |> List.iter(fun i ->
let t = newTask task [fst groups.[i]]
actors.[i].Tell(t, mailbox.Self))
let todo = groups |> Seq.skip n |> Seq.toList |> List.map(fun (x, _) -> [x])
Console.WriteLine("Groups {0}; Running {1}; Todo: {2}", groups.Length, n, todo.Length)
loop todo n
let processor (mailbox: Actor<CTask>) =
let rec loop () = actor {
let! m = mailbox.Receive ()
let sender = mailbox.Sender ()
let akkaName = mailbox.Self.Path.Name
printfn "* %s received message %A from %A" akkaName m sender
sender <! (Ok DateTime.Now.Millisecond :> Result<int, CError>)
printfn "* %s sent to %A." akkaName sender
return! loop()
}
loop ()
let spawnSystems n =
[1..n]
|> List.map(fun i ->
spawn system (sprintf "Processor%d" i) (processor)
)
let startAkka task actorNumber =
let actors = spawnSystems actorNumber
Threading.Thread.Sleep 1000
scheduler actors task
|> spawn system "Scheduler"
|> ignore
system.WhenTerminated.Wait()
[<EntryPoint>]
let main argv =
let c = "priv"
let cycle = new DateTime(2020, 1, 1)
let username, password = "username", "password"
let task = CTask(c, username, password, "", cycle, [], false)
startAkka task 2
0

Answer 1

Before shutting down the Akka.net actor system, you need to tell Serilog to "flush" any buffered messages. There are different ways of doing that depending on how you're using Serilog.
The easiest way to use Serilog is via the global Log class:
Log.Logger = new LoggerConfiguration()
.WriteTo.File(#"myapp\log.txt")
.CreateLogger();
Log.Information("Hello!");
// Your application runs, then:
Log.CloseAndFlush();
If don't use the static Log class, you will use LoggerConfiguration to create an ILogger and dispose that instance.
using (var log = new LoggerConfiguration()
.WriteTo.File(#"myapp\log.txt")
.CreateLogger())
{
log.Information("Hello again!");
// Your app runs, then disposal of `log` flushes any buffers
}
You can see more details on the Lifecycle of Loggers.