Skip to content

Instantly share code, notes, and snippets.

What would you like to do?
Sample of polling reader of EventStore.ClientAPI in F#
// RetryPolicy from
/// Returns an Async computation which evaluates the input computation until the specified condition is met
/// with delays between attempts dictated by the specified retry policy.
let pollUntil (rp:RetryPolicy) (condition:'a -> bool) (a:Async<'a>) : Async<'a option> =
(AsyncSeq.replicateInfiniteAsync a, RetryPolicy.delayStream rp)
||> AsyncSeq.interleaveChoice
|> AsyncSeq.tryPick (function Choice1Of2 a when condition a -> Some a | _ -> None)
// EventStore client
type Conn = string
type Position = int64
type Event = string
let readBatch (c:Conn) (p:Position) : Async<Event[] * Position> = failwith "TODO"
let stream (c:Conn) (p:Position) (rp:RetryPolicy) : AsyncSeq<Event[]> =
p |> AsyncSeq.unfoldAsync (readBatch c >> pollUntil rp (fun (es,_) -> es.Length > 0))
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.