package sihl-queue

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package sihl-queue
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type instance_status = Sihl.Contract.Queue.instance_status =
  1. | Pending
  2. | Succeeded
  3. | Failed
  4. | Cancelled

instance_status is the status of the job on the queue.

type instance = Sihl.Contract.Queue.instance = {
  1. id : string;
  2. name : string;
  3. input : string;
  4. tries : int;
  5. next_run_at : Ptime.t;
  6. max_tries : int;
  7. status : instance_status;
  8. last_error : string option;
  9. last_error_at : Ptime.t option;
}

instance is a queued job with a concrete input.

type 'a job = 'a Sihl.Contract.Queue.job = {
  1. name : string;
  2. encode : 'a -> string;
  3. decode : string -> ('a, string) Result.t;
  4. handle : 'a -> (unit, string) Result.t Lwt.t;
  5. failed : string -> instance -> unit Lwt.t;
  6. max_tries : int;
  7. retry_delay : Ptime.Span.t;
}

'a job is a job that can be dispatched where 'a is the type of the input.

type job' = Sihl.Contract.Queue.job' = {
  1. name : string;
  2. handle : string -> (unit, string) Result.t Lwt.t;
  3. failed : string -> instance -> unit Lwt.t;
  4. max_tries : int;
  5. retry_delay : Ptime.Span.t;
}

job' is a helper type that is used to remove the input type from job. Use job' to register jobs.

val hide : 'a job -> job'

hide job returns a job' that can be registered with the queue service. It hides the input type of the job. A job' can be registered but not dispatched.

val create_job : ('a -> (unit, string) Stdlib.result Lwt.t) -> ?max_tries:int -> ?retry_delay:Ptime.span -> ?failed:(string -> instance -> unit Lwt.t) -> ('a -> string) -> (string -> ('a, string) Result.t) -> string -> 'a job

create_job ?max_tries ?retry_delay ?failed handle encode decode name returns a job that can be placed on the queue (dispatched) for later processing.

max_tries is the maximum times a job can fail. If a job fails max_tries number of times, the status of the job becomes Failed. By default, a job can fail 5 times.

retry_delay is the time span between two retries. By default, this value is one minute.

failed is the error handler that is called when handle returns an error or raises an exception. By default, this function does nothing. Use failed to clean up resources or raise some error in a monitoring system in case a job fails.

handle is the function that is called with the input when processing the job. If an exception is raised, the exception is turned into Error.

encode is called right after dispatching a job. The provided input data is encoded as string which is used for persisting the queue.

decode is called before starting to process a job. decode turns the persisted string into the input data that is passed to the handle function.

name is the name of the job, it has to be unique among all registered jobs.

val pp_job : (Stdlib.Format.formatter -> 'a -> unit) -> Stdlib.Format.formatter -> 'a job -> unit
val pp_job' : Stdlib.Format.formatter -> job' -> unit
val pp_instance : Stdlib.Format.formatter -> instance -> unit
val should_run : instance -> Ptime.t -> bool

should_run job now returns true if the queued job should run now, false if not. If a queued job should run it will be processed by any idle worker as soon as possible.

val log_src : Logs.src
module InMemory : sig ... end
module MariaDb : sig ... end
module PostgreSql : sig ... end