Shell/worker: export functor result signature
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@ -57,12 +57,186 @@ module type TYPES = sig
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val pp : Format.formatter -> view -> unit
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end
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module type T = sig
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module Name: NAME
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module Event: EVENT
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module Request: REQUEST
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module Types: TYPES
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(** A handle to a specific worker, parameterized by the type of
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internal message buffer. *)
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type 'kind t
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(** A handle to a table of workers. *)
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type 'kind table
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(** Internal buffer kinds used as parameters to {!t}. *)
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type 'a queue and bounded and infinite
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type dropbox
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(** Supported kinds of internal buffers. *)
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type _ buffer_kind =
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| Queue : infinite queue buffer_kind
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| Bounded : { size : int } -> bounded queue buffer_kind
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| Dropbox :
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{ merge : (dropbox t ->
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any_request ->
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any_request option ->
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any_request option) }
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-> dropbox buffer_kind
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and any_request = Any_request : _ Request.t -> any_request
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(** Create a table of workers. *)
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val create_table : 'kind buffer_kind -> 'kind table
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(** An error returned when trying to communicate with a worker that
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has been closed. *)
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type Error_monad.error += Closed of Name.t
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(** The callback handlers specific to each worker instance. *)
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module type HANDLERS = sig
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(** Placeholder replaced with {!t} with the right parameters
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provided by the type of buffer chosen at {!launch}.*)
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type self
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(** Builds the initial internal state of a worker at launch.
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It is possible to initialize the message queue.
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Of course calling {!state} will fail at that point. *)
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val on_launch :
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self -> Name.t -> Types.parameters -> Types.state Lwt.t
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(** The main request processor, i.e. the body of the event loop. *)
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val on_request :
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self -> 'a Request.t -> 'a tzresult Lwt.t
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(** Called when no request has been made before the timeout, if
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the parameter has been passed to {!launch}. *)
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val on_no_request :
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self -> unit tzresult Lwt.t
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(** A function called when terminating a worker. *)
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val on_close :
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self -> unit Lwt.t
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(** A function called at the end of the worker loop in case of an
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abnormal error. This function can handle the error by
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returning [Ok ()], or leave the default unexpected error
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behaviour by returning its parameter. A possibility is to
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handle the error for ad-hoc logging, and still use
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{!trigger_shutdown} to kill the worker. *)
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val on_error :
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self ->
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Request.view ->
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Worker_types.request_status ->
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error list ->
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unit tzresult Lwt.t
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(** A function called at the end of the worker loop in case of a
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successful treatment of the current request. *)
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val on_completion :
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self ->
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'a Request.t -> 'a ->
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Worker_types.request_status ->
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unit Lwt.t
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end
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(** Creates a new worker instance.
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Parameter [queue_size] not passed means unlimited queue. *)
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val launch :
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'kind table -> ?timeout:float ->
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Worker_types.limits -> Name.t -> Types.parameters ->
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(module HANDLERS with type self = 'kind t) ->
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'kind t Lwt.t
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(** Triggers a worker termination and waits for its completion.
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Cannot be called from within the handlers. *)
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val shutdown :
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_ t -> unit Lwt.t
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(** Adds a message to the queue and waits for its result.
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Cannot be called from within the handlers. *)
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val push_request_and_wait :
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_ queue t -> 'a Request.t -> 'a tzresult Lwt.t
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(** Adds a message to the queue. *)
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val push_request :
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_ queue t -> 'a Request.t -> unit Lwt.t
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(** Adds a message to the queue immediately.
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Returns [false] if the queue is full. *)
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val try_push_request_now :
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bounded queue t -> 'a Request.t -> bool
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(** Adds a message to the queue immediately. *)
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val push_request_now :
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infinite queue t -> 'a Request.t -> unit
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(** Sets the current request. *)
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val drop_request :
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dropbox t -> 'a Request.t -> unit
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(** Detects cancelation from within the request handler to stop
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asynchronous operations. *)
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val protect :
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_ t ->
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?on_error: (error list -> 'b tzresult Lwt.t) ->
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(unit -> 'b tzresult Lwt.t) ->
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'b tzresult Lwt.t
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(** Exports the canceler to allow cancelation of other tasks when this
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worker is shutdowned or when it dies. *)
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val canceler : _ t -> Lwt_canceler.t
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(** Triggers a worker termination. *)
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val trigger_shutdown : _ t -> unit
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(** Recod an event in the backlog. *)
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val record_event : _ t -> Event.t -> unit
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(** Record an event and make sure it is logged. *)
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val log_event : _ t -> Event.t -> unit Lwt.t
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(** Access the internal state, once initialized. *)
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val state : _ t -> Types.state
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(** Access the event backlog. *)
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val last_events : _ t -> (Logging.level * Event.t list) list
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(** Introspect the message queue, gives the times requests were pushed. *)
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val pending_requests : _ queue t -> (Time.t * Request.view) list
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(** Get the running status of a worker. *)
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val status : _ t -> Worker_types.worker_status
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(** Get the request being treated by a worker.
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Gives the time the request was pushed, and the time its
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treatment started. *)
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val current_request : _ t -> (Time.t * Time.t * Request.view) option
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(** Introspect the state of a worker. *)
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val view : _ t -> Types.view
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(** Lists the running workers in this group.
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After they are killed, workers are kept in the table
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for a number of seconds given in the {!Worker_types.limits}. *)
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val list : 'a table -> (Name.t * 'a t) list
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end
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module Make
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(Name : NAME)
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(Event : EVENT)
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(Request : REQUEST)
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(Types : TYPES) = struct
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module Name = Name
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module Event = Event
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module Request = Request
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module Types = Types
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let base_name = String.concat "." Name.base
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type message = Message: 'a Request.t * 'a tzresult Lwt.u option -> message
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@ -122,11 +122,12 @@ end
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At that point, all the types are fixed and introspectable,
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but the actual parameters and event handlers can be tweaked
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for each individual worker. *)
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module Make
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(Name : NAME)
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(Event : EVENT)
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(Request : REQUEST)
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(Types : TYPES) : sig
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module type T = sig
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module Name: NAME
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module Event: EVENT
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module Request: REQUEST
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module Types: TYPES
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(** A handle to a specific worker, parameterized by the type of
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internal message buffer. *)
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@ -288,5 +289,11 @@ module Make
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After they are killed, workers are kept in the table
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for a number of seconds given in the {!Worker_types.limits}. *)
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val list : 'a table -> (Name.t * 'a t) list
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end
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module Make (Name : NAME) (Event : EVENT) (Request : REQUEST) (Types : TYPES)
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: T with module Name = Name
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and module Event = Event
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and module Request = Request
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and module Types = Types
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