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Make gettime a labelled argument in the new API #67

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Make gettime a labelled argument in the new API #67

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6 changes: 3 additions & 3 deletions lwt/prometheus_lwt.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -22,13 +22,13 @@ end
module Gauge = struct
let track_in_progress = Prometheus.Gauge.track_inprogress

let set_time = Prometheus.Gauge.time
let set_time ~gettime t fn = Prometheus.Gauge.time t gettime fn
end

module Summary = struct
let observe_time = Prometheus.Summary.time
let observe_time ~gettime t fn = Prometheus.Summary.time t gettime fn
end

module Histogram (H : Prometheus.HISTOGRAM) = struct
let observe_time = H.time
let observe_time ~gettime t fn = H.time t gettime fn
end
12 changes: 6 additions & 6 deletions lwt/prometheus_lwt.mli
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Original file line number Diff line number Diff line change
Expand Up @@ -33,17 +33,17 @@ module Gauge : sig
val track_in_progress : Prometheus.Gauge.t -> (unit -> 'a Lwt.t) -> 'a Lwt.t
(** [track_in_progress t f] increases [t] by one while [f ()] is running. *)

val set_time : Prometheus.Gauge.t -> (unit -> float) -> (unit -> 'a Lwt.t) -> 'a Lwt.t
(** [set_time t gettime f] calls [gettime ()] before and after executing [f ()] and
val set_time : gettime:(unit -> float) -> Prometheus.Gauge.t -> (unit -> 'a Lwt.t) -> 'a Lwt.t
(** [set_time ~gettime t f] calls [gettime ()] before and after executing [f ()] and
sets [t] to the difference. *)
end

module Summary : sig
val observe_time : Prometheus.Summary.t -> (unit -> float) -> (unit -> 'a Lwt.t) -> 'a Lwt.t
(** [observe_time t gettime f] observes the duration of [f ()]. *)
val observe_time : gettime:(unit -> float) -> Prometheus.Summary.t -> (unit -> 'a Lwt.t) -> 'a Lwt.t
(** [observe_time ~gettime t f] observes the duration of [f ()]. *)
end

module Histogram (H : Prometheus.HISTOGRAM) : sig
val observe_time : H.t -> (unit -> float) -> (unit -> 'a Lwt.t) -> 'a Lwt.t
(** [observe_time t gettime f] observes the duration of [f ()]. *)
val observe_time : gettime:(unit -> float) -> H.t -> (unit -> 'a Lwt.t) -> 'a Lwt.t
(** [observe_time ~gettime t f] observes the duration of [f ()]. *)
end
2 changes: 1 addition & 1 deletion lwt/test/test_lwt.ml
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Expand Up @@ -46,7 +46,7 @@ let test_timers () =
let gauge = Gauge.v ~registry:core ~help:"Time taken" "gauge_time" in
let clock = ref 0.0 in
let gettime () = !clock in
Prometheus_lwt.Gauge.set_time gauge gettime
Prometheus_lwt.Gauge.set_time gauge ~gettime

@avsm avsm Aug 6, 2026

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If you want this to be optional in the future then the label should go before the fixed parameter shouldn’t it?

@talex5 talex5 Aug 7, 2026 •
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Yes, but that only matters when it's defined, not when it's used.

However, I think perhaps we should go further and get rid of these gettime arguments completely right now. I'll try that out in a new PR...

Update: done in #68

(fun () -> clock := !clock +. 1.5; Lwt.pause ())
>>= fun () ->
Prometheus_lwt.CollectorRegistry.collect registry >|= fun collected ->
Expand Down
20 changes: 10 additions & 10 deletions src/prometheus.ml
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Expand Up @@ -266,11 +266,11 @@ module Gauge = struct
Lwt.return_unit
)

let set_time t gettimeofday fn =
let start = gettimeofday () in
let set_time ~gettime t fn =
let start = gettime () in
Fun.protect fn
~finally:(fun () ->
let finish = gettimeofday () in
let finish = gettime () in
set t (finish -. start)
)
end
Expand Down Expand Up @@ -309,11 +309,11 @@ module Summary = struct
Lwt.return_unit
)

let observe_time t gettimeofday fn =
let start = gettimeofday () in
let observe_time ~gettime t fn =
let start = gettime () in
Fun.protect fn
~finally:(fun () ->
let finish = gettimeofday () in
let finish = gettime () in
observe t (finish -. start)
)
end
Expand Down Expand Up @@ -365,7 +365,7 @@ module type HISTOGRAM = sig
include METRIC
val observe : t -> float -> unit
val time : t -> (unit -> float) -> (unit -> 'a Lwt.t) -> 'a Lwt.t [@@deprecated]
val observe_time : t -> (unit -> float) -> (unit -> 'a) -> 'a
val observe_time : gettime:(unit -> float) -> t -> (unit -> 'a) -> 'a
end

let bucket_label = LabelName.v "le"
Expand Down Expand Up @@ -422,11 +422,11 @@ module Histogram (Buckets : BUCKETS) = struct
Lwt.return_unit
)

let observe_time t gettimeofday fn =
let start = gettimeofday () in
let observe_time ~gettime t fn =
let start = gettime () in
Fun.protect fn
~finally:(fun () ->
let finish = gettimeofday () in
let finish = gettime () in
observe t (finish -. start)
)
end
Expand Down
12 changes: 6 additions & 6 deletions src/prometheus.mli
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Original file line number Diff line number Diff line change
Expand Up @@ -180,8 +180,8 @@ module Gauge : sig
(** [time t gettime f] calls [gettime ()] before and after executing [f ()] and
increases the metric by the difference. *)

val set_time : t -> (unit -> float) -> (unit -> 'a) -> 'a
(** [set_time t gettime f] calls [gettime ()] before and after executing [f ()] and
val set_time : gettime:(unit -> float) -> t -> (unit -> 'a) -> 'a
(** [set_time ~gettime t f] calls [gettime ()] before and after executing [f ()] and
sets [t] to the difference. *)
end
(** A gauge is a metric that represents a single numerical value that can arbitrarily go up and down. *)
Expand All @@ -197,8 +197,8 @@ module Summary : sig
(** [time t gettime f] calls [gettime ()] before and after executing [f ()] and
observes the difference. *)

val observe_time : t -> (unit -> float) -> (unit -> 'a) -> 'a
(** [observe_time t gettime f] calls [gettime ()] before and after executing [f ()] and
val observe_time : gettime:(unit -> float) -> t -> (unit -> 'a) -> 'a
(** [observe_time ~gettime t f] calls [gettime ()] before and after executing [f ()] and
observes the difference. *)
end
(** A summary is a metric that records both the number of readings and their total.
Expand Down Expand Up @@ -235,8 +235,8 @@ module type HISTOGRAM = sig
(** [time t gettime f] calls [gettime ()] before and after executing [f ()] and
observes the difference. *)

val observe_time : t -> (unit -> float) -> (unit -> 'a) -> 'a
(** [observe_time t gettime f] calls [gettime ()] before and after executing [f ()] and
val observe_time : gettime:(unit -> float) -> t -> (unit -> 'a) -> 'a
(** [observe_time ~gettime t f] calls [gettime ()] before and after executing [f ()] and
observes the difference. *)
end

Expand Down
8 changes: 4 additions & 4 deletions tests/test.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -99,11 +99,11 @@ let test_sync_timers () =
let summary = Summary.v ~registry ~help:"Time taken" "summary_time" in
let clock = ref 0.0 in
let gettime () = !clock in
Gauge.set_time gauge gettime (fun () -> clock := !clock +. 1.3);
Gauge.set_time gauge gettime (fun () -> clock := !clock +. 1.5);
Gauge.set_time gauge ~gettime (fun () -> clock := !clock +. 1.3);
Gauge.set_time gauge ~gettime (fun () -> clock := !clock +. 1.5);
Gauge.track_in_progress gauge (fun () -> ());
Summary.observe_time summary gettime (fun () -> clock := !clock +. 0.5);
Summary.observe_time summary gettime (fun () -> clock := !clock +. 1.5);
Summary.observe_time summary ~gettime (fun () -> clock := !clock +. 0.5);
Summary.observe_time summary ~gettime (fun () -> clock := !clock +. 1.5);
CollectorRegistry.collect registry >|= fun collected ->
let output = Fmt.to_to_string TextFormat_0_0_4.output collected in
Alcotest.(check string) "Text output"
Expand Down