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73 lines
1.5 KiB
OCaml
73 lines
1.5 KiB
OCaml
(** Expose metrics over HTTP in the prometheus format *)
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type tags = (string * string) list
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(** Registry for metrics. *)
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module Registry : sig
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type t
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(** The registry contains a group of metrics *)
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val create : unit -> t
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val emit : Buffer.t -> t -> unit
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(** Write metrics into the given buffer. The buffer will be
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cleared first thing. *)
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val emit_str : t -> string
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end
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val global : Registry.t
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(** Counters *)
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module Counter : sig
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type t
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(** A counter, monotonically increasing *)
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val create : Registry.t -> ?tags:tags -> ?descr:string -> string -> t
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val incr : t -> unit
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val incr_by : t -> int -> unit
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val decr : t -> unit
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val decr_by : t -> int -> unit
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end
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(** Gauges *)
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module Gauge : sig
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type t
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(** A gauge, taking arbitrary values *)
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val create : Registry.t -> ?tags:tags -> ?descr:string -> string -> t
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val set : t -> int -> unit
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val incr : t -> unit
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val incr_by : t -> int -> unit
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val decr : t -> unit
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val decr_by : t -> int -> unit
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end
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module Histogram : sig
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type t
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(** Histogram *)
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val create :
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Registry.t ->
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?tags:tags ->
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?descr:string ->
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buckets:float list ->
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string ->
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t
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val add : t -> float -> unit
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end
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(* TODO:
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module Histogram : sig
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end
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*)
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val http_middleware : Registry.t -> Tiny_httpd.Middleware.t
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(** Middleware to get basic metrics about HTTP requests *)
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val add_route_to_server : Tiny_httpd.t -> Registry.t -> unit
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(** Add a "/metrics" route to the server *)
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val instrument_server : Tiny_httpd.t -> Registry.t -> unit
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(** Add middleware and route *)
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