package metrics

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Module type
Class type

Metric sources.


val v : ?doc:string -> ?duration:bool -> ?status:bool -> tags:'a Tags.t -> data:'b -> string -> ('a, 'b) src

v ?doc ~tags name is a new source, accepting arbitrary data points. name is the name of the source; it doesn't need to be unique but it is good practice to prefix the name with the name of your package or library (e.g. ""). doc is a documentation string describing the source, defaults to "undocumented". tags is the collection if (typed) tags which will be used to tag and index the measure and are used identify the various metrics. The source will be enabled on creation iff one of tag in tags has been enabled with enable_tag.

For instance, to create a metric to collect CPU and memory usage on various machines, indexed by PID, host name and IP address:

let src =
   let ipaddr = Tags.v Ipaddr.pp_hum in
   let tags = Tags.[string "host"; ipaddr "IP" ; int "PID" ; ] in
   let data () = Data.v [float "%CPU" (...); int "MEM" (...); ] in
   Src.v "top" ~tags ~data ~doc:"Information about processess"

Listing Sources

type t =
  1. | Src : ('a, 'b) src -> t

    The type for metric sources.

val list : unit -> t list

list () is the current exisiting source list.

val name : t -> string

name src is src's name.

val doc : t -> string

doc src is src's documentation string.

val tags : t -> string list

tags src is the list of src's tag names.

val data : t -> string list

fields src is the list of src's data field names. Note that these are updated dynamically, so a monitoring function has to be called first.

val equal : t -> t -> bool

equal src src' is true iff src and src' are the same source.

val compare : t -> t -> int

compare src src' is a total order on sources.

val duration : t -> bool

duration t is true iff t is a fn source and t requires automatic duration recording.

val status : t -> bool

status t is true iff t is a fn source and t requires automatic duration recording.

val pp : t Fmt.t

pp ppf src prints an unspecified representation of src on ppf.

val is_active : t -> bool

is_active t is true iff t is enabled.

val enable : t -> unit

enable src enables the metric source src.

val disable : t -> unit

disable src disables the metric source src.