package async_unix

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package async_unix
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A library for general logging.

Although this module is fully Async-safe it exposes almost no Deferreds. This is partially a design choice to minimize the impact of logging in code, and partially the result of organic design (i.e., older versions of this interface did the same thing).

A (limited) Blocking module is supplied to accommodate the portion of a program that runs outside of Async.

module Level : sig ... end
module Message : sig ... end
module Rotation : sig ... end
module Output : sig ... end
module Blocking : sig ... end

Async programs often have a non-Async portion that runs before the scheduler begins to capture command line options, do setup, read configs, etc. This module provides limited global logging functions to be used during that period. Calling these functions after the scheduler has started will raise an exception. They otherwise behave similarly to the logging functions in the Async world.

type t
val sexp_of_t : t -> Ppx_sexp_conv_lib.Sexp.t
module type Global_intf = sig ... end

An interface for singleton logs.

This functor can be called to generate "singleton" logging modules.

Programs that want simplistic single-channel logging can open this module. It provides a global logging facility to a single output type at a single level. More nuanced logging can be had by using the functions that operate on a distinct Log.t type.

val set_level_via_param : t -> unit Core.Command.Param.t

Sets the log level via a flag, if provided.

val set_level : t -> Level.t -> unit

Messages sent at a level less than the current level will not be output.

val level : t -> Level.t

Returns the last level passed to set_level, which will be the log level checked as a threshold against the level of the next message sent.

val set_output : t -> Output.t list -> unit

Changes the output type of the log, which can be useful when daemonizing. The new output type will be applied to all subsequent messages.

val get_output : t -> Output.t list
val set_on_error : t -> [ `Raise | `Call of Core.Error.t -> unit ] -> unit

If `Raise is given, then background errors raised by logging will be raised to the monitor that was in scope when create was called. Errors can be redirected anywhere by providing `Call f.

val close : t -> unit Async_kernel.Deferred.t

Any call that writes to a log after close is called will raise.

val is_closed : t -> bool

Returns true if close has been called.

val flushed : t -> unit Async_kernel.Deferred.t

Returns a Deferred.t that is fulfilled when the last message delivered to t before the call to flushed is out the door.

val rotate : t -> unit Async_kernel.Deferred.t

Informs the current Outputs to rotate if possible.

val create : level:Level.t -> output:Output.t list -> on_error:[ `Raise | `Call of Core.Error.t -> unit ] -> t

Creates a new log. See set_level, set_on_error and set_output for more.

Printf-like logging for messages at each log level or raw (no level) messages. Raw messages still include a timestamp.

val raw : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> ('a, unit, string, unit) Core.format4 -> 'a
val debug : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> ('a, unit, string, unit) Core.format4 -> 'a
val info : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> ('a, unit, string, unit) Core.format4 -> 'a
val error : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> ('a, unit, string, unit) Core.format4 -> 'a
val printf : ?level:Level.t -> ?time:Core.Time.t -> ?tags:(string * string) list -> t -> ('a, unit, string, unit) Core.format4 -> 'a

Generalized printf-style logging.

Sexp logging for messages at each log level or raw (no level) messages. Raw messages still include a timestamp

val raw_s : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> Core.Sexp.t -> unit
val info_s : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> Core.Sexp.t -> unit
val error_s : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> Core.Sexp.t -> unit
val debug_s : ?time:Core.Time.t -> ?tags:(string * string) list -> t -> Core.Sexp.t -> unit
val sexp : ?level:Level.t -> ?time:Core.Time.t -> ?tags:(string * string) list -> t -> Core.Sexp.t -> unit

Generalized sexp-style logging.

val string : ?level:Level.t -> ?time:Core.Time.t -> ?tags:(string * string) list -> t -> string -> unit

Log a string directly.

val message : t -> Message.t -> unit

Log a pre-created message.

val surround_s : ?level:Level.t -> ?time:Core.Time.t -> ?tags:(string * string) list -> t -> Core.Sexp.t -> (unit -> 'a Async_kernel.Deferred.t) -> 'a Async_kernel.Deferred.t

surround t message f logs message and a UUID once before calling f and again after f returns or raises. If f raises, the second message will include the exception, and surround itself will re-raise the exception tagged with message. As usual, the logging happens only if level exceeds the minimum level of t.

val surroundf : ?level:Level.t -> ?time:Core.Time.t -> ?tags:(string * string) list -> t -> ('a, unit, string, (unit -> 'b Async_kernel.Deferred.t) -> 'b Async_kernel.Deferred.t) Core.format4 -> 'a
val would_log : t -> Level.t option -> bool

would_log returns true if a message at the given log level would be logged if sent immediately.

module Reader : sig ... end
module For_testing : sig ... end