Module `Async_unix.Log`

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

type t

val sexp_of_t : t -> Ppx_sexp_conv_lib.Sexp.t

module type Global_intf = sig ... end: An interface for singleton logs.

module Make_global : functor () Global_intf: This functor can be called to generate "singleton" logging modules.

module Global : Global_intf: 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 get_time_source : t -> Async_unix__.Import.Synchronous_time_source.t: Changes the time source of the log, which controls the default timestamp on messages.

val set_time_source : t -> Async_unix__.Import.Synchronous_time_source.t -> unit

val get_transform : t -> (Message.t -> Message.t) option

Changes the transform function within log. This allows you to *synchronously* change things about the message at the time that they were written.

The transform function *will not* be called if the initial message is of a level that would not currently be logged.

The transform function *will* be called if even if there are no log outputs.

val set_transform : t -> (Message.t -> Message.t) option -> unit
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_unix__.Import.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_unix__.Import.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_unix__.Import.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 ] -> ?⁠time_source:Async_unix__.Import.Synchronous_time_source.t -> ?⁠transform:(Message.t -> Message.t) -> unit -> t: Creates a new log. See set_level, set_on_error, set_output, set_time_source, and set_transform for more.

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.

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_unix__.Import.Deferred.t) -> 'a Async_unix__.Import.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_unix__.Import.Deferred.t) -> 'b Async_unix__.Import.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.

This will return false if there are no outputs for the log, unless there is a transform set.

module Reader : sig ... end

module For_testing : sig ... end