Log (async_unix.Async

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

include sig ... end

val sexp_of_t : t ‑> Sexplib.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

Set 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_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 ] ‑> t

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

val raw : ?⁠time:Core.Time.t ‑> ?⁠tags:(string * string) list ‑> t ‑> ('a, unit, string, unit) Core.format4 ‑> 'a

raw printf like logging for raw (no level) messages. Raw messages are still output with a timestamp.

val debug : ?⁠time:Core.Time.t ‑> ?⁠tags:(string * string) list ‑> t ‑> ('a, unit, string, unit) Core.format4 ‑> 'a

debug printf like logging at the `Debug log level

val info : ?⁠time:Core.Time.t ‑> ?⁠tags:(string * string) list ‑> t ‑> ('a, unit, string, unit) Core.format4 ‑> 'a

info printf like logging at the `Info log level

val error : ?⁠time:Core.Time.t ‑> ?⁠tags:(string * string) list ‑> t ‑> ('a, unit, string, unit) Core.format4 ‑> 'a

error printf like logging at the `Error log level

val printf : ?⁠level:Level.t ‑> ?⁠time:Core.Time.t ‑> ?⁠tags:(string * string) list ‑> t ‑> ('a, unit, string, unit) Core.format4 ‑> 'a

printf generalized printf style logging

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

sexp log sexps directly

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

string logging of string values

val message : t ‑> Message.t ‑> unit

message log a preexisting 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.