Log (async_extended.Async_extended.Std.Log)

include Async.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 = Async_unix.Log.Level

module Message = Async_unix.Log.Message

module Rotation = Async_unix.Log.Rotation

module Output = Async_unix.Log.Output

module Blocking = Async_unix.Log.Blocking

type t

include sig ... end

val sexp_of_t : t ‑> Base.Sexp.t

module type Global_intf : sig ... end

An interface for singleton logs.

module Make_global = Async_unix.Log.Make_global

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

module Global = Async_unix.Log.Global

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_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

Creates 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

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

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

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

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

Generalized printf-style logging.

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

Log sexps directly.

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

Logging of string values.

val message : t ‑> Message.t ‑> unit

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.

module Reader = Async_unix.Log.Reader