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Module Netlog

module Netlog: sig .. end

Basic logging facility

The purpose of this module is to define a mutable logging function which ensures to be always pointing to a valid logging implementation. By default, the function prints the messages to stderr, prepended by a timestamp. In Netplex context, the implementation is changed so that the Netplex logger is used instead (see Netplex_log), and the log and logf functions below have the same effect as the counterparts in Netplex_cenv with the same name.

type level = [ `Alert | `Crit | `Debug | `Emerg | `Err | `Info | `Notice | `Warning ] 

The log levels (syslog-like)

type logger = level -> string -> unit 

A logging function takes a level, and the message

val channel_logger : Stdlib.out_channel -> level -> logger

channel_logger ch lev: Prints all messages with a level of lev and higher to the channel ch. The output buffer is flushed after each message,

val current_logger : logger Stdlib.ref

The variable containing the current logger function. Defaults to channel_logger stderr `Debug at program startup. Assign something else to this variable in order to change the log destination or the log level.

Note that the function modifies current_logger so log messages are forwarded to the Netplex logger. It is then the Netplex framework that determines log destination and level.

val log : level -> string -> unit

Writes a log message

val logf : level -> ('a, unit, string, unit) Stdlib.format4 -> 'a

Writes a log message like printf

val level_weight : level -> int

A number correspondig to the level

val level_of_string : string -> level
val string_of_level : level -> string

Convert level names to strings and vice versa

val level_names : string array

The level names indexed by weight

type format = [ `ISO | `Std ] 
val format_timestamp : format -> int -> float * int -> string

format_timestamp fmt digits (seconds,nanos): Formats the timestamp (seconds,nanos) and returns the string. Pass in digits the number of digits for fractional seconds.

  • `Std: This is the "%c" format of Netdate
  • `ISO: ISO-8601 format
val current_formatter : (float * int -> string) Stdlib.ref

The current timestamp formatter

Example: Change the format of timestamps to ISO with a precision of milliseconds:

        Netlog.current_formatter := Netlog.format_timestamp `ISO 3
module Debug: sig .. end
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