B0_std.Log
Program log.
Support for program logging. Not to be used by build logic.
The module is modelled after Logs
logging, see this quick introduction. It can be made to log on a Logs
source, see here.
The type for reporting levels. They are meant to be used as follows:
Quiet
doesn't report anything.Stdout
can be used for the standard output or console of an application. Using this instead of stdout
directly allows the output to be silenced by Quiet
which may be desirable, or not.Stderr
can be used for the standard error or error console of an application. Using this instead of stderr
directly allows the output to be silenced by Quiet
which may be desirable, or not.Error
is an error condition that prevents the program from running.Warning
is a suspicious condition that does not prevent the program from running normally but may eventually lead to an error condition.Info
is a condition that allows the program user to get a better understanding of what the program is doing.Debug
is a condition that allows the program developer to get a better understanding of what the program is doing.val level : unit -> level
level ()
is the current reporting level. The initial level is set to Warning
.
val set_level : level -> unit
set_level l
sets the current reporting level to l
.
val level_to_string : level -> string
level_to_string l
converts l
to a string representation.
val level_of_string : string -> (level, string) Stdlib.result
level_of_string s
parses a level from s
according to the representation of level_to_string
.
type ('a, 'b) msgf =
(?header:string ->
('a, Stdlib.Format.formatter, unit, 'b) Stdlib.format4 ->
'a) ->
'b
The type for client specified message formatting functions. See Logs.msgf
.
header
interpretation is up to the reported but None
should automatially output headers that depend on the level and Some ""
should not output any header leaving full control to the client.
type 'a log = ('a, unit) msgf -> unit
The type for log functions. See Logs.log
.
val quiet : 'a log
quiet
is msg Quiet
.
val stdout : 'a log
stdout
is msg Stdout
.
val stderr : 'a log
stderr
is msg Stderr
.
val err : 'a log
err
is msg Error
.
val warn : 'a log
warn
is msg Warning
.
val info : 'a log
info
is msg Info
.
val debug : 'a log
debug
is msg Debug
.
kmsg k level m
logs m
with level level
and continues with k
.
result
value Error
messagesval if_error :
?level:level ->
?header:string ->
use:'a ->
('a, string) Stdlib.result ->
'a
if_error ~level ~use v r
is:
v
, if r
is Ok v
use
and e
is logged with level
(defaults to Error
), if r
is Error e
.val if_error' :
?level:level ->
?header:string ->
use:'a ->
('a, string) Stdlib.result ->
('a, 'b) Stdlib.result
val if_error_pp :
?level:level ->
?header:string ->
'b Fmt.t ->
use:'a ->
('a, 'b) Stdlib.result ->
'a
if_error_pp ~level pp ~use r
is
v
, if r
is Ok v
.use
and e
is logged with level
(defaults to Error
) using pp
, if r
is Error e
.val if_error_pp' :
?level:level ->
?header:string ->
'b Fmt.t ->
use:'a ->
('a, 'b) Stdlib.result ->
('a, 'b) Stdlib.result
if_error_pp'
is if_error_pp'
wrapped by Result.ok
val time :
?level:level ->
('a -> (('b, Stdlib.Format.formatter, unit, 'a) Stdlib.format4 -> 'b) -> 'a) ->
(unit -> 'a) ->
'a
time ~level m f
logs m
with level level
(defaults to Info
) and the time f ()
took as the log header.
Note. The current log level is determined after f
has been called this means f
can change it to affect the log operation. This allows f
to be the main function of your program and let it set the log level.
val spawn_tracer : level -> Os.Cmd.spawn_tracer
spawn_tracer level
is a spawn tracer that logs with level level
. If level
is Log.level.Quiet
this is B0_std.Os.Cmd.spawn_tracer_nop
.
The following function allows to change the logging backend. Note that in this case monitoring and level functions are no longer relevant.
The type for the basic logging function. The function is never invoked with a level of Quiet
.
val kmsg_nop : kmsg
nop_kmsg
is a logger that does nothing.
val kmsg_default : kmsg
kmsg_default
is the default logger that logs messages on Fmt.stderr
except for Log.App
level which logs on Fmt.stdout
.
val set_kmsg : kmsg -> unit
set_kmsg kmsg
sets the logging function to kmsg
.