Logs_cli
Cmdliner
support for Logs
.
See a full example.
val level :
?env:Cmdliner.Cmd.Env.info ->
?docs:string ->
unit ->
Logs.level option Cmdliner.Term.t
level ?env ?docs ()
is a term for three Cmdliner
options that can be used with Logs.set_level
. The options are documented under docs
(defaults to the default of Cmdliner.Arg.info
).
The options work as follows:
-v
or --verbose
, if it appears once, the value of the term is Some Logs.Info
and more than once Some Logs.Debug
.--verbosity=LEVEL
, the value of the term is l
where l
depends on on LEVEL
. Takes over the option -v
.-q
or --quiet
, the value of the term is None
. Takes over the -v
and --verbosity
options.Some Logs.warning
If env
is provided, the default value in case all options are absent can be overridden by the corresponding environment variable.
The following example shows how to setup Logs
and Fmt
so that logging is performed on standard outputs with ANSI coloring if these are tty
s. The command line interface provides options to control the use of colors and the log reporting level.
let hello _ msg =
Logs.app (fun m -> m "%s" msg);
Logs.info (fun m -> m "End-user information.");
Logs.debug (fun m -> m "Developer information.");
Logs.err (fun m -> m "Something bad happened.");
Logs.warn (fun m -> m "Something bad may happen in the future.");
if Logs.err_count () > 0 then 1 else 0
let setup_log style_renderer level =
Fmt_tty.setup_std_outputs ?style_renderer ();
Logs.set_level level;
Logs.set_reporter (Logs_fmt.reporter ())
(* Command line interface *)
open Cmdliner
let setup_log =
let env = Cmd.Env.info "TOOL_VERBOSITY" in
Term.(const setup_log $ Fmt_cli.style_renderer () $ Logs_cli.level ~env ())
let msg =
let doc = "The message to output." in
Arg.(value & pos 0 string "Hello horrible world!" & info [] ~doc)
let main () =
let cmd = Cmd.make (Cmd.info "tool") Term.(const hello $ setup_log $ msg) in
Cmd.eval' cmd
let () = if !Sys.interactive then () else exit (main ())