Add new option to daemonize: ?no_log_is_ok

The default value is `false` which is the previous behavior and the JSon parsing
is backwards compatible thanks to the annotation: `[@default false]`.

We still wait for the starting-timeout before checking that condition; this
seems that the behavior one would expect.

Author: smondet

src/lib/ketrew_daemonize.ml

@@ -34,6 +34,7 @@ module Run_parameters = struct
     using: [ `Nohup_setsid | `Python_daemon ];
     starting_timeout: Time.t;
     shell_command: string list;
+    no_log_is_ok: bool [@default false];
   } [@@deriving yojson]
 
   type running = {
@@ -69,10 +70,12 @@ let script_placeholder = "<script>"
 
 let create
   ?(starting_timeout=5.) ?(call_script=fun s -> [default_shell; s])
-  ?(using=`Nohup_setsid) ?(host=Ketrew_host.tmp_on_localhost) program =
+  ?(using=`Nohup_setsid) ?(host=Ketrew_host.tmp_on_localhost)
+  ?(no_log_is_ok=false)
+  program =
   let shell_command = call_script script_placeholder in
   let c =
-    {host; program; using; starting_timeout; shell_command } in
+    {host; program; using; starting_timeout; shell_command; no_log_is_ok } in
   `Long_running (name, `Created c |> serialize)
 
 let using_to_string = function
@@ -88,6 +91,7 @@ let log =
       "Program", Ketrew_program.log c.program;
       "Starting-timeout", f c.starting_timeout % s " sec.";
       "Call-script", OCaml.list quote c.shell_command;
+      "No-log-is-OK", OCaml.bool c.no_log_is_ok;
     ]
   | `Running rp -> [
       "Status", s "Running" % sp
@@ -314,6 +318,9 @@ let update run_parameters =
           | None when elapsed <= run.created.starting_timeout ->
             (* no log at all *)
             return (`Still_running new_run_parameters)
+          | None when run.created.no_log_is_ok ->
+            (* The caller explicitly asked not to care about the log file. *)
+            return (`Succeeded new_run_parameters)
           | None ->
             return (`Failed (new_run_parameters, "no log file"))
           | Some (`Success  date) ->

src/lib/ketrew_daemonize.mli

@@ -62,7 +62,7 @@ val create:
   ?starting_timeout:float ->
   ?call_script:(string -> string list) ->
   ?using:[ `Nohup_setsid | `Python_daemon] ->
-  ?host:Ketrew_host.t -> Ketrew_program.t ->
+  ?host:Ketrew_host.t -> ?no_log_is_ok: bool -> Ketrew_program.t ->
   [> `Long_running of string * string ]
 (** Create a “long-running” {!Ketrew_target.build_process} (run parameters
     are already serialized), see {!Ketrew_edsl.daemonize} for more

src/lib/ketrew_edsl.mli

@@ -239,6 +239,7 @@ val daemonize :
   ?call_script:(string -> string list) ->
   ?using:[`Nohup_setsid | `Python_daemon] ->
   ?host:Host.t ->
+  ?no_log_is_ok: bool ->
   Program.t ->
   Ketrew_target.Build_process.t
 (** Create a “daemonize” build process:
@@ -251,6 +252,11 @@ val daemonize :
       (default: [(fun script -> ["bash"; script])]).
     - [?using]: which method to use when damonizing on the [host]
     (see {!Ketrew_daemonize} for more details).
+    - [?no_log_is_ok]: consider that if the script run does not
+      produce a log file, the process still has succeeded (the default
+      and most common is [false], this can be useful for example when
+      the [Program.t] or [call_script] do something special over the
+      network).
 
 *)