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Module Netplex_main

module Netplex_main: sig .. end
Main program for Netplex servers

type cmdline_config 
val args : ?defaults:cmdline_config ->
unit -> (Arg.key * Arg.spec * Arg.doc) list * cmdline_config
let (opt_list, cmdline_cfg) = args(): Returns opt_list for inclusion in the Arg.parse option list. The effects made available by the returned cmdline_cfg value.

The defaults (unless overridden by defaults): The config file is derived from the name of the executable (by appending .conf instead of the current extension). There is no config tree.

defaults : The default argument values
val create : ?config_filename:string ->
?config_tree:Netplex_types.config_tree ->
?pidfile:string option ->
?foreground:bool -> unit -> cmdline_config
Creates the command-line configuration object.

By setting config_tree a special configuration can be injected - the file config_filename is not loaded in this case (but may still appear in error messages)

val modify : ?config_filename:string ->
?config_tree:Netplex_types.config_tree ->
?pidfile:string option ->
?foreground:bool ->
cmdline_config -> cmdline_config
Modifies the command-line configuration object
val config_filename : cmdline_config -> string
Returns the filename of the configuration file, or the default if it has not been set on the command-line
val config_filename_opt : cmdline_config -> string option
Returns the filename of the configuration file, or None if it has not been set on the command-line
val config_tree_opt : cmdline_config -> Netplex_types.config_tree option
Returns the tree of the configuration file, or None if it has not been set by create or modify. Note that args never sets the config tree.
val pidfile : cmdline_config -> string option
Returns the location of the PID file (if any)
val foreground : cmdline_config -> bool
Returns whether the daemon runs in the foreground
val startup : ?late_initializer:(Netplex_types.config_file ->
Netplex_types.controller -> unit) ->
?config_parser:(string -> Netplex_types.config_file) ->
Netplex_types.parallelizer ->
Netplex_types.logger_factory list ->
Netplex_types.workload_manager_factory list ->
Netplex_types.processor_factory list -> cmdline_config -> unit
Establishes a configuration and starts the Netplex daemon.

If a ready-made configuration tree is included in the passed configuration it is taken as the configuration. If otherwise only the name of the config file is available, this file is parsed. Fails with Netplex_config.Config_error when an error in the configuration is detected.

The late_initializer is called after the Netplex controller has been fully initialized, and before the main event loop is entered. You can perform here further initializations, e.g. starting helper threads.

The config_parser is by default Netplex_config.read_config_file. You can override it by whatever parser you would like to use. The parser is only used if a configuration tree is unavailable, and the configuration needs to be loaded from a file.

As side-effect, the current logger of the Netlog module is set to selected Netplex logger. Note that this setting remains active even after startup returns to the caller. Also note that log messages submitted via Netlog appear as from component "netplex.other" if they are sent from outside of a container.

It is changed to / as working directory (as required for a daemon).

val run : ?config_parser:(string -> Netplex_types.config_file) ->
late_initializer:(Netplex_types.config_file -> Netplex_types.controller -> 'a) ->
extract_result:(Netplex_types.controller -> 'a -> 'b) ->
Netplex_types.parallelizer ->
Netplex_types.logger_factory list ->
Netplex_types.workload_manager_factory list ->
Netplex_types.processor_factory list -> cmdline_config -> 'b
Similar to startup, but this function is tailored for Netplex systems that compute results (e.g. Netmulticore jobs). In this scenario, it is not sufficient to just fire off child processes, but you also want to return a result to the caller once the processes have finished their tasks. One consequence of this is that you cannot daemonize the program - it always runs in the foreground (no matter whether -fg is given or not).

run expects that the caller passes a function extract_result. This function is invoked once the Netplex system is done, and the user can extract the final result from the controller. The result of extract_result is also the result of run.

At the moment extract_result is invoked, the child processes are already terminated. They should have put their result at a place that is in the controller, or can be reached with the help of the controller. The controller functionality is still fully available.

Note that the controller is shut down as soon as extract_result returns. Further interactions with the controller are not possible.

The late_initializer is now obligatory for typing reasons (so you can get the result of the late_initializer from extract_result). If you don't need it, just return ().

The working directory is left unchanged.


The typical main program for a Netplex server system looks like:

   let my_factories = ...

   let start() =
    let opts, cmdconf = Netplex_main.args() in
      (fun s -> raise(Arg.Bad ("Unknown arg: " ^ s))) 
      "usage: protoserver";
    let par = in  (* or *)

   Sys.set_signal Sys.sigpipe Sys.Signal_ignore;

This main program enables:

  • The standard command-line arguments -conf, -pid and -fg are understood
  • The configuration file is parsed
  • The configuration can refer to all loggers and workload managers coming with Netplex
  • The parallelizer is selected: Here, it is multi-processing (Netplex_mp). One could also select multi-threading (Netplex_mt)
  • The processors defined by my_factories are made available for connection processing

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