Plasma GitLab Archive
Projects Blog Knowledge

Module Rpc_netplex

module Rpc_netplex: sig .. end
Netplex support for RPC servers (TCP only)

val rpc_factory : configure:(Netplex_types.config_file -> Netplex_types.address -> 'a) ->
?socket_config:('a -> Rpc_server.socket_config) ->
?hooks:('a -> Netplex_types.processor_hooks) ->
?supported_ptypes:Netplex_types.parallelization_type list ->
name:string ->
setup:(Rpc_server.t -> 'a -> unit) -> unit -> Netplex_types.processor_factory
A factory for TCP-based RPC servers. In name the name of the processor is defined. This name can be referenced from the config file like:

    processor {
        type = "the passed [name]";

Parameters may be included in the processor section:

  • portmapper: This is a boolean parameter. If set to true, the Internet port is registered with the portmapper program. This will fail if there are several Internet bindings with distinct port numbers!
  • timeout: This is a float parameter. It sets the transport timeout of the RPC server (see Rpc_server.set_timeout). If a connection hangs for this number of seconds, it is shut down by the server.
Further parameters and subsections can be defined by the user. These parameters should be parsed and checked for correctness by the configure callback. The result of configure is also passed to setup and other optional functions. The configure function is called just before the service is added to Netplex (i.e. from the controller context).

The return value of configure can be of any type. This value exists once for every time the processor is instantiated (used) by a service. It is not only useful for passing configuration values down, but also for storing intermediate results while establishing the service.

The Rpc_server.t structure is created every time a new connection is accepted. Of course, this is done from the context of the container. The Rpc_server.t is created without any binding; the user must bind procedures in the setup function. This can be done by calling Rpc_server.bind or the ocamlrpcgen-generated function (by the -srv2 switch of ocamlrpcgen).

For example, a minimal factory for an RPC service may look like:

   let proc_ping () = ()     (* Trivial RPC procedure *)

   let my_factory() =
       ~factory:(fun _ _ -> ())
       ~setup:(fun rpc () ->
                 My_rpc_srv.bind ~proc_ping rpc

The setup function is also called once before a new connection is accepted to get a list of programs and procedures. The Rpc_server.t is a special one in this case, and one can test for it with the Rpc_server.is_dummy function.

socket_config : An optional function computing the socket configuration. By default, Rpc_server.default_socket_config is used. Special socket configuration would, for example, allow SSL.
hooks : An optional function returning the hooks to call. See Netplex_types.processor_hooks for documentation.
supported_ptypes : Which parallelization types are supported by the service. By default, both multi-processing and multi-threading are included in this list.
val debug_rpc_internals : bool Pervasives.ref
val debug_rpc_service : bool Pervasives.ref
These variables control debugging of Rpc_server. If set, the debug messages are sent to the Netplex logger. These variables must be set before an RPC connection is accepted.
This web site is published by Informatikbüro Gerd Stolpmann
Powered by Caml