Re: [Caml-list] library/framework needed for distributed programming in OCaml

["Lauri Alanko" <la@iki.fi>]

Hi.

I also had need of such a library when I started working on a  
distributed programming project, but as I couldn't find anything that  
fulfilled my requirements, I wrote my own.

The library is Lwt-based, and provides pretty straightforward remotely  
callable procedures:

type ('a, 'r) handle
val ($) : ('a, 'r) handle -> 'a -> 'r Lwt.t
val publish : ('a -> 'r Lwt.t) -> ('a, 'r) handle

The library is designed to work in a firewalled environment:  
firewalled nodes can join the distributed network by connecting to any  
accessible host of that network with an open listener. All messages  
between nodes are routed through the network.

type connection
val connect :
     ?host:string -> ?port:int -> unit -> connection Lwt.t
val listen :
     ?port:int -> unit -> unit Lwt.t

Initial values are obtained with "roots". A root (usually a handle, or  
a record or first-class module containing handles) is keyed to a  
string, and once set by a node, it can be discovered by any node in  
the network:

val get_root : string -> 'a Lwt.t
val set_root : string -> 'a -> unit Lwt.t

This is the only unsafe part of the interface: the getter and setter  
_must_ agree on the type of the root or all hell breaks loose.

I haven't published the library yet, since I have wanted to feel free  
to modify it as required by my application, but if you are interested,  
and cannot find a more mature solution, I'd be happy to provide it for  
your inspection.

Cheers,


Lauri