problem getting two erlangs to chat

Garry Hodgson <>
Wed Sep 3 21:55:08 CEST 2003



i'm having a problem getting two erl's to talk to each other.
i suspect this'll be obvious to y'all, but i's escaping me.

the server is written as a gen_server, with a start() that looks like:

    start() ->
        gen_server:start( { global, orbe }, orbe, [], [] ).

it gets started with:

   erl -setcookie cookie -name orbe -s orbe start

so far, so good.  i want to control it via a separate program
that invokes erlang to run a getProcesses() function:

    getProcesses() ->
        gen_server:call( { global, orbe }, getProcesses ).

i run this one with:

    erl -setcookie cookie -name foo

when i try and invoke getProcesses(), i get an error:

    ()1> orbe:getProcesses().
    ** exited: {noproc,{gen_server,call,[{global,orbe},getProcesses]}} **

so i ping it, to see if the other node (on the same machine, incidentally) 
is alive:

    ()2> net_adm:ping( '' ).
    pong

and after that, it works:

    ()3> orbe:getProcesses().
    [{fred,cat,#Port<3942.37>,63229822226},
     {barney,cat,#Port<3942.38>,63229822226}]


so, the question is, what am i neglecting to do
that the net_adm:ping() is doing for me?

is this a reasonable mechanism for controlling a
running erlang server?  the intent is to have a script
that will invoke something like "erl -s orbe status"
or "erl -s orbe reset" to control the server, probably
from someone else's CGI scripts (part of a bigger system,
so i can't rewrite the whole thing or yaws or whatever).

i'm open to suggestions as to a better way.

thanks

----
Garry Hodgson, Technology Consultant, AT&T Labs

Be happy for this moment.
This moment is your life.




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