erlang general question on socket

Question

I have a question about a project I should implement for my Distributed System course.

The project consist in designing and implementing a library that provides a reliable multicast service to user processes. All processes belong to a group, and a message is sent by a member process to all members of the group. The sender is excluded from the recipient list.

This seems to me quite easy to implement in erlang, due to its message passing structure...more points are given if you use rpc call instead of normal sockets based implementation..

Now my question is this: one of the mandatory points of this projects requires that sockets aren't kept open when there is no communication going on between processes...

Our course is held in C, but we are free to use any language we like...can I satisfy this constraint using erlang nodes and rpc calls?

thanks in advance

Answer 1

Despite what the other answers say, Erlang's default behavior does not satisfy your constraints.

A typical network of Erlang nodes using Erlang distribution will remain densely connected (every node connected to every other node) with TCP sockets open even when you're not using them. You will either have to use -connect_all false and manage opening/closing the connections to other nodes yourself, or you will have to develop your own distribution protocol. I would recommend the latter, especially since you are learning. The trick to make it easy is to use term_to_binary and binary_to_term.

Answer 2

Yes. The rpc module even has multicall, which takes a list of nodes and will do exactly what you described. It won't hold your sockets open when it's not using them either.