Sending messages to handler function fibers in TCP server

Question

If handler function passed to tcp_server() from socket module runs as fiber is there possibility to communicate with each tcp_connection by fiber.channel?

Answer 1

Yes, it is.

#!/usr/bin/tarantool

local fiber = require('fiber')
local socket = require('socket')

local clients = {}

function rc_handle(s)
    -- You can save socket reference in some table
    clients[s] = true

    -- You can create a channel
    -- I recommend attaching it to the socket
    -- so it'll be esier to collect garbage
    s.channel = fiber.channel()

    -- You can also get the reference to the handling fiber.
    -- It'll help you to tell alive clients from dead ones
    s.fiber = fiber.self()

    s:write(string.format('Message for %s:%s: %s',
        s:peer().host, s:peer().port, s.channel:get()
    ))

    -- Don't forget to unref the client if it's done manually
    -- Or you could make clients table a weak table.
    clients[s] = nil
end

server = socket.tcp_server('127.0.0.1', 3003, {
    name = 'srv',
    handler = rc_handle,
})

function greet_all(msg)
    -- So you can broadcast your message to all the clients
    for s, _ in pairs(clients) do
        s.channel:put(msg)
    end
end

require('console').start()

Of course, this snippet if far from being perfect, but I hope it'll help you to get the work done.