picodns

picodns is a simple interface to interact with DNS providers in a concurrent way. It's loosely based on OpenResty's DNS resolver and uses a bit modified LuaResolver's parser for now.

Why?

I'm aware that both of the modules mentioned earlier do the same thing but in order to achieve non-blocking connect calls on luasocket, DNS resolving had to be done concurrently. Unfortunately, LuaResolver does not support non-blocking and lua-resty-dns requires cosocket API of ngx_lua, so the options didn't satisfy me.

How-to

local dns = require "picodns"

-- custom DNS endpoints can be used
-- normally it uses cloudflare, google and quad9
local resolver = dns.newResolver({ "1.1.1.1" })

-- blocking DNS query
local data, err = resolver:query("lua.org")
if err then
  error(err)
end

-- when called in a coroutine,
-- it becomes a non-blocking call
local co = coroutine.create(function()
  local answers, err = resolver:query("luajit.org")
  if err then
    error(err)
  end

  for _, answer in ipairs(answers) do
    print(string.format("%s => %s", answer.name, answer.content))
  end
end)

-- so you have to wait 'till it's done,
-- good thing is you can do your other fancy stuff in this loop concurrently!
repeat
  local status = coroutine.resume(co)
  print "do other work here!"
until not status

Installation

git clone git@github.com:nikneym/picodns.git

in your project directory and include it

local dns = require "picodns"

Documentation

Will be added to GitHub wiki page. How-to section mostly explains it though.

Tests

You need busted in order to run the tests.

License

GNU General Public License v3.0, check out license.

nikneym / picodns