An example of optimistic concurrency control to setup a new user's storage records with Nakama server.

setupuser.lua

local nk = require("nakama")

local function setup_user(context, _)
  local value = {
    coins = 100
    level = 1
  }
  local record = {
    Bucket = "mygame",
    Collection = "saves",
    Record = "save"
    UserId = context.user_id, -- must be context.UserId after 1.0 release.
    Value = value,
    Version = "*"             -- only write record if one doesn't already exist.
  }
  local success, err = pcall(nk.storage_write, {record})
  -- An error will be returned if the OCC check fails.
  if (not success) then
    local str = ("Store write error: %q"):format(err)
    nk.logger_info(str)
  end
end

nk.register_after(setup_user, "authenticaterequest_device")