Not sure why this balancer_by_lua example isn't working, could use some help

[CJ Ess]

I'm trying to learn how to use balancer_by_lua using https://github.com/agentzh/lua-resty-balancer as an example. My find() function works in the init_by_lua block and I can see it rotating through the four IPs I have configured with no problem. However, when I call the find() function in the balancer_by_lua block, I always get the same address because self.last_id never updates - as-if I'm working on a copy of "self" in the find function and my changes to it are being lost. I don't see where lua-resty-balancer is doing anything special in its balancer block, so I'm not sure what is going wrong and could use some help. What I am looking for is the find function in balancer_by_lua_block to return a different value every time.

Here is my nginx.conf:

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user                    nginx;

worker_processes        24;

worker_rlimit_nofile    8192;

pid                     /var/run/nginx.pid;

events {

  worker_connections        8192;

}

http {

  error_log /var/log/nginx/error.log debug;

  lua_code_cache off;

  lua_package_path '/etc/nginx/?.lua;;';

  init_by_lua_block {

    local xxtest = require "baltest"

    local test1 = xxtest:new(nil)

    for i=1,10 do

      ngx.log(ngx.NOTICE, "TEST" .. i .. ": " .. test1:find())

    end

    package.loaded.my_test1 = test1

  }

  upstream foo {

    server 0.0.0.1;

    balancer_by_lua_block {

      local b = require "ngx.balancer"

      local test1 = package.loaded.my_test1

      local res = test1:find()

      ngx.log(ngx.NOTICE, "PEER: " .. res)

      assert(b.set_current_peer(res, 80))

    }

  }

  server {

    listen 9080;

    server_name "_";

    location / {

      proxy_http_version 1.1;

      proxy_set_header Connection "";

      proxy_set_header Host $host;

      proxy_set_header X-Real-IP $remote_addr;

      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

      proxy_set_header X-Forwarded-Proto $scheme;

      proxy_buffering off;

      proxy_pass http://foo;

    }

  }

}

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And here is my baltest.lua where I am trying to create a class like lua-resty-balancer does:

--------

local next = next

local setmetatable = setmetatable

local _M = {}

local mt = { __index = _M }

function _M.new(_)

  local newnodes = { "192.168.128.1", "192.168.128.2", "192.168.128.3", "192.168.128.4" }

  local self = {

    nodes = newnodes, -- it's safer to copy one

    last_id = nil,

  }

  return setmetatable(self, mt)

end

local function _find(self)

  local nodes = self.nodes

  local last_id = self.last_id

  id = next(nodes, last_id)

  if (id == nil) then

    id = next(nodes, nil)

  end

  self.last_id = id

  return nodes[id]

end

_M.find = _find

return _M

--------