fix review comments

Co-Authored-By: Enrique García Cota <[email protected]>

README.md

@@ -43,7 +43,7 @@ Versioning is strictly based on [Semantic Versioning](https://semver.org/)
 
 ### 4.1.0 (unreleased)
 
-- Fix: unhelthy balancers would not recover because they would not refresh the
+- Fix: unhealthy balancers would not recover because they would not refresh the
   DNS records used. See [PR 73](https://github.com/Kong/lua-resty-dns-client/pull/73).
 - Added: automatic background resolving of hostnames, expiry will be checked
   every second, and if needed DNS (and balancer) will be updated. See [PR 73](https://github.com/Kong/lua-resty-dns-client/pull/73).

src/resty/dns/balancer/base.lua

@@ -141,7 +141,6 @@ local table_concat = table.concat
 local math_floor = math.floor
 local string_format = string.format
 local ngx_log = ngx.log
-local ngx_ERR = ngx.ERR
 local ngx_DEBUG = ngx.DEBUG
 local ngx_WARN = ngx.WARN
 local balancer_id_counter = 0
@@ -1197,16 +1196,14 @@ end
 -- Timer invoked to update DNS records
 function objBalancer:resolveTimerCallback()
   --check all hosts for expired records,
-  --erroreed ones included
+  --including those with errors
   --we update, so changes on the list while traversing can happen, keep track of that
 
   ngx_log(ngx_DEBUG, self.log_prefix, "executing requery timer")
 
-  local all_ok = true
   for _, host in ipairs(self.hosts) do
     -- only retry the errorred ones
     if (host.lastQuery.expire or 0) < time() then
-      all_ok = false -- note: only if NO requery at all is done, we are 'all_ok'
       host:queryDns(false) -- timer-context; cacheOnly always false
     end
   end
@@ -1380,7 +1377,7 @@ _M.new = function(opts)
       }, self)
 
     if not self.resolveTimer then
-      ngx_log(ngx_ERR, self.log_prefix, "failed to create the timer: ", err)
+      return nil, "failed to create timer for background DNS resolution: " .. err
     end
   end
 

src/resty/dns/balancer/least_connections.lua

@@ -214,7 +214,7 @@ function _M.new(opts)
     opts.log_prefix = "least-connections"
   end
 
-  local self = balancer_base.new(opts)
+  local self = assert(balancer_base.new(opts))
 
   -- inject overridden methods
   for name, method in pairs(lc) do

src/resty/dns/balancer/ring.lua

@@ -429,7 +429,7 @@ function _M.new(opts)
     opts.log_prefix = "ringbalancer"
   end
 
-  local self = balancer_base.new(opts)
+  local self = assert(balancer_base.new(opts))
 
   if (not opts.wheelSize) and opts.order then
     opts.wheelSize = #opts.order