fix(clustering/rpc): warning log level for sync retry failing (#14192)

KAG-6224

---------

Co-authored-by: Xumin <100666470+StarlightIbuki@users.noreply.github.com>

kong/clustering/services/sync/rpc.lua

@@ -27,6 +27,7 @@ local ipairs = ipairs
 local ngx_null = ngx.null
 local ngx_log = ngx.log
 local ngx_ERR = ngx.ERR
+local ngx_WARN = ngx.WARN
 local ngx_INFO = ngx.INFO
 local ngx_DEBUG = ngx.DEBUG
 
@@ -422,8 +423,8 @@ local function sync_once_impl(premature, retry_count)
   -- retry if the version is not updated
   retry_count = retry_count or 0
 
-  if retry_count > MAX_RETRY then
-    ngx_log(ngx_ERR, "sync_once retry count exceeded. retry_count: ", retry_count)
+  if retry_count >= MAX_RETRY then
+    ngx_log(ngx_WARN, "sync_once retry count exceeded. retry_count: ", retry_count)
     return
   end
 
@@ -435,7 +436,7 @@ local function sync_once_impl(premature, retry_count)
   -- in some cases, the new spawned timer will be switched to immediately,
   -- preventing the coroutine who possesses the mutex to run
   -- to let other coroutines has a chance to run
-  local ok, err = kong.timer:at(0.1, sync_once_impl, retry_count or 0)
+  local ok, err = kong.timer:at(0.1, sync_once_impl, retry_count)
   -- this is a workaround for a timerng bug, where tail recursion causes failure
   -- ok could be a string so let's convert it to boolean
   if not ok then

spec/02-integration/18-hybrid_rpc/09-notify_new_version_spec.lua

@@ -61,14 +61,16 @@ for _, strategy in helpers.each_strategy() do
           "no sync runs, version is " .. rep("0", 32), true, 10)
 
         assert.logfile(name).has.line(
-          "sync_once retry count exceeded. retry_count: 6", true, 10)
+          "sync_once retry count exceeded. retry_count: 5", true, 10)
         assert.logfile(name).has.no.line(
           "assertion failed", true, 0)
+        assert.logfile(name).has.no.line(
+          "[error]", true, 0)
 
         local name = nil
 
         -- cp logs
-        for i = 0, 6 do
+        for i = 0, 5 do
           assert.logfile(name).has.line(
             "kong.sync.v2.get_delta ok: " .. i, true, 10)
         end