fix(rate-limiting) remove unneeded phase handlers for better accuracy (Kong#6802)

bungle · web-flow · commit 01c76f761ba2 · 2021-02-04T14:42:28.000+01:00
### Summary The PR Kong#5460 tried to fix rate-limiting accuracy issues as reported with Kong#5311. That PR has stayed open for over a year now. There is a smaller change in that PR that we can make without a lot of work or debating, and this PR contains that only: 1. it removes extra phase handlers and context passing of data and now does everything in `access` phase (this could make it more accurate as well, compared to post-poning that to log phase) 2. it now also sets rate-limiting headers when the limits have exceeded
diff --git a/kong/plugins/rate-limiting/handler.lua b/kong/plugins/rate-limiting/handler.lua
@@ -47,7 +47,7 @@ local RateLimitingHandler = {}
 
 
 RateLimitingHandler.PRIORITY = 901
-RateLimitingHandler.VERSION = "2.2.0"
+RateLimitingHandler.VERSION = "2.2.1"
 
 
 local function get_identifier(conf)
@@ -145,8 +145,9 @@ function RateLimitingHandler:access(conf)
   if usage then
     -- Adding headers
     local reset
+    local headers
     if not conf.hide_client_headers then
-      local headers = {}
+      headers = {}
       local timestamps
       local limit
       local window
@@ -182,38 +183,23 @@ function RateLimitingHandler:access(conf)
       headers[RATELIMIT_LIMIT] = limit
       headers[RATELIMIT_REMAINING] = remaining
       headers[RATELIMIT_RESET] = reset
-
-      kong.ctx.plugin.headers = headers
     end
 
     -- If limit is exceeded, terminate the request
     if stop then
-      return kong.response.error(429, "API rate limit exceeded", {
-        [RETRY_AFTER] = reset
-      })
+      headers = headers or {}
+      headers[RETRY_AFTER] = reset
+      return kong.response.error(429, "API rate limit exceeded", headers)
     end
-  end
 
-  kong.ctx.plugin.timer = function()
-    local ok, err = timer_at(0, increment, conf, limits, identifier, current_timestamp, 1)
-    if not ok then
-      kong.log.err("failed to create timer: ", err)
+    if headers then
+      kong.response.set_headers(headers)
     end
   end
-end
-
-
-function RateLimitingHandler:header_filter(_)
-  local headers = kong.ctx.plugin.headers
-  if headers then
-    kong.response.set_headers(headers)
-  end
-end
-
 
-function RateLimitingHandler:log(_)
-  if kong.ctx.plugin.timer then
-    kong.ctx.plugin.timer()
+  local ok, err = timer_at(0, increment, conf, limits, identifier, current_timestamp, 1)
+  if not ok then
+    kong.log.err("failed to create timer: ", err)
   end
 end
 
