Merge pull request #758 from 3scale/lua-resty-limit-traffic

[resty] use forked resty.limit.count

Author: mikz

CHANGELOG.md

@@ -27,6 +27,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - The `scope` of the Rate Limit policy is `service` by default [PR #704](https://github.com/3scale/apicast/pull/704)
 - Decoded JWTs are now exposed in the policies context by the APIcast policy [PR #718](https://github.com/3scale/apicast/pull/718)
 - Upgraded OpenResty to 1.13.6.2, uses OpenSSL 1.1 [PR #733](https://github.com/3scale/apicast/pull/733)
+- Use forked `resty.limit.count` that uses increments instead of decrements [PR #758](https://github.com/3scale/apicast/pull/758)
 
 ### Fixed
 

gateway/src/apicast/policy/rate_limit/rate_limit.lua

@@ -3,7 +3,7 @@ local _M = policy.new('Rate Limit Policy')
 
 local resty_limit_conn = require('resty.limit.conn')
 local resty_limit_req = require('resty.limit.req')
-local resty_limit_count = require('resty.limit.count')
+local resty_limit_count = require('resty.limit.count-inc')
 
 local ngx_semaphore = require "ngx.semaphore"
 local limit_traffic = require "resty.limit.traffic"

gateway/src/resty/limit/count-inc.lua

@@ -0,0 +1,60 @@
+-- This file applies a patch from
+-- https://github.com/3scale/lua-resty-limit-traffic/commit/c53f2240e953a9656580dbafcc142363ab063100
+-- It can be removed when https://github.com/openresty/lua-resty-limit-traffic/pull/34 is merged and released.
+
+local _M = {}
+local resty_limit_count = require('resty.limit.count')
+local setmetatable = setmetatable
+
+local mt = {
+    __index = _M
+}
+
+function _M.new(...)
+    return setmetatable(resty_limit_count.new(...), mt)
+end
+
+function _M.incoming(self, key, commit)
+    local dict = self.dict
+    local limit = self.limit
+    local window = self.window
+
+    local count, err
+
+    if commit then
+        count, err = dict:incr(key, 1, 0, window)
+
+        if not count then
+            return nil, err
+        end
+    else
+        count = (dict:get(key) or 0) + 1
+    end
+
+    if count > limit then
+        return nil, "rejected"
+    end
+
+    return 0, limit - count
+end
+
+-- uncommit remaining and return remaining value
+function _M.uncommit(self, key)
+    assert(key)
+    local dict = self.dict
+    local limit = self.limit
+
+    local count, err = dict:incr(key, -1)
+    if not count then
+        if err == "not found" then
+            count = 0
+        else
+            return nil, err
+        end
+    end
+
+    return limit - count
+end
+
+return setmetatable(_M, { __index = resty_limit_count })
+

spec/policy/rate_limit/rate_limit_spec.lua

@@ -149,7 +149,7 @@ describe('Rate limit policy', function()
       redis:connect(redis_host, redis_port)
       redis:select(1)
       local fixed_window = redis:get('fixed_window_test3')
-      assert.equal('-1', fixed_window)
+      assert.equal('2', fixed_window)
     end)
 
     it('rejected (count), name_type is liquid', function()
@@ -169,7 +169,7 @@ describe('Rate limit policy', function()
       redis:connect(redis_host, redis_port)
       redis:select(1)
       local fixed_window = redis:get('fixed_window_test3')
-      assert.equal('-1', fixed_window)
+      assert.equal('2', fixed_window)
     end)
 
     it('rejected (count), name_type is liquid, ngx variable', function()
@@ -188,7 +188,7 @@ describe('Rate limit policy', function()
       redis:connect(redis_host, redis_port)
       redis:select(1)
       local fixed_window = redis:get('fixed_window_test3')
-      assert.equal('-1', fixed_window)
+      assert.equal('2', fixed_window)
     end)
 
     it('delay (conn)', function()