membphis commented on code in PR #12605:
URL: https://github.com/apache/apisix/pull/12605#discussion_r2639094869
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apisix/plugins/limit-req/util.lua:
##########
@@ -14,60 +14,66 @@
-- See the License for the specific language governing permissions and
-- limitations under the License.
--
-local math = require "math"
-local abs = math.abs
-local max = math.max
local ngx_now = ngx.now
-local ngx_null = ngx.null
local tonumber = tonumber
+local core = require("apisix.core")
local _M = {version = 0.1}
+local script = core.string.compress_script([=[
+ local state_key = KEYS[1] -- state_key (hash), fields:
"excess", "last"
+ local rate = tonumber(ARGV[1]) -- req/s
+ local now = tonumber(ARGV[2]) -- ms
+ local burst = tonumber(ARGV[3]) -- req/s
+ local commit = tonumber(ARGV[4]) -- 1/0
+
+ local vals = redis.call("HMGET", state_key, "excess", "last")
+ local prev_excess = tonumber(vals[1] or "0")
+ local prev_last = tonumber(vals[2] or "0")
+
+ local new_excess
+ if prev_last > 0 then
+ local elapsed = math.abs(now - prev_last)
+ new_excess = math.max(prev_excess - rate * (elapsed) / 1000 + 1000, 0)
+ else
+ new_excess = 0
+ end
+
+ if new_excess > burst then
+ return {0, new_excess}
+ end
+
+ if commit == 1 then
+ redis.call("HMSET", state_key, "excess", new_excess, "last", now)
+ redis.call("EXPIRE", state_key, 60)
+ end
+
+ return {1, new_excess}
+]=])
+
+
-- the "commit" argument controls whether should we record the event in shm.
function _M.incoming(self, red, key, commit)
local rate = self.rate
local now = ngx_now() * 1000
- key = "limit_req" .. ":" .. key
- local excess_key = key .. "excess"
- local last_key = key .. "last"
+ local state_key = "limit_req:{" .. key .. "}:state"
- local excess, err = red:get(excess_key)
- if err then
- return nil, err
- end
- local last, err = red:get(last_key)
- if err then
+ local commit_flag = commit and "1" or "0"
+
+ local res, err = red:eval(script, 1, state_key,
Review Comment:
we can use `evalsha`, avoid to repeat pass the `script` every time
official website: https://redis.io/docs/latest/commands/evalsha
here is a demo:
```lua
local redis = require "resty.redis"
-- Create redis instance
local red = redis:new()
-- Connect to Redis
local ok, err = red:connect("127.0.0.1", 6379)
if not ok then
ngx.say("failed to connect: ", err)
return
end
-- Step 1: Load script and get SHA1
local script = "return redis.call('get', KEYS[1])"
local sha1, err = red:script("load", script)
if not sha1 then
ngx.say("failed to load script: ", err)
return
end
ngx.say("Script SHA1: ", sha1)
-- Step 2: Set a test key
red:set("mykey", "hello " .. ngx.time())
-- Step 3: Use evalsha to execute script
-- evalsha <sha1> <numkeys> <key1> [key2 ... ] [arg1 arg2 ...]
local res, err = red:evalsha(sha1, 1, "mykey")
if not res then
ngx.say("failed to evalsha: ", err)
return
end
ngx.say("Result: ", res) -- Output: hello
-- Put connection back to the pool
local ok, err = red:set_keepalive(10000, 100)
if not ok then
ngx.say("failed to set keepalive: ", err)
return
end
```
we can cache the `sha1` result
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