feature: supported to use lrucache for plugin developer.

lua/apisix/core.lua

@@ -51,6 +51,6 @@ return {
     },
     resp = require("apisix.core.resp"),
     typeof = require("apisix.core.typeof"),
-    global_lru = require("apisix.core.global_lrucache"),
+    lrucache = require("apisix.core.lrucache"),
     ctx = require("apisix.core.ctx"),
 }

lua/apisix/core/ctx.lua

@@ -1,6 +1,5 @@
 -- Copyright (C) Yuansheng Wang
 
-local ngx_req = ngx.req
 local ngx_var = ngx.var
 local new_tab = require("table.new")
 
@@ -8,6 +7,12 @@ local new_tab = require("table.new")
 local _M = {version = 0.1}
 
 
+local var_methods = {
+    -- todo: support more type
+    method = ngx.req.get_method
+}
+
+
 function _M.get(api_ctx, name)
     local vars = api_ctx.vars
     if not vars then
@@ -20,8 +25,10 @@ function _M.get(api_ctx, name)
         return val
     end
 
-    if name == "method" then
-        val = ngx_req.get_method()
+    -- todo: added more data type
+    local method = var_methods[name]
+    if method then
+        val = method()
     else
         val = ngx_var[name]
     end

lua/apisix/core/global_lrucache.lua

@@ -1,33 +0,0 @@
--- Copyright (C) Yuansheng Wang
-
-local lru_new = require("resty.lrucache").new
-local lru_items = lru_new(200)  -- todo: support to config in yaml.
-
-
-local _M = {version = 0.1}
-
-
-function _M.fetch(name, count, version)
-    local cache = lru_items:get(name)
-    if cache and cache.version == version then
-        return cache
-    end
-
-    cache = lru_new(count)
-    cache.version = version
-    lru_items:set(name, cache)
-    return cache
-end
-
-
-function _M.set(self, name, lru)
-    return lru_items:set(name, lru)
-end
-
-
-function _M.delete(name)
-    return lru_items:delete(name)
-end
-
-
-return _M

lua/apisix/core/lrucache.lua

@@ -0,0 +1,44 @@
+local lru_new = require("resty.lrucache").new
+local global_lrus = lru_new(256)  -- todo: support to config in yaml.
+
+local _M = {version = 0.1}
+
+
+local function _global_lrus(name, count)
+    local lru = global_lrus:get(name)
+    if lru then
+        return lru
+    end
+
+    lru = lru_new(count)
+    global_lrus:set(name, lru)
+    return lru
+end
+_M.global = _global_lrus
+
+
+local function _plugin_key(plugin_name, key, version, callback_fun, ...)
+    local lru_plugin_conf = _global_lrus("/plugin/" .. plugin_name, 32)
+
+    -- todo: support `stale` object
+    local obj = lru_plugin_conf:get(key)
+    if not obj or obj.version ~= version then
+        obj = callback_fun(...)
+        obj.version = version
+        lru_plugin_conf:set(key, obj)
+    end
+
+    return obj
+end
+_M.plugin = _plugin_key
+
+
+function _M.plugin_ctx(plugin_name, api_ctx, callback_fun, ...)
+    local key = api_ctx.conf_type .. "#" .. api_ctx.conf_id
+
+    return _plugin_key(plugin_name, key, api_ctx.conf_version,
+                       callback_fun, ...)
+end
+
+
+return _M

lua/apisix/plugins/example-plugin.lua

@@ -32,14 +32,14 @@ end
 
 
 function _M.rewrite(conf, api_ctx)
-    core.log.warn("plugin rewrite phase, conf: ", core.json.encode(conf),
-                  " ctx: ", core.json.encode(api_ctx, true))
+    core.log.warn("plugin rewrite phase, conf: ", core.json.encode(conf))
+    -- core.log.warn(" ctx: ", core.json.encode(api_ctx, true))
 end
 
 
 function _M.access(conf, api_ctx)
-    core.log.warn("plugin access phase, conf: ", core.json.encode(conf),
-                  " ctx: ", core.json.encode(api_ctx, true))
+    core.log.warn("plugin access phase, conf: ", core.json.encode(conf))
+    -- core.log.warn(" ctx: ", core.json.encode(api_ctx, true))
     -- ngx.say("hit example plugin")
 end
 

lua/apisix/plugins/limit-req.lua

@@ -1,13 +1,12 @@
 local limit_req = require("resty.limit.req")
 local core = require("apisix.core")
--- todo: support to config it in yaml
-local cache = core.global_lru.fetch("/plugin/limit-req", 200)
+local plugin_name = "limit-req"
 
 
 local _M = {
     version = 0.1,
     priority = 1001,        -- TODO: add a type field, may be a good idea
-    name = "limit-req",
+    name = plugin_name,
 }
 
 
@@ -15,19 +14,25 @@ function _M.check_args(conf)
     return true
 end
 
+local function create_limit_obj(conf)
+    core.log.info("create new plugin ins")
+    return limit_req.new("plugin-limit-req",
+                         conf.rate, conf.burst)
+end
+
 
 function _M.access(conf, api_ctx)
-    local key = api_ctx.conf_type .. "#" .. api_ctx.conf_id
-    -- core.log.warn("key: ", key, " conf: ", core.json.encode(conf))
+    -- todo: support to config it in yaml
+    local limit_ins = core.lrucache.plugin_ctx(plugin_name, api_ctx,
+                        create_limit_obj, conf)
 
-    local limit_ins = cache:get(key)
-    if not limit_ins or limit_ins.version ~= api_ctx.conf_version then
-        limit_ins = limit_req.new("plugin-limit-req", conf.rate, conf.burst)
-        cache:set(key, limit_ins)
+    local key = core.ctx.get(api_ctx, conf.key)
+    if not key or key == "" then
+        key = ""
+        core.log.warn("fetched empty string value to limit the request maybe ",
+                      "wrong, please pay attention to this.")
     end
 
-    key = core.ctx.get(api_ctx, conf.key)
-
     local delay, err = limit_ins:incoming(key, true)
     if not delay then
         if err == "rejected" then