1 files changed, 68 insertions, 0 deletions
diff --git a/openresty-ext/src/assembly/resources/openresty/nginx/luaext/loadbalance/policy/roundrobin.lua b/openresty-ext/src/assembly/resources/openresty/nginx/luaext/loadbalance/policy/roundrobin.lua
new file mode 100644
index 0000000..0a1b8e8
--- /dev/null
+++ b/openresty-ext/src/assembly/resources/openresty/nginx/luaext/loadbalance/policy/roundrobin.lua
@@ -0,0 +1,68 @@
+--[[
+
+    Copyright (C) 2016 ZTE, Inc. and others. All rights reserved. (ZTE)
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+            http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+--]]
+
+local _M = {}
+_M._VERSION = '1.0.0'
+
+local tbl_util  = require('lib.utils.table_util')
+local tbl_isempty = tbl_util.isempty
+local rrcache = require('lib.tools.rr_cache')
+
+function _M.select_backserver(servers,svckey)
+	local length = #servers
+	local index = ngx.ctx.last_peer_index
+
+	if index then
+		--if it is a retry request,use the index in the context as the base
+		index = index%length+1
+	else
+		--if it is a normal request,fetch index from cache as the base
+		index = rrcache.get(svckey) or 0
+		index = index%length+1
+		rrcache.set(svckey,index)
+	end
+	ngx.ctx.last_peer_index = index
+
+	--[[
+	local resty_lock = require "resty.lock"
+	local roundrobin_cache = ngx.shared.rr_cache
+
+	--step1:acquire lock
+	local opts = {["timeout"] = 0.002,["exptime"] = 0.05}--this can be set using the conf file
+	local rrlock = resty_lock:new("rr_locks",opts)
+	local elapsed, err = rrlock:lock(svckey)
+	if not elapsed then
+		--return fail("failed to acquire the lock: ", err)
+	end
+	--step2:lock successfully acquired!incr the index
+	local index, err = roundrobin_cache:get(svckey)
+	if not index then
+		index = 0
+	end
+	index = index%length+1
+
+	--step3:update the shm cache with the new index
+	roundrobin_cache:set(svckey,index)
+
+	--step4:release the lock
+	local ok, err = rrlock:unlock()
+	]]
+	return servers[index],nil
+end
+
+return _M
+\ No newline at end of file