Converted sticky session balancers into separate classes.

rootfs/etc/nginx/lua/affinity/persistent.lua

@@ -1,53 +0,0 @@
--- An affinity mode which makes sure a session is always routed to the same endpoint.
--- The advantage of this mode is that a user will never lose his session.
--- The drawback of this mode is that when scaling up a deployment, sessions will not
--- be rebalanced.
---
-local util = require("util")
-local util_nodemap = require("util.nodemap")
-
-local _M = {}
-
-local function get_routing_key(self)
-  local cookie_value = self:get_cookie()
-
-  if cookie_value then
-    -- format <timestamp>.<workder-pid>.<routing-key>
-    local routing_key = string.match(cookie_value, '[^\\.]+$')
-
-    if routing_key == nil then
-      local err = string.format("Failed to extract routing key from cookie '%s'!", cookie_value)
-      return nil, err
-    end
-
-    return routing_key, nil
-  end
-
-  return nil, nil
-end
-
-local function set_routing_key(self, key)
-  local value = string.format("%s.%s.%s", ngx.now(), ngx.worker.pid(), key)
-  self:set_cookie(value);
-end
-
-local function pick_new_upstream(self, failed_upstreams)
-  return self.instance:random_except(failed_upstreams)
-end
-
-function _M.new(self, sticky_balancer, backend)
-  local o = sticky_balancer or {}
-  
-  local nodes = util.get_nodes(backend.endpoints)
-  local hash_salt = backend["name"]
-
-  -- override sticky.balancer methods
-  o.instance = util_nodemap:new(nodes, hash_salt)
-  o.get_routing_key = get_routing_key
-  o.set_routing_key = set_routing_key
-  o.pick_new_upstream = pick_new_upstream
-
-  return sticky_balancer
-end
-
-return _M