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