48 lines
1.1 KiB
Lua
48 lines
1.1 KiB
Lua
local resty_chash = require("resty.chash")
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local util = require("util")
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local string_sub = string.sub
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local _M = {}
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local instances = {}
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-- given an Nginx variable i.e $request_uri
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-- it returns value of ngx.var[request_uri]
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local function get_lua_ngx_var(ngx_var)
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local var_name = string_sub(ngx_var, 2)
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return ngx.var[var_name]
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end
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function _M.balance(backend)
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local instance = instances[backend.name]
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if not instance then
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return nil
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end
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local key = get_lua_ngx_var(backend["upstream-hash-by"])
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local endpoint_string = instance:find(key)
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local address, port = util.split_pair(endpoint_string, ":")
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return { address = address, port = port }
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end
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function _M.reinit(backend)
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local instance = instances[backend.name]
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local nodes = {}
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-- we don't support weighted consistent hashing
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local weight = 1
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for _, endpoint in pairs(backend.endpoints) do
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local endpoint_string = endpoint.address .. ":" .. endpoint.port
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nodes[endpoint_string] = weight
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end
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if instance then
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instance:reinit(nodes)
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else
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instance = resty_chash:new(nodes)
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instances[backend.name] = instance
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end
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end
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return _M
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