leslie-tsang commented on a change in pull request #5682:
URL: https://github.com/apache/apisix/pull/5682#discussion_r763666306
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File path: apisix/patch.lua
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@@ -86,6 +93,44 @@ do
end
+do -- `math.randomseed` patch
+ -- `math.random` generates PRND(pseudo-random numbers) from the seed set
by `math.randomseed`
+ -- Many module libraries use `ngx.time` and `ngx.worker.pid` to generate
seeds which may
+ -- loss randomness in container env (where pids are identical, e.g. root
pid is 1)
+ -- Kubernetes may launch multi instance with deployment RS, so `ngx.time`
may get same return in pods.
+ -- Therefore, this global patch enforce entire framework to use the
best-practice PRND generates.
+
+ local resty_random = require("resty.random")
+ local math_randomseed = math.randomseed
+ local seeded
+
+ -- make linter happy
+ -- luacheck: ignore
+ math.randomseed = function()
+ -- check seed mark
+ if seeded or false then
+ log(ngx.DEBUG, debug.traceback("Random seed has been inited", 2))
+ return
+ end
+
+ -- generate randomseed
+ -- chose 6 from APISIX's SIX, 256 ^ 6 should do the trick
+ -- it shouldn't be large than 16 to prevent overflow.
+ local random_bytes = resty_random.bytes(6)
+ local t = {}
+
+ for i = 1, #random_bytes do
+ t[i] = string.byte(random_bytes, i)
+ end
+
+ local s = table.concat(t)
+
+ seeded = true
+ math_randomseed(tonumber(s))
Review comment:
Make sense. thanks for suggestion. 🥳
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