in lib/skywalking/util.lua [96:120]
local random_seed = function ()
local seed
local frandom = io.open("/dev/urandom", "rb")
if frandom then
local str = frandom:read(4)
frandom:close()
if str then
local s = 0
for i = 1, 4 do
s = 256 * s + str:byte(i)
end
seed = s
end
end
if not seed then
if _M.is_ngx_lua then
seed = ngx.now() * 1000 + ngx.worker.pid()
else
seed = os.clock()
end
end
return seed
end