Nginx A/B test config

abtest.conf.lua

set $target '';

access_by_lua '
	local abtest = 0
	local abtestMax = 1
	local userAgent = ngx.req.get_headers()["User-Agent"]
	
	local cookie = ngx.var.cookie_abtest
	if ngx.re.match(userAgent, "(yandex|google|MSIE|bot)", "i") then
	    cookie = 0
	end
	
	
	
	if cookie == nil then
		math.randomseed( os.time() )
		abtest = math.random(0, abtestMax)
    		ngx.header["Set-Cookie"] = {"abtest=" .. abtest .. "; path=/", "abReason=nil"}
		
	else
		
		if tonumber(cookie) >= 0 and tonumber(cookie) <= abtestMax then
			
			abtest = ngx.var.cookie_abtest
			
			
		else
			abtest = 0
			
			ngx.header["Set-Cookie"] = {"abtest=" .. abtest .. "; path=/", "abReason=badRange"}
		end
		
	end
	
	ngx.var.target = abtest
';

root /var/www/meta$target;