Nginx A\B testing config

ab_testing.conf

# cloudflare config
map $http_cf_connecting_ip $connecting_ip {
	default $http_cf_connecting_ip;
	"" $remote_addr;
}

log_format versioned '[$upstream_group] $remote_addr - $remote_user [$time_local] '
                    '"$request" $status $body_bytes_sent '
                    '"$http_referer" "$http_user_agent"';

map $cookie_app_version $upstream_group {
	default $appversion;
	"version_1" "version_1";
  	"version_2" "version_2";
}

upstream version_1 {
	server 127.0.0.1:3000;
}

upstream version_2 {
	server 127.0.0.1:3001;
}

split_clients "app${remote_addr}${http_user_agent}${date_gmt}" $appversion {
	95%     version_1;
	*       version_2;
}

server {
	listen       *:80;
	server_name  example.com;

	access_log   /var/log/nginx/app.access.log versioned;
	error_log    /var/log/nginx/app.error.log;

	charset      utf-8;
	etag         off;
	gzip         on;

	set $app_version_root "dir1";
	if ($upstream_group = "version_1") {
		set $app_version_root "dir1";
	}

	if ($upstream_group = "version_2") {
		set $app_version_root "dir2";
	}

	root /var/www/$app_version_root;

	location / {
		add_header Set-Cookie "app_version=$upstream_group;Path=/;Max-Age=518400;";
		try_files $uri @frontend;
	}

	location @frontend {
		proxy_buffers          8 32k;
		proxy_buffer_size      64k;
		proxy_http_version     1.1;
		proxy_set_header       X-FORWARDED-PROTO http;
		proxy_set_header       Upgrade $http_upgrade;
		proxy_set_header       Connection $http_connection;
		proxy_set_header       X-Real-IP $connecting_ip;
		proxy_set_header       X-Forwarded-For $connecting_ip;
		# proxy_set_header       X-Real-IP $remote_addr;
		# proxy_set_header       X-Forwarded-For $remote_addr;
		proxy_set_header       Host $host;

		add_header Set-Cookie "app_version=$upstream_group;Path=/;Max-Age=518400;";
		if ($upstream_group = "version_1") {
			proxy_pass http://127.0.0.1:3000;
			break;
		}

		if ($upstream_group = "version_2") {
			proxy_pass http://127.0.0.1:3001;
			break;
		}

		proxy_pass http://$appversion;
	}
}