nginx lua redis

gistfile1.txt

worker_processes  2;
error_log /var/log/nginx/error.log info;

events {
    worker_connections 1024;
}

http {
    init_by_lua '
        function split(inputstr, sep)
            if inputstr == nil then
                return {}
            end
            if sep == nil then
                sep = "%s"
            end
            local t = {}
            for str in string.gmatch(inputstr, "([^" .. sep .. "]+)") do
                table.insert(t, str)
            end
            return t
        end
    ';

    server {
        listen 80;

        location / {
            resolver 8.8.4.4;  # use Google's open DNS server

            set $target '';
            access_by_lua '
                local key = ngx.var.http_host
                if not key then
                    ngx.log(ngx.ERR, "no host found")
                    return ngx.exit(400)
                end

                local redis = require "resty.redis"
                local r = redis:new()

                r:set_timeout(1000) -- 1 second

                local ok, err = r:connect("127.0.0.1", 6379)
                if not ok then
                    ngx.log(ngx.ERR, "failed to connect to ris: ", err)
                    return ngx.exit(500)
                end

                local upstream_addrs, err = r:get(key)
                if not upstream_addrs then
                    ngx.log(ngx.ERR, "failed to get redis key: ", err)
                    return ngx.exit(500)
                end

                if upstream_addrs == ngx.null then
                    ngx.log(ngx.ERR, "no host found for key ", key)
                    return ngx.exit(400)
                end

                upstream_addrs = split(upstream_addrs, ",")
                local upstream_addr = upstream_addrs[math.random(#upstream_addrs)]
                ngx.var.target = upstream_addr
            ';

            proxy_pass http://$target;
        }
    }
}