Nginxのリクエスト数/秒をcloudwatchへ連携する

nginx stubをonにしておく。

curl http://hoge/server-stub

Active connections: 17 
server accepts handled requests
 1177899 1177899 7047859 
Reading: 0 Writing: 1 Waiting: 16 

差分を取得するrubyメソッド

nginxのstubだと、起動してからの累計しか取れないため、
定期的に差分を取得=>差分秒で割る

req_per_sec.rb

# get request count per sec from nginx stub
def req_per_sec stub_url, conf_path
    now = Time.now

    last_json = FileTest.exists?(conf_path) && JSON.parse(File.read(conf_path))

    txt = `curl #{stub_url}`
    req_counts = txt.split("\n")[2].split(" ")[0].to_i
    File.write conf_path, JSON::generate({time:now, req_counts:req_counts})

    if last_json
        diff_sec = now - Time.parse(last_json['time'])
        req_per_sec = (req_counts - last_json['req_counts']) / diff_sec
        return req_per_sec
    else
        return nil
    end
end

call the method

p req_per_sec('http://hoge/server-stub','/path/to/hoge.json')