Question

I wrote a simple application in C#. It downloads a log file via ftp, checked whether firefox is running on the PC, changes the log string, uploads the log back to server.

I am running it every 10 seconds using a Timer.

When the service starts, its memory usage is 10Mb and CPU usage <1%. After about two minutes, its memory usage is ~12Mb, but the CPU usage jumps to over 90%!

This is what my app does every 10 seconds:
1) Download log via ftp and store in string log.
2) Go through a list of processes running on the PC, and if there if a firefox.exe process, appropriately change the log string to indicate firefox running.
3) Save the log string to as a txt file, read the file to send id via ftp back to the server.

I doubt saving/reading a couple of lines of text onto hard-drive requires so much CPU power.

Any guesses on what might be going on? Thanks!!

EDIT: Here is my whole class

class Program : System.ServiceProcess.ServiceBase
{
    private static System.Timers.Timer timer;

    static string myIP = "";

    static void start()
    {
        string strHostName = Dns.GetHostName();
        IPHostEntry ipEntry = Dns.GetHostEntry(strHostName);
        IPAddress[] addr = ipEntry.AddressList;

        int i = 0;
        foreach (IPAddress address in addr)
        {
            if (("" + addr[i].AddressFamily).Equals("InterNetwork"))
                myIP = "" + addr[i];
            i++;
        }

        timer = new System.Timers.Timer();
        timer.Elapsed += new ElapsedEventHandler(firefoxChecker); // Everytime timer ticks, timer_Tick will be called
        timer.Interval = (1000) * (5);             
        timer.Enabled = true;                       // Enable the timer
        timer.Start();
    }

    protected override void OnStart(string[] args)
    {
        start();
    }


    public static void Main()
    {
        System.ServiceProcess.ServiceBase.Run(new Program());
    }

    static string downloadLog()
    {
        FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://server/log.txt"));

        // Provide the WebPermission Credintials
        reqFTP.Credentials = new NetworkCredential("username", "password");
        reqFTP.Proxy = null;
        reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;

        FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();

        Stream responseStream = response.GetResponseStream();
        StreamReader reader = new StreamReader(responseStream);
        string log = reader.ReadToEnd();
        reader.Close();
        reader.Dispose();
        return log;
    }

    static void sendLogThroughFTP(string log)
    {
        FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://server/log.txt"));

        reqFTP.Credentials = new NetworkCredential("username", "password");
        reqFTP.Proxy = null;
        reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
        StreamWriter wr = new StreamWriter(@"C:\logs\temp.txt");
        wr.Write(log);
        wr.Close();

        StreamReader sourceStream = new StreamReader(@"C:\logs\temp.txt");
        byte[] fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
        sourceStream.Close();
        reqFTP.ContentLength = fileContents.Length;
        Stream requestStream = reqFTP.GetRequestStream();
        requestStream.Write(fileContents, 0, fileContents.Length);
        requestStream.Close();
        sourceStream.Dispose();
    }

    static void firefoxChecker(object sender, EventArgs e)
    {

        string firefoxOwner = "----------";
        TerminalServicesManager manager = new TerminalServicesManager();
        ITerminalServer server = null;

        string log = downloadLog();

        bool diceFirefoxRunning = false;
        bool monsterFirefoxRunning = false;
        bool careerbuilderFirefoxRunning = false;

        try
        {
            server = manager.GetLocalServer();
            server.Open();
            foreach (ITerminalServicesSession session in server.GetSessions())
            {
                if (session.ConnectionState == ConnectionState.Active)
                {
                    firefoxOwner = session.UserAccount.ToString();
                    string ip = session.ClientIPAddress.ToString();

                    string user = session.UserAccount.ToString();

                    System.Collections.Generic.IList<Cassia.ITerminalServicesProcess> list = session.GetProcesses();
                    foreach (ITerminalServicesProcess process in list)
                    {
                        if (Equals(process.ProcessName, "firefox.exe"))
                        {
                            // change firefoxOwner string appropriately
                            log = updateLog(log, user, firefoxOwner);
                        }
                    }
                }
            }
            server.Close();
            sendLogThroughFTP(log);
        }
        catch
        {
            // do nothing
        }
    }

    static string updateLog(string log, string username, string ffOwner)
    {
                // make some changes to log string
                return log;
    }
}

}

Thanks for all the inputs!

Answer 1

Disable the timer when you start doing your work and re-enable it when you are done.

You are downloading and uploading via FTP which could take more than the 5 seconds you have set fro your timer. If you disable the timer before you start and re-enable it at the end, you will poll 5 seconds after the last upload completed.

You may also want to consider upping your polling time to something a little more reasonable. Do you really need to poll every 5 seconds to make sure firefox is still running?