How to create new file only after 5 minutes and write all 5 minutes data into that file

Question

I am generating data every 1 second to write in a file but I want a new file every 5 minutes rather than every 1 second and want to writes all 5 minutes data into that file.

Below code generate a new file every 1 second and for that period data writes in the file. How I can generate a new file every 5 minutes?

 static void Main(string[] args)
    {
        var incremental = 0;

        while (true)
        {
            Go(incremental);

            incremental++;
            Thread.Sleep(1000);
        }
    }


private static void Go(int incremental)
    {
        var fileFullPath = GetDynamicFullPath(@"C:\Temp\");

        using var rewrite = new StreamWriter(fileFullPath);
        rewrite.WriteLine(incremental);
    }

    private static string GetDynamicFullPath(string basePath)
    {
        var dynamicFileName = $"file-{DateTime.Now:yyyyMMddHHmmssfff}.txt";

        return basePath + dynamicFileName;
    } 

Answer 1

This is exactly the case where the .Net Reactive library (System.Reactive) shines. Install it via NuGet package maneger, then the code will look like this:

1:declare buffer variable:

private readonly Subject<int> _myBuffer = new Subject<int>();

2:setup buffer subscription

_myBuffer.Buffer(TimeSpan.FromMinutes(5))
    .Subscribe(bufferData => Go(bufferData.ToArray()));

3:your Do method is little changed to accept array of ints

private void Go(int[] bufferData)
{
    var fileFullPath = GetDynamicFullPath(@"C:\Temp\");

    using var rewrite = new StreamWriter(fileFullPath);
    rewrite.WriteLine(bufferData);
}

4:finally, the infinite loop

var incremental = 0;

while (true)
{
    _myBuffer.OnNext(incremental++);
    Thread.Sleep(1000);
}

It can not be simpler!

The point is that Buffer method will automatically collect all received data for the specified period. You just need to subscribe to it (start listening to it) and then your `Do' method will be executed every 5 minutes with the buffered data.

Answer 2

I would advice you to use a Timer to flush and create the files all 5 Minutes. You then also should use a SemaphoreSlim to synchronize the access to the StreamWriter, because the callback for the timer may be executed on any Thread-Pool-Thread. So I would do something like:

public static StreamWriter writer;
public static SemaphoreSlim mutex;

static void Main(string[] args)
{
    mutex = new SemaphoreSlim(1,1);

    var incremental = 0;

    using var timer = new Timer(5 * 60 * 1000);

    static void Timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        CreateNewFile();
    }

    timer.Elapsed += Timer_Elapsed;
    timer.AutoReset = true;
    timer.Start();

    while (true)
    {
        WriteData(incremental);
        Thread.Sleep(1000);
        incremental++;
    }
}

private static void WriteData(int data)
{
    mutex.Wait();

    try
    {
        // write you data ...
    }
    finally
    {
        mutex.Release();
    }
}

private static void CreateNewFile()
{
    mutex.Wait();
    try
    {
        if (writer != null)
        {
            writer.Dispose();
            writer = null;
        }

        var fileFullPath = GetDynamicFullPath(@"C:\Temp\");

        writer = new StreamWriter(fileFullPath);
    }
    finally
    {
        mutex.Release();
    }
}

private static string GetDynamicFullPath(string basePath)
{
    var dynamicFileName = $"file-{DateTime.Now:yyyyMMddHHmmssfff}.txt";

    return basePath + dynamicFileName;
}

In addition I would suggest to use the async versions of all these methodes. So WaitAsync(), WriteLineAsync, ...

public static StreamWriter writer;
public static SemaphoreSlim mutex;

static async Task Main(string[] args)
{
    mutex = new SemaphoreSlim(1, 1);

    var incremental = 0;

    using var timer = new Timer(5 * 60 * 1000);

    static async void Timer_ElapsedAsync(object sender, ElapsedEventArgs e)
    {
        await CreateNewFileAsync();
    }

    timer.Elapsed += Timer_ElapsedAsync;
    timer.AutoReset = true;
    timer.Start();

    while (true)
    {
        await WriteDataAsync(incremental);

        await Task.Delay(1000);

        incremental++;
    }
}

private static async Task WriteDataAsync(int data)
{
    await mutex.WaitAsync();

    try
    {
        // write you data ...
        await writer.WriteLineAsync(data.ToString());
    }
    finally
    {
        mutex.Release();
    }
}

private static async Task CreateNewFileAsync()
{
    await mutex.WaitAsync();
    try
    {
        if (writer != null)
        {
            await writer.DisposeAsync();
            writer = null;
        }

        var fileFullPath = GetDynamicFullPath(@"C:\Temp\");

        writer = new StreamWriter(fileFullPath);
    }
    finally
    {
        mutex.Release();
    }
}

private static string GetDynamicFullPath(string basePath)
{
    var dynamicFileName = $"file-{DateTime.Now:yyyyMMddHHmmssfff}.txt";

    return basePath + dynamicFileName;
}

Answer 3

I would suggest the simplest solution:

• You can store a datetime when the last file was created.
• You can also define a 5 mins threshold.
• You should call the file create method when the current datetime is greater than the sum of the last created timestamp and the threshold.

Sample code:

private static readonly TimeSpan threshold = TimeSpan.FromMinutes(5);
private static DateTime lastCreated = DateTime.UtcNow;
public static void Main()
{
    while(true)
    {
        if(DateTime.UtcNow >= lastCreated.Add(threshold))
        {
            //call the file create method
            lastCreated = DateTime.UtcNow;
        }
        Thread.Sleep(1000);
    }
}