Flush-to-disk option

In Windows 10 and Windows Server 2012 R2, StreamWriter.Flush won’t write the data to disk immediately.

You can know this by running under code and watching the file size through “dir” command.

Log.Logger = new LoggerConfiguration()
    .WriteTo.File("log.txt")
    .CreateLogger();

for (var i = 0; i < 100; ++i)
{
    Console.WriteLine(i);
    Log.Information("Hello, file logger!");
    System.Threading.Thread.Sleep(1000);
}

We can write to disk immediately by touching the file like this.

var touched = new FileInfo("log.txt").LastWriteTime;

Could you please improve “buffered:false” or add new option to do this?

P.S. I’m using Serilog.Sinks.RollingFile for windows service logging, and collecting the logs by Microsoft Operations Management Suite (OMS). I found OMS log collection is not working good, because above.

[nblumhardt]

@pakrym thanks for the info, sounds like this is something we’ll need to accommodate.

A simple wrapper that closed/reopened the file by disposing/re-creating the sink on a timer could be implemented atop what’s there now, but doesn’t seem like a long-term option.

Going one step further might look like:

1. Add FlushToDisk() on both FileSink and RollingFileSink
2. Create a wrapper sink PeriodicFlushToDisk that calls the wrapped sink’s FlushToDisk() method on a timer at some specified interval
3. Add TimeSpan? flushToDiskInterval as an optional argument to WriteTo.File() and WriteTo.RollingFile(), and wrap the configured sink if it is specified

Sound like a plan?

[nblumhardt]

@muratg I’ll put some time aside on Monday to upgrade some apps and test more rigorously. Considering it’s an “opt-in” feature there’s no great danger in putting it out there, ideally we’ll just be confident that it works 😃 … If I can’t break it, I’m happy to push the button 👍