Do log entries always get flushed to file?

[Marv51]

I am investigating a crash in our app by analyzing the logging just before the crash. That got me wondering: Is the last logging message reliable? If an exception occurs, will the logging queue be flushed completely?

I could not find any method to manually flush the logging messages to the file. Is that because it is not necessary?

[VitaliyMF]

That got me wondering: Is the last logging message reliable? If an exception occurs, will the logging queue be flushed completely?

It seems only answer I can get is: "it depends".

From one side, FileLoggerProvider is implemented in a way that should contribute to this desired behavior: in FileLoggerProvider.ProcessQueue where log messages queue is processed, then the last log entry is written to a file an explicit Flush is called (see FileWriter.WriteMessage(string message, bool flush). Also, on FileLoggerProvider.Dispose opened file is closed and before that all remaining messages are queue are processed - this should guarantee that all last log entries are written to a file.

However, it could be an exception in your app that causes immedia crush and in this case it might be possible situation that some log entries that were in the queue are either not processed (=not written to a file) or flush wasn't called because of the same reason.

I could not find any method to manually flush the logging messages to the file. Is that because it is not necessary?

Normally this is not needed:

• flush is called on FileLoggerProvider.Dispose (when your .NET app shutdowns correctly)
• flush is called each time when the last log message in queue is written

[Marv51]

Hey, thanks for the details @VitaliyMF.

Your library performed perfectly. The problem we had is super weird, but with NReco.Logging we narrowed it down to the exact line that was causing the crash.

In this case, the answer to my question "Do log entries always get flushed to file?" was absolutely "YES".

Thanks for the great work on this library.