Missing logs in .NET

[linusalnervik]

Hi. When logging with a .NET application at the end of the program, the last logging is not committed to the file. Could it be that the dispose method is not waiting for the writing to complete? Have also noticed that when creating a new file for logging, creating a log event, and then closing the console, only a empty file is created, with no logging included.

[VitaliyMF]

FileLoggerProvider implements IDispose, and normally it should be called on the app shut down. If you use Microsoft.Logging with DI container, it does that by default. If not, you might need to call LoggerFactory.Dispose explicitely on the app stop.

[linusalnervik]

Ok. Well we do use Microsoft.Logging with DI container. But shouldn't the filewriter thread of the event keep the main thread (that call the disposal due to ending) from closing?

Right now the garbage collection seems to close out the filewriter thread to early.

[VitaliyMF]

@linusalnervik I'm not aware about your .NET app specifics; normally FileLoggerProvider works in this way:

• it is registered as logging provider on the app start. An active log file is opened immediately and remains open while app is working
• when app logs messages, they are queued and flushed to the file from the special background thread (this is a best-practice for logger providers)
• when app stops, LoggingFactory is disposed, and it calls Dispose for all registered logging providers. In the case of FileLoggingProvider it just ensures that queue is empty and all log messages are written to the file, and then closes the file.

Hope this helps.

[linusalnervik]

Hi again. This code will sometimes only create an empty file (it's a bit flaky would say 50% of the times).

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

var serviceProvider = new ServiceCollection()
           .AddLogging(loggingBuilder => {
               loggingBuilder.AddFile("app.log", append: true);
           }).BuildServiceProvider();

var logger = serviceProvider.GetService<ILoggerFactory>()
           .CreateLogger<Program>();
logger.LogInformation("Starting application");

When adding a wait in the end the logging row is always commited to the file

Thread.Sleep(2000);

[VitaliyMF]

Do you call serviceProvider.Dispose() when your program ends?

[linusalnervik]

Yee that was the issue.

Thanks for help