Potential Xamarin Issue

[CostaTC]

Hi there,

Found an odd issue when running the following code in Xamarin:

Log.Logger = new LoggerConfiguration() .WriteTo.File(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "XamarinLib-{Date}.txt") , outputTemplate: "{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} [{Level}] [{SourceContext}] {Message}{NewLine}{Exception}", fileSizeLimitBytes: 100000000, rollingInterval: RollingInterval.Day, rollOnFileSizeLimit: true, shared: true, retainedFileCountLimit: 31, encoding: Encoding.UTF8) .WriteTo.AndroidLog() .CreateLogger();

When the parameter "shared" is set to true, no file is created. When set to false it correctly creates the file. I'm not sure if this is a bug or if I'm misunderstanding how the shared property works :)

[nblumhardt]

Hi! To be honest, I didn't realize that this package even runs under Xamarin :-) ... I'd guess it's a platform limitation, but couldn't pinpoint it without some digging around. @geoffreyhuntley may have encountered this somewhere.

[helsq]

Hi, there!
I have same problem in Xamarin.iOS.
Yes, if you set the parameter "shared" to true then log file isn't created. Because file sink use named mutex for synchronization. Named mutex isn't supported on mobile platforms.
Caught exception while emitting to sink Serilog.Sinks.File.RollingFileSink: System.NotSupportedException: Specified method is not supported. at System.Threading.Mutex..ctor (System.Boolean initiallyOwned, System.String name) [0x00006] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.6.1.3/src/mono/mcs/class/corlib/System.Threading/Mutex.cs:167 at Serilog.Sinks.File.SharedFileSink..ctor (System.String path, Serilog.Formatting.ITextFormatter textFormatter, System.Nullable1[T] fileSizeLimitBytes, System.Text.Encoding encoding)`

[CostaTC]

Thanks for the info @helsq!

I suppose this means this isn't resolvable - or, at least, not really an issue for this library?
Pity, as file sharing has been a bit of a nightmare to deal with!

[helsq]

I think that this isn't resolvable if won't change method of processors synchronization.

[nblumhardt]

I think it's superficially resolvable - we could not synchronize access to the shared file for Xamarin, but then the file might show garbled/interleaved/corrupted data if multiple processes write to it concurrently. May be a fair trade-off to explore, if anyone's interested in putting together a proposal/PR. Cheers!

[nblumhardt]

Closing while we don't have any action items on this, but please feel free to jump in if you're keen to dig in deeper.

[kyurkchyan]

Came across this issue while investigating another one #109

[salamoun]

I can confirm that shared flag DOES NOT works on Xamarin.iOS/Android even when serilog is only process that is accessing file.
Setting shared to true and no file is created.
I think that is some problem on Xamarin platform. On .NET Standard project on Windows, shared flag works as expected.

[nblumhardt]

@salamoun thanks for jumping in!

As far as I know, no one maintaining this project currently uses Xamarin, so we're not able to make progress on this without some help.

Collecting SelfLog output to see whether shared: true generates an exceptions, and raising a new ticket with the exception message/stack trace, would be a great help if you (or anyone else watching this ticket) have a chance to investigate further. Thanks!

[Wolfteam]

Hi, sorry to revive this one, but what about just using the mutex ctor without providing a name in case of a not supported ex?

In the SharedFileSink ctor
            try
            {
                _mutex = new Mutex(false, mutexName);
            }
            catch (Exception)
            {
                _mutex = new Mutex(false);
            }

[nblumhardt]

@Wolfteam thanks for the suggestion; the semantics of the two constructors are very different, one is interprocess, the other isn't. Cheers!

[cesar-moya]

Hi guys,

I'm interested on using this sink on Xamarin forms but I'm also encountering the same issue when setting the shared flag. Is there any work ongoing to allow supporting Xamarin? Thanks!