Possible Reloadable Logger Issue

[simbaja]

I've got .netcore31 application (both a generic host and ASP.NET) application where a logger is throwing an exception when using the reloadable logger. I haven't developed a minimum test case, but it may have to do with static loggers being accessed early in the lifetime. The pattern is as follows:

1. Create a class with a static logger (private static ILogger _log = Log.ForContext();
2. Add another static method/property to the class, call a log method (i.e. _log.Debug) in the method.
3. Add a non-static method that calls three log methods (i.e. _log.Debug x3)
4. During services initialization, call the static method
5. Initialize the CreateBootstrapLogger/UseSerilog as normal
6. In the worker, get an instance of the class and call the non-static method.
7. The first log method will succeed, as will the second
8. The third throws an exception, because _cached is somehow null but _frozen is true (so it's trying to directly call the _cached logger)

If I get some time, I'll try to get a minimum reproducible example written, but I'm under some tight work deadlines at the moment. Hopefully the description above will help find the logic issue. Presumably, _cached = null and _frozen = true should never happen.

[nblumhardt]

It looks like we should probably be publishing the new (hopefully non-null) _cached here before we publish _frozen:

https://github.com/serilog/serilog-extensions-hosting/blob/dev/src/Serilog.Extensions.Hosting/Extensions/Hosting/CachingReloadableLogger.cs#L170

I'm a little suspicious of:

serilog-extensions-hosting/src/Serilog.Extensions.Hosting/Extensions/Hosting/ReloadableLogger.cs

Line 657 in 5540199

var (logger, _) = UpdateForCaller(root, cachedParent, parent, out newRoot, out newCached, out frozen);

though, since I can't immediately figure out how newCached is going to be non-null when this method returns; we might actually need to coalesce it with the logger we're ignoring via the _ discard in the returned tuple.

Needs 👀 :-)

[nblumhardt]

Would be great if you're able to share a partial stack trace, and the exception message, @simbaja - thanks!

[simbaja]

SerilogException.zip

I think that this is a minimal reproduction of the issue (hopefully it fails on your machine too). Let me know if anything else would be helpful.

[nblumhardt]

Reproduced - thanks! Will update the thread when I have further info.

Best regards,
Nick

[nblumhardt]

Version 4.1.1-dev-00058 is now published on NuGet and should resolve the issue. Any chance you can confirm, @simbaja ? I'll queue up a release version if the fix works in your original code.

[simbaja]

Confirmed that the fix works in the original code. Thanks for investigating and resolving!