Serilog: Contextual logging with log context enricher not working

[brgrz]

I've configured the logger this way:

Log.Logger = new LoggerConfiguration()
                .Enrich.FromLogContext()
                .WriteTo.File(logsFile, rollingInterval: RollingInterval.Day)
                .CreateLogger();

then used this code to create a contextual logger in my POCO classes:

private readonly ILogger _logger = Log.ForContext<Site>();

I am not seeing any contextual information in my log files. Does the file sink not support the contextual info or something else is wrong?

[tsimbalar]

Hi,

You are using the default output format for the File sink, which is
{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} [{Level:u3}] {Message:lj}{NewLine}{Exception}.

This means that by default, you will see the rendered message + properties ({Message}) but not attached properties (like contextual information) that are not part of the log message template.

You can use the {Properties} element in the output format to show remaining properties that are not used in the log message template. This is documented here : https://github.com/serilog/serilog/wiki/Formatting-Output#formatting-plain-text

If you try :

Log.Logger = new LoggerConfiguration()
                .Enrich.FromLogContext()
                .WriteTo.File(logsFile, 
                    outputTemplate: "{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} [{Level:u3}] {Message:lj}{NewLine}{Exception}{NewLine}{Properties}"
                    rollingInterval: RollingInterval.Day)
                .CreateLogger();

You should see the extra properties (like SourceContext or values from LogContext).
You can also change formatting of the {Properties} to {Properties:j} for JSON-formatting of the properties.

I hope this helps !

[sanzor]

Hello is there any way to display only certain properties ?
Can you do something like
outputTemplate: "{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} [{Level:u3}] {Message:lj}{NewLine}{Exception}{NewLine}{Properties : SomePropertyOnly }"

[bartelink]

@sanzor main tool at your disposal is to plug in an Enricher that does a RemoveProperty before you reach that point in the emission chain (about to be wrapped) ETA: see the gitter chat for similar discussion over last week