Serilog.Sinks.ContextRollingFile

Writes Serilog events to a set of text files, one per day for each context.

Getting started

Install the Serilog.Sinks.ContextRollingFile package from NuGet:

Install-Package Serilog.Sinks.ContextRollingFile

To configure the sink in C# code, call WriteTo.ContextRollingFile() during logger configuration:

var log = new LoggerConfiguration()
    .WriteTo.ContextRollingFile("log-{MyProperty:l}-{Date}.txt")
    .CreateLogger();
    
Log.Information("This will be written to the rolling file set");

Predefined Placeholders (HalfHour, Hour, Date)

The filename should include one the the predefined placeholders {HalfHour}, {Hour} or {Date} , which will be replaced with the date of the events contained in the file. Filenames use the yyyyMMdd date format so that files can be ordered using a lexicographic sort:

log-foo-20160631.txt
log-foo-20160701.txt
log-foo-20160702.txt

Custom Placeholders

The filename may include one or more placeholders, which will be replaced with the properties of each log event. This can be useful if you want to have seperate log files depending on the context. Please be aware that Serilog renders string values in double quotes by default. Since quotes are not allowed in paths and filenames, you omit them using the :l literal format specifier on the property, e.g. {MyProperty:l}

The following sample creates two seperate files based on the Context property.

var log = new LoggerConfiguration()
    .WriteTo.ContextRollingFile("log-{Context:l}-{Date}.txt")
    .CreateLogger();
    
Log.Information("This will be written to the {Context} file set", "Foo");
Log.Information("This will be written to the {Context} file set", "Bar");

log-Foo-20160701.txt
log-Bar-20160702.txt

Note: HalfHour, Hour and Date are predefined placeholders. As such they won't be replaced in the path template by your own properties.

Source Contexts

Although you can use any placeholders you like, this can be particularly useful in combination with the ForContext method:

var log = new LoggerConfiguration()
    .WriteTo.ContextRollingFile("log-{SourceContext:l}-{Date}.txt")
    .CreateLogger()
    .ForContext<MyClass>();
    
myLog.Information("Hello!");

The event written will include a property SourceContext with value "MyNamespace.MyClass" that is used in the path template to create the log files.

log-MyNamespace.MyClass-20160631.txt
log-MyNamespace.MyClass-20160701.txt
log-MyNamespace.MyClass-20160702.txt

Other Configuration Options

The ContextRollingFile sink extends the RollingFile sink and supports the same configuration options. Refer to the Serilog.Sinks.RollingFile documentation for these options and their usage.