DanHartley/Serilog.Sinks.Intercepterv1.0.4

Modify, filter, buffer event logs. Buffer log messages and conditionally output them based on later events.

A wrapper for other Serilog sinks. This sink allows you to "intercept" log events just as they are written to a wrapped sink. This is used to modify, filter, buffer event logs. This is especially suited to reducing log volume, for example only writing logs when an error has occurred.

Getting started

Assuming you have already installed the target sink, such as the console sink, move the wrapped sink's configuration within a WriteTo.Intercepter() statement:

Log.Logger = new LoggerConfiguration()
  .WriteTo.Intercepter(x => x.Console())
  // Other logger configuration
  .CreateLogger()

Log.Information("Continue to use the log as normal");

// At application shutdown
Log.CloseAndFlush();

or if using Serilog.Settings.Configuration JSON:

{
  "Serilog": {
    "WriteTo": [{
    "Name": "Intercepter",
    "Args": {
      "configure": [{
        "Name": "Console"
        }]
      }
    }]
  }
}

Whilst no Intercepter has been set, all log messages will be sent onwards to the wrapped sink (Console in this case).

LogLevelBuffer Intercepter

This Intercepter is designed to reduce log volume by storing log events and only writing when an error level log event is received.

// add the Intercepter
using (IntercepterContext.PushLogLevelBuffer(Serilog.Events.LogEventLevel.Error))
{
    Log.Information("This log is stored by the intercepter.");
    Log.Error("On this error, this and all previous log events are sent to the wrapped sink");
    Log.Information("As there has already been an error, this is sent to");
}

Can be used per application request to only write the logs of requests where there was an error.

Log event ordering

In the event of any buffering, the log events sent to the output are in the original order and with the original timestamps.

ASP.NET Core integration

Please see here for details.