Edit on GitHub

Logging

An implementation-free logging API for .Net

ServiceStack.Logging is an implementation and dependency-free logging API with adapters for all of .NET’s popular logging providers. It allows your business logic to bind to an easily-mockable and testable dependency-free interface whilst providing the flexibility to switch logging providers at runtime.

Download on NuGet

Currently there are 5 different .NET logging providers available on NuGet:

NLog

PM> Install-Package ServiceStack.Logging.NLog

Elmah

PM> Install-Package ServiceStack.Logging.Elmah

Log4Net

PM> Install-Package ServiceStack.Logging.Log4Net

EventLog

PM> Install-Package ServiceStack.Logging.EventLog

SlackLog

PM> Install-Package ServiceStack.Logging.Slack

SerilogLogger

PM> Install-Package ServiceStack.Logging.Serilog

Note: The ConsoleLogFactory and DebugLogFactory and are already built-in and bind to .NET Framework’s Console and Debug loggers.

Why a Logging Interface?

Even in the spirit of Bind to interfaces, not implementations, many .NET projects still have a hard dependency to log4net.

Although log4net is the standard for logging in .NET, potential problems can arise from your libraries having a hard dependency on it:

  • Your library needs to be shipped with a third-party dependency
  • Potential conflicts can occur when different libraries have dependency on different versions of log4net (e.g. the 1.2.9 / 1.2.10 dependency problem).
  • You may want to use a different logging provider (i.e. network distributed logging)
  • You want your logging for Unit and Integration tests to redirect to the Console or Debug logger without any configuraiton.
  • Something better like elmah can come along requiring a major rewrite to take advantage of it

ServiceStack.Logging solves these problems by providing an implementation-free ILog interface that your application logic can bind to where your Application Host project can bind to the concrete logging implementation at deploy or runtime.

ServiceStack.Logging also includes adapters for the following logging providers:

  • Elmah
  • NLog
  • Log4Net 1.2.10+
  • Log4Net 1.2.9
  • EventLog
  • SlackLog
  • Serilog
  • Console Log
  • Debug Log
  • Null / Empty Log

Registration Examples

Once on your App Startup, either In your AppHost.cs or Global.asax file inject the concrete logging implementation that your app should use, e.g.

Built-in Loggers

//Console.WriteLine
LogManager.LogFactory = new ConsoleLogFactory(debugEnabled:true); 
//Debug.WriteLine
LogManager.LogFactory = new DebugLogFactory(debugEnabled:true);   
//Capture logs in StringBuilder
LogManager.LogFactory = new StringBuilderLogFactory(); 
//No Logging (default)
LogManager.LogFactory = new NullLogFactory();   

NLog

LogManager.LogFactory = new NLogFactory(); 

Log4Net

//Also runs log4net.Config.XmlConfigurator.Configure()
LogManager.LogFactory = new Log4NetFactory(configureLog4Net:true); 

Event Log

LogManager.LogFactory = new EventLogFactory("Logging.Tests", "Application");

Then your application logic can bind to and use a lightweight implementation-free ILog which at runtime will be an instance of the concrete implementation configured in your host:

ILog log = LogManager.GetLogger(GetType());

log.Debug("Debug Event Log Entry.");
log.Warn("Warning Event Log Entry.");

Elmah

To configure Elmah register it before initializing ServiceStack’s AppHost, passing in the Global HttpApplication Instance and an alternate logger you’d like to use to for your Debug and Info messages, e.g:

public class Global : System.Web.HttpApplication
{
    protected void Application_Start(object sender, EventArgs e)
    {
        var debugMessagesLog = new ConsoleLogFactory();
        LogManager.LogFactory = new ElmahLogFactory(debugMessagesLog, this);
        new AppHost().Init();
    }
}

Elmah also requires its handlers and modules to be registered in the Web.config which lets you view your Elmah Error Log at: /elmah.xsd:

<configuration>
  <system.web>
    ...
    <httpHandlers>
      <add verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" />
    </httpHandlers>
    <httpModules>
      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah"/>
    </httpModules>
  </system.web>

  <system.webServer>
    <handlers>
      ...
      <add name="Elmah" path="elmah.axd" verb="POST,GET,HEAD" 
           type="Elmah.ErrorLogPageFactory, Elmah" preCondition="integratedMode" />
    </handlers>
    <modules>
      <add name="Elmah.ErrorLog" type="Elmah.ErrorLogModule, Elmah" preCondition="managedHandler" />
    </modules>
  </system.webServer>

</configuration>

For a working example see the Logging.Elmah UseCase which has ServiceStack and Elmah configured together.

Slack

Configure Slack Logger with the channels you want to log it to, e.g:

LogManager.LogFactory = new SlackLogFactory("{GeneratedSlackUrlFromCreatingIncomingWebhook}", 
    debugEnabled:true)
{
    //Alternate default channel than one specified when creating Incoming Webhook.
    DefaultChannel = "other-default-channel",
    //Custom channel for Fatal logs. Warn, Info etc will fallback to DefaultChannel or 
    //channel specified when Incoming Webhook was created.
    FatalChannel = "more-grog-logs",
    //Custom bot username other than default
    BotUsername = "Guybrush Threepwood",
    //Custom channel prefix can be provided to help filter logs from different users or environments. 
    ChannelPrefix = System.Security.Principal.WindowsIdentity.GetCurrent().Name
};

LogManager.LogFactory = new SlackLogFactory(appSettings);

More usage examples are available in SlackLogFactoryTests.

Serilog

To Configure Serilog Logging, first download ServiceStack.Logging.Serilog from NuGet:

PM> Install-Package ServiceStack.Logging.Serilog

Then configure ServiceStack to use SerilogFactory:

LogManager.LogFactory =  new SerilogFactory();

The Serilog adapter includes enhanced Serilog-specific APIs:

ILog.Debug(Exception ex, string messageTemplate, params object[] propertyValues)
ILog.Info(Exception ex, string messageTemplate, params object[] propertyValues)
ILog.Warn(Exception ex, string messageTemplate, params object[] propertyValues)
ILog.Error(Exception ex, string messageTemplate, params object[] propertyValues)
ILog.Fatal(Exception ex, string messageTemplate, params object[] propertyValues)
ILog.ForContext(Type type)
ILog.ForContext<T>()
ILog.ForContext(ILogEventEnricher enricher)
ILog.ForContext(IEnumerable<ILogEventEnricher> enrichers)
ILog.ForContext(string propertyName, object value, bool destructureObjects = false)

Usage Example

Using a logger in your Service is similar to other .NET Logging providers, e.g. you can initialize a static property for the class and use it in your services, e.g:

public class MyService : Service
{
    public static ILog Log = LogManager.GetLogger(typeof(MyService));

    public object Any(Request request)
    {
        if (Log.IsDebugEnabled)
            Log.Debug("In Request Service");
    }
}

Community Logging Providers

ServiceStack.Seq.RequestLogsFeature

Servicestack plugin that logs requests to Seq.

Community Resources