Serilog.Settings.AppSettings

An XML <appSettings> reader for Serilog.

Getting started

The <appSettings> support package needs to be installed from NuGet:

Install-Package Serilog.Settings.AppSettings

To read configuration from <appSettings> use the ReadFrom.AppSettings() extension method on your LoggerConfiguration:

Log.Logger = new LoggerConfiguration()
  .ReadFrom.AppSettings()
  ... // Other configuration here, then
  .CreateLogger()

You can mix and match XML and code-based configuration, but each sink must be configured either using XML or in code - sinks added in code can't be modified via app settings.

Configuration syntax

To configure the logger, an <appSettings> element should be included in the program's App.config or Web.config file.

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="serilog:minimum-level" value="Verbose" />
    <!-- More settings here -->

Serilog settings are prefixed with serilog:.

Setting the minimum level

To set the logging level for the app use the serilog:minimum-level setting key.

    <add key="serilog:minimum-level" value="Verbose" />

Valid values are those defined in the LogEventLevel enumeration: Verbose, Debug, Information, Warning, Error, Fatal.

Adding a sink

Sinks are added with the serilog:write-to key. The setting name matches the configuration method name that you'd use in code, so the following are equivalent:

    .WriteTo.Console()

In XML:

    <add key="serilog:write-to:Console" />

NOTE: When using serilog:* keys need to be unique.

Sink assemblies must be specified using the serilog:using syntax. For example, to configure

<add key="serilog:using:Console" value="Serilog.Sinks.Console" />
<add key="serilog:write-to:Console"/>

If the sink accepts parameters, these are specified by appending the parameter name to the setting.

    .WriteTo.File(@"C:\Logs\myapp-{Date}.txt", retainedFileCountLimit: 10)

In XML:

    <add key="serilog:write-to:File.path" value="C:\Logs\myapp-{Date}.txt" />
    <add key="serilog:write-to:File.retainedFileCountLimit" value="10" />

Any environment variables specified in a setting value (e.g. %TEMP%) will be expanded appropriately when read.

Using sink extensions from additional assemblies

To use sinks and enrichers from additional assemblies, specify them with a serilog:using key.

For example, to use configuration from the Serilog.Sinks.EventLog assembly:

    <add key="serilog:using:EventLog" value="Serilog.Sinks.EventLog" />
    <add key="serilog:write-to:EventLog.source" value="Serilog Demo" />

Enriching with properties

To attach additional properties to log events, specify them with the serilog:enrich:with-property directive.

For example, to add the property Release with the value "1.2-develop" to all events:

    <add key="serilog:enrich:with-property:Release" value="1.2-develop" />

Adding minimum level overrides

Since Serilog 2.1, minimum level overrides can be added to change the minimum level for some specific namespaces. This is done with the setting key serilog:minimum-level:override: followed by the source context prefix.

For instance, the following are equivalent :

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Information()
    .MinimumLevel.Override("Microsoft", LogEventLevel.Warning)
    .MinimumLevel.Override("Microsoft.AspNetCore.Mvc", LogEventLevel.Error)

and in XML

    <add key="serilog:minimum-level" value="Information" />
    <add key="serilog:minimum-level:override:Microsoft" value="Warning" />
    <add key="serilog:minimum-level:override:Microsoft.AspNetCore.Mvc" value="Error" />

Filtering

Filters can be specified using the Serilog.Filters.Expressions package; see the README there for more information.

Setting values from enumerations

When configuring sink settings with values from enumerations, use the member name, without specifying the name of the enumeration.

For example, to configure the RollingInterval of the File Sink to create a new log file per day, use Day instead of RollingInterval.Day:

    <add key="serilog:write-to:File.rollingInterval" value="Day"/>

If you specify the the name of the enumeration, you'll receive an error similar to System.ArgumentException: Requested value 'RollingInterval.Day' was not found

Destructuring

LoggerConfiguration
    .Destructure.ToMaximumDepth(maximumDestructuringDepth: 3)
    .Destructure.ToMaximumStringLength(maximumStringLength: 3)
    .Destructure.ToMaximumCollectionCount(maximumCollectionCount: 3)
    .Destructure.AsScalar(typeof(System.Version))
    .Destructure.With(new CustomPolicy());

and in XML

<add key="serilog:destructure:ToMaximumDepth.maximumDestructuringDepth" value="3" />
<add key="serilog:destructure:ToMaximumStringLength.maximumStringLength" value="3" />
<add key="serilog:destructure:ToMaximumCollectionCount.maximumCollectionCount" value="3" />
<add key="serilog:destructure:AsScalar.scalarType" value="System.Version" />
<add key="serilog:destructure:With.policy" value="My.CustomPolicy, MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />