Mustache layout renderer for NLog.

PM> Install-Package NLog.Mustache

Templates must be embedded resources in an assembly loaded in the app domain. They are cached so the lookup for any given template happens only once for the life of the app domain. Typically the filename is all that is needed to find the template, but you may need to include the namespace if there are ambiguous resource names (e.g. MyApp.Logging.Template.html). The template filename is the default parameter and can be used as follows:

var target = new MemoryTarget
{
    Layout = "${mustache:Template.mustache}"
};

An optional debug flag can be passed if the template is not rendering. This flag will cause the renderer to return debugging information.

Layout = "${mustache:Template.mustache:debug=true}"

The model that is passed to the template is a wrapper around the LogEventInfo object and exposes all its properties.

{{level}}: {{#exception}}{{message}}{{/exception}}

An additional Exceptions (plural) property has been added to allow you to enumerate a flattened list of the exception and inner exceptions. The additional number property indicates the 1-based index of the exception.

{{#exceptions}}
    {{number}}: {{message}}
{{/exceptions}}

Exceptions also have an additional properties property that allows you to enumerate all the properties on the exception. These have a Name, Value and HasValue property.

{{#exceptions}}
    {{message}}
    {{#properties}}
        {{#hasvalue}}
            {{name}}: {{value}}
        {{/hasvalue}}
    {{/properties}}
{{/exceptions}}

Properties of System.Exception are directly accessible with the standard mustache syntax (e.g. {{message}}). Properties of System.Exception subtypes can only be accessed with the property helper. For example if your exception subtype has an Id property you can access it as follows:

{{property exception "id"}}: {{message}}
{{#exceptions}}
    {{property . "id"}}: {{message}}
{{/exceptions}}

The first parameter indicates where the property is declared, either on the current object (As indicated with a .) or a property of the current object. The second is the property itself.

The property helper optionally supports a .NET format string:

{{property exception "timestamp" "yyyyMMdd"}}

See the next section for more information on format string syntax.

Values can be formatted with the format helper and a .NET format string:

{{format timestamp "yyyyMMdd"}}

NOTE: Format strings do not support whitespace. Whitespace can be passed url encoded e.g. yyyyMMdd%20hh:mm:ss.

By default a blank string is returned if there is a formatting error. To return the error message when an error occurs, prefix the format string with a ! as follows:

{{format timestamp "!yyyyMMdd"}}}

Values can be replaced with the replace helper. You can specify one or multiple replacements as demonstrated below:

{{replace message "search" "replacement" "search" "replacement" ...}}

NOTE: Search and replacement strings do not support whitespace. Whitespace can be passed url encoded e.g. %0D%0A for new lines or %20 for spaces.

MIT License.