NLog adapter¶

An implementation of the logging abstraction (ILog/IFluentLogBuilder) that targets NLog as the back‑end. It maps fluent builder calls to NLog’s LogEventInfo, supports semantic properties, and integrates cleanly with NLog targets including Seq.

Package: TA.Utils.Logging.Nlog
Classes: LoggingService, LogBuilder, LogServiceOptions

Quick start¶

using TA.Utils.Logging.NLog;

var options = LogServiceOptions.DefaultOptions
    .UseVerbosity()
    .CustomSeverityPropertyName("CustomLevel");

ILog log = new LoggingService(options)
    .WithAmbientProperty("CorrelationId", Guid.NewGuid());

log.Info().Message("Hello {who}").Property("who", "world").Write();
log.Level("Important").Message("This is important").Write();

Verbosity and custom levels¶

UseVerbosity(propertyName = "verbosity")
Adds a numeric verbosity property to each entry when you pass the number to the severity method (e.g., Info(2)).
CustomSeverityPropertyName(name = "CustomLevel")
The custom severity property used when you call log.Level("Name").

Seq target mapping example¶

To use custom levels with Seq, configure the Seq target to take its level from the custom property when present:

<target xsi:type="Seq" name="seq"
        serverUrl="http://your-server-url:5341"
        apiKey="your-seq-api-key"
        seqLevel="${event-properties:CustomLevel:whenEmpty=${level}}" />

Logger names and ambient properties¶

WithName("Source") sets the logger name, which NLog can use for routing and filtering (e.g., ${logger} in layouts).
WithAmbientProperty("name", value) adds a property to all subsequent entries; useful for correlation IDs, component, tenant, etc.

Message templates and properties¶

Use either indexed placeholders ({0}) or named placeholders ({name}); named placeholders are recommended for semantic logging.
Attach additional properties explicitly via .Property("name", value) or .Properties(dict).

Shutdown¶

Call log.Shutdown() or rely on NLog’s AutoShutdown = true set by the adapter type initialiser.

Troubleshooting¶

If a property name collides, the adapter auto‑deconflicts by suffixing a number (e.g., property, property2).
Ensure IsEnabled(Level) is true for the chosen level; otherwise .Write() is a no‑op.