LoggerExtensions

LoggerExtensions is a static utility class that provides extension methods for the ILogger interface, enabling convenient and consistent logging across .NET applications. It is part of the Microsoft.Extensions.Logging infrastructure and is widely used by ASP.NET Core and other platforms relying on the logging abstractions.

The extension methods cover the common log levels, including Information, Debug, Warning, Error, and Critical, and offer overloads that accept a message template, parameters, an exception, and an EventId. Message templates support structured logging with placeholders such as {Name} and {Id}, which are populated by the supplied arguments. These methods are designed to avoid performing string formatting when the target log level is disabled, improving runtime efficiency.

LoggerExtensions also facilitates attaching contextual data through EventId and, via the underlying ILogger interface, supports logging scopes to cluster related log entries and provide richer diagnostics. This helps developers produce more searchable and analyzable logs across different providers.

Usage emphasizes readability and structured data. A typical call passes a template and arguments, producing structured logs that log providers can serialize and index. Because formatting is deferred until enabled, unused arguments incur minimal cost at runtime.

In practice, LoggerExtensions underpins most logging usage in modern .NET applications, serving as a bridge between the ILogger interface and concrete logging providers such as Console, Debug, and third-party sinks. It standardizes how messages are authored and emitted, contributing to consistent observability across an application.