> For the complete documentation index, see [llms.txt](https://vostok.gitbook.io/logging/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vostok.gitbook.io/logging/concepts/syntax/logging-extensions.md).

# Logging extensions

[Abstractions module](/logging/modules/abstractions.md) provides a wide set of extensions that take care of constructing [log events](/logging/concepts/log-events.md).

These extensions can be grouped in two ways:

* By level and name: **Debug**, **Info**, **Warn**, **Error**, **Fatal**.

* By parameters:
  * **string**:

    * Produces an event with given [message template](/logging/concepts/syntax/message-templates.md) and no properties.
    * ```csharp
      log.Info("Hello, world!");
      ```

  * **string + T**:

    * Produces an event with given [message template](/logging/concepts/syntax/message-templates.md) and properties of given object.
    * ```csharp
      log.Info("Hello, {Who}!", new { Who = "world" });
      ```

  * **string + object\[]**:

    * Produces an event with given [message template](/logging/concepts/syntax/message-templates.md) and given property values (names are inferred from message template).
    * ```csharp
      log.Info("Hello, {Who}!", "world");
      ```

  * **Exception**:

    * Produces an event with given exception and no message or properties.
    * ```csharp
      log.Error(new Exception());
      ```

  * **Exception + string**:

    * Produces an event with given exception and [message template](/logging/concepts/syntax/message-templates.md).
    * ```csharp
      log.Error(new Exception(), "I have failed.");
      ```

  * **Exception + string + T**:

    * Produces an event with given exception, [message template](/logging/concepts/syntax/message-templates.md) and properties of given object.
    * ```csharp
      log.Error(new Exception(), "{Who} have/has failed.", new { Who = "I" });
      ```

  * **Exception + string + object\[]**:

    * Produces an event with given exception, [message template](/logging/concepts/syntax/message-templates.md) and given property values (names are inferred from message template).
    * ```csharp
      log.Error(new Exception(), "{Who} have/has failed.", "He");
      ```

  * **interpolated string**:
    * Produces an event with given [message template](/logging/concepts/syntax/message-templates.md) and given property values (names are extracted from argument names).
    * [Requires](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-10.0/improved-interpolated-strings) C# 10.
    * ```csharp
      var Who = "world";
      log.Info($"Hello, {Who}!");
      ```

  * **Exception + interpolated string**:
    * Produces an event with given exception, [message template](/logging/concepts/syntax/message-templates.md) and given property values (names are extracted from argument names).
    * [Requires](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-10.0/improved-interpolated-strings) C# 10.
    * ```csharp
      var Who = "world";
      log.Info(new Exception(), $"Hello, {Who}!");
      ```

See the section about [providing property values](/logging/concepts/syntax/passing-properties.md) to extensions to get a grasp of how to provide values for placeholders in message template.

All extensions produce events with timestamp set to current time and level corresponding to method name.