Cause
Use of logger extension methods, such as Microsoft.Extensions.Logging.LoggerExtensions.LogInformation and Microsoft.Extensions.Logging.LoggerExtensions.LogDebug.
Rule description
For high-performance logging scenarios, use the LoggerMessage pattern instead of Microsoft.Extensions.Logging.Logger extension methods.
How to fix violations
Use Microsoft.Extensions.Logging.LoggerMessageAttribute to fix violations of this rule. (Or, if you're using .NET 5 or earlier, use the Microsoft.Extensions.Logging.LoggerMessage class.)
public class SomethingDoer
{
private readonly ILogger _logger;
public SomethingDoer(ILogger<SomethingDoer> logger)
{
_logger = logger;
}
public void DoSomething()
{
// This call violates CA1848.
_logger.LogInformation("Did something!");
}
}The following code fixes the violation.
public partial class SomethingDoer
{
private readonly ILogger _logger;
public SomethingDoer(ILogger<SomethingDoer> logger)
{
_logger = logger;
}
public void DoSomething()
{
Log_DidSomething();
}
[LoggerMessage(Level = LogLevel.Information, Message = "Did something!")]
private partial void Log_DidSomething();
}Microsoft.Extensions.Logging.LoggerMessage provides the following performance advantages over Microsoft.Extensions.Logging.Logger extension methods:
- Logger extension methods require "boxing" (converting) value types, such as
int, intoobject. The Microsoft.Extensions.Logging.LoggerMessage pattern avoids boxing by using static System.Action fields and extension methods with strongly typed parameters. - Logger extension methods must parse the message template (named format string) every time a log message is written. Microsoft.Extensions.Logging.LoggerMessage only requires parsing a template once when the message is defined.
When to suppress warnings
Do not suppress a warning from this rule.