Customize the C# SDK logger

The logger logs information about your experiments to help you with debugging. You can customize where log information is sent and what kind of information is tracked.

To improve your experience setting up the SDK and configuring your production environment, we recommend that you pass in a logger for your Optimizely client. See the code example below.

using OptimizelySDK.Logger;

public class CustomLogger : ILogger
{
    private readonly LogLevel _minLogLevel;

    public CustomLogger(LogLevel minLogLevel) => _minLogLevel = minLogLevel;

    public void Log(LogLevel level, string message)
    {
        if (level < _minLogLevel) return;

        switch (level)
        {
            case LogLevel.DEBUG:
                // DEBUG log message
                break;
            case LogLevel.INFO:
                // INFO log message
                break;
            case LogLevel.WARN:
                // WARNING log message
                break;
            case LogLevel.ERROR:
                // ERROR log message
                break;
        }
    }
}

Log levels

The table below lists the log levels for the C# SDK.

Log Level	Explanation
OptimizelySDK.Logger.LogLevel.ERROR	Events that prevent feature flags from functioning correctly (for example, invalid datafile in initialization and invalid feature keys) are logged. The user can take action to correct.
OptimizelySDK.Logger.LogLevel.WARN	Events that do not prevent feature flags from functioning correctly, but can have unexpected outcomes (for example, future API deprecation, logger or error handler are not set properly, and nil values from getters) are logged.
OptimizelySDK.Logger.LogLevel.INFO	Events of significance (for example, decision started, decision succeeded, tracking started, and tracking succeeded) are logged. This is helpful in showing the lifecycle of an API call.
OptimizelySDK.Logger.LogLevel.DEBUG	Any information related to errors that can help us debug the issue (for example, the feature flag is not running, user is not included in the rollout) are logged.