# Extensions and Tools

### Logging

#### Using NLog

```
public class HomeViewModel : PortalMasterModel
{
    private static readonly Logger _logger = LogManager.GetCurrentClassLogger();
    private static readonly Logger _lmsLogger = LogManager.GetLogger("LMS");
 
    public HomeViewModel()
    {
        // Using the class name as the name of the logger
        _logger.Info("Initializing HomeViewModel");
 
        // Using a new logger instance with a property automatically added
        _lmsLogger.WithProperty("ActiveTab", activeTab).Info("Initializing HomeViewModel");
 
        // Setting a property permanently on a logger
        _logger.SetProperty("Key", "Value");
        _logger.Info("Testing EventProperties");
 
        // Adding properties automatically in the message
        _logger.Info("Testing dynamic EventProperty Key={PropertyName}", "PropertyValue");
 
        // Logging an exception
        _logger.WarnException("Exception", new System.Exception("Example Exception"));
    }
}
```

##### Example of log levels

<table class="table table-bordered" id="bkmrk-level-message-logger"><tbody><tr><th>Level</th><th>Message</th><th>Logger</th><th>Properties</th><th>Callsite</th><th>Exception</th></tr><tr><td>Info</td><td>Initializing HomeViewModel</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel</td><td> </td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel..ctor</td><td> </td></tr><tr><td>Info</td><td>Initializing HomeViewModel</td><td>LMS</td><td>ActiveTab=TrainingRequirements</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel..ctor</td><td> </td></tr><tr><td>Info</td><td>Testing EventProperties</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel</td><td>Key=Value</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel..ctor</td><td> </td></tr><tr><td>Info</td><td>Testing dynamic EventProperty Key="PropertyValue"</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel</td><td>PropertyName=PropertyValue|Key=Value</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel..ctor</td><td> </td></tr><tr><td>Warn</td><td>Exception</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel</td><td>Key=Value</td><td>SignifyHR.Areas.Portal.ViewModels.HomeViewModel..ctor</td><td>System.Exception: Example Exception</td></tr></tbody></table>

##### Log Levels

<table class="table table-bordered" id="bkmrk-level-typical-use-fa"><tbody><tr><th>Level</th><th>Typical Use</th></tr><tr><td>Fatal</td><td>Something bad happened; application is going down</td></tr><tr><td>Error</td><td>Something failed; application may or may not continue</td></tr><tr><td>Warn</td><td>Something unexpected; application will continue</td></tr><tr><td>Info</td><td>Normal behavior like mail sent, user updated profile etc.</td></tr><tr><td>Debug</td><td>For debugging; executed query, user authenticated, session expired</td></tr><tr><td>Trace</td><td>For trace debugging; begin method X, end method X</td></tr></tbody></table>

##### Rules

A rule is a logger element with the following attributes:

- name – logger name filter - may include wildcard characters (\* and ?)
- minlevel – minimal level to log
- maxlevel – maximum level to log
- level – single level to log
- levels - comma separated list of levels to log
- writeTo – comma separated list of targets to write to
- final – no rules are processed after a final rule matches
- enabled - set to false to disable the rule without deleting it
- ruleName - rule identifier to allow rule lookup with Configuration.FindRuleByName and Configuration.RemoveRuleByName.

##### NLog.config

```
!--
    Create a rule to only log entries from the LMS HomeViewModel logger,
    using the logDatabase target, and applicable on log levels Info and above
-->
<logger name="SignifyHR.Areas.Portal.ViewModels.HomeViewModel" minlevel="Info" writeTo="logDatabase" enabled="true" final="true" />
```