Writing To Log Files

Overview

This article covers how to write to the Decisions logs from code. A DecisionsFramework.Log file must be instantiated first. Many of the levels used to write custom log files in code have the same input data. Here is a list of the pieces of input data used by these levels and how that data is used in the logs.

• object sourceObject : The logger will attempt to do a .ToString() on the object and write that string in the log entry.
• string message : This is the main part of the log message. Write custom text here to signal wherein the code the user is. Only error messages that have been caught can be merged into the log.
• params object[] arguments : This allows for the input parameter into the log message. For example, the log entry could be written as: LogDebug(this,"{0} {1} {2} is today", "Thursday", "Jan 10th", "2013");

Below is the comments sample code that explains the different levels. The attached project contains this code and can be compiled and deployed as a step to allow for testing different combinations with the logging levels.

   WriteToLogFile  

 using DecisionsFramework;
using System;
using DecisionsFramework.Design.Flow;
 
namespace DecisionsLoggingSample
{
  [AutoRegisterMethodsOnClass(true, "SampleSteps", "Logging", RegisterForAgents = true)]
  public class LoggingExample
  {
    //Note: the name (e.g. "Example Log") you provide here will prefix the logs
    //that you write with this instance of Log.
    //For example an info level log written with this Log will look like the following:
    //[Info],09 Jan 2013 16:39:11,Thread 23,Exmaple Log [Message]:Info level message
    private static Log log = new Log("Example Log");
 
    public static void writeToDecisionsLogs()
    {       
      //create an exception we can use in logging
      try
      {
        int zero = 0;
        int number = 5 / zero;
      }
      catch (Exception ex)
      {
        //The Info, Debug and Warn levels are very similar.
        //They take the same inputs and using one instead of the other
        //just changes the level at which the log is written.
        //Currently the first (object) parameter is not used in these levels and can be set to null.
        //Looks like: [Info],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Info level message. Today is Thursday Jan 10th 2013
        log.LogInfo(null, "Info level message. Today is {0} {1} {2}", "Thursday", "Jan 10th", "2013");
         
        //Looks like: [Debug],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Debug level message
        log.LogDebug(null, "Debug level message");
 
        //Looks like: [Warn],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Warm level message
        log.LogWarn(null, "Warm level message");
 
 
 
        //LogError can be used in three ways. This level does use the object input parameter and so can be set to null or to a value;
        //Looks like: [Error],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Error level message
        log.LogError(null, "Error level message");
 
        //Looks like: [Error],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Attempted to divide by zero. [Exception]:System.DivideByZeroException: Attempted to divide by zero.  at DecisionsLoggingSample.LoggingExample.writeToDecisionsLogs()
        log.LogError(null, ex);
         
        //Looks like: [Error],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Error level message [Exception]:System.DivideByZeroException: Attempted to divide by zero.  at DecisionsLoggingSample.LoggingExample.writeToDecisionsLogs()
        log.LogError(null, ex, "Error level message");
 
 
 
        //Currently the first (object) parameter is not used in these levels and can be set to null.
        //Looks like: [Fatal],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Fatal level message [Exception]:System.DivideByZeroException: Attempted to divide by zero.  at DecisionsLoggingSample.LoggingExample.writeToDecisionsLogs()
        log.LogFatal(null, "Fatal level message", ex);
 
        //Looks like: [Fatal],14 Jan 2013 11:12:05,Thread 17,Example Log [Message]:Fatal level message
        log.LogFatal(null, "Fatal level message");
      }
    }
  }
}

Accessing Logs

The Decisions logs can be accessed in two ways. An admin user can open the CSV file directly. This file is stored at C:\Program Files\Decisions\Decisions Services Manager\Logs\Decisions.CONTROLINSTANCE.log.csv. Alternatively, view the logs from the Decisions portal by navigating to System > Administration > System Tools > Logging.

Fatal and error-level errors are also logged as Windows events for monitoring by external tools.

Logging Types.