Adding log information to a process

This article shows how to add log messages from a process to the Runtime's log files, console and log database.

Our sample process

You can download the sample process here :    archive processWithUserLog (1 KB) . 

It does nothing special except logging messages.

 

 

Here is a description of the process, step by step. Have a close look to each "Meta-inf" property of the different actions.

• START (EmptyAction) : does nothing, but logs the "START of processWithUserLog" message. See how we used the ${/CORE_SESSION_NAME}$ variable.
• Sleep : this one logs two messages : pay attention to the trigger attribute which can be "beforeExecution" and "afterExecution".
• Scripting : the script sets the ~/param parameter to "newvalue". The actions logs two messages : one beforeExecution and one afterExecution. This can be usefull when we want to "watch" a variable before / after an action.
• subprocess/EmptyAction : logs three messages at different levels - see the path attribute.
• END : logs the "End of processWithUserLog" message.

This is the "Meta-Inf" property for the "Sleep" action:

<userLog path="../START/SleepInfo" trigger="beforeExecution">
    <info>Before Sleep</info>
    <logger>stambiaLog</logger> 
    <logger>mainConsole</logger> 
</userLog>

 

Result on the Runtime console

28/10/2014 17:44:57,338 - processWithUserLog (c0a84bc5014957a56459674d16d1ffbd) is started
28/10/2014 17:44:57,344 - START of processWithUserLog
28/10/2014 17:44:57,360 - Before Sleep
28/10/2014 17:44:58,363 - After Sleep
28/10/2014 17:44:58,368 - Before Scripting: param=value1
28/10/2014 17:44:58,385 - After Scripting: param=newvalue
28/10/2014 17:44:58,391 - Before processWithUserLog/subprocess/EmptyAction/EmptyAction - 1
28/10/2014 17:44:58,392 - Before processWithUserLog/subprocess/EmptyAction/EmptyAction - 2
28/10/2014 17:44:58,394 - Before processWithUserLog/subprocess/EmptyAction/EmptyAction - 3
28/10/2014 17:44:58,405 - END of processWithUserLog
28/10/2014 17:44:58,412 - processWithUserLog (c0a84bc5014957a56459674d16d1ffbd) is ended

 

Result in Analytics

The messages that appear in analytics are the ones that use the "stambiaLog" logger.

For each message:

• the "Name" column is set with the Meta-Inf's "path" attribute value,
• the "Message" column is set with the Meta-Inf's "info" element content.

 

Note : in our example, most messages are logged explicitly under the "START" action, thanks to the "path" attribute. This provides to Analytics Users a single entry point to read messages, which can be helpful.

 

Things to remember

It is possible to log information into the Runtime's log files and log database, using the Meta-Inf properties of your process' actions.

You can declare several userLog elements within the same action.

Each <userLog/> element has the following properties :

• "path" attribute: the Name of the message (and optionnally the path to the process step it should be attached to) - usefull in analytics
• "trigger" attribute: when the message should be logged, beforeExecution or afterExecution of the action
• "info" element: defines the message content
• "logger" element(s): specifies which logger will receive the message - by default you can use:
  
  • userConsole: logs into the Runtime's standard output
  • mainConsole: same as userConsole, prefixed with date/time
  • stambiaLog: logs into the Runtime's log database

Note: the first two loggers are declared in the "properties/log4j.xml" file and they can be personalized. You can also add your own loggers. For more information, check out http://logging.apache.org/log4j/1.2/.

 

Here is a sample userLog Meta-Inf :

<userLog path="../START/ScriptingWatcher" trigger="beforeExecution">
 <info>Before Scripting: param=${~/param}$</info>
 <logger>stambiaLog</logger> 
 <logger>mainConsole</logger> 
</userLog>

<userLog path="../START/ScriptingWatcher" trigger="afterExecution">
 <info>After Scripting: param=${~/param}$</info>
 <logger>stambiaLog</logger> 
 <logger>mainConsole</logger> 
</userLog>