Logging for Script Based Datasources.
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Problem Statement:
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1. In WFA, the script based Datasource Types don't have Datasource specific logging mechanism the way command executions have in a workflow.
2. The WFA Powershell logging cmdlet Get-WfaLogger doesn't serve me well here. All the log data for all acquistion instances of all DataSources gets dumped into a common wfa.log with which apart from these log data has tons of other Java logs.
3. The wfa.log is a common logging file for a number of WFA activities. It just has too much data from everywhere. Its massive file and searching/debugging for anything is very diffcilut.
4. Its keeps getting archieved from time to time. This adds to the problem of digging out an execution instance specific log-data. One needs to hunt though multiple files.
Araprt from the above problems being solved, I wanted the following too:
1. Flexible and configurable logger for every single DataSource Type. I may not want one common logging configuration for all my Datasource Types.
2. Every single Data source instance for a given Datasource Type to have separate log files.
3. To be able to view the logs from WFA GUI.
Solution:
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WFA is a very flexible framework and allows multiple 3rd party powershell modules/snapins/dlls to be plugged in.
Download Apache Log4net
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Log4net is a very good logger for .NET platform. Download it from here: http://apache.bytenet.in//logging/log4net/binaries/log4net-1.2.13-bin-newkey.zip . Extracting it will have show numerous files but we need only 1, the log4net.dll . You can use the one at log4net-1.2.13\bin\net\3.5\release for you .NET version 3.5
Configuring log4net
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Most configurations for log4net are based on a common configuration file. But this can't serve my purpose. I wanted flexible configuration for every Datasource Type. So I need to set the configurations in the powershell code.
Here is an example logger definition inside a DataSource Type code.
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###### Create the Logger Configuration ######
#Load the assembley from your dll location
[void][Reflection.Assembly]::LoadFrom("C:\log4net\log4net.dll")
#Define your logging pattern. See more about it here: http://logging.apache.org/log4net/release/sdk/log4net.Layout.PatternLayout.html
$pattern="%d %w %-5p %c : %m%n"
#Reset the log4net configuration
[log4net.LogManager]::ResetConfiguration()
#Create the Logging file for every single Datasource based on the Hostname.
$DSHostName = Get-WfaRestParameter "host"
$PSScriptRoot = Split-Path $MyInvocation.MyCommand.Path -Parent
$logFile=$PSScriptRoot.Substring(0, $($PSScriptRoot.Length - 8)) + "\log\" + $DSHostName +".log"
#Create the log4net config Appender
$Appender = new-object log4net.Appender.FileAppender
$Appender.File = $logFile
$Appender.Layout = new-object log4net.Layout.PatternLayout($pattern)
$Appender.Threshold = [log4net.Core.Level]::All
$Appender.ActivateOptions()
[log4net.Config.BasicConfigurator]::Configure($Appender)
#Create Logger for the DataSource Type Name. You can actually put anything
$logg = [log4net.LogManager]::GetLogger("[Person Data source with logging]")
####### Logger is Ready #########
$PersonFile = "./person.csv"
New-Item -Path $PersonFile -type file -Force
Add-Content $PersonFile ([Byte[]][Char[]] "`\N`tAron`tFinch`t011-12345678`n") -Encoding Byte
Add-Content $PersonFile ([Byte[]][Char[]] "`\N`tDavid`tWarner`t011-12345677`n") -Encoding Byte
Add-Content $PersonFile ([Byte[]][Char[]] "`\N`tSteven`tSmith`t011-12345676`n") -Encoding Byte
#Now log whatever you want.
$logg.Info("This is an info message on Host: $DSHostName")
$logg.Debug("This is a debug message")
$logg.Warn("This is a warning message")
$logg.Error("this is an error Message")
$logg.Fatal("this is a fatal error Message")
###### END Code #############
To view the logs fom WFA GUI, go to WFA Administration -> Log Viewer . You'll see a log file with name as the name of the Data Source host ( e.g. Host01.log ). Now every single DataSource belonging to this Datasource type will have separate log file.
