When you begin learning Workflow Studio, you quickly learn that the Workflow Studio Designer can execute workflows for initial testing purposes and the Workflow Studio Console can execute workflows as a scheduled job.  A lot of people have been asking about how you can automate the execution of a workflow from an external system, such as Powershell, a Windows application, and an ASP.NET web application.  The real power of Workflow Studio is being able to execute a workflow when you want it to run, either manually, on a schedule, or on-demand when needed by external systems. 

This is the first blog of a new series I’m starting on how you can automate the execution of workflows from external systems, beginning with Powershell.  One thing I didn’t realize when I started using Workflow Studio was how much this product was connected to Powershell.  Essentially, any action you can perform within the Workflow Studio Console has an equivalent Powershell cmdlet for it.  Using these cmdlets allows us to automate the various tasks within the Workflow Studio Console, such as executing the workflows themselves.

Workflow Setup:
If you want to execute a workflow with Powershell, the workflow needs to be in the Ready state within the Workflow Studio Console.  One thing that I prefer to do to keep the Powershell script fairly short is to pre-deploy the workflow to the Jobs section in the Workflow Studio Console.  When you pre-deploy a workflow, you are just making it available to execute as a Job without actually executing it yet.  By doing this simple step ahead of time, we can actually cut our Powershell script in half.  Please note that this is just a one time step – once you deploy it to the Jobs section you really don’t have to open the Workflow Studio Console again (unless you want to make changes to your workflow itself).  The two screen shots below demonstrate how to pre-deploy the workflow to the Jobs section.



 



Registration of Xceed DLLs:
The Workflow Studio cmdlets leverage a few Xceed DLLs on the system.  These Xceed DLLs are part of the Workflow Studio installation and need to be present within the global assembly cache (GAC) in order for several of the Workflow Studio cmdlets to run properly.  Workflow Studio 1.1 does not actually place these DLLs into the GAC so you need to do that manually for this release.  I was told in future releases that this step will already be done for us.

There are three Xceed DLLs you need to place into the GAC:  Xceed.Compression.dll, Xceed.FileSystem.dll, and Xceed.ZIP.dll

Drag these DLLs from the C:\Program Files\Citrix\Workflow Studio folder to the C:\Windows\Assembly folder.  This process adds them to the GAC.  The end result is shown below.




Powershell Setup:
An interesting thing to note about Powershell is that scripting is turned off by default.  You can’t execute a Powershell script until you enable scripting at a desired level.  I’m not exactly sure why Microsoft chose to do that since Powershell is supposed to be a scripting language, but it is fairly easy to enable scripting.

Launch Powershell (Start->Programs->Windows Powershell 1.0->Windows Powershell) and type the following command to get the current execution setting:

Get-ExecutionPolicy

If the execution policy is set to Restricted, you need to enable script execution by typing the following command:

Set-ExecutionPolicy RemoteSigned




Powershell Script:
The table below is a sample Powershell script for executing a workflow on your Workflow Studio machine.  I’ve tested the Workflow Studio cmdlets pretty extensively and this seems to be the simplest script I was able to create to execute a workflow. 

To use this script in your environment, just copy and paste this script into Notepad, and rename the file as a .PS1 file.  Then update the value of the $strWorkflowName variable to be the name of the workflow you want to execute.  In my next blog, I’ll explain how you can tweak this script to pass parameters into the workflow.  The script below will work for any workflow that does not require parameters.

#Set variables <span class="code-keyword">for</span> the workflow
$strWorkflowName = <span class="code-quote">"Workflow1"</span>
 
#Add the Workflow Studio snap-ins to the current Powershell session 
Get-PSSnapin -registered | Add-PSSnapin
 
#Get reference to the Workflow Studio runtime
$rt = Get-WorkflowRuntime
 
#Get reference to the deployed workflow
$workflow = get-deployedworkflow -workflowruntime $rt -workflowname $strWorkflowName -includeschedule
 
#Schedule the workflow to run immediately
schedule-workflow -workflowruntime $rt -workflowstrongname $workflow.WorkflowStrongName -runimmediately

Executing the Powershell script:
After the PS1 file is created, place it within an accessible place on your Workflow Studio machine.  For example, I’ve placed my scripts within C:\Citrix\PowershellScripts.  One thing I found out is that you want the path to the script to have no spaces, so keep that in mind as you place your PS1 file into a directory.

Next, open the Run window and type the statement below to execute your Powershell script (my script was called ExecuteWorkflow.ps1)
           powershell.exe -noexit C:\Citrix\PowershellScripts\ExecuteWorkflow.ps1

The -noexit switch above keeps the Powershell window open after the script is executed.  If the script execution was successful, you should see a Job ID as noted below.  This tells you that the workflow was successfully executed.




Troubleshooting the Powershell script:
If you are having issues with your Powershell script, the approach I typically take for troubleshooting is to launch Powershell and execute each line of the script manually until you come across the error.  Powershell can be launched from the Start Menu (Start->Programs->Windows Powershell 1.0->Windows Powershell) or by typing Powershell.exe in the Run window.

If you receive Access Denied errors, there is a good chance that the account you are running Powershell under is not a Workflow Studio admin, or does not have permissions within Workflow Studio to execute various workflow actions.  Check that your logged on user account is either a Workflow Studio admin or has these permissions.  These permissions are set inside the Workflow Studio Console within the Security section.

Most of the commands in the script above use variables.  To see the value of a variable, use the echo statement. For example:

echo $strWorkflowName



If the variable is an object, you can also display the value of its individual properties.  For example:

echo $workflow.WorkflowStrongName



If you want to see the list of all the Workflow Studio cmdlets, use this statement:











Get-Command -PSSnapin citrix*

The output of the above statement is shown below:



If you want more information on how to use a specific Workflow Studio cmdlet, use a statement such as this:

Get-Help schedule-workflow

Blogs in this series: