Description

This can be used as a template for an app that uses Daniel Gerlags workflow-core library inside a windows service with a web ui for management.

Recommendations

• You have to specify a business key (BK) as the workflows REFERENCE when starting it, like so:

  var BK = "order.5023423499";
  await host.StartWorkflow("checkoutmail", null, BK);
  

  The asset directory will be named after the BK. Make sure it does not contain invalid path characters like colon ':' etc.! (could have named it like the WorkflowInstanceId but decided against it)
• I like to use the workflow engine in a simple fashion, just to perform one step after another, and suspend if something unexpected happens.
• I like to store all business relevant data in the file system for various reasons. (instead of using workflow-core's db for that) That also means if I want to pass some initial data to a workflow I will put it in the asset directory instead of letting workflow-core handle it.

WalzWorkflow

I made generic classes which address some of our usual requirements and put them in the folder 'WalzWorkflow'.
For a usage example please check out the folder 'Workflow_Demo'.

Management UI

We want an overview of workflows, especially unfinished ones.
We want to see the details of a failed workflow and a button to easily retry at its current step. (e.g. after manual intervention)
The UI uses active directory/cookie authentication in order to identify the users who resume/terminate worfklows.

Assets

We want to use a folder for each workflow to store related data.
This is so you can easily save intermediate files in one step and use them in a later step.
(for example, create a pdf in step 1 and send it via mail in step 2) The base directory of the assets can be controlled with appsettings.json.

Traceability

We want a history of what happened, stored separately for each workflow:

• meta info, like at what time the individual steps started
• custom logs
• exceptions
• user interactions (resuming / termination)

Note about obsolete method in library

• GetWorkflowInstances is marked as obsolete
• I'm still using it, as its useful and there is no alternative in the API yet
• a workaround could be to bypass the API and access the DB directly
• see danielgerlag/workflow-core#861

Ideas

• assets should be purged at some point too (together with workflows?) we use a separate automated script file for now

Some notes if you want to use it in your app

• I installed signalr "as a client library", see libman.js
• Nuget Packages
  • WorkflowCore
  • WorkflowCore.Persistence.Sqlite
  • Microsoft.Extensions.Hosting.WindowsServices
• I think you could simply copy the following directories
  • Pages/Account
  • Pages/Workflows
  • Generic/WalzWorkflow
• I used SQLite to be independent of a standalone db server
• check out what you need from Program.cs, it has comments
• Complete/Terminated workflows get purged after 14 days (see CleanupWorkflowService.cs)
• Remove jQuery (in _Layout.cshtml and from wwwroot)
• copy walzworkflow.css and reference it in Lyout.cshtml