Support process applications (first iteration)

[nikku]

Supporting https://github.com/camunda/product-hub/issues/2458.

Introduction

Process applications are a feature of the Web Modeler that should be supported in the Desktop Modeler, too. Users should be able to work with and deploy process applications in the Desktop Modeler while still being able to work with and deploy single files at the same time.

Tasks

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1. Be able to create process application #4666
   enhancement in progress process applications +3
   
2. Be able to open process application #4675
   enhancement in progress process applications +3
   
3. Be able to close process application #4687
   enhancement in progress process applications +3
   
4. Be able to deploy process application #4667
   backlog enhancement process applications +3
   
5. Be able to set Camunda 8 version in process application #4677
   backlog enhancement process applications +3
   
6. Be able to add/remove resources to/from a process application #4688
   backlog enhancement process applications +3
   
7. Be able to link resources in process application #4668
   backlog enhancement process applications ready +4
   
8. Be able to open linked resources in process application #4676
   backlog enhancement process applications +3
   
9. Be able to lint process application #4704
   backlog enhancement process applications +3
   
10. Be able to get autocompletion in process application #4705
    backlog enhancement process applications +3
    
11. Process Applications UI #4664
    backlog enhancement process applications +3
    
12. Be able to discover and learn about process applications #4795
    backlog enhancement +2
    

Out of scope

• Process Applications Sync Between Desktop and Web Modeler #4669
• Support versioning of a process application #4671
• Element Template Editor #4670
• Be able to configure preferences / settings / flags via UI #2913

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Related to https://github.com/bpmn-io/internal-docs/issues/519

[philippfromme]

Architecture Discussion

I (@philippfromme) discussed with @barmac.

Key Points

• Process applications feature should be independent of React
• Process application files will be managed separately from tabs, rather than as a new supported file type that isn't opened in a tab
• No decision reached on supporting files only or folders

File vs. Folder Support

Files

Pros:

• Easier to implement (single file reading and writing already implemented)
• Flat list of files more closely resembles process applications in Web Modeler
• Potentially easier to use in both modelers

Cons:

• Deleting, renaming, or moving a file will break the process application

Folders (reading BPMN, DMN, and Form files only)

Pros:

• Adding a single folder automatically picks up all files within
• No need to explicitly add files
• Deleting, renaming, or moving a file will not break the process application

Cons:

• Requires folder reading functionality, which is currently not implemented

Next Steps

1. Create a diagram to visualize the proposed architecture at the C4 components level
2. Make a decision on whether to support files only or folders

@nikku I would appreciate your input.

[nikku]

I strongly support "folder reading support". We don't want to oversimplify our process applications feature, but support the full power of what pro-coders do:

• Resources relevant to the application may be arbitrarily nested within a certain root folder
• They may be moved, renamed, etc. and the app must react to that.
• In simple terms this can be accomplished by not only watching files (we already do this), but by watching a folder; we must watch it anyway in order to do smart background indexing (to derive intelligence)

[philippfromme]

Okay, we'll implement folders then. I'm also in favor of folders as I think with files only we'll end up wishing we'd implemented folders. 🤔

[lmbateman]

Deleting, renaming, or moving a file will not break the process application

Is that because we create a pointer to each file, or for some other reason? In other words, is the process application only aware of the files in that folder, or does it track files even after they're moved out of the folder?

[philippfromme]

Is that because we create a pointer to each file, or for some other reason? In other words, is the process application only aware of the files in that folder, or does it track files even after they're moved out of the folder?

The process application tracks any relevant files (BPMN, DMN and Form) in the root directory or any of its child directories. Moving a file out of that root directory will effectively remove the file from the process application.

[lmbateman]

Deleting, renaming, or moving a file will not break the process application
Moving a file outside of that root directory will effectively remove the file from the process application.

If the moved/deleted file is a linked resource, wouldn't that break the process application? Or is the first sentence above only referring to BPMN files?

[nikku]

If the moved/deleted file is a linked resource, wouldn't that break the process application? Or is the first sentence above only referring to BPMN files?

Of course it would break the process application, in similar ways like you fool someone by removing the chair he sits on: If the thing is used ("you sit on the chair") you'll notice that the thing ("the chair") is missing. If you're not sitting on it, then the operation is absolutely fine.

We should build our validation in a robust manner, so that we detect that a piece we criticially rely on is now gone ("someone removed the chair I sit on"). This is out of question. But we should also build the underlying system in a way that it is robust, i.e. will be able to handle the situation where the chair you sit on is gone.

(Not sure if that makes sense).

[lmbateman]

That makes sense. Since "Deleting, renaming, or moving a file will not break the process application" was offered as a Pro of using folders, I'm trying to make sure I'm clear on what that means.

[philippfromme]

Yes, we would show an error that the linked resource is now missing. 🙂