Re-using deploymentEnvironment and nodes

[plehmann-next]

Is it possible to somehow share one deploymentEnvironment element and re-use it?

Background

We've separated the model definition of our large system into separate files, one per dev team, which are included into the main workspace.dsl. External systems many of our services interact with are modelled into an additional file and can be referenced in the team's files as needed. Now we want to add deployment diagram model files, separated by teams also. There is basically one production environment which we would model with the deploymentEnvironment element, some nested deploymentNode elements and some infrastructure elements for load-balancers etc.

Problem description

It's not possible to model more than one deploymentEnvironment "Production" (with the same name) which makes sense. But how can we model this environment only once and refer to it for individual deployments? Maybe something like this:

deploymentEnvironment "Production" {
  vm1 = deploymentNode "VM 1" "" "Windows Server 2019"
}

as production_environment.dsl

And then per team something like:

vm1 {
  deploymentNode "Docker container" {
    shinyServiceBE = containerInstance shinyServiceBackend
  }
}

to make use of the earlier defined Production environment.
I know that this code throws errors, but maybe it makes clear what I am asking. Is there any way to achieve this or do we need to maintain the whole Production environment with all container instance deployments in a single file?

Thank you in advance!

Best,
Patrick.

[simonbrowndotje]

This seems to work:

base.dsl

workspace {

    model {
        a = softwareSystem "A"

        live = deploymentEnvironment "Live" {
            deploymentNode "Server 1" {
                softwareSystemInstance a
            }
        }
    }

}

workspace.dsl

workspace extends base.dsl {

    model {
        b = softwareSystem "B"

        !ref live {
            deploymentNode "Server 2" {
                softwareSystemInstance b
            }
        }
    }

    views {
        deployment * live {
            include *
            autolayout
        }
    }

}

[plehmann-next]

Great, that works as intended. I was not aware of the ref! keyword. Thank you!

[renannprado]

@simonbrowndotje I have one followup question: is it possible to extend/reference multiple workspaces?

That's probably when things get even more complicated, but still 😄 .

[simonbrowndotje]

It's not.

[renannprado]

@simonbrowndotje thanks for the quick reply!

Do you have any recommendations/best practices in this case?

Just as an idea. To support multiple "extends", the "objects" could be prefixed with the file name perhaps...?

i.e. in the case above, you'd reference the objects with base.live, to avoid conflicts between different files.

edit:

Another thing that probably gets complicated is that there would have to be support for cyclic dependencies, because that does happen: Service A calls service B and Service B calls Service A.

[simonbrowndotje]

Do you have any recommendations/best practices in this case?

You can have workspace3 extending workspace2, which itself extends workspace1. This in conjunction with !include should get you quite far.

Just as an idea. To support multiple "extends", the "objects" could be prefixed with the file name perhaps...?

Feel free to put a POC together on a branch and I'll take a look.