Support for empty cluster nodes

[aaronsteers]

It appears that cluster nodes are not rendered if they are empty. However there are use cases, such as diagramming a VPC with public/private subnets, where it would be beneficial to render them even if there is nothing in them.

Would it be feasible to add either a blank/white dummy node to hold space inside the cluster, or else support clusters to be rendered (with some minimal height and width) even if they are empty?

[leandrodamascena]

Hmm I have this problem too .. I'm provisioning a new architecture that need to show an empty Cluster which I'll add resources in next project sprint .. But I need to show now that I have provisioned that separated cluster to add resources in future ...

Python syntax doesn't allow a "with" block code with no code inside ... Maybe using keyword "pass" inside the block to avoid syntax error and change init.py code to detect a empty Cluster block and force to generate a " fake id "in graph section ...

Empty Cluster block in current version

digraph "IOT Diagram" {
        graph [fontcolor="#2D3436" fontname="Sans-Serif" fontsize=15 label="IOT Diagram" nodesep=0.60 pad=2.0 rankdir=LR ranksep=0.75 splines=ortho]
        node [fixedsize=true fontcolor="#2D3436" fontname="Sans-Serif" fontsize=13 height=1.4 imagescale=true labelloc=b shape=box style=rounded width=1.4]
        edge [color="#7B8894"]
        "1fc76bf100e4470bb115e08766f689be" [label=LEO height=1.9 image="D:\DEVEL-PYTHON\github\diagrams2\resources/aws/iot\internet-of-things.png" shape=none]
        subgraph "cluster_AWS Serverless IOT2" {
                graph [bgcolor="#E5F5FD" fontname="Sans-Serif" fontsize=12 label="AWS Serverless IOT2" labeljust=l pencolor="#AEB6BE" rankdir=LR shape=box style=rounded]
        }
}

"Fake id" with patch

digraph "IOT Diagram" {
        graph [fontcolor="#2D3436" fontname="Sans-Serif" fontsize=15 label="IOT Diagram" nodesep=0.60 pad=2.0 rankdir=LR ranksep=0.75 splines=ortho]
        node [fixedsize=true fontcolor="#2D3436" fontname="Sans-Serif" fontsize=13 height=1.4 imagescale=true labelloc=b shape=box style=rounded width=1.4]
        edge [color="#7B8894"]
        "1fc76bf100e4470bb115e08766f689be" [label=LEO height=1.9 image="D:\DEVEL-PYTHON\github\diagrams2\resources/aws/iot\internet-of-things.png" shape=none]
        subgraph "cluster_AWS Serverless IOT2" {
                graph [bgcolor="#E5F5FD" fontname="Sans-Serif" fontsize=12 label="AWS Serverless IOT2" labeljust=l pencolor="#AEB6BE" rankdir=LR shape=box style=rounded]
                "fk_9fdd9f23ffbb4aff8b1c965e3ac259b8" [label="" height=1.9 shape=none]
        }
}

In my option is not a good approach because we are doing a little hack. As @aaronsteers commented, the better option is to create use a dummy resource with a transparent image.

@mingrammer

[aaronsteers]

I returned to this issue just to check in, and was very pleased to see the completion of #171. I've tested this out and it meets my minimum requirements for empty nodes (via the new "Blank" node type inside a cluster).

I'll close this issue because I'm happily unblocked now, but others may re-open if needed.

Thank you!