Add system architecture diagram

[lorenyu]

Ticket

n/a

Changes

see title

Context

Most projects need a system architecture diagram that they can review with a security team in order to get the authority to deploy their system to production. This change adds a template system architecture diagram in Lucid.

I know that there are some folks who would prefer these diagrams to be built with Mermaid syntax, and I tried giving that option a good faith effort and I think Mermaid is just not that effective of a tool when visual design matters. In particular, when you want to pack a lot of visual information in a small space so that you can reuse the diagram in documents like Confluence, System Security Plan word docs, etc, having full control over the diagram I think is still the best option. You can see the attempt I did with Mermaid here. I got stuck annotating the protocol/ports, there's no way to make the annotation on one side of the line, the text annotation only sits in the middle of the line, so you can't tell if it's the outgoing port or incoming port. Also, the diagram itself isn't very space efficient, and not very pretty.

Testing

n/a

[acouch]

LGTM.

I know that there are some folks who would prefer these diagrams to be built with Mermaid syntax, and I tried giving that option a good faith effort and I think Mermaid is just not that effective of a tool when visual design matters.

I kind of agree here, but ultimately is a personal preference. One reason there was a preference for mermaid on our project is the desire to capture updates to the architecture in code. You could argue that updated images in markdown docs with appropriate descriptions would capture that as well.

One tool we looked at is https://diagrams.mingrammer.com/ but didn't try, which creates diagrams in code and is more visually appealing, though likely runs up against the same issue you described above for anything more than a simple architecture.

We did use Mermaid for a similar architecture https://github.com/HHS/simpler-grants-gov/tree/main/documentation/architecture#architecture (noting that the ECS cluster should be in the VPC).