d2.md

D2 language - Declarative Diagrams

https://d2lang.com/

Excellent declarative language good for creating Cloud & Architecture diagrams.

• Key Points
• Real World Architecture Diagrams
• D2 Template
• Tutorial
• Interactive Online Sandbox
• Install
• Local Development
• Themes
• Layouts
• Issues
• Libraries

Key Points

• less code than Python diagrams
• CLI watch mode - interactive local web server auto-updates from code file for fast interactive development
• output formats - SVG, PNG, PDF
• good for Cloud Architecture diagrams with icons
• multiple layout engines - use --layout dagre or --layout elk
• nice dark theme

Real World Architecture Diagrams

HariSekhon/Diagrams-as-Code - ready made architecture diagrams

See thse D2 Code files.

D2 Template

HariSekhon/Templates - diagram.d2

Tutorial

https://d2lang.com/tour/hello-world

Interactive Online Sandbox

https://play.d2lang.com/

Install

In DevOps-Bash-tools install/ directory:

install_d2.sh

Auto-format the .d2 file:

d2 fmt "$filename.d2"

Every compile auto-formats your $filename.d2 file so you don't even need to run fmt manually.

d2 input.d2 output.svg

Gives a hand drawn appearance:

d2 --sketch ...

Local Development

Launch local webserver - auto-updates page upon write to diagram.d2:

d2 --watch --theme 200 "$templates/diagram.d2" /tmp/template.png

d2 --watch --dark-theme 200 "$templates/diagram.d2" /tmp/template.svg

Interactive development sandbox - doesn't export png files right though, see github issue.

d2 -w -t 200 ...

Bug - animate-interval requires something in the base to work, see:

d2 --animate-interval=1200 ...

Themes

https://d2lang.com/tour/themes

Show list of available themes:

d2 themes

Set theme for both light and dark mode

d2 --theme <number>

Set only when when user's browser is set in dark mode - only works for SVGs, not PNGs:

d2 --dark-theme

200 is Dark Mauve color theme - my favourite

Define in environment variables:

export D2_THEME=200
export D2_DARK_THEME=200

Layouts

https://d2lang.com/tour/layouts

show layout engines

d2 layout

Issues

Some things I'd like to see improved:

• Icon Placement Control
• Jenkins Blue Ocean CI/CD pipelines diagram support
• Icon Shortnames

Libraries

https://terrastruct.com/blog/post/generate-diagrams-programmatically/

Ported from private Knowledge Base page 2023+