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Docker - Diagrams as code

ยท 3 min read

Docker - Diagrams as code

But what a joy it is to be able to draw diagrams by, well, just writing text. Some tools are better known than others, e.g. Mermaid.

Did you know Let's explore it using, of course, a Docker ready-to-use image.

Take a look on the different examples you can retrieve on

Like always, for the demo, please start a Linux shell and run mkdir -p /tmp/docker-diagrams && cd $_ to create a folder called java in your Linux temporary folder and jump in it.

Please create a new file called with this content:

from diagrams import Diagram
from import EC2
from import RDS
from import ELB

with Diagram("My Team", show=False, direction="TB"):
ELB("Olivier") >> [
EC2("Stijn") ] >> RDS("Work together")

To run the conversion, go back to your console and run the following command:

cat | docker run -i --rm -v $(pwd):/out -u 1000:1000 gtramontina/diagrams:0.23.3
Windows notation

If you're working Windows, replace $(pwd) by %CD%. And replace cat by type.

And bingo, the script is converted to the image here below:


0.23.3 is the latest version available when writing this document. See to retrieve the latest one.

Easy no?

Another example:

from diagrams import Cluster, Diagram
from diagrams.k8s.compute import Pod, StatefulSet
from import Service
from import PV, PVC, StorageClass

with Diagram("Stateful Architecture", show=False):
with Cluster("Apps"):
svc = Service("svc")
sts = StatefulSet("sts")

apps = []
for _ in range(3):
pod = Pod("pod")
pvc = PVC("pvc")
pod - sts - pvc
apps.append(svc >> pod >> pvc)

apps << PV("pv") << StorageClass("sc")

And the resulting image:

Stateful Architecture

Crazy no? And all without installing anything!

The Docker image code base is here:

Icons (called Nodes)โ€‹

A tremendous list of icons/nodes is available on multiple pages at See OnPrem, AWS, Azure, GCP, IBM, K8S, ... and also how to create our owns (using local .png images): Custom.

Other toolsโ€‹

  • DB Diagram
  • DBML-renderer, dbml-renderer renders DBML files to SVG images
  • Graphviz, Graphviz is open source graph visualization software
  • JSON Crack, seamlessly visualize your JSON data instantly into graphs
  • Kroki, creates diagrams from textual descriptions
  • Mermaid, his live editor, the preview addon for vscode and the convert tool as a CLI tool
  • Nomnoml, tool for drawing UML diagrams based on a simple syntax
  • Pikchr, Pikchr (pronounced "picture") is a PIC-like markup language for diagrams in technical documentation
  • Plantuml, generate diagrams from textual description
  • Sequence diagram (seems based on Mermaid)
  • Structurizr, a way to create Structurizr software architecture models based upon the C4 model using a textual domain specific language
  • svgbob, convert your ascii diagram scribbles into happy little SVG
  • Vega, a Visualization Grammar
  • yEd Graph Editor, Graphical interface, you'll need to drag & drop objects, resize, ... It doesn't support text files like the other tools already mentioned here.