Code your Concepts: A Guide to Diagrams As Code in DevOps World

Creating diagrams as code has become a popular practice, especially in the context of infrastructure as code (IaC) and documentation. In this blog, we'll explore some of the popular tools for creating diagrams as code and discuss how they can be used in different scenarios.

- Diagram
Using Diagram we can create diagrams for multiple environment like AWS,AZURE,GCP,Kubernetes.

Requirements

It requires Python 3.6 or higher, check your Python version first. It uses Graphviz to render the diagram, so you need to install Graphviz to use diagrams. After installing graphviz (or already have it), install the diagrams.

# pip install diagrams

(On Ubuntu)
# apt install graphviz

(On RHEL)
# yum install graphviz

Create Diagram For Kubernetes

from diagrams import Cluster, Diagram, Node, Edge
from diagrams.k8s.compute import Pod
from diagrams.k8s.compute import Deploy
from diagrams.k8s.network import Ing
from diagrams.k8s.group import NS
from diagrams.k8s.podconfig import Secret
from diagrams.k8s.storage import PVC
from diagrams.k8s.rbac import CRole
from diagrams.k8s.rbac import CRB

with Diagram("Kubernetes Cluster", show=False):
  with Cluster("Kubernetes"):
    with Cluster("Rbac"):
      rbac = CRB("")
      with Cluster("Role"):
        role = CRole("")
    with Cluster("App"):
      ns = NS("")
      with Cluster("Ingress"):
        ingress = Ing("")
        with Cluster("Secret"):
          secrets = Secret("")
        with Cluster("App"):
          deploy = Deploy("")
          with Cluster("Pods"):
            pod = Pod("")
        with Cluster("PVC"):
           pvc = PVC("")
  rbac >> role >> ns
  ns >> deploy >> pod >> pvc
  pod >> secrets
  deploy >> ingress

- Mermaid
Mermaid is a JavaScript-based diagramming and charting tool that allows users to create diagrams and flowcharts using a simple and human-readable text-based syntax. It is particularly popular for its integration with Markdown, making it easy to embed diagrams directly into documentation, README files, or other text-based formats.

graph LR;
 IpBlockS([IpBlock])-. Traffic Out From <br> The Cluster .->|![Ingress Image](images/ingress.png)| ingress;
 PodNetworkS([PodNetwork])-. Traffic From <br> PodNetwork  .->|![Ingress Image](images/ingress.png)| ingress;
 NameSpaceNetworkS([NameSpaceNetwork])-. Traffic From <br> NameSpaceNetwork  .->|![Ingress Image](images/ingress.png)| ingress;
 ingress .->|routing <br> rule|namespace[namespace];
 subgraph cluster
 ingress;
 namespace .->|routing <br> rule|egress[Egress];
 end
 egress[Egress]-. Traffic Out To <br> The Cluster  .->IpBlockD([IpBlock]);
 egress[Egress]-. Traffic To <br> PodNetwork  .->PodNetworkD([PodNetwork]);
 egress[Egress]-. Traffic To <br> NameSpaceNetwork  .->NameSpaceNetworkD([NameSpaceNetwork]);
 classDef plain fill:#ddd,stroke:#fff,stroke-width:4px,color:#000;
 classDef k8s fill:#326ce5,stroke:#fff,stroke-width:4px,color:#fff;
 classDef cluster fill:#fff,stroke:#bbb,stroke-width:2px,color:#326ce5;
 class ingress,namespace,egress k8s;
 class client plain;
 class cluster cluster;

- PlantUML
PlantUML is an open-source tool that allows users to create Unified Modeling Language (UML) diagrams using a simple and human-readable text-based syntax. UML diagrams are widely used in software development to visually represent different aspects of a system's architecture, design, and behavior. PlantUML makes it easy to express complex UML diagrams in a concise and maintainable manner.

@startyaml
!theme lightgray
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80
@endyaml

We have a variety of tools at our disposal, but I've identified these specific ones for drawing diagrams. I've seamlessly integrated them into my GitLab CI/CD pipeline. I encourage you to give them a try; they prove to be highly effective for creating and managing our diagrams.

Hope you will like this blog and start using it in your CI/CD pipelines.