Why Diagram Your Infrastructure as Code?
Cloud infrastructure has become increasingly complex. A typical production environment spans multiple services, regions, and providers — and keeping track of how all the pieces connect is a challenge that whiteboard diagrams and static documentation can’t solve.
Infrastructure Diagram as Code (DaC) tools solve this by generating architecture diagrams directly from your actual infrastructure definitions. Instead of manually drawing boxes and arrows in a diagramming tool — and inevitably letting them go stale — DaC tools read your Terraform state files, HCL configurations, or cloud provider APIs and produce accurate, up-to-date visualizations automatically.
In this guide, we compare three leading open-source approaches to infrastructure diagramming: Python Diagrams (for authoring diagrams from scratch), Inframap (for visualizing existing Terraform state), and Terraform Graph plus visualization tools (for dependency analysis). Each serves a different purpose in the infrastructure documentation lifecycle.
Comparison Table
| Feature | Python Diagrams | Inframap | Terraform Graph + Blast Radius |
|---|---|---|---|
| Primary Use Case | Author architecture diagrams | Visualize Terraform state | Analyze Terraform dependencies |
| Stars | 42,357 | 2,036 | Varies (built-in + community) |
| Language | Python | Go | Go (built into Terraform) |
| Input Source | Python code (DSL) | Terraform state/HCL | Terraform state/HCL |
| Output Format | PNG, JPG, SVG, PDF | Graphviz DOT, PNG | Graphviz DOT, interactive HTML |
| Auto-Update | Manual (re-run script) | Yes (re-read state) | Yes (re-read state) |
| Cloud Providers | AWS, Azure, GCP, K8s, etc. | AWS, Azure, GCP, OCI | All Terraform providers |
| Custom Nodes | Yes (extensible) | Limited | Limited |
| CI/CD Integration | Easy (Python script) | CLI-based | CLI-based |
| Learning Curve | Low (Python) | Very Low (single command) | Low-Medium |
Tool Deep Dive
Python Diagrams: Code-First Architecture Design
Diagrams (42,357 stars) by MinJae Kwon is the most popular infrastructure diagram tool on GitHub — and for good reason. It lets you describe your cloud architecture using clean, readable Python code and generates professional-quality diagrams automatically.
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Diagrams supports all major cloud providers (AWS, Azure, GCP, Alibaba Cloud, Oracle Cloud), Kubernetes, and on-premise components. It’s ideal for designing new architectures, creating proposals, and documenting systems where the actual infrastructure doesn’t yet exist.
Inframap: Reverse-Engineering Your Live Infrastructure
Inframap (2,036 stars) by Cycloid takes the opposite approach — instead of authoring diagrams by hand, it reads your existing Terraform state files or HCL configurations and generates a visual map automatically.
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Inframap excels in environments where the Terraform code is the source of truth but no diagram was ever drawn. It’s particularly useful for onboarding new team members, performing architecture reviews, and documenting legacy infrastructure that was built before DaC practices were adopted.
Terraform Graph & Blast Radius: Dependency Analysis
Terraform itself ships with a built-in terraform graph command that outputs resource dependencies in Graphviz DOT format. While basic, it forms the foundation for several visualization tools:
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Blast Radius adds an interactive web interface on top of terraform graph, allowing you to hover over resources, see their attributes, and filter by resource type. It’s particularly useful for understanding complex resource dependencies and identifying potential circular dependencies before applying changes.
Deployment & Automation
All three tools can be integrated into your CI/CD pipeline to generate up-to-date diagrams on every infrastructure change:
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Why Self-Host Your Infrastructure Diagrams?
Keeping architecture diagrams inside your own infrastructure rather than relying on SaaS diagramming tools offers several compelling advantages. First, your infrastructure diagrams contain sensitive information about your system architecture — internal IP ranges, service topologies, resource naming conventions, and dependency relationships. Uploading this data to a third-party cloud service creates an unnecessary security surface.
Second, self-hosted diagram tools integrate directly with your CI/CD pipeline. Every time Terraform applies a change, your diagrams update automatically — no manual export, no screenshotting, no stale documentation. This “documentation as code” approach ensures your diagrams are always synchronized with reality.
Third, cost scales predictably. Commercial diagramming tools like Lucidchart or Cloudcraft charge per user per month, which becomes expensive for growing teams. Self-hosted tools run on your existing infrastructure with zero per-seat licensing costs.
For organizations with compliance requirements (SOC 2, HIPAA, FedRAMP), self-hosting ensures your architecture documentation never leaves your controlled environment. Combined with our infrastructure drift detection guide, you can build a complete infrastructure governance pipeline that runs entirely within your own environment.
Integrating Diagrams into Your Development Workflow
Beyond one-off diagram generation, the real power of Diagram as Code tools comes from integrating them into your daily development workflow. Here’s a practical example of how to incorporate infrastructure diagrams into your pull request process:
When a developer proposes a Terraform change, your CI pipeline should:
- Run
terraform planto validate the change - Execute the diagram generation tool against the proposed state
- Upload the generated diagram as a PR comment or artifact
- Enable reviewers to visually verify the infrastructure impact before approving
This turns infrastructure diagrams from a documentation afterthought into an active review tool. Reviewers can see at a glance whether the proposed change introduces new dependencies, removes critical components, or creates unexpected connections between resources.
For teams using Python Diagrams alongside Terraform, maintain separate diagram scripts in a docs/diagrams/ directory within your infrastructure repository. These scripts serve double duty — they document the intended architecture and can be compared against Inframap’s output (what’s actually deployed) to detect configuration drift.
FAQ
Do I need to run these tools on every commit?
It depends on your workflow. For design-phase diagrams (Python Diagrams), regenerate them when the architecture changes. For state-based diagrams (Inframap, Terraform Graph), it’s best practice to regenerate on every Terraform apply to ensure documentation stays current.
Can I use these tools with Pulumi or CloudFormation?
Python Diagrams is provider-agnostic and works with any infrastructure tool. Inframap and Terraform Graph are specific to Terraform state/HCL. For Pulumi users, check Pulumi’s pulumi graph command or export state to a format Inframap can consume.
How do I handle sensitive information in diagrams?
All three tools read resource metadata (types, names, relationships), not sensitive data like connection strings or passwords. Resource names are included by default — if your naming convention includes sensitive information, use Terraform’s resource tags to control what appears.
What’s the best tool for documenting existing undocumented infrastructure?
Inframap is the best starting point — run it once against your Terraform state and you’ll have a comprehensive diagram in seconds. Use Terraform Graph with Blast Radius if you need to understand specific resource dependencies. Python Diagrams is better suited for planned or proposed architecture rather than reverse-engineering.
Are there hosted alternatives that don’t require self-hosting?
Yes, commercial tools like Cloudcraft, Lucidscale, and Hava offer SaaS-based infrastructure visualization. However, self-hosting these open-source tools gives you full control over your data, integrates directly into your CI/CD pipeline, and avoids per-user licensing costs.
For more on infrastructure management, see our infrastructure drift detection guide. If you use Terraform extensively, our Terragrunt vs Atmos vs Terraspace comparison covers IaC orchestration. For automation, see our Semaphore vs AWX vs Rundeck guide.
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