Infrastructure coder

Infrastructure Coder

Generate, review, and analyze Infrastructure-as-Code. Terraform/OpenTofu modules, Kubernetes manifests, Dockerfiles.

Scope: IaC generation and analysis only. NOT for CI/CD pipelines (devops-engineer), application code, cloud console operations, or actual cost calculation.

Canonical Vocabulary

Term	Definition
module	A self-contained Terraform/OpenTofu unit with variables, resources, and outputs
manifest	A Kubernetes YAML resource definition
chart	A Helm package containing templated K8s manifests
stage	A Docker build stage in a multi-stage Dockerfile
resource	A cloud infrastructure primitive (instance, bucket, network, etc.)
misconfiguration	A security or reliability issue in IaC (open ports, missing encryption, no limits)
cost-relative	Comparison between resource types/tiers, NOT absolute dollar pricing
hardening	Applying security best practices to reduce attack surface
drift	Difference between declared IaC state and actual infrastructure
blast radius	How many dependent resources would be affected by a change

Dispatch

$ARGUMENTS	Mode
terraform <requirements>	Generate Terraform/OpenTofu modules
kubernetes <requirements> / k8s <requirements>	Generate K8s manifests and Helm charts
docker <requirements>	Optimize Dockerfiles (multi-stage, caching, security)
review <file-or-path>	Audit IaC for correctness and best practices
cost <config-or-path>	Cost-relative estimation (compare resource types)
security <config-or-path>	Security scan for IaC misconfigurations
Empty	Show mode menu with examples

Mode: Terraform

Generate production-ready Terraform/OpenTofu modules.

Terraform Steps

1. Parse requirements — identify resources, provider, region, dependencies
2. Run uv run python scripts/terraform-module-scanner.py <path> on any existing .tf files to understand current state
3. Generate module structure:
   • main.tf — resource definitions
   • variables.tf — input variables with descriptions, types, defaults, validation
   • outputs.tf — useful outputs for downstream consumption
   • versions.tf — required providers and version constraints
4. Apply patterns from references/terraform-patterns.md

Generation Rules

• Always pin provider versions with ~> constraints
• Use for_each over count for named resources
• Tag all resources with Name, Environment, ManagedBy = "terraform"
• Use data sources for existing infrastructure, never hardcode ARNs/IDs
• Separate state per environment using workspaces or backend config
• Reference references/cloud-equivalents.md for multi-cloud alternatives

Mode: Kubernetes

Generate Kubernetes manifests or Helm charts.

Manifest Steps

1. Parse requirements — identify workload type, scaling, networking, storage
2. Run uv run python scripts/k8s-manifest-validator.py <path> on existing manifests
3. Generate manifests with best practices:
   • Resource limits and requests on every container
   • Health checks (liveness, readiness, startup probes)
   • Security context (non-root, read-only root filesystem, drop capabilities)
   • Pod disruption budgets for HA workloads
   • NetworkPolicies for pod-to-pod communication

Helm Charts

4. For Helm charts: parameterize environment-specific values, use values.yaml defaults
5. Apply patterns from references/kubernetes-patterns.md

Mode: Docker

Optimize Dockerfiles for size, build speed, and security.

1. Run uv run python scripts/dockerfile-analyzer.py <path> on existing Dockerfile
2. Parse JSON output for issues and optimization opportunities
3. Apply optimizations:
   • Multi-stage builds separating build and runtime
   • Order layers by change frequency (dependencies before source)
   • Use specific base image tags (never latest)
   • Distroless or Alpine for runtime images
   • Non-root USER directive
   • COPY specific files, avoid COPY . .
   • Combine RUN commands to reduce layers
   • Use .dockerignore
4. Reference references/dockerfile-guide.md for detailed patterns

Mode: Review

Audit IaC files for correctness, best practices, and reliability.

Analysis Pipeline

1. Identify file type (Terraform, K8s manifest, Dockerfile, Helm chart)
2. Run the appropriate analysis script:
   • .tf files: terraform-module-scanner.py
   • K8s YAML: k8s-manifest-validator.py
   • Dockerfile: dockerfile-analyzer.py
3. Multi-pass analysis (adapted from review pipeline):
   • Pass 1 — Correctness: syntax, valid references, API version compatibility
   • Pass 2 — Best practices: patterns from reference files, anti-patterns
   • Pass 3 — Reliability: failure modes, blast radius, recovery paths

Findings Report

4. Present findings grouped by severity (Critical / Warning / Info)
5. For each finding: file location, issue description, recommended fix
6. Reference references/security-hardening.md for security-specific checks

Mode: Cost

Cost-relative comparison between resource configurations. NOT absolute pricing.

1. Identify resources in the configuration
2. Reference references/cloud-equivalents.md for cross-cloud mapping
3. Compare configurations on relative axes:
   • Instance families: compute-optimized vs memory-optimized vs general-purpose
   • Storage tiers: standard vs infrequent-access vs archive
   • Network: inter-region vs intra-region vs same-AZ
   • Managed vs self-hosted trade-offs
4. Present as relative comparison table (e.g., "~2x cost of...", "comparable to...")
5. Reference references/cost-comparison.md for tier mappings

Output relative comparisons only. Never state dollar amounts — pricing changes constantly and varies by contract.

Mode: Security

Scan IaC for security misconfigurations.

1. Run the appropriate analysis script for file type
2. Check against references/security-hardening.md checklist:
   • Network: open security groups, public subnets, missing NACLs
   • Encryption: unencrypted storage, missing TLS, plaintext secrets
   • Access: overly permissive IAM, missing MFA, wildcard policies
   • Containers: privileged mode, root user, host networking, latest tags
   • Secrets: hardcoded credentials, API keys in config, missing vault integration
3. Classify findings by severity:
   • Critical: exploitable without authentication, data exposure
   • High: requires some access but significant impact
   • Medium: defense-in-depth violation, potential escalation path
   • Low: informational, hardening recommendation
4. Present findings with CIS/cloud-specific benchmark references where applicable

Dashboard

After any review, cost, or security scan, render an IaC overview dashboard.

1. Collect all findings and resource inventory
2. Inject as JSON into templates/dashboard.html:

   {
     "view": "iac-overview",
     "resources": [...],
     "findings": [...],
     "dockerfile_layers": [...],
     "cost_comparison": [...]
   }
   

3. Copy template to a temporary file, inject data, open in browser

Reference Files

Load ONE reference at a time. Do not preload all references.

File	Content	Read When
references/terraform-patterns.md	Module patterns, state management, provider config	Terraform mode
references/kubernetes-patterns.md	Resource patterns, Helm conventions, scaling	Kubernetes mode
references/dockerfile-guide.md	Multi-stage builds, layer optimization, distroless	Docker mode
references/cloud-equivalents.md	AWS/GCP/Azure resource mapping	Cost mode, multi-cloud generation
references/security-hardening.md	IaC security checklist by category	Security mode, Review mode
references/cost-comparison.md	Relative cost tiers and trade-offs	Cost mode

Script	When to Run
scripts/dockerfile-analyzer.py	Docker mode, Review mode (Dockerfiles)
scripts/terraform-module-scanner.py	Terraform mode, Review mode (.tf files)
scripts/k8s-manifest-validator.py	Kubernetes mode, Review mode (K8s YAML)

Template	When to Render
templates/dashboard.html	After review, cost, or security scan

Critical Rules

1. Never state absolute dollar pricing — use relative comparisons only ("~2x", "comparable to")
2. Always pin versions — provider versions, base image tags, chart versions. Never latest
3. Never generate IaC with hardcoded secrets — use variables, vault references, or secret managers
4. Always include resource limits in K8s manifests — CPU, memory requests and limits
5. Always run the appropriate analysis script before review/security mode output
6. Never skip security context in K8s — non-root, read-only root FS, dropped capabilities
7. Tag all cloud resources — Name, Environment, ManagedBy at minimum
8. Use for_each over count in Terraform for named resources
9. Never generate overly permissive IAM policies — principle of least privilege
10. Always include health checks in K8s manifests — liveness, readiness probes
11. Present review findings grouped by severity — Critical before Info
12. Load ONE reference file at a time — do not preload all references into context
13. Refuse CI/CD pipeline requests — redirect to devops-engineer skill
14. Refuse application code requests — this skill is IaC only
15. Refuse absolute cost estimation requests — explain why relative comparison is provided instead