terraform-dev

name	terraform-dev
description	Continuous validation during Terraform module development. Use when actively developing Terraform code and needing fast feedback loops — runs format, validate, lint, and plan automatically. Covers inner loop (fast, local) and outer loop (TFC deployment) development patterns.

Terraform Development Loop

Fast feedback during active Terraform development using Makefile targets.

Plan caching

Always capture plan output to a temp file. Plans are expensive (network, credentials, time). Cache once, grep/parse many times.

PLAN_DIR=$(mktemp -d)
terraform plan -no-color 2>&1 | tee "$PLAN_DIR/plan.txt"
echo "Plan cached: $PLAN_DIR/plan.txt"

Then use the cached file for all post-hoc analysis:

# Quick summary
grep '^Plan:' "$PLAN_DIR/plan.txt"

# Find destroys
grep 'will be destroyed' "$PLAN_DIR/plan.txt"

# Non-tag attribute changes
grep -E '^\s+[~+-].*=' "$PLAN_DIR/plan.txt" | grep -v 'tags'

# Feed to plan parser for structured analysis
# See terraform-plan-parser skill

For multi-env work, namespace per env:

PLAN_DIR=$(mktemp -d)
for env in dev tst prd; do
  (cd iac/$env && terraform plan -no-color 2>&1 | tee "$PLAN_DIR/${env}-plan.txt")
done
echo "Plans cached in: $PLAN_DIR"

Prerequisites

• make — drives all targets below
• terraform — for format, validate, and plan
• tflint — for lint targets
• entr or watchexec — optional, for file-watch mode (see Watching for Changes)

Inner Loop (Fast — < 30s)

Run after every meaningful code change:

make format          # terraform fmt -recursive (~1s)
make validate        # terraform validate (~2s)
make lint            # tflint (~5s)

Compose for a single fast-fail check:

make format && make validate && make lint

What each catches:

• make format — inconsistent indentation, alignment
• make validate — type errors, undefined references, malformed HCL
• make lint — security defaults too open, missing types, lookup() usage, line length

Outer Loop (Full — 2–5 min)

Run before pushing or opening a PR:

make pre-pr          # format + validate-full + lint + docs + examples

Example Testing Loop

When changing module interface (variables, outputs, resources):

# Convert to local source for testing
make relative-source

# Test all examples against local code
make test-examples

# Revert to registry source before committing
make registry-source

TFC Deployment Loop

For real-world validation against a live AWS account:

# Deploy example to test workspace
make deploy EXAMPLE=basic WORKSPACE=<tec-dce-inn-dev-XXXXX-username>

# Monitor run
make tfc-run-status EXAMPLE=basic

# Inspect deployed resources (tags, names, outputs)
make tfc-workspace-state EXAMPLE=basic

# Tear down
make deploy-clean EXAMPLE=basic

Safe Experimentation

Before risky refactors:

make checkpoint MSG="before restructuring locals"
# ... make changes ...
# If it goes wrong: git reset --soft HEAD~1

Watching for Changes

For continuous validation while editing multiple files:

# Run inner loop on every save (requires entr or watchexec)
find . -name "*.tf" | entr -c make format validate lint

# Or use terraform-docs watcher if available

Common Failures and Fixes

Failure	Likely cause	Fix
validate fails on type	Variable uses any type	Specify explicit type
lint complains about lookup()	Using lookup()	Replace with local.map[var.key]
test-examples fails init	Registry source, no TFC auth	make relative-source first
docs fails	Missing variable description	Add description to all variables
format changes files	Ran code before make format	Run make format before all commits

References

• tfc-api skill — direct TFC API queries for deeper workspace inspection
• terraform-plan-parser skill — structured analysis of terraform plan output for import validation and drift detection