dockerfile-validator

Dockerfile Validator

Validate Dockerfiles with deterministic stages, clear severity reporting, and explicit fallbacks when tools or network access are constrained.

Trigger Phrases

Use this skill when the user asks for tasks like:

• "validate this Dockerfile"
• "lint/check my Dockerfile"
• "security scan Dockerfile"
• "optimize Docker image size/build time"
• "review Dockerfile before merge"
• "find issues in Dockerfile.prod/Dockerfile.dev"

Use / Do Not Use

Use this skill for:

• Syntax and lint validation
• Security and secrets checks
• Best-practice and performance review
• Dockerfile hardening before CI/CD or production

Do not use this skill for:

• Generating a new Dockerfile from scratch (use dockerfile-generator)
• Running containers, debugging runtime behavior, or image registry operations

Local Files In This Skill

• Validator script: scripts/dockerfile-validate.sh
• References:
  • references/security_checklist.md
  • references/optimization_guide.md
  • references/docker_best_practices.md
• Example Dockerfiles: examples/*.Dockerfile

Deterministic Execution Flow (Required)

Run these steps in order. Do not skip steps unless a documented fallback branch applies.

1. Preflight and Path Setup

Assume repo root as working directory:

cd /path/to/repo
SKILL_DIR="devops-skills-plugin/skills/dockerfile-validator"
TARGET_DOCKERFILE="Dockerfile"   # replace when user provides a path

Validate inputs before running tools:

test -f "$SKILL_DIR/scripts/dockerfile-validate.sh"
test -f "$TARGET_DOCKERFILE"

If either check fails, stop and report the exact missing path.

2. Read the Target Dockerfile Explicitly

Use explicit file-read commands (not abstract "Read tool" wording):

sed -n '1,220p' "$TARGET_DOCKERFILE"

If needed for long files:

sed -n '220,440p' "$TARGET_DOCKERFILE"

3. Run Validation Script

Primary command:

bash "$SKILL_DIR/scripts/dockerfile-validate.sh" "$TARGET_DOCKERFILE"