Dockerfile

[H1][DOCKERFILE]

Dictum: Structured generation and validation produce secure, minimal container images.

Docker Engine 27+ | BuildKit 0.27+ | Dockerfile syntax 1.14 | Node 24 LTS Krypton | Alpine 3.23

Tasks:

1. Gather requirements -- language, version, framework, entry point, package manager
2. Read dockerfile_knowledge.md -- Generation patterns and language substitution
3. (framework research) Query context7 MCP or WebSearch for "<framework> <version> dockerfile production 2026"
4. Generate Dockerfile -- Apply universal template with language-specific substitution
5. Generate .dockerignore -- See exemplar at examples/example.dockerignore
6. Validate -- Read validation.md and apply 5-stage pipeline (hadolint + Checkov + custom)
7. Iterate -- Fix, re-validate, repeat (max 3 iterations)

Scope:

• Generation: Dockerfiles for Node.js (pnpm/npm), Python (uv), Go, Java, Rust
• Validation: All Dockerfile variants (Dockerfile, Dockerfile.prod, Dockerfile.dev)
• Orchestration: docker-bake.hcl for monorepo multi-target builds
• Not: Building/running containers, debugging runtime issues

[1][REQUIREMENTS]

Dictum: Complete requirements prevent generation rework.

Guidance:

• Language -- Language, version, framework, entry point, package manager (pnpm/npm/uv/go mod/maven/gradle)
• Build -- Build commands, Nx target (monorepo), compilation flags, system deps.
• Runtime -- Port(s), env vars, health endpoint, image size constraints, multi-arch (amd64/arm64).

Best-Practices:

• Base images (February 2026): node:24-slim-trixie (pnpm), node:24-alpine3.23 (npm), python:3.14-slim-trixie, golang:1.24-alpine3.23, rust:1.84-slim-trixie, eclipse-temurin:21-jdk-alpine
• Chainguard: cgr.dev/chainguard/node:latest-dev (build) / cgr.dev/chainguard/node:latest (runtime) -- daily CVE rebuilds, zero known vulnerabilities

[REFERENCE]: dockerfile_knowledge.md -- Generation patterns, language substitution, cache mounts.

[2][MANDATORY_FEATURES]

Dictum: Every generated Dockerfile includes these features.

Guidance:

• Syntax -- # syntax=docker/dockerfile:1 as first line (enables BuildKit frontend).
• Multi-stage -- Named stages: deps, build, runtime (minimum).
• Security -- Non-root USER 1001:1001, no secrets in ENV/ARG, exec-form ENTRYPOINT.

Best-Practices:

• BuildKit mounts: --mount=type=cache for all pkg managers, --mount=type=secret,id=key,env=VAR for build secrets
• Layer optimization: COPY --link on every COPY, COPY --chmod=555 (no extra RUN chmod layer), heredoc RUN <<EOF for multi-line scripts
• Metadata: OCI labels (org.opencontainers.image.title/source/licenses/revision/created/version), Pulumi-injectable ARGs (GIT_SHA, BUILD_DATE, IMAGE_VERSION)
• Runtime: HEALTHCHECK with --start-interval=2s (exec-form CMD), STOPSIGNAL SIGTERM, non-privileged ports (>1024)

[3][PNPM_MONOREPO]

Dictum: This project uses pnpm monorepo with Nx build orchestration.

Guidance:

• Fetch-first -- pnpm fetch --frozen-lockfile downloads to store without installing (maximizes cache hits).
• Deploy -- pnpm deploy --filter=@scope/app --prod /prod/app extracts standalone prod deployment.

Best-Practices:

• corepack: RUN corepack enable (no global pnpm install)
• Offline install: pnpm install --frozen-lockfile --offline --ignore-scripts
• Selective copy: Only needed packages/*/package.json files (not entire workspace)
• Base image: node:24-slim-trixie (glibc, Debian 13 -- not alpine for musl compat)
• Exemplar: apps/api/Dockerfile is the production reference

[REFERENCE]: dockerfile_knowledge.md -- pnpm monorepo pattern, cache mount targets.

[4][DELIVERABLES]

Dictum: Output quality measured by image size and security posture.

Deliverables: Validated Dockerfile + .dockerignore + validation summary.

Build command with attestations:

docker buildx build \
    --platform linux/amd64,linux/arm64 \
    --sbom=true --provenance=mode=max \
    --build-arg GIT_SHA="$(git rev-parse HEAD)" \
    --build-arg BUILD_DATE="$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
    -t myapp:latest --push .

[5][VALIDATION]

Dictum: Five-stage pipeline enforces security and build quality.

Severity classification:

• Critical -- Hardcoded secrets in ENV/ARG, cert bypass flags, no USER directive.
• High -- :latest tag, sudo usage, SSH port (22), no HEALTHCHECK for services.
• Medium -- Missing version pins, cache cleanup, missing OCI labels, no --no-install-recommends.
• Low -- Style (layer count, STOPSIGNAL, heredoc opportunities).

Fix order: Critical first, then high, medium, low. Resolve all critical before moving to high. Max 3 fix-validate cycles.

Tool installation:

Troubleshooting:

[REFERENCE]: validation.md -- Security rules, hadolint/Checkov catalogs, BuildKit version matrix.

[VERIFY] Completion:

• Syntax directive: # syntax=docker/dockerfile:1 as first line
• Multi-stage: Named stages with minimal final base
• Security: Non-root USER, no secrets in ENV/ARG, exec-form ENTRYPOINT
• BuildKit: COPY --link, --mount=type=cache, heredoc RUN
• Metadata: OCI labels, Pulumi ARGs, STOPSIGNAL, HEALTHCHECK with --start-interval
• All critical and high validation issues resolved (medium/low: fix or document rationale)

Integration:

• k8s-debug -- Container debugging when builds fail at runtime
• pulumi-k8s-generator -- Pulumi K8s resources with the container image