Containerfile.lite

# syntax=docker/dockerfile:1.7

###############################################################################
# MCP Gateway (lite) - OCI-compliant container build
#
# This multi-stage Dockerfile produces an ultra-slim, scratch-based runtime
# image that automatically tracks the latest Python 3.12.x patch release
# from the RHEL 10 repositories and is fully patched on each rebuild.
#
# Key design points:
#   - Builder stage has full DNF + devel headers for wheel compilation
#   - Runtime stage is scratch: only the Python runtime and app
#   - Both builder and runtime rootfs receive `dnf upgrade -y`
#   - Development headers are dropped from the final image
#   - Hadolint DL3041 is suppressed to allow "latest patch" RPM usage
###############################################################################

###########################
# Build-time arguments
###########################
# Temporary dir for assembling the scratch rootfs
ARG ROOTFS_PATH=/tmp/rootfs
# Python major.minor series to track
ARG PYTHON_VERSION=3.12

###########################
# Builder stage
###########################
FROM registry.access.redhat.com/ubi10/ubi:10.0-1756805986 AS builder
SHELL ["/bin/bash", "-euo", "pipefail", "-c"]

ARG PYTHON_VERSION
ARG ROOTFS_PATH

# ----------------------------------------------------------------------------
# 1) Patch the OS
# 2) Install Python + headers for building wheels
# 3) Install binutils for strip command
# 4) Register python3 alternative
# 5) Clean caches to reduce layer size
# ----------------------------------------------------------------------------
# hadolint ignore=DL3041
RUN set -euo pipefail \
    && dnf upgrade -y \
    && dnf install -y \
         python${PYTHON_VERSION} \
         python${PYTHON_VERSION}-devel \
         binutils \
    && update-alternatives --install /usr/bin/python3 python3 /usr/bin/python${PYTHON_VERSION} 1 \
    && dnf clean all

WORKDIR /app

# ----------------------------------------------------------------------------
# Copy only the files needed for dependency installation first
# This maximizes Docker layer caching - dependencies change less often
# ----------------------------------------------------------------------------
COPY pyproject.toml /app/

# ----------------------------------------------------------------------------
# Create and populate virtual environment
#  - Upgrade pip, setuptools, wheel, pdm, uv
#  - Install project dependencies and package
#  - Include observability packages for OpenTelemetry support
#  - Remove build tools but keep runtime dist-info
#  - Remove build caches and build artifacts
# ----------------------------------------------------------------------------
RUN set -euo pipefail \
    && python3 -m venv /app/.venv \
    && /app/.venv/bin/pip install --no-cache-dir --upgrade pip setuptools wheel pdm uv \
    && /app/.venv/bin/uv pip install ".[redis,postgres,mysql,observability]" \
    && /app/.venv/bin/pip uninstall --yes uv pip setuptools wheel pdm \
    && rm -rf /root/.cache /var/cache/dnf \
    && find /app/.venv -name "*.dist-info" -type d \
        \( -name "pip-*" -o -name "setuptools-*" -o -name "wheel-*" -o -name "pdm-*" -o -name "uv-*" \) \
        -exec rm -rf {} + 2>/dev/null || true \
    && rm -rf /app/.venv/share/python-wheels \
    && rm -rf /app/*.egg-info /app/build /app/dist /app/.eggs

# ----------------------------------------------------------------------------
# Now copy only the application files needed for runtime
# This ensures code changes don't invalidate the dependency layer
# ----------------------------------------------------------------------------
COPY run-gunicorn.sh /app/
COPY mcpgateway/ /app/mcpgateway/
COPY gunicorn.config.py /app/
COPY plugins/ /app/plugins/

# Optional: Copy run.sh if it's needed in production
COPY run.sh /app/

# ----------------------------------------------------------------------------
# Ensure executable permissions for scripts
# ----------------------------------------------------------------------------
RUN chmod +x /app/run-gunicorn.sh /app/run.sh

# ----------------------------------------------------------------------------
# Pre-compile Python bytecode with -OO optimization
#  - Strips docstrings and assertions
#  - Improves startup performance
#  - Must be done before copying to rootfs
#  - Remove __pycache__ directories after compilation
# ----------------------------------------------------------------------------
RUN python3 -OO -m compileall -q /app/.venv /app/mcpgateway /app/plugins \
    && find /app -type d -name "__pycache__" -exec rm -rf {} + 2>/dev/null || true

# ----------------------------------------------------------------------------
# Build a minimal, fully-patched rootfs containing only the runtime Python
# Include ca-certificates for HTTPS connections
# ----------------------------------------------------------------------------
# hadolint ignore=DL3041
RUN set -euo pipefail \
    && mkdir -p "${ROOTFS_PATH:?}" \
    && dnf --installroot="${ROOTFS_PATH:?}" --releasever=10 upgrade -y \
    && dnf --installroot="${ROOTFS_PATH:?}" --releasever=10 install -y \
         --setopt=install_weak_deps=0 \
         --setopt=tsflags=nodocs \
         python${PYTHON_VERSION} \
         ca-certificates \
         procps-ng \
    && dnf clean all --installroot="${ROOTFS_PATH:?}"

# ----------------------------------------------------------------------------
# Create `python3` symlink in the rootfs for compatibility
# ----------------------------------------------------------------------------
RUN ln -sf /usr/bin/python${PYTHON_VERSION} ${ROOTFS_PATH:?}/usr/bin/python3

# ----------------------------------------------------------------------------
# Clean up unnecessary files from rootfs (if they exist)
#  - Remove development headers, documentation
#  - Use ${var:?} to prevent accidental deletion of host directories
# ----------------------------------------------------------------------------
RUN set -euo pipefail \
    && rm -rf ${ROOTFS_PATH:?}/usr/include/* \
    ${ROOTFS_PATH:?}/usr/share/man/* \
    ${ROOTFS_PATH:?}/usr/share/doc/* \
    ${ROOTFS_PATH:?}/usr/share/info/* \
    ${ROOTFS_PATH:?}/usr/share/locale/* \
    ${ROOTFS_PATH:?}/var/log/* \
    ${ROOTFS_PATH:?}/boot \
    ${ROOTFS_PATH:?}/media \
    ${ROOTFS_PATH:?}/srv \
    ${ROOTFS_PATH:?}/usr/games \
    && find ${ROOTFS_PATH:?}/usr/lib*/python*/ -type d -name "test" -exec rm -rf {} + 2>/dev/null || true \
    && find ${ROOTFS_PATH:?}/usr/lib*/python*/ -type d -name "tests" -exec rm -rf {} + 2>/dev/null || true \
    && find ${ROOTFS_PATH:?}/usr/lib*/python*/ -type d -name "idle_test" -exec rm -rf {} + 2>/dev/null || true \
    && find ${ROOTFS_PATH:?}/usr/lib*/python*/ -name "*.mo" -delete 2>/dev/null || true \
    && rm -rf ${ROOTFS_PATH:?}/usr/lib*/python*/ensurepip \
    ${ROOTFS_PATH:?}/usr/lib*/python*/idlelib \
    ${ROOTFS_PATH:?}/usr/lib*/python*/tkinter \
    ${ROOTFS_PATH:?}/usr/lib*/python*/turtle* \
    ${ROOTFS_PATH:?}/usr/lib*/python*/distutils/command/*.exe

# ----------------------------------------------------------------------------
# Remove package managers and unnecessary system tools from rootfs
# - Keep RPM database for security scanning with Trivy/Dockle
# - This keeps the final image size minimal while allowing vulnerability scanning
# ----------------------------------------------------------------------------
RUN rm -rf ${ROOTFS_PATH:?}/usr/bin/dnf* \
    ${ROOTFS_PATH:?}/usr/bin/yum* \
    ${ROOTFS_PATH:?}/usr/bin/rpm* \
    ${ROOTFS_PATH:?}/usr/bin/microdnf \
    ${ROOTFS_PATH:?}/usr/lib/rpm \
    ${ROOTFS_PATH:?}/usr/lib/dnf \
    ${ROOTFS_PATH:?}/usr/lib/yum* \
    ${ROOTFS_PATH:?}/etc/dnf \
    ${ROOTFS_PATH:?}/etc/yum*

# ----------------------------------------------------------------------------
# Strip unneeded symbols from shared libraries and remove binutils
# - This reduces the final image size and removes the build tool in one step
# ----------------------------------------------------------------------------
RUN find "${ROOTFS_PATH:?}/usr/lib64" -name '*.so*' -exec strip --strip-unneeded {} + 2>/dev/null || true \
    && dnf remove -y binutils \
    && dnf clean all

# ----------------------------------------------------------------------------
# Remove setuid/setgid binaries for security
# ----------------------------------------------------------------------------
RUN find ${ROOTFS_PATH:?} -perm /4000 -o -perm /2000 -type f -delete 2>/dev/null || true

# ----------------------------------------------------------------------------
# Create minimal passwd/group files for user 1001
# - Using GID 1001 to match UID for consistency
# - OpenShift compatible (accepts any UID in group 1001)
# ----------------------------------------------------------------------------
RUN printf 'app:x:1001:1001:app:/app:/sbin/nologin\n' > "${ROOTFS_PATH:?}/etc/passwd" && \
    printf 'app:x:1001:\n' > "${ROOTFS_PATH:?}/etc/group"

# ----------------------------------------------------------------------------
# Create necessary directories in the rootfs
#  - /tmp and /var/tmp with sticky bit for security
# ----------------------------------------------------------------------------
RUN chmod 1777 ${ROOTFS_PATH:?}/tmp ${ROOTFS_PATH:?}/var/tmp 2>/dev/null || true \
    && chown 1001:1001 ${ROOTFS_PATH:?}/tmp ${ROOTFS_PATH:?}/var/tmp

# ----------------------------------------------------------------------------
# Copy application directory into the rootfs and fix permissions for non-root
# - Set ownership to 1001:1001 (matching passwd/group)
# - Allow group write permissions for OpenShift compatibility
# ----------------------------------------------------------------------------
RUN cp -r /app ${ROOTFS_PATH:?}/app \
    && chown -R 1001:1001 ${ROOTFS_PATH:?}/app \
    && chmod -R g=u ${ROOTFS_PATH:?}/app

###########################
# Final runtime (squashed)
###########################
FROM scratch AS runtime

ARG PYTHON_VERSION
ARG ROOTFS_PATH

# ----------------------------------------------------------------------------
# OCI image metadata
# ----------------------------------------------------------------------------
LABEL maintainer="Mihai Criveti" \
      org.opencontainers.image.title="mcp/mcpgateway" \
      org.opencontainers.image.description="MCP Gateway: An enterprise-ready Model Context Protocol Gateway" \
      org.opencontainers.image.licenses="Apache-2.0" \
      org.opencontainers.image.version="0.7.0"

# ----------------------------------------------------------------------------
# Copy the entire prepared root filesystem from the builder stage
# ----------------------------------------------------------------------------
COPY --from=builder ${ROOTFS_PATH}/ /

# ----------------------------------------------------------------------------
# Ensure our virtual environment binaries have priority in PATH
# - Don't write bytecode files (we pre-compiled with -OO)
# - Unbuffered output for better logging
# - Random hash seed for security
# - Disable pip cache to save space
# - Disable pip version check to reduce startup time
# ----------------------------------------------------------------------------
ENV PATH="/app/.venv/bin:${PATH}" \
    PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PYTHONHASHSEED=random \
    PIP_NO_CACHE_DIR=1 \
    PIP_DISABLE_PIP_VERSION_CHECK=1

# ----------------------------------------------------------------------------
# Application working directory
# ----------------------------------------------------------------------------
WORKDIR /app

# ----------------------------------------------------------------------------
# Expose application port
# ----------------------------------------------------------------------------
EXPOSE 4444

# ----------------------------------------------------------------------------
# Run as non-root user (1001)
# ----------------------------------------------------------------------------
USER 1001

# ----------------------------------------------------------------------------
# Health check
# ----------------------------------------------------------------------------
HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --retries=3 \
  CMD ["python3", "-c", "import httpx,sys;sys.exit(0 if httpx.get('http://localhost:4444/health',timeout=5).status_code==200 else 1)"]

# ----------------------------------------------------------------------------
# Entrypoint
# ----------------------------------------------------------------------------
CMD ["./run-gunicorn.sh"]