Containerfile

###########################################################################
## Production image #######################################################
###########################################################################
FROM public.ecr.aws/lts/ubuntu:20.04 AS prod

#########################
## Build-time arguments #
#########################
# Increase this arbitary number to force all image layers to be rebuilt.
# This is designed to invalidate the layer cache inside CI, not locally.
ARG invalidate_all_cached_layers=202412030000
# Base path for the app install build process.
ARG APP_ROOT=/dc/ynr
# Path for the app's virtualenv.
ARG APP_VENV=$APP_ROOT/venv
# Path for the app's code.
ARG APP_CODE=$APP_ROOT/code

########################
## System dependencies #
########################
ARG DEBIAN_FRONTEND=noninteractive
# Copy system dependency manifest into the container image.
COPY container/build/system-packages /tmp/apt-packages
# Install dependencies.
RUN date \
 && apt update \
 && </tmp/apt-packages xargs apt install --no-install-suggests --assume-yes \
 && apt-get clean \
 && rm -rf /var/lib/apt/lists/* \
 && date

######################
## Node dependencies #
######################
ARG NODE_ENV=production
ENV NODE_ENV=$NODE_ENV
# Copy node dependency manifests into the container image.
COPY package.json package-lock.json $APP_CODE/
# Install dependencies.
# The version of npm we currently use doesn't appear to offer any way to make
# "npm ci" install the devDependencies (which include the "gulp" command that's
# required later in this build) when NODE_ENV="production". We fix this by
# overriding NODE_ENV for these npm commands. Whilst "npm cache clean" might
# not require the same value, we keep it aligned in case it has some effect
# (e.g. maybe the cache location is env-specific, etc).
RUN date \
 && export NODE_ENV=development \
 && cd $APP_CODE/ \
 && npm ci \
 && npm cache clean --force \
 && date

########################
## Python dependencies #
########################
# Set up a virtualenv to avoid interactions with system packages.
# Install a common pre-req.
RUN date \
 && python -m venv $APP_VENV \
 && $APP_VENV/bin/pip install --upgrade pip wheel \
 && date
# Use the virtualenv without explicit activation.
ENV PATH="$APP_VENV/bin:$PATH"
# Copy dependency manifests into the container image.
COPY requirements.txt $APP_CODE/
COPY requirements/    $APP_CODE/requirements/
# Install dependencies.
# Instruct pip not to use a cache directory to inprove container-image-level
# cache effectiveness.
RUN date \
 && pip install --no-cache-dir -r $APP_CODE/requirements/sopn_parsing.txt \
 && date

#############
## App code #
#############
# Copy the client-side directory "." (the build context passed to the build
# command) into the container image, obeying the inclusions & exclusions
# encoded in the ./.dockerignore file.
COPY . $APP_CODE/
# Create the empty directory that will hold the intermediate static assets
# output by `npm run build` and consumed by `collectstatic`. It is deliberately
# /not/ bind-mounted during local development so that the developer doesn't
# need to re-run `npm run build` after container startup, and isn't included as
# an empty directory in the repository so as not to give the false impression
# that the dev-visible directory will be populated by some containerised
# process.
RUN mkdir $APP_CODE/vendor_assets/
# Set the working directory for the container entrypoint.
WORKDIR $APP_CODE

###########
## Checks #
###########
# Invoke a lightweight, post-build test that proves the container reaches a
# baseline level of correctness, whilst also generating .pyc files for faster
# app startup.
RUN DJANGO_SECRET_KEY=insecure python manage.py check

###########
## Assets #
###########
RUN date \
 && npm run build \
 && DJANGO_SECRET_KEY=insecure python manage.py collectstatic --no-input \
 && date

###########################################################################
## Testing image ##########################################################
###########################################################################
FROM prod AS test

# Base path for the app install build process.
ARG APP_ROOT=/dc/ynr
# Path for the app's code.
ARG APP_CODE=$APP_ROOT/code

# Install additional test dependencies.
RUN date \
 && pip install --no-cache-dir -r $APP_CODE/requirements/testing.txt \
 && date