DM-38102: Prepare backpack for deployment

.github/workflows/ci.yaml

@@ -55,6 +55,32 @@ jobs:
           tox-envs: "py,coverage-report,typing"
           tox-requirements: "requirements/tox.txt"
 
+  build:
+    runs-on: ubuntu-latest
+    needs: [lint, test]
+    timeout-minutes: 10
+
+    # Only do Docker builds of tagged releases and pull requests from ticket
+    # branches.  This will still trigger on pull requests from untrusted
+    # repositories whose branch names match our tickets/* branch convention,
+    # but in this case the build will fail with an error since the secret
+    # won't be set.
+    if: >
+      startsWith(github.ref, 'refs/tags/')
+      || startsWith(github.head_ref, 'tickets/')
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: lsst-sqre/build-and-push-to-ghcr@v1
+        id: build
+        with:
+          image: ${{ github.repository }}
+          # TODO: set token
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+
   docs:
 
     runs-on: ubuntu-latest

Dockerfile

@@ -0,0 +1,64 @@
+# This Dockerfile has three stages:
+#
+# base-image
+#   Updates the base Python image with security patches and common system
+#   packages. This image becomes the base of all other images.
+# install-image
+#   Installs third-party dependencies (requirements/main.txt) and the
+#   application into a virtual environment. This virtual environment is
+#   ideal for copying across build stages.
+# runtime-image
+#   - Copies the virtual environment into place.
+#   - Runs a non-root user.
+#   - Sets up the entrypoint and port.
+
+FROM python:3.12.4-slim-bookworm as base-image
+
+# Update system packages
+COPY scripts/install-base-packages.sh .
+RUN ./install-base-packages.sh && rm ./install-base-packages.sh
+
+FROM base-image AS install-image
+
+# Install system packages only needed for building dependencies.
+COPY scripts/install-dependency-packages.sh .
+RUN ./install-dependency-packages.sh
+
+# Create a Python virtual environment
+ENV VIRTUAL_ENV=/opt/venv
+RUN python -m venv $VIRTUAL_ENV
+
+# Make sure we use the virtualenv
+ENV PATH="$VIRTUAL_ENV/bin:$PATH"
+
+# Put the latest pip and setuptools in the virtualenv
+RUN pip install --upgrade --no-cache-dir pip setuptools wheel
+
+# Install the app's Python runtime dependencies
+COPY requirements/main.txt ./requirements.txt
+RUN pip install --quiet --no-cache-dir -r requirements.txt
+
+# Install the application.
+COPY . /workdir
+WORKDIR /workdir
+RUN pip install --no-cache-dir .
+
+FROM base-image AS runtime-image
+
+# Create a non-root user.
+RUN useradd --create-home appuser
+
+# Copy the virtualenv.
+COPY --from=install-image /opt/venv /opt/venv
+
+# Make sure we use the virtualenv.
+ENV PATH="/opt/venv/bin:$PATH"
+
+# Switch to the non-root user.
+USER appuser
+
+# Expose the port.
+EXPOSE 8080
+
+# Run the application.
+CMD ["sasquatchbackpack", "usgs-earthquake-data", "-d", "10", "0"]

scripts/docker-tag.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+# Determine the tag for Docker images based on GitHub Actions environment
+# variables.
+
+set -eo pipefail
+
+if [ -n "$GITHUB_HEAD_REF" ]; then
+    # For pull requests
+    echo ${GITHUB_HEAD_REF} | sed -E 's,/,-,g'
+else
+    # For push events
+    echo ${GITHUB_REF} | sed -E 's,refs/(heads|tags)/,,' | sed -E 's,/,-,g'
+fi

scripts/install-base-packages.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+# This script updates packages in the base Docker image that's used by both
+# the build and runtime images, and gives us a place to install additional
+# system-level packages with apt-get.
+#
+# Based on the blog post:
+# https://pythonspeed.com/articles/system-packages-docker/
+
+# Bash "strict mode", to help catch problems and bugs in the shell
+# script. Every bash script you write should include this. See
+# http://redsymbol.net/articles/unofficial-bash-strict-mode/ for details.
+set -euo pipefail
+
+# Display each command as it's run.
+set -x
+
+# Tell apt-get we're never going to be able to give manual feedback.
+export DEBIAN_FRONTEND=noninteractive
+
+# Update the package listing, so we know what packages exist.
+apt-get update
+
+# Install security updates.
+apt-get -y upgrade
+
+# Install dependencies required at runtime. git is used to check out notebook
+# repositories.  git-lfs is required to check the Git LFS service.
+apt-get -y install --no-install-recommends git git-lfs
+
+# Delete cached files we don't need anymore.
+apt-get clean
+rm -rf /var/lib/apt/lists/*

scripts/install-dependency-packages.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+# This script installs additional packages used by the dependency image but
+# not needed by the runtime image, such as additional packages required to
+# build Python dependencies.
+#
+# Since the base image wipes all the apt caches to clean up the image that
+# will be reused by the runtime image, we unfortunately have to do another
+# apt-get update here, which wastes some time and network.
+
+# Bash "strict mode", to help catch problems and bugs in the shell
+# script. Every bash script you write should include this. See
+# http://redsymbol.net/articles/unofficial-bash-strict-mode/ for details.
+set -euo pipefail
+
+# Display each command as it's run.
+set -x
+
+# Tell apt-get we're never going to be able to give manual feedback.
+export DEBIAN_FRONTEND=noninteractive
+
+# Update the package listing, so we know what packages exist.
+apt-get update
+
+# Install various dependencies that may be required to install mobu:
+#
+# build-essential: sometimes needed to build Python modules
+# libffi-dev: sometimes needed to build cffi, a cryptography dependency
+apt-get -y install --no-install-recommends build-essential libffi-dev
+
+# Delete cached files we don't need anymore.
+apt-get clean
+rm -rf /var/lib/apt/lists/*

src/sasquatchbackpack/sources.py

@@ -51,13 +51,19 @@ class USGSConfig:
         Directory path to the relevant source schema
         (src/sasquatchbackpack/schemas/schema_name_here.avsc), optional,
         defaults to src/sasquatchbackpack/schemas/usgs.avsc
+    cron_schema : `str`, optional
+        Directory path to the relevant source schema from a cronjob.
     """
 
     duration: timedelta
     radius: int
     coords: tuple[float, float]
     magnitude_bounds: tuple[int, int]
     schema_file: str = "src/sasquatchbackpack/schemas/usgs.avsc"
+    cron_schema: str = (
+        "/opt/venv/lib/python3.12/site-packages/"
+        "sasquatchbackpack/schemas/usgs.avsc"
+    )
 
 
 class USGSSource(DataSource):
@@ -88,8 +94,12 @@ def load_schema(self) -> str:
         """Query the USGS API using the current provided parameters,
         then update results.
         """
-        with Path(self.config.schema_file).open("r") as file:
-            return file.read()
+        try:
+            with Path(self.config.schema_file).open("r") as file:
+                return file.read()
+        except FileNotFoundError:
+            with Path(self.config.cron_schema).open("r") as file:
+                return file.read()
 
     def get_records(self) -> list[dict]:
         """Call the USGS Comcat API and assembles records.