add worker dockerfile

Dockerfile.worker

@@ -0,0 +1,78 @@
+# syntax=docker/dockerfile:1
+# check=error=true;skip=SecretsUsedInArgOrEnv
+
+# Worker Dockerfile for running GoodJob background jobs
+# Build: docker build -f Dockerfile.worker -t theseus-worker .
+# Run: docker run -d -e RAILS_MASTER_KEY=<value from config/master.key> --name theseus-worker theseus-worker
+
+# Make sure RUBY_VERSION matches the Ruby version in .ruby-version
+ARG RUBY_VERSION=3.4.4
+FROM docker.io/library/ruby:$RUBY_VERSION-slim
+
+# Set production environment
+ENV RAILS_ENV="production" \
+    BUNDLE_DEPLOYMENT="1" \
+    BUNDLE_PATH="/usr/local/bundle" \
+    BUNDLE_WITHOUT="development"
+
+# Install base packages and build dependencies
+RUN apt-get update -qq && apt-get install --no-install-recommends -y \
+    curl \
+    libjemalloc2 \
+    libvips \
+    postgresql-client \
+    wget \
+    build-essential \
+    git \
+    libpq-dev \
+    node-gyp \
+    pkg-config \
+    python-is-python3 \
+    imagemagick \
+    libmagickwand-dev \
+    ghostscript \
+    libyaml-dev \
+    chromium
+
+RUN sed -i '/disable ghostscript format types/,+6d' /etc/ImageMagick-6/policy.xml
+
+# Install Node.js and Yarn
+ARG NODE_VERSION=23.6.0
+ARG YARN_VERSION=1.22.22
+ENV PATH=/usr/local/node/bin:$PATH
+RUN curl -sL https://github.com/nodenv/node-build/archive/master.tar.gz | tar xz -C /tmp/ && \
+    /tmp/node-build-master/bin/node-build "${NODE_VERSION}" /usr/local/node && \
+    npm install -g yarn@$YARN_VERSION && \
+    rm -rf /tmp/node-build-master
+
+# Rails app lives here
+WORKDIR /rails
+
+# Install application gems
+COPY Gemfile Gemfile.lock ./
+RUN bundle install && \
+    rm -rf ~/.bundle/ "${BUNDLE_PATH}"/ruby/*/cache "${BUNDLE_PATH}"/ruby/*/bundler/gems/*/.git && \
+    bundle exec bootsnap precompile --gemfile
+
+# Install node modules
+COPY package.json yarn.lock ./
+RUN yarn install --frozen-lockfile
+
+# Copy application code
+COPY . .
+
+# Precompile bootsnap code (skip asset precompilation for worker)
+RUN bundle exec bootsnap precompile app/ lib/ && \
+    rm -rf node_modules
+
+# Run and own only the runtime files as a non-root user for security
+RUN groupadd --system --gid 1000 rails && \
+    useradd rails --uid 1000 --gid 1000 --create-home --shell /bin/bash && \
+    chown -R rails:rails db log storage tmp
+USER 1000:1000
+
+# Entrypoint prepares the database.
+ENTRYPOINT ["/rails/bin/docker-entrypoint"]
+
+# Start GoodJob worker
+CMD ["bundle", "exec", "good_job", "start"]

config/initializers/good_job.rb

@@ -1,7 +1,7 @@
 Rails.application.configure do
   config.good_job.preserve_job_records = true
   config.good_job.enable_cron = Rails.env.production?
-  config.good_job.execution_mode = :async
+  config.good_job.execution_mode = :external
 
   config.good_job.cron = {
     update_mailing_info: {