feat: do multi stage build

Signed-off-by: Robert Waffen <[email protected]>

Dockerfile

@@ -1,4 +1,4 @@
-FROM ruby:3.3.5-slim-bookworm
+FROM ruby:3.3.5-slim-bookworm AS builder
 
 RUN apt update && apt install -y \
       g++ \
@@ -17,19 +17,30 @@ RUN apt update && apt install -y \
       tzdata \
       && rm -rf /var/lib/apt/lists/*
 
-ENV APP_HOME /hdm
-ENV RAILS_ENV production
-ENV HDM_PORT 3000
-ENV HDM_HOST 0.0.0.0
+ENV APP_HOME=/hdm
+WORKDIR $APP_HOME
+
+COPY . $APP_HOME
+COPY config/hdm.yml.template $APP_HOME/config/hdm.yml
+
+RUN bundle check || (bundle config set --local without 'development test release' && bundle install)
+
+###############################################################################
+
+FROM ruby:3.3.5-slim-bookworm
+
+ENV APP_HOME=/hdm
+ENV RAILS_ENV=production
+ENV HDM_PORT=3000
+ENV HDM_HOST=0.0.0.0
 ENV RUBYOPT="--yjit"
 
 EXPOSE $HDM_PORT
 
 WORKDIR $APP_HOME
 
-COPY . $APP_HOME
-COPY config/hdm.yml.template $APP_HOME/config/hdm.yml
-
-RUN bundle check || (bundle config set --local without 'development test' && bundle install)
+# copy only the needed files from the builder image
+COPY --from=builder /usr/local/bundle /usr/local/bundle
+COPY --from=builder $APP_HOME $APP_HOME
 
 CMD ["sh", "-c", "/hdm/bin/entry.sh ${HDM_PORT} ${HDM_HOST}"]