Put gems in local vendor/bundle mount

.env.example

@@ -35,6 +35,9 @@ export SECRET_KEY_BASE=insecure_key_for_dev
 export RAILS_ENV=development
 export NODE_ENV=development
 
+# Where should gems be installed
+export BUNDLE_PATH=/app/vendor/bundle
+
 # The bind port for puma.
 #
 # Be warned that if you change this value you'll need to change 8000 in both

.gitignore

@@ -28,3 +28,4 @@ yarn-debug.log*
 .env*
 !.env.example
 docker-compose.override.yml
+vendor/bundle

Dockerfile

@@ -20,9 +20,6 @@ RUN bash -c "set -o pipefail && apt-get update \
 
 USER ruby
 
-COPY --chown=ruby:ruby Gemfile* ./
-RUN bundle install
-
 COPY --chown=ruby:ruby package.json *yarn* ./
 RUN yarn install
 
@@ -68,12 +65,11 @@ ENV RAILS_ENV="${RAILS_ENV}" \
     PATH="${PATH}:/home/ruby/.local/bin" \
     USER="ruby"
 
-COPY --chown=ruby:ruby --from=assets /usr/local/bundle /usr/local/bundle
 COPY --chown=ruby:ruby --from=assets /app/public /public
 COPY --chown=ruby:ruby . .
 
 ENTRYPOINT ["/app/bin/docker-entrypoint-web"]
 
 EXPOSE 8000
 
-CMD ["rails", "s"]
+CMD ["bundle", "exec", "rails", "s"]

bin/docker-entrypoint-web

@@ -21,4 +21,12 @@ if compgen -G "${manifest_files}" > /dev/null 2>&1; then
     -delete
 fi
 
+if bundle check
+then
+  echo "Bundle installing..."
+  bundle install --jobs="$(nproc)" > ${BUNDLE_PATH}/bundle_install
+  tail -n 2 ${BUNDLE_PATH}/bundle_install
+else
+  bundle install --jobs=$(nproc)
+fi
 exec "$@"

docker-compose.yml

@@ -21,6 +21,7 @@ x-app: &default-app
   tty: true
   volumes:
     - "${DOCKER_WEB_VOLUME:-./public:/app/public}"
+    - "${DOCKER_BUNDLE_VOLUME:-./vendor/bundle:/app/vendor/bundle}"
 
 x-assets: &default-assets
   build:
@@ -39,6 +40,8 @@ x-assets: &default-assets
   tty: true
   volumes:
     - ".:/app"
+    - "${DOCKER_BUNDLE_VOLUME:-./vendor/bundle:/app/vendor/bundle}"
+
 
 services:
   postgres:
@@ -101,7 +104,7 @@ services:
 
   cable:
     <<: *default-app
-    command: "puma -p 28080 cable/config.ru"
+    command: "bundle exec puma -p 28080 cable/config.ru"
     entrypoint: []
     deploy:
       resources: