Railsサーバとwebpack-dev-serverを別コンテナで起動して、
WEBPACKER_DEV_SERVER_HOST
でRailsにwebpack-dev-serverの居場所を教えてあげる形にした。version: "3.7" services: web: &app_base build: . ports: - "3000:3000" volumes: - .:/app - bundle:/app/.bundle - node_modules:/app/node_modules - home:/root environment: BUNDLE_PATH: /app/.bundle BUNDLE_JOBS: 4 WEBPACKER_DEV_SERVER_HOST: webpacker command: /bin/sh -c "rm -f tmp/pids/server.pid && bin/rails s -p 3000 -b '0.0.0.0'" depends_on: - db webpacker: <<: *app_base ports: - "3035:3035" command: bin/webpack-dev-server db: image: postgres:11.2 ports: - "5432:5432" volumes: - pg_data:/data environment: PGDATA: /data volumes: bundle: node_modules: pg_data: home: