容器需要重建并重新启动。 无法从浏览器重新加载

Question

I have a pretty standard rails (5.0.1) project, using docker-compose (Docker version 1.12.5, build 7392c3b/docker-compose version 1.9.0, build 2585387) to manage the development environment. Unfortunately the usual development mode, where Rails reloads classes on every reload doesn't seem to work. Instead, my coding cycle has become:

1. ^C out of docker-compose up
2. docker-compose build
3. docker-compose up
4. Lather, rinse, repeat

Because I have several services running, every time I am forced to ^C out of docker-compose up , rebuild the world and then restart, it costs time and I'm worried about kicking my Postgres (database) instance too many times in the head.

It's clear that mounting the app is working, because I can change view files and see the changes instantly. But if I change any class , I'm forced to do the cancel-compile-restart dance.

docker-compose.yml

services:
  app:
    env_file:
    - .env
    depends_on:
    - database
    - redis
    build:
      context: .
      args:
      - environment
    command: bin/rails server --port 3000 --binding 0.0.0.0
    environment:
      REDIS_URL: "redis://redis:6379/0"
    links:
    - database
    - redis
    network_mode: bridge
    ports:
    - "3000:3000"
    expose:
    - 3000
    volumes:
    - .:/app:rw

Dockerfile

# https://hub.docker.com/_/ruby/
FROM ruby:2.3-slim

# Install apt based dependencies required to run Rails as
# well as RubyGems. As the Ruby image itself is based on a 
# Debian image, we use apt-get to install those.
# nodejs for JavaScript runtime
RUN apt-get update -qq && \
    apt-get install -y --no-install-recommends build-essential libpq-dev nodejs git && \
    rm -rf /var/lib/apt/lists/* && \
    echo "linux up-to-date"

# Configure the main working directory. This is the base
# directory used in any further RUN, COPY, and ENTRYPOINT 
# commands.
RUN mkdir /app
WORKDIR /app

# build args, provided --build-arg
ARG environment=production
ARG GIT_COMMIT=unknown
ARG VERSION=unknown

# May be overridden by docker-compose.yml
ENV RAILS_ENV=$environment RACK_ENV=$environment NODE_ENV=$environment

# Copy the Gemfile as well as the Gemfile.lock and install
# the RubyGems. This is a separate step so the dependencies 
# will be cached unless changes to one of those two files 
# are made.
COPY Gemfile Gemfile.lock ./
RUN gem install bundler && bundle install --jobs 20 --retry 5

# Copy the main application.
COPY . ./

# Precompile Rails assets
RUN bundle exec rake assets:precompile

# Start console (starting puma creates a .pid file that we don't want)
CMD bundle exec rails console

Answer 1

Late answer, but I found that setting this in development.rb fixed the issue.

config.reload_classes_only_on_change = false

It might have something to do with https://github.com/rails/rails/issues/16678 , which suggests it's an issue between VirtualBox file timestamps and the Rails reloader.

Answer 2

You will want to add restart: always to your Docker compose file and run it as a daemon by going docker compose up -d . This will run it as a daemon no longer running it the foreground after build. It will also restart the container after if you restart the machine. Be aware that you should set restart=always on the dependencies as well to have them start up on reboot. Lastly, you should mount your application as a volume so you can modify the code and cycle it via docker restart app . When you cop files into a Docker container you are creating a snapshot which is why you have to rebuild it every time. The solution to this is mount your code directory as a volume and set the compile command as The start CMD so it excites the build on restart.