Why is Guard not detecting file changes after dockerizing Rails app?

问题

I am trying to "dockerize" an existing Rails development app. This is my first time experimenting with Docker.

I want to set up Guard to listen for file changes and run relevant specs.

The Guard service appears to be running correctly, and the logs show:

guard_1     | 16:35:12 - INFO - Guard is now watching at '/app'

But when I edit/save spec files Guard is not running any tests.

This is an existing app that I'm moving into Docker. It has a guardfile that works outside of Docker.

I've searched and read a number of posts (e.g. this one), but I'm not sure where to start debugging this. Can anyone point me in the right direction and get Guard listening to file changes.

My docker-compose.yml looks like this:

version: '3'

services:
  postgres:
    ports:
      - "5432:5432"
    volumes:
      - $HOME/postgres-data:/var/lib/postgresql
    image: postgres:9.6.9

  redis:
    ports:
      - "6379:6379"
    depends_on:
      - postgres
    image: redis:5.0-rc

  web:
    build: .
    ports:
      - "3000:3000"
    command: /bin/sh -c "rails s -b 0.0.0.0 -p 3000"
    depends_on:
      - postgres
      - redis
    env_file:
      - .env

  guard:
    build: .
    env_file:
      - .env
    command: bundle exec guard --no-bundler-warning --no-interactions

  sidekiq:
    build: .
    command: bundle exec sidekiq -C config/sidekiq.yml
    depends_on:
      - postgres
      - redis
    env_file:
      - .env

volumes:
  redis:
  postgres:
  sidekiq:
  guard:

Guardfile

guard 'spring', bundler: true do
  watch('Gemfile.lock')
  watch(%r{^config/})
  watch(%r{^spec/(support|factories)/})
  watch(%r{^spec/factory.rb})
end

guard :rspec, cmd: "bundle exec rspec" do
  require "guard/rspec/dsl"
  dsl = Guard::RSpec::Dsl.new(self)

  # RSpec files
  rspec = dsl.rspec
  watch(rspec.spec_files)

  # Ruby files
  ruby = dsl.ruby
  dsl.watch_spec_files_for(ruby.lib_files)

  # Rails files
  rails = dsl.rails(view_extensions: %w(erb haml slim))
  dsl.watch_spec_files_for(rails.app_files)
  dsl.watch_spec_files_for(rails.views)

  watch(rails.controllers) do |m|
    [
      rspec.spec.call("routing/#{m[1]}_routing"),
      rspec.spec.call("controllers/#{m[1]}_controller"),
      rspec.spec.call("acceptance/#{m[1]}")
    ]
  end

  # Rails config changes
  watch(rails.spec_helper)     { rspec.spec_dir }
  watch(rails.routes)          { "#{rspec.spec_dir}/routing" }
  watch(rails.app_controller)  { "#{rspec.spec_dir}/controllers" }

  # Capybara features specs
  watch(rails.view_dirs)     { |m| rspec.spec.call("features/#{m[1]}") }
  watch(rails.layouts)       { |m| rspec.spec.call("features/#{m[1]}") }

  # Turnip features and steps
  watch(%r{^spec/acceptance/(.+)\.feature$})
  watch(%r{^spec/acceptance/steps/(.+)_steps\.rb$}) do |m|
    Dir[File.join("**/#{m[1]}.feature")][0] || "spec/acceptance"
  end
  ignore %r{^spec/support/concerns/}
end

guard 'brakeman', :run_on_start => true do
  watch(%r{^app/.+\.(erb|haml|rhtml|rb)$})
  watch(%r{^config/.+\.rb$})
  watch(%r{^lib/.+\.rb$})
  watch('Gemfile')
end

回答1:

I'm assuming you're making changes on your local filesystem and expected guard, inside the container, to trigger.

If so, the missing link is your docker-compose.yml file.

guard:
  build: .
  env_file:
    - .env
  command: bundle exec guard --no-bundler-warning --no-interactions
  volumes:
    - .:/app

You need to mount the volume of your root (Rails root) directory inside the container so that the changes are reflected. Without this line, your container(s) only sees what was available at build time, and not the changes.

回答2:

I faced the exact same problem and have been wondering about existing solutions that didn't really work. The key solution to your problem (if you are on OSX of course) is to understand the difference between "Docker Toolbox" and "Docker for Mac".

This article gives a lot of insight: https://docs.docker.com/docker-for-mac/docker-toolbox/

TL;DR

If you are on Mac, you need to use Docker for Mac to have the benefits of osxfs. If you do this you will not need docker-sync!

来源：https://stackoverflow.com/questions/54026795/why-is-guard-not-detecting-file-changes-after-dockerizing-rails-app