/home/web/.gem/ruby/2.2.0/gems/redis-3.2.1/lib/redis/connection/ruby.rb:152:in `getaddrinfo ': getaddrinfo: name or service unknown (SocketError)

Question

I use docker-compose to provide a development environment for developers using the tech stack ROR, postgres, redis, mongo. docker-compose build works successfully, but when I started docker-compose up , an error occurred.

 web_1 | => Booting Thin web_1 | => Rails 4.2.3 application starting in development on http://0.0.0.0:3000 web_1 | => Run `rails server -h` for more startup options web_1 | => Ctrl-C to shutdown server web_1 | Exiting web_1 | /home/web/.gem/ruby/2.2.0/gems/redis-3.2.1/lib/redis/connection/ruby.rb:152:in `getaddrinfo': getaddrinfo: Name or service not known (SocketError) web_1 | from /home/web/.gem/ruby/2.2.0/gems/redis-3.2.1/lib/redis/connection/ruby.rb:152:in `connect' web_1 | from /home/web/.gem/ruby/2.2.0/gems/redis-3.2.1/lib/redis/connection/ruby.rb:211:in `connect' web_1 | from /home/web/.gem/ruby/2.2.0/gems/redis-3.2.1/lib/redis/client.rb:322:in `establish_connection' web_1 | from /home/web/.gem/ruby/2.2.0/gems/redis-3.2.1/lib/redis/client.rb:94:in `block in connect' web_1 | from /home/web/.gem/ruby/2.2.0/gems/redis-3.2.1/lib/redis/client.rb:279:in `with_reconnect' 

Below is the Dockerfile

 # Base image. FROM atlashealth/ruby:2.2.1 # System dependencies for gems. #RUN apt-get update #RUN apt-get install -y --no-install-recommends libmysqlclient-dev RUN apt-get update -qq && apt-get install -y build-essential libpq-dev # Add 'web' user which will run the application. RUN adduser web --home /home/web --shell /bin/bash --disabled-password --gecos "" # Add directory where all application code will live and own it by the web user. RUN mkdir /app RUN chown -R web:web /app # Install gems separately here to take advantage of container caching of `bundle install`. # Also, ensure that gems are installed as the web user and not system-wide so that we can run # `fig web bundle install` and the web user will have permissions to update the shared Gemfile.lock. ADD Gemfile /app/ ADD Gemfile.lock /app/ RUN chown -R web:web /app USER web ENV HOME /home/web ENV PATH $PATH:/home/web/.gem/ruby/2.2.0/bin ENV GEM_HOME /home/web/.gem/ruby/2.2.0 ENV GEM_PATH $GEM_HOME RUN gem install --user-install bundler WORKDIR /app/ RUN bundle install USER root # Add the whole application source to the image and own it all by web:web. # Note: this is overwritten in development because fig mounts a shared volume at /app. ADD . /app/ RUN chown -R web:web /app # Clean up APT and /tmp when done. RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* # Default command to run when this container is run. USER web WORKDIR /app/ CMD ["bundle", "exec", "rails", "server"] 

Docker-compose.yml

 db: image: postgres ports: - "5432" redis: image: redis ports: - "6379" sidekiq: build: . command: bundle exec sidekiq links: - db - redis web: build: . command: bundle exec rails s -b 0.0.0.0 volumes: - .:/app ports: - "3000:3000" links: - db - redis 

I set the environment variable for postgres and redis host and port according to the output of the docker-compose run web env .

the output of the docker-compose run web cat /etc/hosts

 Starting xyz_db_1... Starting xyz_redis_1... 172.17.0.32 2b231a706e7b 127.0.0.1 localhost ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 172.17.0.31 redis 799b65ac89cd xyz_redis_1 172.17.0.31 redis_1 799b65ac89cd xyz_redis_1 172.17.0.30 db 0bd898e19822 xyz_db_1 172.17.0.30 db_1 0bd898e19822 xyz_db_1 172.17.0.30 xyz_db_1 0bd898e19822 172.17.0.31 xyz_redis_1 799b65ac89cd 

configurations / sidekiq.yml

 concurrency: 25 pidfile: ./tmp/pids/sidekiq.pid logfile: ./log/sidekiq.log queues: - default - [priority, 2] daemon: true 

config / app-config.yml

 default: &default redis_host: <%= ENV['XYZ_REDIS_1_PORT_6379_TCP_ADDR'] %> redis_port: <%= ENV ['XYZ_REDIS_1_PORT_6379_TCP_PORT'] %> redis_namespace: 'RAILS_CACHE' development: <<: *default redis_host: <%= ENV['XYZ_REDIS_1_PORT_6379_TCP_ADDR'] %> redis_port: <%= ENV['XYZ_REDIS_1_PORT_6379_TCP_PORT'] %> 

configurations / Initializers / redis.rb

 # global variable to access Redis cache # Requirement: Redis server should be up and running # at below specified host and port $redis = Redis.new( :host => APP_CONFIG["redis_host"], :port => APP_CONFIG["redis_port"] ) 

Answer 1

The REDIS_URL environment REDIS_URL can be used to pass Redis URLs to both Sidekiq and Redis pearls.

This environment variable can be set in docker-compose.yml as follows:

 db: image: postgres ports: - "5432" redis: image: redis ports: - "6379" web: build: . command: bundle exec rails s -b 0.0.0.0 volumes: - .:/app ports: - "3000:3000" links: - db - redis environment: REDIS_URL: "redis://redis:6379" 

As Boxers Sidekiq and Redis use REDIS_URL by default, you also need to make sure that you do not override this default behavior in your configuration files. You no longer need the config/initializers/redis.rb , and your config/app-config.yml should only contain your namespace:

 default: &default redis_namespace: 'RAILS_CACHE' development: <<: *default