如何使用Docker构建Sidekiq和Rails镜像？

Question

I am trying another way to build a rails application into a docker image.

The structure of my services:

• redis -- from official docker hub registry
• fluentd -- from official docker hub registry
• mysql -- from official docker hub registry
• sidekiq -- build myself(maybe there isn't a official image for this)
• web -- build myself

I created two Dockerfiles like:

• Dockerfile.sidekiq
• Dockerfile.web

Dockerfile.sidekiq

FROM ruby:2.2.2

ENV APP_HOME /myapp
RUN mkdir $APP_HOME
WORKDIR $APP_HOME

ADD Gemfile $APP_HOME/Gemfile
ADD Gemfile.lock $APP_HOME/Gemfile.lock
ADD config/sidekiq.yml $APP_HOME/config/sidekiq.yml
ADD init_sidekiq.sh $APP_HOME/

RUN export LANG=C.UTF-8 && bundle install

ADD . $APP_HOME

CMD ["sh", "init_sidekiq.sh"]

init_sidekiq.sh

#!/bin/sh
bundle exec sidekiq -C config/sidekiq.yml

Dockerfile.web

FROM rails:4.2.1

ENV APP_HOME /myapp
RUN mkdir $APP_HOME
WORKDIR $APP_HOME

ADD Gemfile $APP_HOME/Gemfile
ADD Gemfile.lock $APP_HOME/Gemfile.lock
ADD init_web.sh $APP_HOME/

RUN export LANG=C.UTF-8 && bundle install

ADD . $APP_HOME

CMD ["sh", "init_web.sh"]

init_web.sh

#!/bin/sh
bundle exec rake db:create db:migrate
bundle exec rails server -b 0.0.0.0

Use them I built two images:

• myapp_web
• myapp_sidekiq

Then run these containers:

$ docker run --name redis -d redis
$ docker run --name fluentd -d -p 24224:24224 fluent/fluentd
$ docker run --name mysql -e MYSQL_ROOT_PASSWORD=my_password -d mysql

Make env.list

RAILS_ENV=production
DATABASE_URL=mysql2://root:my_password@172.17.0.4/myapp?checkout_timeout=20000

Go on run these containers:

$ docker run --name web -d -p 3000:3000 --link mysql:mysql --env-file ./env.list myapp_web
$ docker run --name sidekiq -d --link mysql:mysql --env-file ./env.list myapp_sidekiq

The result:

• redis -- success
• fluentd -- success
• mysql -- success
• web -- success
• sidekiq -- failure

The sidekiq log:

$ docker logs sidekiq
Unknown database 'myapp'
/usr/local/bundle/gems/activerecord-4.2.1/lib/active_record/connection_adapters/mysql2_adapter.rb:23:in `rescue in mysql2_connection'

I used the same method both web and sidekiq to connect mysql. I believe that in the mysql container there exists a myapp database. But why it can't find it?

Is it a wrong way to make them been two containers? How to run sidekiq correctly?

Answer 1

I think the problem there is how are you connecting to redis? The message appears to come from sidekiq and somehow it can't connect to your redis server. (and I think trying to connect to some bogus db server/database)

So I think you need to link your sidekiq container to both your db container and also your redis container.

docker run --name sidekiq -d --link mysql:mysql --link redis:redis --env-file ./env.list myapp_sidekiq

Also, would be nice if you can share your env.list