docker web server exiting without error message - ruby-on-rails

Question

I have my project set with docker-compose. Was working fine until today when I rebuilt the web container. Now whenever I want to start it using docker-compose up it just exits without an Error message:
web_1 | => Booting Unicorn
web_1 | => Rails 3.2.22.5 application starting in development on http://0.0.0.0:3000
web_1 | => Call with -d to detach
web_1 | => Ctrl-C to shutdown server
web_1 | Exiting
If I run it with --verbose, docker-compose --verbose up, the following lines show after 'Exiting':
compose.cli.verbose_proxy.proxy_callable: docker wait <- (u'a03b58f2116698d670f86155cd68605a148143b83ee3351a5e5a4808d682afc9')
compose.cli.verbose_proxy.proxy_callable: docker inspect_container <- (u'a03b58f2116698d670f86155cd68605a148143b83ee3351a5e5a4808d682afc9')
urllib3.connectionpool._make_request: http://localhost:None "POST /v1.25/containers/a03b58f2116698d670f86155cd68605a148143b83ee3351a5e5a4808d682afc9/wait HTTP/1.1" 200 30
compose.cli.verbose_proxy.proxy_callable: docker wait -> 1
urllib3.connectionpool._make_request: http://localhost:None "GET /v1.25/containers/a03b58f2116698d670f86155cd68605a148143b83ee3351a5e5a4808d682afc9/json HTTP/1.1" 200 None
compose.cli.verbose_proxy.proxy_callable: docker inspect_container -> {u'AppArmorProfile': u'docker-default',
u'Args': [u'redis:6379',
u'--',
u'./wait-for-it.sh',
u'postgres:5432',
u'--',
u'bundle',
u'exec',
u'rails',
u's',
This is my docker-compose.yml:
version: '3'
services:
memcached:
image: memcached:1.5.2-alpine
restart: always
ports:
- "11211:11211"
postgres:
image: postgres:9.4-alpine
restart: always
volumes:
- ~/.myapp-data/postgres:/var/lib/postgresql/data
ports:
- "5432:5432"
environment:
- POSTGRES_DB=myapp_development
- POSTGRES_USER=default
- POSTGRES_PASSWORD=secret
redis:
image: redis:3.2.0-alpine
restart: always
volumes:
- ~/.myapp-data/redis:/data
ports:
- "6379:6379"
web:
build:
context: .
dockerfile: "Dockerfile-dev"
stdin_open: true
tty: true
command: ./wait-for-it.sh redis:6379 -- ./wait-for-it.sh postgres:5432 -- bundle exec rails s -p 3000 -b '0.0.0.0'
volumes:
- .:/opt/apps/myapp
depends_on:
- memcached
- redis
- postgres
ports:
- "80:3000"
env_file:
- .env
extra_hosts:
- "api.myapp:127.0.0.1"
- "api.getmyapp:127.0.0.1"
- "my.app:127.0.0.1"
EDIT:
Here are the contents of Dockerfile-dev, required on the comments:
FROM ruby:2.3.7-slim
RUN apt-get update
RUN apt-get -y install software-properties-common libpq-dev build-essential \
python-dev python-pip wget curl git-core \
--fix-missing --no-install-recommends --allow-unauthenticated
# Set install path for reference later.
ENV INSTALL_PATH /opt/apps/engine
RUN mkdir -p $INSTALL_PATH
RUN gem install bundler
WORKDIR $INSTALL_PATH
ADD Gemfile $INSTALL_PATH
ADD Gemfile.lock $INSTALL_PATH
RUN bundle install
RUN find /tmp -type f -atime +10 -delete
ADD . $INSTALL_PATH
RUN cp config/database.docker-dev.yml config/database.yml
CMD [ "bundle", "exec", "rails", "s", "-p", "3000", "-b" "0.0.0.0" ]

Answer 1

Docker containers exit as soon as the commands run inside them are finished. From the logs you have posted, it seems like the container has 'nothing else' to do after starting up the server. You need to run the process in the foreground or have some sort of sleep to keep the container alive.