docker development setup

.dockerignore

@@ -0,0 +1,9 @@
+.git
+.gitignore
+
+Dockerfile
+docker-compose.yml
+.dockerignore
+
+log/*
+tmp/*

.env

@@ -0,0 +1,2 @@
+POSTGRES_USER=abhinavnepal
+POSTGRES_PASSWORD=helloworld

.gitignore

@@ -4,6 +4,12 @@
 # or operating system, you probably want to add a global ignore instead:
 #   git config --global core.excludesfile '~/.gitignore_global'
 
+# specific to each app instance
+/config/database.yml
+
+# avoid secrets in source control
+/config/secrets.yml
+
 # Ignore bundler config.
 /.bundle
 

Dockerfile

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+FROM ruby:2.3.1
+
+# install system libraries
+RUN apt-get update -yqq \
+  && apt-get install -yqq build-essential libpq-dev nodejs qt5-default \
+  && apt-get -q clean \
+  && rm -rf /var/lib/apt/lists
+
+# install path setup
+ENV INSTALL_PATH /abhinav-nepal
+RUN mkdir -p $INSTALL_PATH
+
+# install gems
+COPY Gemfile* ./
+RUN bundle install
+COPY . .
+
+CMD script/start

config/database.yml

@@ -1,20 +1,20 @@
 default: &default
   adapter: postgresql
+  encoding: unicode
+  host: db
+  username: <%= ENV["POSTGRES_USER"] %>
+  password: <%= ENV["POSTGRES_PASSWORD"] %>
+  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
 
 development:
   <<: *default
-  encoding: unicode
   database: abhinav_dev
-  pool: 5
-  host: localhost
 
-# Warning: The database defined as "test" will be erased and
-# re-generated from your development database when you run "rake".
-# Do not set this db to the same as development or production.
 test:
   <<: *default
   database: abhinav_test
 
 production:
   <<: *default
+  host: <%= ENV["POSTGRES_HOST"] %>
   database: abhinav_prod

config/puma.rb

@@ -10,6 +10,12 @@
 # Specifies the `port` that Puma will listen on to receive requests; default is 3000.
 #
 port        ENV.fetch("PORT") { 3000 }
+# By default, puma was putting the pidfile in the rails app `tmp` directory.
+# This was leading to the pid file existing when creating a new container, thus
+# making puma fail to start saying that there was already a server running.
+# Since we're running in containers we've set the pid file to be in the `/tmp`
+# directory that will start clean with every container run.
+pidfile "/tmp/puma.pid"
 
 # Specifies the `environment` that Puma will run in.
 #

docker-compose.yml

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+version: "2"
+
+services:
+  db:
+    image: postgres:9.6-alpine
+    volumes:
+      - db-data:/var/lib/postgresql/db-data
+    ports:
+      - "5432:5432"
+    env_file:
+      - .env
+  app:
+    build: .
+    volumes:
+      - .:/usr/src/app
+    ports:
+      - "3000:3000"
+    depends_on:
+      - db
+    env_file:
+      - .env
+
+volumes:
+  db-data:

script/start

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+#!/bin/bash -e
+
+if [[ -a /tmp/puma.pid ]]; then
+  rm /tmp/puma.pid
+fi
+
+if [[ $RAILS_ENV == "production" ]]; then
+  rake assets:precompile
+  rake db:migrate
+  mkdir -p /usr/share/nginx/html
+  cp -R public/* /usr/share/nginx/html
+  mkdir -p /etc/nginx/conf.d/
+  cp site.conf /etc/nginx/conf.d/default.conf
+fi
+
+rails server -b 0.0.0.0 -P /tmp/puma.pid