Improve Docker development environment

- Wait for database to start on boot so only a single command is
  needed.
- Tidied up readme.
- Explicitly specify build steps instead of using onbuild so
  the apt package cache isn't busted by new code.
- Rename built image to be "octobox"

Dockerfile

@@ -1,7 +1,16 @@
-FROM ruby:2.3-onbuild
-
+FROM ruby:2.3
 RUN \
     apt-get update \
-    && apt-get install -y --no-install-recommends nodejs \
+    && apt-get install -y --no-install-recommends netcat nodejs \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+# throw errors if Gemfile has been modified since Gemfile.lock
+RUN bundle config --global frozen 1
+RUN mkdir -p /usr/src/app
+WORKDIR /usr/src/app
+
+COPY Gemfile /usr/src/app/
+COPY Gemfile.lock /usr/src/app/
+RUN bundle install
+
+COPY . /usr/src/app

README.md

@@ -108,21 +108,19 @@ Finally you can boot the rails app:
 ```bash
 rails s
 ```
-#### Docker Compose
+#### Docker
 
-If you're familiar with [Docker](https://docs.docker.com/engine/) and [Docker Compose](https://docs.docker.com/compose/), the included `docker-compose.yml` configuration allows you to spin up the application locally.
+You can use Docker to run Octobox in development.
 
-First, launch an instance of PostgreSQL and wait for it to fully initialize:
+First, [install Docker](https://docs.docker.com/engine/installation/). If you've got run macOS or Windows, Docker for Mac/Windows makes this really easy.
+
+Then, run:
 
 ```bash
-docker-compose up database
+GITHUB_CLIENT_ID=yourclientid GITHUB_CLIENT_SECRET=yourclientsecret docker-compose up --build
 ```
 
-Once the PostgreSQL initialization process is complete, launch the application using another terminal session:
-
-```bash
-GITHUB_CLIENT_ID=yourclientid GITHUB_CLIENT_SECRET=yourclientsecret docker-compose up app
-```
+Octobox will be running on [http://localhost:3000](http://localhost:3000).
 
 **Note**: You can add `GITHUB_CLIENT_ID` and `GITHUB_CLIENT_SECRET` to a `.env` file instead of supplying them directly on the command-line.
 

bin/docker-start

@@ -0,0 +1,12 @@
+#!/bin/sh
+set -e
+
+while ! nc -z database.service.octobox.internal 5432; do
+  echo "Waiting for database to be available..."
+  sleep 1
+done
+
+bundle exec rake db:migrate
+rm -rf tmp/pids
+
+exec rails s -b 0.0.0.0

docker-compose.yml

@@ -7,7 +7,7 @@ services:
       - POSTGRES_PASSWORD=development
 
   app:
-    image: github-inbox
+    image: octobox
     build:
       context: ./
       dockerfile: Dockerfile
@@ -23,4 +23,4 @@ services:
       - OCTOBOX_DATABASE_USER=postgres
       - OCTOBOX_DATABASE_PASSWORD=development
       - OCTOBOX_DATABASE_HOST=database.service.octobox.internal
-    command: sh -c 'bundle exec rake db:migrate && rm -rf tmp/pids && rails s -b 0.0.0.0'
+    command: bin/docker-start