Improve Docker setup

.docker/entrypoint.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+set -e
+
+# Remove a potentially pre-existing server.pid for Rails.
+rm -f /app/tmp/pids/server.pid
+
+# Then exec the container's main process (what's set as CMD in the Dockerfile).
+exec "$@"

.docker/ruby/Dockerfile

@@ -1,30 +1,26 @@
 FROM ruby:2.7
 
-RUN apt-get update -qq && apt-get install -y build-essential
+RUN curl -sL https://deb.nodesource.com/setup_12.x | bash -
 
-# for postgres
-RUN apt-get install -y libpq-dev
+RUN apt-get update -qq && \
+    apt-get install -y --no-install-recommends build-essential \
+    libpq-dev postgresql-client \ 
+    libxml2-dev libxslt1-dev \
+    libmagickwand-dev imagemagick \
+    nodejs
 
-# for nokogiri
-RUN apt-get install -y libxml2-dev libxslt1-dev
+RUN rm -rf /var/lib/apt/lists/*
 
-# for images
-RUN apt-get install -y libmagickwand-dev imagemagick
+RUN mkdir /app
+WORKDIR /app
 
-# for a JS runtime
-RUN curl -sL https://deb.nodesource.com/setup_6.x | bash -
-RUN apt-get install -y nodejs
-
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends \
-        postgresql-client \
-    && rm -rf /var/lib/apt/lists/*
-
-ENV APP_HOME /app
-RUN mkdir $APP_HOME
-WORKDIR $APP_HOME
-
-ADD Gemfile* $APP_HOME/
+ADD Gemfile* /app/
 RUN bundle install
+COPY . /app
 
+COPY .docker/entrypoint.sh /usr/bin/
+RUN chmod +x /usr/bin/entrypoint.sh
+ENTRYPOINT ["entrypoint.sh"]
 EXPOSE 3000
+
+CMD ["rails", "server", "-b", "0.0.0.0"]

docker-compose.yml

@@ -5,9 +5,8 @@ services:
     build:
       context: .
       dockerfile: .docker/ruby/Dockerfile
-    command:
-      ruby bin/rails server --port 3000 --binding 0.0.0.0
-    links:
+    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
+    depends_on:
       - postgres
       - redis
     environment: