Docker + Rails configuration + Docker Sync

database.yml

default: &default
  adapter: postgresql
  encoding: unicode
  # For details on connection pooling, see rails configuration guide
  # http://guides.rubyonrails.org/configuring.html#database-pooling
  pool: 5

development:
  <<: *default
  database: dev_database
  host: db_service
  username: postgres
  
development:
  <<: *default
  database: test_database
  host: db_service
  username: postgres

docker-compose.non_mac.yml

version: '2'
services:
  db_service:
    image: postgres:9.6
    ports:
      - "5432:5432"
    volumes:
      - pgdata:/pgdata
      - ./backup:/app-db-dumps # We're mounting this folder so we can backup/restore database dumps from our app folder.
    environment:
      LC_ALL: C.UTF-8
      POSTGRES_PASSWORD: devpassword
      PGDATA : /pgdata

  web:
    build:
      context: .
      dockerfile: Dockerfile.dev
    command: ./scripts/start_web_service.sh
    entrypoint: ["/app/scripts/wait-for-it.sh", "db_service:5432", "-t", "120", "--"]
    expose:
      -  "3000"
    ports:
      - "3000:3000"
    volumes:
      - .:/app
      - bundle:/bundle
    tmpfs:
      - /app/tmp
    depends_on:
      - db_service
    environment:
      RAILS_ENV: development
    env_file: .env

volumes:
  pgdata: {}
  bundle: {}

docker-compose.yml

version: '2'
services:
  db_service:
    image: postgres:9.6
    ports:
      - "5432:5432"
    volumes:
      - pgdata:/pgdata
      - ./backup:/app-db-dumps # We're mounting this folder so we can backup/restore database dumps from our app folder.
    environment:
      LC_ALL: C.UTF-8
      POSTGRES_PASSWORD: devpassword
      PGDATA : /pgdata

  web:
    build:
      context: .
      dockerfile: Dockerfile.dev
    command: ./scripts/start_web_service.sh
    entrypoint: ["/app/scripts/wait-for-it.sh", "db_service:5432", "-t", "120", "--"]
    expose:
      -  "3000"
    ports:
      - "3000:3000"
    volumes:
      - bundle:/bundle
      - p2p-web-sync:/app:rw
    tmpfs:
      - /app/tmp
    depends_on:
      - db_service
    environment:
      RAILS_ENV: development
    env_file: .env

volumes:
  pgdata: {}
  bundle: {}
  p2p-web-sync:
    external: true

docker-sync.yml

# https://github.com/EugenMayer/docker-sync/wiki/8.-Strategies
syncs:
  p2p-web-sync:
    src: '.'
    dest: '/app'
    sync_strategy: 'unison'
    sync_excludes: ['.idea', '.git', 'tmp', '.DS_Store']
    #sync_excludes_type: 'log'
    sync_host_ip: '127.0.0.1'
    sync_host_port: 10872

Dockerfile

# This Dockerfile is intended to build a production-ready app image.
#
# This is not required for development environments

FROM sagittaros/rails-base:latest
MAINTAINER Felix Tioh <[email protected]>

COPY . /app
WORKDIR /app
EXPOSE 5000
ENV RAILS_ENV=production

RUN bundle check || bundle install

CMD rails s -p 5000 -b 0.0.0.0

Dockerfile.dev

# This Dockerfile is intended to build a development app image.

FROM sagittaros/rails-base:latest
MAINTAINER Felix Tioh <[email protected]>

COPY ./Gemfile /app/Gemfile
COPY ./Gemfile.lock /app/Gemfile.lock
WORKDIR /app
EXPOSE 3000

ENV BUNDLE_PATH /bundle
ENV GEM_HOME /bundle
ENV PATH $GEM_HOME/bin:$PATH

start_web_service.sh

#!/bin/bash

bundle check || bundle install

bundle exec rails s -b 0.0.0.0

wait-for-it.sh

#!/usr/bin/env bash
#   Use this script to test if a given TCP host/port are available

cmdname=$(basename $0)

echoerr() { if [[ $QUIET -ne 1 ]]; then echo "$@" 1>&2; fi }

usage()
{
    cat << USAGE >&2
Usage:
    $cmdname host:port [-s] [-t timeout] [-- command args]
    -h HOST | --host=HOST       Host or IP under test
    -p PORT | --port=PORT       TCP port under test
                                Alternatively, you specify the host and port as host:port
    -s | --strict               Only execute subcommand if the test succeeds
    -q | --quiet                Don't output any status messages
    -t TIMEOUT | --timeout=TIMEOUT
                                Timeout in seconds, zero for no timeout
    -- COMMAND ARGS             Execute command with args after the test finishes
USAGE
    exit 1
}

wait_for()
{
    if [[ $TIMEOUT -gt 0 ]]; then
        echoerr "$cmdname: waiting $TIMEOUT seconds for $HOST:$PORT"
    else
        echoerr "$cmdname: waiting for $HOST:$PORT without a timeout"
    fi
    start_ts=$(date +%s)
    while :
    do
        (echo > /dev/tcp/$HOST/$PORT) >/dev/null 2>&1
        result=$?
        if [[ $result -eq 0 ]]; then
            end_ts=$(date +%s)
            echoerr "$cmdname: $HOST:$PORT is available after $((end_ts - start_ts)) seconds"
            break
        fi
        sleep 1
    done
    return $result
}

wait_for_wrapper()
{
    # In order to support SIGINT during timeout: http://unix.stackexchange.com/a/57692
    if [[ $QUIET -eq 1 ]]; then
        timeout $TIMEOUT $0 --quiet --child --host=$HOST --port=$PORT --timeout=$TIMEOUT &
    else
        timeout $TIMEOUT $0 --child --host=$HOST --port=$PORT --timeout=$TIMEOUT &
    fi
    PID=$!
    trap "kill -INT -$PID" INT
    wait $PID
    RESULT=$?
    if [[ $RESULT -ne 0 ]]; then
        echoerr "$cmdname: timeout occurred after waiting $TIMEOUT seconds for $HOST:$PORT"
    fi
    return $RESULT
}

# process arguments
while [[ $# -gt 0 ]]
do
    case "$1" in
        *:* )
        hostport=(${1//:/ })
        HOST=${hostport[0]}
        PORT=${hostport[1]}
        shift 1
        ;;
        --child)
        CHILD=1
        shift 1
        ;;
        -q | --quiet)
        QUIET=1
        shift 1
        ;;
        -s | --strict)
        STRICT=1
        shift 1
        ;;
        -h)
        HOST="$2"
        if [[ $HOST == "" ]]; then break; fi
        shift 2
        ;;
        --host=*)
        HOST="${1#*=}"
        shift 1
        ;;
        -p)
        PORT="$2"
        if [[ $PORT == "" ]]; then break; fi
        shift 2
        ;;
        --port=*)
        PORT="${1#*=}"
        shift 1
        ;;
        -t)
        TIMEOUT="$2"
        if [[ $TIMEOUT == "" ]]; then break; fi
        shift 2
        ;;
        --timeout=*)
        TIMEOUT="${1#*=}"
        shift 1
        ;;
        --)
        shift
        CLI="$@"
        break
        ;;
        --help)
        usage
        ;;
        *)
        echoerr "Unknown argument: $1"
        usage
        ;;
    esac
done

if [[ "$HOST" == "" || "$PORT" == "" ]]; then
    echoerr "Error: you need to provide a host and port to test."
    usage
fi

TIMEOUT=${TIMEOUT:-15}
STRICT=${STRICT:-0}
CHILD=${CHILD:-0}
QUIET=${QUIET:-0}

if [[ $CHILD -gt 0 ]]; then
    wait_for
    RESULT=$?
    exit $RESULT
else
    if [[ $TIMEOUT -gt 0 ]]; then
        wait_for_wrapper
        RESULT=$?
    else
        wait_for
        RESULT=$?
    fi
fi

if [[ $CLI != "" ]]; then
    if [[ $RESULT -ne 0 && $STRICT -eq 1 ]]; then
        echoerr "$cmdname: strict mode, refusing to execute subprocess"
        exit $RESULT
    fi
    exec $CLI
else
    exit $RESULT
fi